Physical conditioning as part of a return to work strategy to reduce sickness absence for workers with back pain

Frederieke G Schaafsma; Karyn Whelan; Allard J van der Beek; Ludeke C van der Es‐Lambeek; Anneli Ojajärvi; Jos H Verbeek

doi:10.1002/14651858.CD001822.pub3

. 2013 Aug 30;2013(8):CD001822. doi: 10.1002/14651858.CD001822.pub3

Physical conditioning as part of a return to work strategy to reduce sickness absence for workers with back pain

Frederieke G Schaafsma ^1,^✉, Karyn Whelan ², Allard J van der Beek ³, Ludeke C van der Es‐Lambeek ⁴, Anneli Ojajärvi ⁵, Jos H Verbeek ⁶

Editor: Cochrane Back and Neck Group

PMCID: PMC7074637 PMID: 23990391

Abstract

Background

Physical conditioning as part of a return to work strategy aims to improve work status for workers on sick leave due to back pain. This is the second update of a Cochrane Review (originally titled 'Work conditioning, work hardening and functional restoration for workers with back and neck pain') first published in 2003, updated in 2010, and updated again in 2013.

Objectives

To assess the effectiveness of physical conditioning as part of a return to work strategy in reducing time lost from work and improving work status for workers with back pain. Further, to assess which aspects of physical conditioning are related to a faster return to work for workers with back pain.

Search methods

We searched the following databases to March 2012: CENTRAL, MEDLINE (from 1966), EMBASE (from 1980), CINAHL (from 1982), PsycINFO (from 1967), and PEDro.

Selection criteria

Randomized controlled trials (RCTs) and cluster RCTs that studied workers with work disability related to back pain and who were included in physical conditioning programmes.

Data collection and analysis

Two review authors independently extracted data and assessed risk of bias. We used standard methodological procedures expected by The Cochrane Collaboration.

Main results

We included 41 articles reporting on 25 RCTs with 4404 participants. Risk of bias was low in 16 studies.

Three studies involved workers with acute back pain, eight studies workers with subacute back pain, and 14 studies workers with chronic back pain.

In 14 studies, physical conditioning as part of a return to work strategy was compared to usual care. The physical conditioning mostly consisted of graded activity with work‐related exercises aimed at increasing back strength and flexibility, together with a set date for return to work. The programmes were divided into a light version with a maximum of five sessions, or an intense version with more than five sessions up to full time or as inpatient treatment.

For acute back pain, there was low quality evidence that both light and intense physical conditioning programmes made little or no difference in sickness absence duration compared with care as usual at three to 12 months follow‐up (3 studies with 340 workers).

For subacute back pain, the evidence on the effectiveness of intense physical conditioning combined with care as usual compared to usual care alone was conflicting (four studies with 395 workers). However, subgroup analysis showed low quality evidence that if the intervention was executed at the workplace, or included a workplace visit, it may have reduced sickness absence duration at 12 months follow‐up (3 studies with 283 workers; SMD ‐0.42, 95% CI ‐0.65 to ‐0.18).

For chronic back pain, there was low quality evidence that physical conditioning as part of integrated care management in addition to usual care may have reduced sickness absence days compared to usual care at 12 months follow‐up (1 study, 134 workers; SMD ‐4.42, 95% CI ‐5.06 to ‐3.79). What part of the integrated care management was most effective remained unclear. There was moderate quality evidence that intense physical conditioning probably reduced sickness absence duration only slightly compared with usual care at 12 months follow‐up (5 studies, 1093 workers; SMD ‐0.23, 95% CI ‐0.42 to ‐0.03).

Physical conditioning compared to exercise therapy showed conflicting results for workers with subacute and chronic back pain. Cognitive behavioural therapy was probably not superior to physical conditioning as an alternative or in addition to physical conditioning.

Authors' conclusions

The effectiveness of physical conditioning as part of a return to work strategy in reducing sick leave for workers with back pain, compared to usual care or exercise therapy, remains uncertain. For workers with acute back pain, physical conditioning may have no effect on sickness absence duration. There is conflicting evidence regarding the reduction of sickness absence duration with intense physical conditioning versus usual care for workers with subacute back pain. It may be that including workplace visits or execution of the intervention at the workplace is the component that renders a physical conditioning programme effective. For workers with chronic back pain physical conditioning has a small effect on reducing sick leave compared to care as usual after 12 months follow‐up. To what extent physical conditioning as part of integrated care management may alter the effect on sick leave for workers with chronic back pain needs further research.

Plain language summary

Physical conditioning as part of a return to work strategy to reduce sickness absence for workers with back pain

Review question

We reviewed the evidence about the effect of physical conditioning as part of a return to work strategy in people with low back pain. We found 25 studies.

Background

The main goal of physical conditioning as part of a return to work strategy, sometimes called work conditioning, work hardening or functional restoration and exercise programmes, is to return injured or disabled workers to work or improve the work status for workers performing modified duties. Such programmes may also simulate or duplicate work or functional tasks, or both, using exercises in a safe, supervised environment. These exercises or tasks are structured and progressively graded to increase psychological, physical and emotional tolerance and to improve endurance and work feasibility. In such environments, injured workers improve their general physical condition through an exercise programme aimed at increasing strength, endurance, flexibility and cardiovascular fitness. We wanted to discover whether physical conditioning was more or less effective than usual care and other types of interventions like exercise therapy.

Study characteristics

The evidence was current to March 2012. We analysed 17 comparisons of physical conditioning as part of a return to work strategy. Some trials examined physical conditioning in addition to care as usual versus care as usual only, and others compared physical conditioning to other types of interventions such as standard exercise therapy. Participants had either acute back pain (duration of symptoms less than six weeks), subacute back pain (duration of symptoms more than six but less than 12 weeks), or chronic back pain (duration of symptoms more than 12 weeks). Participants were followed for anywhere from three weeks to three years. We divided physical conditioning into light or intense, depending on its intensity and duration.

Key results

Results showed that light physical conditioning has no effect on sickness absence duration for workers with subacute or chronic back pain. We found conflicting results for intense physical conditioning for workers with subacute back pain. Intense physical conditioning probably had a small effect on reducing sick leave at 12 months follow‐up compared to usual care for workers with chronic back pain. Involving the workplace, or physical conditioning being part of integrated care management may have had a positive effect on reducing sick leave, but this needs further research.

Quality of the evidence

The quality of the evidence ranged from very low to moderate. Although 16 of the included studies were well designed and had no major flaws, some studies were poorly conducted and the small number of participants in most studies lowered the overall quality of the evidence.

Background

Description of the condition

Back pain is a major health and economic problem for society. In Western countries, the reported point prevalence varies from 12% to 30% (Anema 2009). Whether back symptoms are attributed to work, are reported to workers' compensation systems, lead to healthcare‐seeking behaviour, result in time off work, or any combination of these scenarios depend on complex individual psychosocial and work organizational and social security factors. People with physically or psychologically demanding jobs may have more difficulty working when they have back pain and so lose more time from work, but that can also be the effect rather than the cause of their pain (Waddell 1999). Nevertheless, most workers with back pain, their employers, and insurers agree that the goal of managing back pain is a timely return‐to‐work following back pain‐related work disability.

Description of the intervention

Physical conditioning as part of a return to work strategy, variously called work conditioning, work hardening or functional restoration and exercise programmes, aims for return‐to‐work or improvement in work status for workers performing modified duties. Such programmes either simulate or duplicate work or functional tasks, or both, in a safe, supervised environment. These tasks are structured and progressively graded to increase psychological, physical and emotional tolerance and improve endurance and work feasibility (Lechner 1994). In such environments, injured workers learn appropriate job performance skills in addition to improving their physical condition through an exercise programme aimed at increasing strength, endurance, flexibility and cardiovascular fitness. Work hardening programmes are individualized, work‐oriented activities that involve clients in simulated or actual work tasks. Work conditioning is a programme with an emphasis on physical conditioning, which addresses the issues of strength, endurance, flexibility, motor control and cardiopulmonary function (Lechner 1994). Functional restoration refers to any intervention aimed at restoring a reasonable functional level for activities of daily living, including work (Bendix 1996).

These programmes differ in their goals from other programmes, such as patient care management, multidisciplinary treatments, pain clinics, standard medical care or physiotherapy, which aim to reduce symptoms, pain intensity, use of medications and health services, and to increase global improvement and quality of life (Guzman 2001; Guzman 2002), physiological outcomes such as range of motion and spinal flexibility (Hayden 2005), or behavioural outcomes such as anxiety, depression and cognition (Ostelo 2000). Recent years have shown a development towards more involvement of the workplace in interventions aiming for return to work for various musculoskeletal disorders including back pain. A systematic review by Carroll 2010 reported that stakeholder participation and work modification are more effective and cost‐effective for returning adults with musculoskeletal conditions to work than other workplace‐linked interventions, including exercise.

How the intervention might work

Physical conditioning as part of a return to work strategy is characterized by some form of structured exercise or advice about exercise based on the idea that inactivity due to avoidance of painful activities can lead to so‐called ‘deconditioning syndrome’, which in turn can lead to more pain from attempts to move joints that are stiffened and muscles weakened by disuse. Central to these programmes is the notion that as physical and functional capacities improve, so will the person’s capability of returning to work. The programme may be comprised of actual or simulated work tasks, or interventions addressing individual and work‐related psychosocial factors that may play an important role in persisting symptoms and disability, or both (Waddell 1999). This intended work outcome or job‐attached status to the pre‐injury employer is important for a successful outcome with these physical conditioning programmes (Schonstein 1999).

Maintenance of a job‐attached status to the pre‐injury employer is often best accomplished by the provision of suitable modified duties (Voaklander 1995). The effectiveness of modified duties has been studied and comprehensively reviewed (Krause 1998; Loisel 2005) and results indicate that the provision of suitable duties facilitates return‐to‐work, reduces days lost due to injury, and is cost‐effective. Accordingly, this review documents work conditioning programmes that include the availability of modified duties in the back pain management plan.

Why it is important to do this review

This review focuses exclusively on workers with back pain who are either off work or are at risk of being off work due to reduced work capacity, and evaluates the effectiveness of work hardening and functional restoration in improving their work status. This review is the second update of a Cochrane review first published in 2003 that summarised the evidence on the effectiveness of physical conditioning programmes for workers with back and neck pain (Schonstein 2003; Schonstein 2003a). An update was performed in 2010 (Schaafsma 2010). Results of the in 2010 updated review indicated that the effectiveness of physical conditioning programmes in reducing sick leave, when compared to usual care or to other exercises, in workers with back pain remains uncertain. In workers with acute back pain, these programmes probably have no effect on sick leave, but there may be a positive effect on sick leave for workers with subacute and chronic back pain. Workplace involvement may improve the outcome. Better understanding of the mechanism behind physical conditioning programmes and return‐to‐work is needed to be able to develop more effective interventions.

Other reviews have evaluated the efficacy of multidisciplinary back pain management programmes (Guzman 2001; Heymans 2005; Karjalainen 2000; Teasell 1996) in reducing disability related to back pain. In a review of functional restoration programmes for chronic low‐back pain, Teasell 1996 concluded that evidence to support physical conditioning was lacking. In contrast, Karjalainen 2000 reported that multidisciplinary biopsychosocial rehabilitation reduces subacute low‐back pain among working age adults, and that a work site visit increases its effectiveness. While some of these reviews have incorporated return‐to‐work in their outcome measures, none have focused exclusively on work outcomes.

The review by Heymans 2005 on back schools for non‐specific low‐back pain stated that there is moderate evidence suggesting that back schools, in an occupational setting, reduce pain and improve function and return‐to‐work status, in the short‐ and intermediate‐term. This is compared with exercises, manipulation, myofascial therapy, advice, placebo or waiting list controls for workers with chronic and recurrent low‐back pain. Back schools are defined as programmes consisting of educational and skills acquisition components, including exercises, in which all sessions are given to groups of workers and supervised by allied health professionals or a medical specialist. Unlike the interventions of this review, the components of back schools are not generally tailored specifically to job demands.

Hayden 2005 questioned whether exercise is more effective than reference treatments for individuals with non‐specific low‐back pain. They concluded that specific exercises are as effective as either no treatment or other conservative treatments for acute low‐back pain. However, exercise therapy is slightly more effective than no treatment or other conservative treatments at decreasing pain and improving function in adults with chronic low‐back pain. For subacute low‐back pain, there is some evidence that a graded activity programme reduces absenteeism, though evidence for other types of exercise is unclear. Despite the fact that exercise is an integral component of physical conditioning programmes, in our review physical conditioning programmes also needed to have a stated focus on functional job demands.

This review is unique because it addresses the specific question of whether physical conditioning that has a stated focus on functional job demands is effective in reducing sick leave and improving work status for workers with work‐related low‐back pain. As a result, some of the studies are also included in other reviews that explore the effects of specific interventions on pain, function, general well‐being and disability (Guzman 2002; Hayden 2005; Heymans 2005; Karjalainen 2000; Ostelo 2000).

In this update, we changed the title from 'Physical conditioning programs for improving work outcomes in workers with back pain' to 'Physical conditioning as part of a return to work strategy to reduce sickness absence for workers with back pain;. This new title illustrates that over the years physical conditioning has become more and more part of an integrated care programme including various modules and more explicitly involving the workplace. We focused exclusively on workers with back pain and on work status outcomes and therefore excluded neck pain and secondary outcomes such as functional status and physiological outcomes, which were included in the original review. We only included interventions that have a stated relationship with the workplace, a focus on job demands, and measured work outcomes. We reviewed new evidence available since the previous search carried out in 2008. In the results section of this updated review, a distinction is again made between workers with acute (less than six weeks), subacute (between six and 12 weeks) and chronic (more than 12 weeks) back pain. Further, we made a distinction between comparisons of physical conditioning in addition to care as usual compared to care as usual only, or physical conditioning compared to care as usual.

Objectives

Methods

Criteria for considering studies for this review

Types of studies

Only randomized controlled trials (RCTs) and cluster RCTs, regardless of the language in which they were published, were included in this review.

Types of participants

Male and female adults (> 16 years) with work disability related to back pain who took part in physical conditioning programmes were included in this review. Back pain was defined as pain in the thoracic, lumbar or gluteal region, or a combination, with or without radiation to the lower extremities. Studies with at least 50% of workers with back pain were included. Work disability was defined as being on full or partial sick leave, or not being able to perform adequately at work due to back pain.

All workers who were accepted into physical conditioning programmes, whether they had acute (duration of symptoms less than six weeks), subacute (duration of symptoms more than six but less than 12 weeks) or chronic back pain (duration of symptoms more than 12 weeks), met our inclusion criteria.

Studies with non‐workers, or workers with specific diagnoses such as infection, neoplasm, metastasis, osteoporosis, rheumatoid arthritis, fracture, inflammatory processes or other conditions for which valid diagnoses had been demonstrated were excluded.

Types of interventions

Physical conditioning programmes are also known as work conditioning or hardening, or functional restoration and exercise programmes. They include advice about exercise and may also simulate or duplicate work or functional tasks, or both, in a safe, supervised environment. These exercises or tasks are structured and progressively graded to increase psychological, physical and emotional tolerance and improve endurance and work feasibility. We included studies on physical conditioning programmes when they included the following three key elements:

(advice about ) exercises specifically designed to restore an individual's systemic, neurological, musculoskeletal (strength, endurance, movement, flexibility and motor control) or cardiopulmonary function, or a combination;

explicitly stated to have an intended improvement of work status;

a stated relationship between the intervention and functional job demands.

In addition to these three key elements, physical conditioning programmes could include components such as operant conditioning behavioural approach, pain management, back pain education, advice on return‐to‐work, workplace involvement and case‐management. The delivery of physical conditioning programmes could involve multidisciplinary teams or individual health professionals. In addition, they could be delivered in a one‐to‐one fashion or in a group situation.

Based on the intensity of the programme we differentiated between the following.

Light physical conditioning: these programmes included the three key elements and were delivered in fewer than five sessions (of one to two hours) or were described by the primary study author as a light intervention programme.

Intense physical conditioning: these programmes included the three key elements and were delivered in more than five sessions or were delivered on a full‐time basis for more than two weeks.

Types of outcome measures

Work status outcomes were:

1. time between intervention and return‐to‐work;

2. return‐to‐work status in terms of 'at work' or ‘off work';

3. time on light or modified duties.

Search methods for identification of studies

For this updated review, searches were conducted in the same databases as in the original review, for the period of June 2008 to March 2012. Searches were performed by the Trials Search Co‐ordinator of the Cochrane Back Review Group (CBRG). RCTs were identified by searching electronic databases, using the Ovid search strategy. Databases included were: CENTRAL, MEDLINE (from 1966), EMBASE (from 1980), CINAHL (from 1982), PsycINFO (from 1967), and PEDro. The CBRG Trials Register, ClinicalTrials.gov, and World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) were also searched until March 2012. In May 2013 we ran an additional search and all relevant trials were added to the 'Studies awaiting assessment' reference list.

All RCTs were included regardless of the language in which they were published. The highly sensitive search strategies of The Cochrane Collaboration were run in conjunction with a specific search for back pain and the interventions investigated (Furlan 2009). The MEDLINE search is based on the first two stages of the MEDLINE search strategy recommended by the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). This search update added terms to the original search strategy, based on the results of testing terms synonymous with work. These were added with a combination of year limits and NOT. The logic here was to retroactively search for the new terms without retrieving all of the same results that were already retrieved in the previous searches up to 2008. See Appendix 1.

This strategy was modified for EMBASE, CINAHL, and PsycINFO. Search words used for the PEDro database were: low‐back pain, backache, lumbar, thoracic, work conditioning, work hardening, functional restoration, exercise, and gym.

Data collection and analysis

Selection of studies

Two review authors (FS, KW) independently examined search results and independently applied the selection criteria to the studies retrieved. A consensus method was used to resolve disagreements concerning inclusion of RCTs. A third review author (JV) was consulted if disagreements persisted.

Two review authors (FS, KW) read all papers independently and determined eligibility according to the inclusion and exclusion criteria listed above.

Data extraction and management

Data were independently extracted from the studies by two review authors (FS and LE) using an adapted version of the pre‐designed form from the CBRG for data extraction. Discrepancies were resolved by consensus or by consulting a third author (JV). The following criteria were used in our data extraction.

1. Characteristics of study population: number of workers, gender, age and setting, country and date of the study, duration of symptoms, work status.

2. Characteristics of interventions: the content, duration and frequency of the physical conditioning programmes and control interventions.

3. Results on outcomes of interest.

Assessment of risk of bias in included studies

We used the criteria recommended by the CBRG (Furlan 2009) to assess the risk of bias of the selected RCTs. The criteria and their operational definitions are outlined in Appendix 2. Each of the criteria were scored 'high', 'low' or 'unclear' according to the operationalisation of the criteria. Following the recommendations of the CBRG (Furlan 2009), studies were rated as having a ‘low risk of bias’ when at least six of the 12 CBRG criteria were met and the study had no serious flaws. Serious flaws were inadequate concealment of treatment allocation, a large dropout rate, or statistically significant and clinically important baseline differences not accounted for in the analyses. Studies with serious flaws or those in which fewer than six of the criteria were met were rated as having a ‘high risk of bias’. The results of the assessment are presented in the 'Risk of bias' table and Figure 1.

The risk of bias in the RCTs was independently assessed by two review authors (LE, AB). This process was not blinded with regard to the authors, institution or journal. A consensus method was used to resolve disagreements, and a third review author (JV) was consulted for persisting disagreements. If information was absent for evaluation of the methodological criteria, the authors of the study were contacted with a request to provide additional information.

Measures of treatment effect

Quantitative analysis

Studies expressed time to return‐to‐work as mean numbers of days off work. Rate of return‐to‐work was expressed as odds ratios (ORs). We regarded both time to return‐to‐work and the rate of return‐to‐work sufficiently alike, if they were measured at the same follow‐up time, to combine them as similar outcomes in the meta‐analysis. We converted the outcomes into standardized mean difference (SMD) because of the different scales used. We assumed that the continuous measurements in each intervention group followed a logistic distribution, and that the variability of the outcomes was the same in both the treated and control groups. Therefore, we were able to re‐express the calculated ORs as a standardized mean difference (SMD) according to the following simple formula (Chinn 2000; Chinn 2002) as recommended in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2008): lnOR = π/√3 x SMD.

Pooling of studies was only considered when statistical heterogeneity was less than moderate (I² less than 60%).

Clinically worthwhile effect

Translating SMDs into daily practice and knowing what is a clinically worthwhile effect is difficult. Following the rules of thumb on SMDs from the Cochrane Handbook for Systematic Reviews of Interventions and the Cochrane Back Review Group (CBRG) guidelines (Furlan 2009; Higgins 2011), a SMD of more than 0.2 can be considered a small effect, more than 0.5 a moderate effect, and more than 0.8 a large effect.

However, in the original review it was stated that for continuous outcomes, a mean saving of 10 sick days per year was considered the smallest effect that would be clinically worthwhile, based on the assumption of the cost of providing physical conditioning programmes. For dichotomous outcomes, an OR of 0.65 was used as the smallest clinically worthwhile effect. This corresponded to a number needed to treat (NNT) of 10 when the baseline rate (prevalence of the event measured (on or off work)) was about 40%, based on the two comparisons from the original review (Schonstein 2003). An intervention that affected fewer than one in 10 people was considered not clinically worthwhile.

Following this original hypothesis, we decided that we would use an OR of 0.65 as the smallest clinically worthwhile effect. As we would recalculate all the continuous outcomes into SMDs, we also converted the OR of 0.65 back into a SMD. For this, we used the same formula: lnOR = π/ √3 x SMD. This led to a SMD of ‐0.24, which we considered the smallest clinically worthwhile effect.

Quality of the evidence

We assessed the overall quality of the evidence for each outcome using an adapted GRADE approach (Atkins 2004) as recommended by the CBRG (Furlan 2009). The quality of the evidence for a specific outcome was based on the study design, limitations of the study, consistency, directness, precision of results, and publication bias. For further details see Appendix 3.

The GRADE Working Group recommends four levels of evidence; the CBRG recommends the addition of a fifth.

High quality evidence: where there are consistent findings among 75% of RCTs with low risk of bias that are generalisable to the population in question; there are sufficient data, with narrow confidence intervals; there is no known or suspected publication bias; further research is unlikely to change either the estimate or our confidence in the results.

Moderate quality evidence: one of the domains is not met; further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.

Low quality evidence: two of the domains are not met; further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.

Very low quality evidence: three of the domains are not met; we are very uncertain about the estimate.

No evidence: no RCTs are identified that address this outcome.

Assessment of clinical relevance

The clinical relevance of the studies was independently assessed by two review author (FS and AB). Clinical relevance tables were constructed using the five questions recommended by the CBRG (Furlan 2009).

1. Are the patients described in detail so that you can decide whether they are comparable to those that you see in your practice?

2. Are the interventions and treatment settings described well enough so that you can provide the same for your patients?

3. Were all clinically relevant outcomes measured and reported?

4. Is the size of the effect clinically important?

5. Are the likely treatment benefits worth the potential harms?

Regarding question 4. above, we converted the outcome data of studies into SMDs or ORs. We calculated cut‐off scores for these two effect sizes, as explained under 'Measures of treatment effect' below, to decide whether the size of the effect was considered clinically important and worthwhile. This conversion of study data and the use of cut‐off scores sometimes resulted in a conclusion that was different than the study authors' conclusions.

To clearly express the quality of the evidence and the magnitude of the effect on worker important outcomes we used the recommended statements by the GRADE Working Group in the results‐ and discussion sections.

Unit of analysis issues

For cluster designs we used the group estimates taking into account the cluster randomisation. For multiarm studies we used the data from both comparisons that included the physical conditioning programme.

Data synthesis

First, we assessed which studies were clinically homogeneous, with similar populations, interventions, comparisons and outcomes measured at the same follow‐up point. Populations were considered similar if their symptoms were of a similar duration (acute, subacute or chronic).

Interventions were considered homogeneous if they satisfied the inclusion criteria (that is exercises, improvement of work status, and explicit relation to job tasks), regardless of the inclusion of extra components or modes of delivery (that is group or individual, multi or monodisciplinary). Sensitivity analyses were performed to evaluate the effects of the variable components (see below).

We compared light or intense physical conditioning, with or without care as usual, to care as usual, exercise therapy, cognitive behavioural therapy (CBT), a cognitive intervention and to a brief clinical intervention. In addition, we compared intense physical conditioning to a combination of physical conditioning with a CBT component.

Outcomes were considered similar when they measured either the time to return‐to‐work or the proportion of workers that resumed work at specific times. These outcomes were similar because they both measured the time between injury and return‐to‐work, but were expressed in either days or percentages of workers returning to work. Follow‐up was classified into four categories: short‐term follow‐up refers to measures taken closest to three months, intermediate‐term follow‐up refers to measures taken closest to six months, long‐term follow‐up refers to outcomes closest to one year, very long‐term follow‐up refers to measures taken closest to two years. For an outcome measure of return‐to‐work, the return‐to‐work should be sustainable over a longer period of time, generally at least four weeks. For this reason, we did not consider a measurement of outcome at one month follow‐up as recommended by the CBRG method guidelines.

We tested for statistical heterogeneity by means of the I²in the meta‐analysis graphs. We used the criterion of 50%, mentioned in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2008), to discern the presence or absence of heterogeneity between studies. When studies were statistically heterogeneous according to the I² statistic, a random‐effects model was used, otherwise a fixed‐effect model was used.

Subgroup analysis and investigation of heterogeneity

A subgroup analysis was performed for differences in components of physical conditioning programmes such as an operant conditioning behavioural approach, pain management, back pain education, advice on return‐to‐work and a workplace visit. A subgroup analysis was also performed on the mode of delivery of physical conditioning programmes, such as multidisciplinary or monodisciplinary and group or individual exercises.

Sensitivity analysis

A sensitivity analysis was performed to determine whether the overall results were the same when studies with different definitions of low or high risk of bias were analysed and when studies with different types of participants on full‐time or part‐time sick leave at baseline were analysed.

Results

Description of studies

Results of the search

Search results

The updated database search was run from 2008 up to March‐April 2012. This resulted in 358 references from CENTRAL, 544 references from MEDLINE, 725 references from CINAHL, 1114 references from EMBASE, and 22 references from PsycINFO. A separate search was conducted for the PEDro database until the end of March 2012, which yielded 13 references. Another separate search was conducted for the CBRG trial register, which resulted in 70 references. In April 2012 a search in ClinicalTrials.gov and WHO ICTRP resulted in another 46 registered trials. Duplicates of references and irrelevant articles were removed leaving 1761 references and 37 registered trials. Two review authors (FS and KW) independently assessed (by title or key words, or both) these references for appropriateness for inclusion.

Study selection results

After screening the abstracts of articles from the searches, seven papers were considered. An evaluation of the full text led to four new papers meeting our inclusion criteria. One paper reported a third set of follow‐up results from the same study (Roche 2007). Therefore, only the remaining three new studies were included in this updated version of the review. In the previous update we presented the data from Roche 2007 separately from the same study by Jousset 2004. In this update both articles will be referred to by only one reference: Roche 2007. The addition of three new studies (Bethge 2011; Jensen 2011; Lambeek 2010) resulted in a total of 25 studies published in 41 papers in this updated review. All data used in this review were obtained from these published studies.

Included studies

Participants

There were five small studies with fewer than 100 participants (Altmaier 1992; Bendix 1996; Meyer 2005; Storheim 2003; Wright 2005) and nine studies with more than 200 participants (Bethge 2011; Corey 1996; Faas 1995; Heymans 2006; Jensen 2001;Jensen 2011;Lambeek 2010; Mitchell 1994; Skouen 2002). The rest of the studies had between 100 and 200 participants (Bendix 1997; Bendix 2000; Gatchel 2003; Karjalainen 2003; Kool 2005; Lindstrom 1992; Loisel 1997; Roche 2007; Staal 2004; Steenstra 2006; van den Hout 2003).

We found four studies that did not specifically focus on back pain, but on workers with musculoskeletal pain (Bethge 2011; Corey 1996; Meyer 2005; Mitchell 1994). However, all three studies did have more than 50% of the workers with back pain and were therefore included in this updated review. All studies were RCTs, carried out between 1992 and 2012. Two studies had a cluster randomised design (Bethge 2011; Loisel 1997).

Fourteen studies focused on workers with chronic back pain (Altmaier 1992; Bendix 1996; Bendix 1997; Bendix 2000; Bethge 2011; Corey 1996; Jensen 2001; Jensen 2011; Lambeek 2010; Meyer 2005; Mitchell 1994; Roche 2007; Skouen 2002; van den Hout 2003), eight studies focused on workers with subacute back pain (Heymans 2006; Karjalainen 2003; Kool 2005; Lindstrom 1992; Loisel 1997; Staal 2004; Steenstra 2006; Storheim 2003), and three studies focused on workers with acute back pain (Faas 1995; Gatchel 2003; Wright 2005).

In 15 studies all workers were on sick leave, either part‐time or full‐time (Altmaier 1992; Corey 1996; Heymans 2006; Jensen 2001; Jensen 2011; Lambeek 2010; Lindstrom 1992; Loisel 1997; Meyer 2005; Mitchell 1994; Staal 2004; Steenstra 2006; Storheim 2003; van den Hout 2003; Wright 2005). In the other 10 studies not all workers were on sick leave, but all workers were described as having decreased ability to perform job requirements or may have had an episode of sick leave before randomisation (Bendix 1996; Bendix 1997; Bendix 2000; Bethge 2011; Faas 1995; Gatchel 2003; Karjalainen 2003; Kool 2005; Roche 2007; Skouen 2002). The average period of sick leave correlated with the duration of the back pain, between three weeks and six months.

Interventions

All interventions were related to work, contained physical exercises or advice about physical exercises, and had a focus on return‐to‐work. However, the number of sessions and their content varied greatly. For example, one intervention included one session only during which the worker was examined and engaged in a discussion about working conditions, trained to use five exercises and then referred back to the general practitioner (GP) with specific recommendations (Karjalainen 2003); another included a full‐time multidisciplinary treatment of eight weeks (Mitchell 1994). We labelled four interventions as light physical conditioning (Faas 1995; Heymans 2006; Jensen 2011; Karjalainen 2003; Skouen 2002; Wright 2005); the other 21 studies were labelled as intense physical conditioning. Seventeen interventions were delivered by a multidisciplinary group (for example physiotherapist, occupational therapist, ergonomist, social worker, case manager, rehabilitation physician, occupational health physician or nurse); five interventions were delivered by a physiotherapist (Faas 1995; Heymans 2006; Lindstrom 1992; Steenstra 2006; Storheim 2003). In Mitchell 1994, it was unclear who delivered the intervention.

Sixteen interventions included an operant conditioning behavioural approach (Altmaier 1992; Bendix 1996; Bendix 1997; Bendix 2000; Corey 1996; Heymans 2006; Jensen 2001; Lambeek 2010; Lindstrom 1992; Loisel 1997; Meyer 2005; Mitchell 1994; Skouen 2002; Staal 2004; Steenstra 2006; van den Hout 2003). Sixteen interventions included occupational training or ergonomic advice (Bendix 1996; Bendix 1997; Bendix 2000; Bethge 2011; Gatchel 2003; Heymans 2006; Jensen 2001; Jensen 2011; Kool 2005; Lambeek 2010; Meyer 2005; Roche 2007; Skouen 2002; Storheim 2003; van den Hout 2003; Wright 2005) and 12 mentioned explicitly that return‐to‐work advice was included in the intervention (Bethge 2011; Heymans 2006; Jensen 2001; Jensen 2011; Karjalainen 2003; Lambeek 2010; Lindstrom 1992; Loisel 1997; Meyer 2005; Staal 2004; Steenstra 2006; van den Hout 2003). Eight interventions also included a workplace visit in their intervention or explicitly involved the workplace in other ways (Jensen 2001; Jensen 2011; Karjalainen 2003; Lambeek 2010; Lindstrom 1992; Loisel 1997; Meyer 2005; van den Hout 2003) and one intervention was executed at the workplace (Staal 2004).

For more details about the content of the interventions, see Table 1; Table 2; Table 3; Table 4.

1. Contents of light physical conditioning programme (PCP).

	Faas 1995	Heymans 2006	Jensen 2011	Karjalainen 2003	Skouen 2002	Wright 2005
Time span of training	5 wks	4 wks	18 weeks median duration	na	na	2 wks
Number of sessions	2 per week	1 per week	after the interview, the participant was seen at least once, and four times on average	2	approx. 4 hrs at the start + 6 follow up or individual sessions over a period of 1 year	1 examination + treatment initially then 3 per week
Length of sessions	20 min	120 min	1‐2 hrs	1‐1,5 hr	unclear	1 hr
Full time	no	no	no	no	no	no
group or individual	individual	group	individual	individual	both	both
exercises	yes	yes	yes in advice	yes	yes, advice and programme	yes
work related exercises	yes	yes	yes in advice	yes	yes in advice	yes
operant conditioning behavioural approach	no	no	no	no, although intervention was based on graded activity programme	no	no
pain coping/ management	no	no	yes	no	no	no
back pain education	no	yes	yes	no	no	no
ergonomic advice or occupational training	no	yes	no	no	no	advice on how to modify physical activities specific to the individual's work situation
return‐to‐work advice	no	yes	yes	no	no	no
workplace visit	no	no	yes	yes	no (not for all individuals)	no
therapists involved	physiotherapist	physiotherapist, occupational physician	rehabilitation physician, specialist in clinical social medicine, physiotherapist, social worker, occupational therapist, case manager	physiotherapist, physician	physio therapist, nurse, psychologist	physiotherapist
other aspects	written compliance contract	CAU	brief clinical examination	CAU	no	CAU being a back book and advice on how to modify physical activities specific to the indivual's work situation
comparison	CAU	CAU/ intense PCP	brief clinical examination only	CAU	CAU / intense PCP	CAU being a back book and advice on how to modify physical activities specific to the individual's work situation ‐ only

	Altmaier 1992	Bendix 1996	Bendix 1997	Bendix 2000	Bethge 2011	Corey 1996	Gatchel 2003	Heymans 2006
Time span of training	3 wks	3 wks	6 wks	3 wks	3 wks	33 days	3 wks	8 wks
Number of sessions	2 per day	39 hrs per week + 3x6 hrs follow up	135 hr in total	39 hours per week + 3x6 hrs follow‐up	total of 82.2 hours of therapy	6.5 hr per day	up to 41	2 per week
Length of sessions	?	na	na	na	1‐1.5 hrs	na	15 min‐1hr	1 hr
Full time	no	yes	yes	yes	yes	yes	no	no
group or individual	both	group	group	group	group	both	both	individual
exercises	yes	yes	yes	yes	yes	yes	yes	yes
work related exercises	yes	yes	yes	yes	yes	yes	yes	yes
operant conditioning behavioural approach	yes	yes	yes	yes	yes	yes	not clear	yes
pain coping/ management	yes	yes	yes	yes	unclear	yes	yes	no
back pain education	yes	yes	yes	yes	yes	yes	no	no
ergonomic advice or occupational training	no	occupational therapy and ergonomic training	occupational therapy and ergonomic training	occupational therapy and ergonomic training	no	no	occupational therapy	yes
return‐to‐work advice	no	no	no	no	yes	no	no	yes
workplace visit	no	no	no	no	no	no	no	no
therapists involved	multidisciplinary	multidisciplinary	multidisciplinary including physician, psychologist	occupational therapist, physician, psychologist,physical therapist, social worker	physician, social worker, psychologist, physical therapist	interdisciplinary programme	physiotherapist, occupational therapist, nurse, physician	physiotherapist
other aspects	vocational rehabilitation	recreation activities	aerobics, recreational activities	recreation activities	no	no	no	CAU
comparison	PCP + CBT	CAU	exercise therapy / pain management	outpatient intensive physical training	inpatient conventional musculoskeletal rehabilitation	CAU	CAU	CAU‐only/ light PCP

	Jensen 2001	Kool 2005	Lambeek 2010	Lindstrom 1992	Loisel 1997	Meyer 2005	Mitchell 1994	Roche 2007
Time span of training	4 wks	3 wks	12 wks	until RTW	13 wks	8 wks	8 wks	5 wks
Number of sessions	6 sessions + 20 hrs exercise + 6 booster sessions	4 hrs per day / 6 days a week	varying	approx. 11 with physical therapist, approx 10 self training sessions (3 per week)		3,5 hr per day, 5 days a week		6 hrs per day, 5 days a week
Lenght of sessions
Full time	no	almost	no	no	unclear	almost	yes	yes
group or individual	both	group	individual	individual	unclear	both	group	group
exercises	yes	yes	yes	yes	yes	yes	yes	yes
work related exercises	yes	yes	yes	yes	yes	yes	yes	yes
operant conditioning behavioural approach	yes	no	yes	yes	yes	yes	yes	no
pain coping/ management	2 didactic sessions on psychological aspects of pain + 2 sessions on medical aspects of pain	no	no	no	no	yes	no	no
back pain education	yes	no	no	yes	yes	no	yes	no
ergonomic advice or occupational training	2 sessions on ergonomics	work simulation	yes	no	yes, participatory ergonomics evaluation	education in ergonomics	no	occupational therapy
return‐to‐work advice	yes, workplace visit + rehabilitation plan	no	yes	yes	yes	yes	no	no
workplace visit	yes	no	yes	yes	yes	yes	no	no
therapists involved	physician, physical therapist, psychologist,	rheumatologist, physical and occupational therapist, sports therapist, social worker, nurse	clinical occupational physician, medical specialist, physiotherapist	physical therapist	back pain specialist; multidisciplinary medical, ergonomic and rehabilitation staff	interdisciplinary:rehabilitation physicians, psychologist, social worker, occupational therapist, physiotherapist	unclear	specialist in physical medicine, physiotherapist, psychologist
other aspects	no	no	CAU	CAU	CAU	case‐manager recreational activities	no	no
comparison	CAU / CBT PCP + CBT	pain centred treatment	CAU‐only	CAU‐only	CAU‐only	exercise therapy	CAU	active individual therapy

	Skouen 2002	Staal 2004	Steenstra 2006	Storheim 2003	van den Hout 2003
Time span of training	4 wks	max 3 months	13 wks	15 wks	8 wks
Number of sessions	5 per week for 4 weeks + follow‐up as in LMT	2 per week until RTW	2 per week 26 in total	2‐3 per week	28
Lenght of sessions	6 hr	1 hr	1 hr	1 hr	30‐90 min
Full time	almost	no	no	no	no
group or individual	both	individual	individual	group	both
exercises	yes	yes	yes	yes	yes
work related exercises	yes	yes	yes	not clear	yes
operant conditioning behavioural approach	yes	yes	yes	no	yes
pain/ coping management	no	no	no	no	no
back pain education	yes	no	no	no	yes
ergonomic advice or occupational training	yes	no	no	yes, training had a focus on ergonomic principles and functional tasks	yes, training by occupational therapist
return‐to‐work advice	no	yes	yes	no	yes
Workplace visit	no, occasional workplace intervention	no, but intervention was at workplace	no	no	yes, if necessary
therapists involved	physio therapist, nurse, psychologist	physiotherapist, occupational physician	physiotherapist, occupational physician	physical therapist	physiotherapist, occupational therapist, psychologist, occupational physician
other aspects	no	CAU/gradually increasing exercise, GP or occupational physician if workers wanted to	CAU/gradually increasing exercise	exercises accompanied by music	contact with patients' supervisor
comparison	CAU/ light PCP	CAU‐only	CAU‐only	CAU/ cognitive intervention	PCP + CBT

Study ID	1	2	3	4	5
Altmaier 1992	+	‐	+	‐	+
Bendix 1996	+	+	+	‐	+
Bendix 1997	+	+	+	+	+
Bendix 2000	+	+	+	‐	+
Bethge 2011	+	+	+	‐	+
Corey 1996	+	+	‐	‐	+
Faas 1995	+	+	+	‐	+
Gatchel 2003	+	+	+	‐	+
Heymans 2006	+	+	+	‐	+
Jensen 2001	+	+	+	‐	+
Jensen 2011	+	+	+	‐	+
Karjalainen 2003	+	+	+	+	+
Kool 2005	+	+	+	+	+
Lambeek 2010	+	+	+	+	+
Lindstrom 1992	+	+	+	+	+
Loisel 1997	+	+	+	+	+
Meyer 2005	+	+	+	‐	+
Mitchell 1994	+	+	+	‐	+
Staal 2004	+	+	+	+	+
Steenstra 2006	+	+	+	‐	+
Storheim 2003	+	+	‐	‐	+
Skouen 2002	+	+	+	‐	+
Roche 2007	+	+	+	‐	+
van den Hout 2003	+	+	+	‐	+
Wright 2005	+	+	+	‐	+

Date	Event	Description
5 June 2013	New citation required but conclusions have not changed	Conclusions have not changed.
5 June 2013	New search has been performed	3 new trials were incorporated into this update.

Date	Event	Description
19 January 2011	Amended	Contact details updated.
17 February 2010	Amended	typos corrected in abstract and plain language summary
9 June 2009	New citation required and conclusions have changed	New GRADE approach to assessment of the quality of the evidence led to change in conclusions.
30 June 2008	New search has been performed	inclusion/exclusion criteria, methodology and outcome measures revised. Based on changes, literature search updated. New criteria led to exclusion of 12 studies from the previous review. Revised and updated search led to inclusion of 15 new studies.
22 May 2008	Amended	Converted to new review format.
23 May 2003	Amended	Issue 3, 2003  The authors of this review have made one modification since Issue 2, 2003. They removed the sensitivity analysis and subsequent tables (01/02) as they discovered an error with the data entered. Accordingly, they have also modified relevant text and removed one reference (Altman 2001).
30 April 2003	New citation required and conclusions have changed	Substantive amendment

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Proportion off work	1		Risk Difference (M‐H, Fixed, 95% CI)	Totals not selected
1.1 3 months fu	1		Risk Difference (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Time to return to work long term follow up	1	190	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.02 [‐0.30, 0.27]
1.1 12 months fu	1	190	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.02 [‐0.30, 0.27]

Outcome or subgroup title	No. of studies	Statistical method	Effect size
1 Time to return to work	2	Std. Mean Difference (IV, Fixed, 95% CI)	Totals not selected
1.1 6 months fu	1	Std. Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
1.2 12 months fu	1	Std. Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
1.3 24 months fu	1	Std. Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Time to return to work	1	351	Std. Mean Difference (IV, Fixed, 95% CI)	0.21 [0.00, 0.42]
1.1 12 months fu	1	351	Std. Mean Difference (IV, Fixed, 95% CI)	0.21 [0.00, 0.42]

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Time to return to work	5		Std. Mean Difference (IV, Fixed, 95% CI)	Subtotals only
1.1 6 months fu	3	447	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.03 [‐0.22, 0.15]
1.2 12 months fu	4	395	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.19 [‐0.39, 0.01]
2 Time to return to work very long term follow up	2		Std. Mean Difference (Fixed, 95% CI)	‐0.39 [‐0.76, ‐0.02]

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Time to return to work	1		Std. Mean Difference (IV, Random, 95% CI)	Totals not selected
1.1 6 months fu	1		Std. Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Time to return to work	1	59	Mean Difference (IV, Fixed, 95% CI)	‐7.20 [‐43.64, 29.24]
1.1 3 months fu	1	59	Mean Difference (IV, Fixed, 95% CI)	‐7.20 [‐43.64, 29.24]

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Proportion off work short term follow up	2	623	Odds Ratio (M‐H, Fixed, 95% CI)	0.58 [0.42, 0.80]
1.1 3 months fu	1	173	Odds Ratio (M‐H, Fixed, 95% CI)	0.41 [0.22, 0.78]
1.2 6 months fu	1	149	Odds Ratio (M‐H, Fixed, 95% CI)	0.72 [0.38, 1.38]
1.3 12 months fu	2	301	Odds Ratio (M‐H, Fixed, 95% CI)	0.63 [0.40, 0.99]

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Time to Return to Work	1		Std. Mean Difference (Fixed, 95% CI)	‐4.42 [‐5.06, ‐3.79]
1.1 12 months fu	1		Std. Mean Difference (Fixed, 95% CI)	‐4.42 [‐5.06, ‐3.79]

Outcome or subgroup title	No. of studies	Statistical method	Effect size
1 Time to return to work	5	Std. Mean Difference (Random, 95% CI)	Subtotals only
1.1 3 months fu	1	Std. Mean Difference (Random, 95% CI)	‐1.01 [‐2.11, 0.09]
1.2 12 months fu	5	Std. Mean Difference (Random, 95% CI)	‐0.23 [‐0.42, ‐0.03]
1.3 24 months fu	3	Std. Mean Difference (Random, 95% CI)	‐0.26 [‐0.61, 0.10]

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Proportion off work short term follow up	1	136	Odds Ratio (M‐H, Fixed, 95% CI)	1.0 [0.37, 2.70]
2 Time to return to work	4		Std. Mean Difference (IV, Random, 95% CI)	Subtotals only
2.1 6 months fu	2	114	Std. Mean Difference (IV, Random, 95% CI)	‐0.19 [‐0.63, 0.24]
2.2 12 months fu	3	256	Std. Mean Difference (IV, Random, 95% CI)	‐0.46 [‐0.96, 0.04]
2.3 24 months fu	1	52	Std. Mean Difference (IV, Random, 95% CI)	‐0.62 [‐1.21, ‐0.04]

Methods	RCT
Participants	Workers (33 males and 12 females) disabled and not working due to low‐back pain for at least 3 month duration, with or without referred pain, mean age 39.91(8.91).
Interventions	Intervention 1 : Standard treatment programme was a in‐patient, multidisciplinary approach to assisting workers in returning to function, that included twice daily sessions of physical therapy and daily aerobic fitness training to increase activity tolerance levels. Daily education classes on mechanisms of pain and group support were also added. Vocational rehabilitation was included through group and individual educational sessions. In addition, patients' medication intake was monitored (n =24). Intervention 2 : Psychological programme included in addition to the standard treatment programme an operant conditioning component involving daily charting of exercise behaviour, with contingent verbal praise, daily relaxation and biofeedback sessions. Group and individual training sessions to teach cognitive behavioural coping skills such as reconceptualisation of pain as an experience were also included. In addition, patients completed daily home work exercises that were reviewed with them on a daily basis (n = 21). Programme duration: three weeks.
Outcomes	Outcome assessed at 6 months after treatment. Return to employment (conservative ie full employment at same job; and liberal measures ie if full time on light duties or part‐time work or training)
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Does not state
Allocation concealment (selection bias)	Unclear risk	Does not state
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	High risk	Does not state
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware of allocation and intervention content
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care provider aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	All subjects recorded follow‐up data
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	High risk	21 subjects in each group analysed (there was 2 workers in psychological group)
Selective reporting (reporting bias)	Low risk	no suggestion found
Similarity of baseline characteristics?	Low risk	no statistical significant differences between groups in terms of demographic differences
Co‐interventions avoided or similar?	Low risk	no co‐interventions mentioned
Compliance acceptable?	Unclear risk	measured, but not reported what was considered non‐compliant
Timing of the outcome assessment similar?	Low risk	all measurements post‐treatment programme at 6 months

Methods	RCT
Participants	workers (28 males and 66 females) with low‐back pain with or without radiation for over 6 months. 78% not working or on suitable duties.
Interventions	Intervention 1(A1) : A combination of 3 modalities was offered: 1. Intensive physical training including aerobic capacity, coordination, muscle strength, and endurance, flexibility, stretching exercises, work hardening, ergonomic training and recreation including ball games, swimming for 5 hrs/day. 2. Psychological pain management that included relaxation and biofeedback for 2 hours a day guided by the clinical psychologist. 3. Patient education of 1 hour/day on a variety of topics led by physicians, therapists, psychologists, social worker and nutritionist (n = 50). Programme duration: a full day (eight hour) programme every weekday for three consecutive weeks followed by a full day per week during the following three weeks (Total: 135 hours). Control: CAU: consisted of no treatment offered, but patients could receive treatment elsewhere. 80% reported seeking treatment elsewhere mostly traditional physical therapy with passive modalities (61%) and manipulation by chiropractor (35%).
Outcomes	Outcome assessed at 12 months. 1. Ability to work (5 categories); 2. contacts with healthcare system; 3. number of sick leave days; 4. back pain (scale of 0‐10); 5. leg pain (scale 0‐10); 6. activities of daily living (scale 0‐30)
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Does not state
Allocation concealment (selection bias)	High risk	Does not state
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	The project was blinded in that the physician who saw the the patients for the initial examination and the 4‐month follow‐up did not know which group each patient was in. The same physician saw all the patients in both groups throughout the study. The blinding was broken in about 10% of the cases.
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware of allocation and intervention content
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	2 before the treatment programme, 7 during the programme
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	High risk	dropouts not analysed at follow‐up
Selective reporting (reporting bias)	Low risk	no suggestion found
Similarity of baseline characteristics?	Low risk	no significant differences
Co‐interventions avoided or similar?	High risk	intervention group had significantly less contacts with healthcare system than control group
Compliance acceptable?	Low risk	except for the dropouts.
Timing of the outcome assessment similar?	Low risk	all workers were analysed at baseline and after 4 months

Methods	RCT
Participants	Workers (28 males and 75 females) with chronic low‐back pain for over 6 months, and 73% not working or on suitable duties.
Interventions	Intervention 1(B1): A combination of 3 modalities was offered: 1. Intensive physical training including aerobic capacity, coordination, muscle strength, and endurance, flexibility, stretching exercises, work hardening, ergonomic training and recreation including ball games, swimming for 5 hrs/day. 2. Psychological pain management that included relaxation and biofeedback for 2 hours a day guided by the clinical psychologist. 3. Patient education of 1 hour/day on a variety of topics led by physicians, therapists, psychologists, social worker and nutritionist (n = 50). Programme duration: a full day (eight hour) programme every week day for three consecutive weeks followed by a full day per week during the following three weeks (Total: 135 hours). Intervention 2 (B2): Outpatient programme for small group (7‐8) people receiving physical training: 45 min aerobics and 45 min progressive resistance training, twice a week for 6 weeks. One hour of theoretical back school lessons every second day. Intervention 3 (B3): Outpatient programme for small group (7‐8) people receiving 45 min physical training and 75 min psychological pain management. Twice a week for 6 weeks.
Outcomes	Measurement at 1 year after randomization. 1. Ability to work (5 categories); 2. Contacts with healthcare system; 3. Number of sick leave days; 4. Back pain (scale 0‐10); 5. Leg pain (scale 0‐10); 6. Activities of daily living (scale 0‐30); 7. Use of prescription medication (%); 8. Sports activity (%); 9. Overall assessment (scale 1‐5)
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	randomization procedure followed minimization principle
Allocation concealment (selection bias)	High risk	Does not state
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Unclear risk	physician was blinded to treatment allocation, but the blinding was broken by patients in about 10% of cases. Unsure regarding RTW outcomes
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware of allocation and intervention content
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	14 out of 123 patients dropped out
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	High risk	dropouts not analysed at follow‐up
Selective reporting (reporting bias)	Low risk	No suggestion found
Similarity of baseline characteristics?	Low risk	No differences found
Co‐interventions avoided or similar?	High risk	All groups had contact with other health professionals before follow‐up
Compliance acceptable?	Low risk	14 out of 123 did not complete programme
Timing of the outcome assessment similar?	Low risk	all subjects follow‐up at 1 year after completion of programme

PERMALINK

Physical conditioning as part of a return to work strategy to reduce sickness absence for workers with back pain

Frederieke G Schaafsma

Karyn Whelan

Allard J van der Beek

Ludeke C van der Es‐Lambeek

Anneli Ojajärvi

Jos H Verbeek

Abstract

Background

Objectives

Search methods

Selection criteria

Data collection and analysis

Main results

Authors' conclusions

Plain language summary

Background

Description of the condition

Description of the intervention

How the intervention might work

Why it is important to do this review

Objectives

Methods

Criteria for considering studies for this review

Types of studies

Types of participants

Types of interventions

Types of outcome measures

Search methods for identification of studies

Data collection and analysis

Selection of studies

Data extraction and management

Assessment of risk of bias in included studies

1.

Measures of treatment effect

Quantitative analysis

Clinically worthwhile effect

Quality of the evidence

Assessment of clinical relevance

Unit of analysis issues

Data synthesis

Subgroup analysis and investigation of heterogeneity

Sensitivity analysis

Results

Description of studies

Results of the search

Search results

Study selection results

Included studies

Participants

Interventions

1. Contents of light physical conditioning programme (PCP).

2. Contents of intense physical conditioning programme (PCP).

3. Contents of intense physical conditioning programme (PCP).

4. Contents of intense physical conditioning programme (PCP).

Comparisons

Outcomes

Clinical relevance

5. Clinical relevance.

Excluded studies

Risk of bias in included studies

Effects of interventions

Acute back pain

Subacute back pain

Chronic back pain

Acute back pain

1. Light physical conditioning and back book versus back book

2. Light physical conditioning versus care as usual

3. Intense physical conditioning versus care as usual

Subacute back pain

4. Light physical conditioning and care as usual versus care as usual

Intermediate follow‐up

Long‐ and very long‐term follow‐up

5. Light physical conditioning with a brief clinical intervention versus a brief clinical intervention

6. Intense physical conditioning with care as usual versus care as usual

Intermediate follow‐up

Long‐term follow‐up

2.

Very long‐term follow‐up

Methods	RCT
Participants	138 workers with chronic low‐back pain from Copenhagen Back Center of which 54% were sick listed; mean age 40, 32% men
Interventions	Intervention: Function Restoration programme, including aerobics, strengthening excercises, occupational therapy, pain management/ group therapy or individual psychological sessions, stretching, theory/back school classes and recreational activities. 3 week schedule full time (8hrs per day) Control: Outpatient intensive physical training including aerobics and strenghtening exercises for 3x1, 5 hr for 8 weeks
Outcomes	Measurement at 1 year after treatment: work capability, number of sick leave days
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	stratification by minimization
Allocation concealment (selection bias)	Unclear risk	does not state
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	at 1 year follow‐up evaluation a few queries were discussed with the physician, who was blinded to treatment each specific patient had undergone. This blinding was successful for approx 80% of the patients, but relevant for less than half of the patients because most of them had filled out their quesitonnaire before their meeting with physician
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware of allocation and intervention content
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	21 out of 127 dropped out
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	High risk	intention‐to‐treat data were analysed but provided data were per protocol
Selective reporting (reporting bias)	Low risk	No suggestion found
Similarity of baseline characteristics?	High risk	not regarding sick leave; work capability better for FR group
Co‐interventions avoided or similar?	Unclear risk	no other interventions mentioned
Compliance acceptable?	Unclear risk	does not state
Timing of the outcome assessment similar?	Low risk	all subjects followed up at 1 year

Methods	cluster RCT
Participants	236 patients with MSDs resulting in severe restriction of work ability and who requested rehabilitation. Inclusion criteria were at least 12 weeks of sick leave in the year before rehabilitation OR subjective expectation of long‐term restrictions affecting occupational duties OR health‐related unemployment
Interventions	Multimodal work hardening: a three week inpatient group programme for 6‐10 patients with 6 modules: work and health; occupational competence; exercise; aquatic exercise; functional capacity training; relaxation. Conventional musculoskeletal rehabilitation: 3 weeks inpatients therapy including exercises, patient education, and psychosocial interventions.
Outcomes	Work status at 6 and 12 months defined as positive if the patient was working and had <6 or <12 (after 12 months) weeks of sick leave.
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	computer‐generated random numbers blocked to two sequences of 16 numbers
Allocation concealment (selection bias)	Low risk	Performed externally by the method centre of the Rehabilitation Research Association of Berlin‐Brandenburg‐Saxony
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Unclear risk	no report
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients were aware of their treatment
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers were not blinded
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	High risk	questionnaires after 6 and 12 months follow‐up were completed and returned by 169 (71.6%) and 146 (61.9%) patients, respectively
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	Low risk	intention‐to‐treat analysis regardless of premature dropout
Selective reporting (reporting bias)	Low risk	No suggestion found
Similarity of baseline characteristics?	Low risk	two differences in parameters at baseline were considered as covariates in the analyses
Co‐interventions avoided or similar?	Unclear risk	no report
Compliance acceptable?	Low risk	treatment was completed according to protocol in 5 out of 6 modules for 91.5% of the MWH participants
Timing of the outcome assessment similar?	Low risk	at 6 and 12 months follow‐up

Methods	RCT
Participants	214 workers, with work related soft tissue injury and off work between 3 to 6 months. More than 50% had low‐back pain.
Interventions	Intervention 1: Functional restoration approach: active physical therapy including stretching, strengthening and endurance building; work hardening; education and counselling to address pain related disability issues, attitudinal barriers to recovery, job satisfaction and entitlements, depression, anger and anxiety, medication reduction, sleep disruption, family problems and pain behaviours. Patients were also taught active pain management strategies, stress management and problem solving techniques, relaxation and guided imagery techniques as well as a multidimensional theory of pain. The emphasis was on acquisition of active strategies rather than reliance on passive methods to manage pain (n = 74). Programme duration: maximum of thirty five days at 6.5 hours per day. Intervention 2: Contol group: patients were discharged back to their treating physicians with a note re assessment findings, and recommendation for pro‐active management, including advice to limit narcotic medication and encourage activity despite pain (n = 64).
Outcomes	Outcome assessed at 18 months. 1. Self‐reported work status (dichotomous, 2 versions, %); 2. Pain rating (scale 0‐10); 3. Sleep rating (scale 1‐3); 4. Mean reported narcotic intake (pills/week).
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"following intake, the claimant was randomly assigned to a treatment of usual care condition by an employee of the WCB, who was blind to the results of the intake assessment"
Allocation concealment (selection bias)	Low risk	Adequate
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	outcome assessor had no familiarity with the patients or the programme and was blind as to the patients group status
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware of allocation and intervention content
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	High risk	26% for treatment and 36% for control dropped out, which could have led to substantial bias according to the authors
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	High risk	"only 74% and 64% in each group respectively were available for analysis"
Selective reporting (reporting bias)	Low risk	no suggestion found
Similarity of baseline characteristics?	Low risk	subjects were screened in order to make sure all workers were similar in terms of prognostic indicators
Co‐interventions avoided or similar?	Unclear risk	does not state
Compliance acceptable?	Unclear risk	does not state
Timing of the outcome assessment similar?	High risk	17 months ‐ 18.9 months

Methods	RCT
Participants	363 workers (240 males and 123 females) aged 16‐65 (mean age 36) with acute (< 3 weeks) pain radiating above knee who consulted their GP for back pain. 64% of workers had reported full sick leave at study entry.
Interventions	Intervention 1: 20 minutes of individual instruction from a physiotherapist, consisting of 8 exercises and 7 pieces of advice applying to daily life, including work. Exercises (in supine) were: semi‐fowler resting position, knees on chest, limbering exercise, stretching of iliopsoas, pelvic flexion, isometric abdominal exercises. The patients were taught anatomy, and were given instructions on how to stand, bend, lift, and carry objects. Work Work difficulties and problems performing the exercises were discussed, and attempts were made, together with the patient, to find solutions in order to maximise compliance. Patients received an audiotape, as well as a book with complete instructions (n = 96). Programme duration: five weeks, twice weekly. Intervention 2: (usual care): information given by GP regarding cause and course of back pain. The role of GP was to exclude other specific causes of back pain, emphasise the importance of heat, movement and short‐lasting bed rest to deal with back pain, and the requirement of return visits by the patient to the GP for follow up (n = 94).
Outcomes	Measurement at 12 months after treatment. 1. Sickness absence during the follow‐up period (% of N; several levels); 2. Absence during back pain (% of N)  3. Relative duration of sickness absence (total sick days/total pain days); 4. Sickness absence during short, intermediate, and long episodes (several levels)
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	block randomization ( blocks of 6)
Allocation concealment (selection bias)	Low risk	Adequate; patients were given sealed envelopes containing treatment group handled by nurse
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	blinded general practitioner
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware of allocation and intervention content
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	exercise group 30 out of 122 dropouts; placebo 11out of 119 dropouts
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	Low risk	ITT analysis for all available data
Selective reporting (reporting bias)	Low risk	no suggestion found
Similarity of baseline characteristics?	Low risk	no significant differences found
Co‐interventions avoided or similar?	Low risk	no other interventions noted
Compliance acceptable?	Unclear risk	exercise group; 92 out of 122 met criteria for 'on treatment', and 40 patients had a good compliance; placebo group108 out of 119 met criteria for 'on treatment'
Timing of the outcome assessment similar?	Low risk	all workers followed up after 2 and weeks and then every months until 12 months

Methods	RCT
Participants	124 workers from orthopaedic practices with acute low‐back pain and decreased ability to perform normal job requirements because of pain for about 3.8 weeks. Mean age was 38.2 and 65% was male.
Interventions	Intervention: a functional restoration early intervention of 3 weeks which consisted of four major components‐pscyhology, physical therapy, occupational therapy and case‐management. Contents were 3 physical evaluations, 1 physician evaluation, 18 physical therapy sessions (individual and group) 9 biofeedback/pain management sessions, 9 group didactic sessions, 9 case manager/occupational therapy sessions and 3 interdisciplinary team conferences. The number of sessions administered to patients was tailored to their specific needs, with most patients not needing all of the aforementioned number of sessions. Control: non‐intervention, care as usual
Outcomes	measured at 1 year after first evaluation: % return‐to‐work
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	urn randomization procedure
Allocation concealment (selection bias)	Unclear risk	not stated
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	'by raters blind to study hypotheses'
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware of allocation and intervention content
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	no dropouts
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	Low risk	ITT analysis
Selective reporting (reporting bias)	Low risk	no suggestion found
Similarity of baseline characteristics?	Low risk	'these three groups matched for age, gender, race, and time since original injury based upon and urn randomization procedure'
Co‐interventions avoided or similar?	High risk	control group received various types of treatment initiated by themselves
Compliance acceptable?	Unclear risk	not stated
Timing of the outcome assessment similar?	Low risk	all subjects followed up at 3, 6, 9, 12 months

Methods	RCT
Participants	299 workers with subacute LBP and sick leave between 3 and 6 weeks. Mean age 40.3, 79% male. 98 in high intensity back school, 98 in Low intensity back school, 103 in usual care group
Interventions	Intervention 1: High‐Intensity Back School. This back school was conducted twice a week, for 8 weeks. It consisted of 16 sessions, each lasting 1 hour, supervised by a physiotherapist. Principles of cognitive‐behavioural therapy were applied throughout the back school programme. The physiotherapist promoted a timecontingent increase in the level of activity. The first two sessions consisted of individual exercises simulating the activities the worker experienced as the most problematic at the workplace. Work‐simulating and strength training exercises during subsequent sessions were performed with gradually increasing resistance. The workers were also given home exercises during the time they were participating in the back school programme. Intevention 2: Low‐Intensity Back School. This back school was based on the Swedish model and consisted of four group sessions once a week for 4 consecutive weeks. Each session was divided into an educational (30 minutes) and a practical part (90 minutes) and guided by written information and a standardized exercise programme. Workers were told that functional activities, like working, could be continued despite back pain. During the educational sessions, the physiotherapist discussed the workplace situation. Not only the most problematic activities experienced by the worker because of the low‐back pain will be discussed, workers also received information on how to cope with these activities. The practical part comprised of a standardized exercise programme consisting of strength training and home exercises. The strength training involved progressive resistance training as well as functional exercises. Workers were instructed to perform exercises at home twice a day, and again if they had any recurrences of back complaints. Control: usual cary by occupational physician according to Dutch guidelines for management of low‐back pain
Outcomes	number of sick leave days at 3 and 6 months follow‐up
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	sealed opaque envelopes, coded according to a computerized random number generator, workers were randomly allocated
Allocation concealment (selection bias)	Low risk	done by non‐involved researcher
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	comment by author: researcher was unaware of the randomization scheme
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware of allocation and intervention content
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	44 (15%) workers withdrew from the study
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	Low risk	ITT analysis performed
Selective reporting (reporting bias)	Low risk	no suggestion found
Similarity of baseline characteristics?	Low risk	no significant differences noted at baseline
Co‐interventions avoided or similar?	High risk	workers in the control group had free access and used other interventions
Compliance acceptable?	Low risk	of the 103 workers in the usual care group, 88 (85%) returned the diaries containing information about the content of their treatments. Of the 98 workers allocated to the low‐intensity back school, 75 (77%) completed all treatment sessions. In the high‐intensity back school group, 70 (71%) workers completed all treatments
Timing of the outcome assessment similar?	Low risk	all subjects followed up 3 and 6 months

Methods	RCT
Participants	208 workers with non‐specific spinal pain, sick listed for at least 1 month. Mean age 43.5, 45% male
Interventions	Intervention: 4 weeks in groups of 4‐8 workers with 6 didactic sessions addressing psychological aspects of chronic pain, ergonomics and medical aspects of chronic pain, visits to the workplace; work managers and rehabilitation officials were invited to participate in the discharge session at which a rehabilitation plan was agreed upon. 6 booster sessions were held over a period of 1 year after the treatment. A combination of Behaviour‐oriented therapy (PT) for 20 hrs per week. Aimed at enhancing the physical functioning and facilitate a lasting behaviour change of the individual. And cognitive behaviour therapy (CBT) for 13‐14 hrs per week. Aimed at improving the subjects’ ability to manage their pain and resume a normal level of activity. Programme included activity planning, goal setting, problem solving, applied relaxation, cognitive coping techniques, activity pacing , the role of vicious circles and how to break them, the role of significant others and assertion training. Individually tailored homework assignments were given at the end of each session. Control 1: only behaviour oriented therapy (PT) Control 2: only cognitive behaviour therapy (CBT) Control 3: care as usual (usual routines in health care)
Outcomes	Measured at 18 and 36 months after rehabilitation: absence from work for more than 14 days
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	group randomization via blocks
Allocation concealment (selection bias)	Low risk	'screening personnel were blinded to the results of the randomisation'
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	information from author
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware of allocation and intervention content
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	28 workers dropped out of treatment
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	Low risk	both PP and ITT analysis
Selective reporting (reporting bias)	Low risk	no suggestion found
Similarity of baseline characteristics?	Low risk	pg 66 (Jensen 2001)
Co‐interventions avoided or similar?	High risk	control group could seek other medical advice or therapy
Compliance acceptable?	Low risk	56%‐70% adherence to treatment plan
Timing of the outcome assessment similar?	Low risk	all subjects followed up post‐treatment at 6 and 12 months

Methods	RCT
Participants	351 patients between 16 to 60 years, partly or fully sick‐listed from work for 4 to 12 weeks because of LBP
Interventions	Intervention 1: brief clinical intervention: standard clinical LBP examination by a physician, relevant imaging and examinations were ordered and treatment options were discussed. Patients were informed about cause, prognosis and treatment options. Furthermore, they were informed about exercise being beneficial, medical pain management, and they were advised to resume work when possible. Physiotherapy examination, with advise about exercise, and general advise about increasing physical activity and exercise. Coordination between stakeholders was ensured. Follow‐up visit at physiotherapist after 2 weeks, and physician if necessary. Intervention 2: brief clinical intervention and case management. This included an interview with a case‐manager within 2‐3 days; with questions about work history, private life, pain and disability perception. The case manager and the participant made a tailored rehabilitaion plan aiming at full or partial RTW. Each case was discussed several times by the entire multidisciplinary team including the rehabilitation physician, a specialist in clinical social medicine, a physiotherapist, a social worker, and a occupational therapist.
Outcomes	return to work defined as the first 4 week period within the first year after inclusion, during which the participant received no social transfer payments. Follow‐up was 1 year.
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated block randomization
Allocation concealment (selection bias)	Low risk	Performed by a secretary
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	data analyses were carried out by researchers outside the hospital
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients were aware of the result of the randomization
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	at the follow‐up consultation caregivers were aware of the result of the randomization
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	For primary outcome no dropouts
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	Low risk	100% follow‐up
Selective reporting (reporting bias)	Low risk	no suggestions found
Similarity of baseline characteristics?	Low risk	Adequate correction for any differences at baseline
Co‐interventions avoided or similar?	Unclear risk	not described
Compliance acceptable?	Unclear risk	no information
Timing of the outcome assessment similar?	Low risk	yes

Methods	RCT
Participants	107 workers with subacute low‐back pain which made working difficult for > 4 weeks and < 3 months. Mean age 44, % female 58.7
Interventions	Intervention 1: Mini‐Intervention Group (A) (60 min). Interview and examination of patient, discussion of working conditions and result of clinical examination were explained. The main aim was to reduce the patients’ concerns about their back pain by providing accurate information and to encourage physical activity. Back straining activities were appraised and special movements required at the patient’s work were trained if necessary. No more than five exercises for improving the function of deep abdominal muscles and establishing symmetric use of the back. Other daily exercises were planned feasible enough for the patient to commit to and execute them. The aim was to increase body control and exercising in everyday life. Feedback to the patient’s GP included recommendations on further diagnostic tests, treatment, work, and sick leave. The GP at the patient’s local health care center subsequently coordinated the recommended treatment in his/her usual manner at the health care centre. Intervention 2: Work Site Visit Group (B). Identical to mini‐intervention plus a visit of the physiotherapist to the patient’s work site. The patient’s work supervisor and company nurse, physiotherapist, and physician were asked to join in the session to ensure that the patient had adapted to the information and practical instructions of appropriate ways of using the back at work and to encourage their cooperation.  The company physician was advised to refer any patient who still had disabling low‐back pain or was on sick leave 3 months after randomization for inpatient rehabilitation. Control: usual care group received a leaflet on back pain and were treated by their GP in the usual manner
Outcomes	Measurement at 1 and 2 year after randomization: back pain related sick leave
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	research nurse randomized each patient into 1 out of 3 study groups using four piles of sealed envelopes. the randomization was done in blocks of 15.
Allocation concealment (selection bias)	Low risk	a biostatistician had prepared the order from a random number table. A secretary unconnected with the patients had numbered the envelopes sequentially to prevent their rearrangement. Research nurse and researchers were not aware of block size and therefore could not predict the group assignments
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	was not aware
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	Low risk	until the end of intervention at the FIOH. The work site visit made the difference at the end
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	Low risk	until the end of intervention at the FIOH. The work site visit made the difference at the end
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	1 dropout
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	Low risk	ITT analysis
Selective reporting (reporting bias)	Low risk	nu suggestions found
Similarity of baseline characteristics?	Low risk	no significant differences at baseline
Co‐interventions avoided or similar?	High risk	control group were free to go seek help and went to more physiotherapists and spent more money on diagnostic tests
Compliance acceptable?	Low risk	high follow‐up percentages (94‐100%) in each group
Timing of the outcome assessment similar?	Low risk	all subjects followed up at 3,6,12 months

Methods	RCT
Participants	174 workers with subacute LBP and sick leave of > 6 weeks in last half year. mean age 42, 79% male
Interventions	Intervention: Function‐Centered Treatment for 6 days a week for 3 weeks. The FCT was based on work hardening and functional restoration programmes. Treatment activities were chosen based on a patient’s required capacities, as identified in the work‐related assessment. Treatment consisted of work simulation, strength and endurance training through isokinetic exercise, cardiovascular training performed by walking and aqua‐aerobics, sports therapy, and self‐exercise. Patients were told that increasing activity might cause more pain because the body had to adjust to the activity again. All team members emphasized that patients should continue therapeutic activities even if their pain increased. The treatment protocol did not contain massage, hot packs, and other passive treatments because we did not believe that they facilitate an increase in activity and self‐efficacy, nor has the research literature shown them to be effective. Control: Pain‐Centered Treatment. The primary goal in the PCT group was to reduce pain. The secondary goal was to increase strength and decrease disability. The physical therapist examined the patients to identify painful movements and limitations in mobility, strength, and muscle length in the lumbar region and lower extremities. Treatment was for 2.5 hours a day and consisted of individually selected passive and active mobilization, stretching, strength training, and a mini back school. Unlike with the FCT group, patients in the PCT group were told to stop activities when pain increased. Passive pain modulating treatments such as hot packs, electrotherapy, or massage were used daily. Low‐intensity movement therapy in the pool and progressive muscle relaxation further enhanced relaxation. Progressive muscle relaxation used systematic contraction and relaxation of specific muscle groups. Patients were encouraged to incorporate relaxation techniques into daily living as a coping skill to reduce stress, muscle tension, and pain.
Outcomes	Measured at 1 year after treatment: number of calender work days, the rate of patients receiving unemployment benefits or permanent benefits.
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	an independent and blinded research assistant performed concealed randomisation within these 4 strata using a randomisation schedule with blocks of 2 generated on a computer by an independent researcher
Allocation concealment (selection bias)	Low risk	see above
Blinding (performance bias and detection bias)   All outcomes ‐ outcome assessors?	Low risk	days at work and other work‐related outcomes were assessed with a questionnaire sent to employers and the patients' primary physicians, who were blinded to the patients' group assignment
Blinding (performance bias and detection bias)   All outcomes ‐ patients?	High risk	patients aware intervention content, but not of other treatment
Blinding (performance bias and detection bias)   All outcomes ‐ care provider?	High risk	care providers aware of allocation and intervention content
Incomplete outcome data (attrition bias)   All outcomes ‐ drop‐outs?	Low risk	1 dropout
Incomplete outcome data (attrition bias)   All outcomes ‐ ITT analysis?	Low risk	ITT analysis
Selective reporting (reporting bias)	Low risk	no such suggestions found
Similarity of baseline characteristics?	Low risk	no significant differences found
Co‐interventions avoided or similar?	High risk	subjects used other health care providers between 3 and 12 months
Compliance acceptable?	Low risk	all patients attended at least 90% of the scheduled treatments
Timing of the outcome assessment similar?	Low risk	all subjects followed up post treatment and at 3 months