Bernaards 2007

Methods	The study is a randomised controlled trial with a block‐randomised design. The study had two intervention groups and one control group. To prevent unbalanced randomisation, participants were pre‐stratified by company and self‐reported sports participation. The intervention period lasted six months in the years of 2004‐2005 and took place in the Netherlands.
Participants	The participants were computer workers from head‐offices of seven companies in various branches (insurance, science, energy, transportation policy and taxes). The companies were located in different regions in the Netherlands. The inclusion criteria were: Frequent (i.e. at least once a week) long‐term pain, stiffness and tingles in neck, shoulders, arms, wrists and/or hands in the preceding six months and/or the last two weeks. Performing computer work for at least three days a week during at least three hours a day. Having a working contract until the last follow‐up measurement. Not being under treatment of a doctor or (physical) therapist for complaints in the neck, shoulders, arms, wrists and/or hands. Not having non‐work‐related or clear somatic diseases (e.g. rheumatoid arthritis, cervical hernia, tennis elbow, carpal tunnel syndrome). Finally, having sickness absence of less than 50% of the total working time (i.e. worker was working at least 50% of the hours he or she was supposed to work according to his or her working contract). Excluded were women who were pregnant in the start of the study. A short questionnaire was sent to 8000 workers. The number of workers who responded was 1875, of which 466 met the inclusion criteria and were randomised into three groups. The intervention group 1 (work style group) had 152 participants, the intervention group 2 (work style and physical activity group) had 156 participants and the control group had 158 participants. The follow‐up rate at 12 months was 68%. Mean age was 43.8, 43.6 and 44.4 years in the intervention group 1, intervention group 2 and control group respectively. Male sex was 54.6%, 53.8% and 58.2% respectively. Mean workdays a week were 4.5 days. MSD is described as symptoms in neck and upper limbs. The distribution of average pain at baseline was 4.1, 3.9 and 3.7 in intervention group 1, intervention group 2 and control group respectively on a scale from 0 'no pain' to 10 'worst pain ever'. Median duration of pain at baseline was 36 months, 30 months and 36 months respectively. Accordingly, prevalence of neck shoulder symptoms at baseline was 87.4%, 86.2% and 90.3% in the three groups.
Interventions	The intervention for the two intervention groups both consisted of six interactive group meetings of 15 to 60 minutes duration in a six‐month period. Four group meetings were large (with maximally ten participants) and two group meetings were small (with maximally three participants). The goal of all group meetings was behavioural change with regard to physical activity and/or work style. All group meetings took place at the workplace during work time under the supervision of a specially trained counsellor. The counsellors used standardised protocols. Intervention group 1: Work style group. The goal of the intervention was to stimulate work place adjustment and to improve body posture, the number and quality of breaks, and coping behaviour with regard to high work demands. Intervention group 2: Work style and physical activity group. In the combined intervention the additional goal was to increase moderate to heavy intensity physical activities, in addition to the interventions presented above. Performing physical exercise was not part of the intervention itself. Control group: The control group did not attend any of the group meetings, no intervention was given.
Outcomes	All outcomes except degree of recovery, were measured at baseline (October 2004). In addition, all outcomes were measured at six months follow‐up (April 2005) and twelve months follow‐up (October 2005). The primary outcomes were: Recovery: Degree of recovery from neck and upper limb symptoms was assessed using a seven‐point Visual Analogue Scale ranging from 'much worse' to 'completely recovered'. Pain intensity: Current pain, average pain and worst pain in the past four weeks were assessed using a validated eleven‐points numerical scale ranging from 0  'no pain' to 10 'worst pain ever'. Disability at work: Change in ability to work in the past four weeks was assessed with a validated eleven‐point scale ranging from 0  'no change' to 10 'extreme change'. Number of days with neck and upper limb symptoms: Participants reported the number of days with neck/shoulder symptoms and arm/wrist/hand symptoms in the past six months (no symptoms, 1‐7 days, 8‐30 days, 31‐90 days, 91‐180 days) and the past week (no symptoms, 1 day, 2‐3 days, 4‐7 days) using the validated Dutch Musculoskeletal Questionnaire.  Number of months without symptoms: The number of months without neck and upper limb symptoms in the past six months was assessed using one question: “In how many of the past six months did you have no symptoms in neck and upper extremities?”
Notes	Additional information about the trial was found in two other publications (Bernaards 2006; Bernaards 2008). First author was contacted for missing information and responded.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	Quote: “An independent statistician prepared the randomisation by using a computer‐generated randomisation.... Furthermore, block randomisation with blocks of three was used”. According to the first author, the generated sequences were like 123, 213, 321 etc, where number 1 was referring to group 1, 2 was referring group 2, and 3 was referring to group 3. The numbers were put in envelopes in this order. The first participants was given the first envelope, the second participant was given the second envelope etc. To conclude, this is an adequate method computer‐generated block randomisation.
Allocation concealment?	Low risk	Information about treatment allocation was kept in envelopes. The researchers were not aware of numbers inside the envelopes. After baseline measurements, the researchers opened the envelopes and informed the workers about group allocation. Some workers were informed about their treatment allocation by phone. This was the case when the participants were unable to collect their number themselves. The envelopes were opened during the call. The description above is based on information from the article and information given by author. To conclude, it is our impression that the allocation was adequately concealed.
Blinding? All outcomes ‐ participants?	High risk	Quote: "Unfortunate, it was impossible to blind participants and counsellors for the treatment allocation”. Blinding of participants to the intervention was not performed.
Blinding? All outcomes ‐ providers?	High risk	Blinding of care providers to the intervention was not performed either.
Blinding? All outcomes ‐ outcome assessors?	Low risk	The researchers who performed the follow‐up were not aware of the treatment allocation of participants, except for the counsellors who also performed part of the measurements. According to the author the counsellors could have known treatment allocation for less than 10% of the participants. Since the outcomes assessors were blinded in more than 90% of the cases, we score 'yes' here.
Incomplete outcome data addressed? All outcomes ‐ drop‐outs?	High risk	The drop‐out rate at 12 months follow‐up was 32 %, which is considered to be too high.
Incomplete outcome data addressed? All outcomes ‐ ITT analysis?	Low risk	Quote. “Intention‐ to‐treat analyses were used to estimate the effect of the intervention. This means that all participants who were randomly assigned to one of the two intervention groups, were included in the analyses regardless of whether they attended the group meetings”. Intention‐to‐treat analyses were performed.
Free of selective reporting?	Low risk	All outcomes are reported thoroughly. There is no reason to suspect selective outcome reporting.
Similarity of baseline characteristics?	Low risk	According to table 1 in the article, the baseline characteristics of the participants were largely similar in all three study groups.
Co‐interventions avoided or similar?	Low risk	According to author all companies were instructed not to start any co‐interventions during the intervention period. If there were co‐interventions by means of discussions between the groups, they were similar in index groups and control group.
Compliance acceptable?	High risk	The main part of the intervention was attending group meetings. Compliance to the group meetings is reported in table 2 in the article in form of number of participants who attended the six meetings. Even though the compliance was quite similar in the two intervention groups, it was not high (less than 50% attended the meetings). Hence, compliance was not acceptable.
Timing outcome assessments similar?	Low risk	All groups were assessed simultaneously at baseline, 6 months and 12 months follow‐up.