| Study characteristics |
| Methods |
Study design: RCT
Setting: Norway, occupational
Exercise groups: 1
Comparison groups: 2 |
| Participants |
Number of participants: 214 (E1 = 60, C1 = 99, C2 = 55)
Chronic LBP duration: 11.48 years (long)
Neurological/radicular symptoms: Some participants
Mean age (years): 45
Sex (female): 50% |
| Interventions |
Exercise Group 1 (E1): Group Physical Exercise and Brief Cognitive Intervention: exercises were adapted by physiotherapist, strength and endurance training, relaxation; type = functional restoration; duration = 12 weeks; dose = high; design = individualised; delivery = group; additional intervention = advice/education & psychological therapy
Comparison Group 1 (C1): Other conservative treatment (psychological therapy)
Comparison Group 2 (C2): Other conservative treatment (psychological therapy) |
| Outcomes |
Core outcomes reported: Function (Oswestry Disability Index); work (% still on sick leave)
Follow‐up time periods available for syntheses: 52 weeks (long) |
| Notes |
Conflicts of interest: None to declare
Funding source: Research Council of Norway (175466/V50); Norwegian Extra Foundation for Health and Rehabilitation (EXTRA funds)
Other: Sufficient data not available for inclusion in meta‐analyses |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Randomisation was adequate, performed according to a computer‐generated randomisation list, generated by the trial statistician; stratified by clinic and gender. |
| Allocation concealment (selection bias) |
Low risk |
Treatment allocation was concealed using a central telephone randomisation system. |
| Blinding of participants and personnel (performance bias)
All outcomes |
Low risk |
1. Patients could not be blinded to their assignment due to the nature of the treatments; 2. Unlikely that lack of patient blinding altered the intended interventions, as intervention delivery was controlled by care providers |
| Blinding of care provider (performance bias) |
Low risk |
1. Care providers could not be blinded to allocation due to the nature of the treatments; 2. Different care providers specialised in different treatments provided the care. |
| Blinding of outcome assessment (detection bias)
All outcomes |
High risk |
1. Outcome assessors were patients, who could not be blinded to treatment assignment due to nature of interventions; 2. Pain and functional questionnaires are subjective, and responses could be altered by awareness of intervention; 3. Because all of the treatment groups were quite distinct and there were clearly "better" groups, it is quite likely that lack of patient blinding led to biased outcome assessments. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
1. 68 of 215 had no follow‐up information for the outcomes of interest, 32% lost; 2. Mixed ANOVA dropped observations with missing data; 3. Missingness could be caused by increased disability from low back pain; 4. 25%, 25.5%, 39% |
| Participants analysed in group allocated (attrition bias) |
Low risk |
1. Intent‐to‐treat analysis was included. |
| Selective reporting (reporting bias) |
Low risk |
1. No linked protocol found: all planned analyses were executed and reported for all primary and secondary outcomes. |
| Groups similar at baseline (selection bias) |
Low risk |
All relevant characteristics were measured at baseline and were similar across treatment groups. |
| Co‐interventions avoided or similar (performance bias) |
High risk |
No mention of co‐interventions in the study or in its protocols |
| Compliance acceptable in all groups (performance bias) |
High risk |
No mention of compliance or adherence to the interventions |
| Timing of outcome assessment similar in all groups (detection bias) |
Low risk |
1. All patients were assessed for outcomes identically, regardless of treatment group; 2. Oswestry Disability Index (for function) is a well‐validated tool in the low back pain context. |
| Other bias |
Low risk |
To increase statistical power, all participants allocated to Brief Cognitive Intervention regardless of centre were compared to the two experimental groups; broke requirements for RCT; sensitivity analysis done but vague |
