| Study characteristics |
| Methods |
Study design: RCT (NCT01653782)
Setting: Sweden, mixed
Exercise groups: 2
Comparison groups: 1 |
| Participants |
Number of participants: 159 (E1 = 52, E2 = 52, C1 = 55)
Chronic LBP duration: Not specified (not specified)
Neurological/radicular symptoms: Not specified
Mean age (years): 46
Sex (female): 71% |
| Interventions |
Exercise Group 1 (E1): Kundalini Yoga; type = yoga; duration = 6 weeks; dose = low; design = standardised; delivery = group; additional intervention = advice/education
Exercise Group 2 (E2): Strength training: focusses on core muscle strengthening and stabilisation; type = core strengthening; duration = 6 weeks; dose = low; design = partially individualised; delivery = individual; additional intervention = advice/education
Comparison Group 1 (C1): Other conservative treatment (education) |
| Outcomes |
Core outcomes reported: Pain (Chronic Pain Grade Scale ‐ Pain Subscale); function (Chronic Pain Grade Scale‐ Disability Subscale); work (sickness absence, sickness presenteeism)
Follow‐up time periods available for syntheses: 24 weeks (moderate) |
| Notes |
Conflicts of interest: None to declare
Funding source: Swedish Research Council for Health, Working life and Welfare (2008‐0849)
Other: Information modified for author contact |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
"A random allocation sequence was generated by the statistician". |
| Allocation concealment (selection bias) |
Low risk |
"For each participant an opaque envelope was opened, in consecutive order, by an external research assistant not involved in the inclusion process". |
| Blinding of participants and personnel (performance bias)
All outcomes |
Low risk |
1. Patients were not blinded to their assigned intervention; 2. Patients did not know the content of the different intervention arms; no report of external activity. |
| Blinding of care provider (performance bias) |
Low risk |
1. "The yoga leader and physiotherapist were not blinded"; 2. Lack of care provider blinding probably did not cause deviations from intended interventions because each intervention was clearly defined and distinct. |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
1. Outcomes in question were assessed by the patient who was not blinded to the intervention; 2. Patients did not know the content of the different intervention arms; no reason to alter patient response. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
1. Dropout rate was 26% (40/152) which introduces a risk of bias; 2. Used last‐value‐carried‐forward method, and also relative frequency imputation; not valid methods, artificially improve precision and do not necessarily remove bias; 3. No significant differences between those who were lost to follow‐up and participants in terms of age, sex, or pre‐intervention values on neck and back pain |
| Participants analysed in group allocated (attrition bias) |
Low risk |
1. "An intention‐to‐treat analysis was conducted which included all randomized individuals, irrespective of whether they had adhered to the intervention programme or not". |
| Selective reporting (reporting bias) |
Low risk |
1. Study was analysed and reported according to registered protocol (NCT01653782), with some additional outcomes (pain intensity at 6 and 12 months). |
| Groups similar at baseline (selection bias) |
Low risk |
Groups were similar on all relevant characteristics at baseline except duration of symptoms was not reported. |
| Co‐interventions avoided or similar (performance bias) |
High risk |
Some element of co‐intervention was encouraged in the control group based on educational materials. |
| Compliance acceptable in all groups (performance bias) |
High risk |
Proportion of participants who adhered to the recommendations (exercised at least 2 times/week) during the 6‐month follow‐up was: 54% (yoga), 34% (strength training) and 42% (control group). |
| Timing of outcome assessment similar in all groups (detection bias) |
Low risk |
1. Outcome assessments were identical for all patients, regardless of treatment group; 2. Chronic Pain Grade Scale analysed using the von Korff protocol (for pain) is a well‐validated tool in the low back pain context. |
| Other bias |
Low risk |
No other sources of bias noticed; generally well‐reported |
