Saper 2017.

Study characteristics
Methods	Study design: RCT (NCT01343927) Setting: USA, mixed Exercise groups: 2 Comparison groups: 1
Participants	Number of participants: 320 (E1 = 127, E2 = 129, C1 = 64) Chronic LBP duration: Not specified (not specified) Neurological/radicular symptoms: Not specified Mean age (years): 46 Sex (female): 64%
Interventions	Exercise Group 1 (E1): Yoga: relaxation and meditation exercises, yoga breathing, and yoga philosophy (30 minutes of daily home practice, facilitated by a video, a manual, and take‐home yoga supplies); type = yoga; duration = 12 weeks; dose = low; design = standardised; delivery = group; additional intervention = none Exercise Group 2 (E2): Physiotherapy: treatment‐based classification, graded exercise, and screening for fear‐avoidance beliefs. Exercise involved supervised aerobic exercises For patients with high fear‐avoidance beliefs, a therapist provided a copy of a Back Book and counselled participants to reduce their fear. Participants received written instructions and supplies for home practice and logged the number of exercises completed daily; type = core strengthening & aerobic; duration = 12 weeks; dose = low; design = individualised; delivery = individual; additional intervention = psychological therapy Comparison Group 1 (C1): Other conservative treatment (education)
Outcomes	Core outcomes reported: Pain (Numerical Rating Scale); function (Roland‐Morris Disability Questionnaire); work (work productivity); HRQoL (36‐Item Short Form Survey); Global Perceived Health or Recovery (Global Perceived Health or Recovery (Global Rating of Change Scale)) Follow‐up time periods available for syntheses: 12 weeks (short)
Notes	Conflicts of interest: Dr. Saper reported grants from the National Center for Complementary and Integrative Health of the National Institutes of Health during the conduct of the study. Dr. Sherman reported grants from National Institutes of Health during the conduct of the study. Dr. Herman reported grants from the National Center for Complementary and Integrative Health during the conduct of the study. Dr. Weinberg reported grants from the National Institutes of Health during the conduct of the study. Authors not named here have disclosed no conflicts of interest. Funding source: National Center for Complementary and Integrative Health, National Institutes of Health (5R01‐AT005956) Other: None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation sequence using permuted block randomisation with varying block sizes and a 2:2:1 ratio of yoga, physiotherapy, and education
Allocation concealment (selection bias)	Low risk	Randomisation all done by computer program; nothing calculated by hand; study staff did find out before participants (allocation was not revealed to participant and study staff at the same time).
Blinding of participants and personnel (performance bias) All outcomes	High risk	1. Patients could not be blinded to intervention due to nature of treatments; 2. Yoga protocol was defined, it was not unlike the sequence one would receive at an external class; accessible outside of study; 3. No information on any deviations; 4. Seeking the treatment could reduce low back pain.
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. Unlikely that lack of provider blinding led to deviations from intended intervention; different providers delivered each treatment, i.e. yoga instructors only saw yoga participants.
Blinding of outcome assessment (detection bias) All outcomes	High risk	1. For outcomes of interest (pain and disability), outcome assessors were patients, who could not be blinded to intervention; 2. Pain and functional questionnaires are subjective, and responses could be altered by awareness of intervention; 3. Particularly for control group participants, lack of blinding likely led to them feeling underserved by their treatment allocation, and were biased in a perception of lack of improvement in outcomes.
Incomplete outcome data (attrition bias) All outcomes	Low risk	1. At 12 weeks follow‐up was 88% versus 98% versus 95%.
Participants analysed in group allocated (attrition bias)	Low risk	1. Intention‐to‐treat analyses of the full study population performed
Selective reporting (reporting bias)	Low risk	1. Published protocol (Saper 2014) and registered (NCT01343927): all analysis conducted and reported in these documents; work productivity not reported here but noted it would be in separate publication
Groups similar at baseline (selection bias)	Low risk	All group characteristics were similar at baseline; duration of symptoms was not measured or reported.
Co‐interventions avoided or similar (performance bias)	High risk	Medication use during treatment period was reported; education group had slightly higher use of all medications, though it differed by subtype of medication; no other co‐interventions discussed
Compliance acceptable in all groups (performance bias)	High risk	Compliance for yoga group: median 7 out of 12 classes attended (58%); compliance for physiotherapy group: median 7 out of 15 appointments (47%); compliance for education: 44% read at least 75% of education book.
Timing of outcome assessment similar in all groups (detection bias)	Low risk	1. All outcomes were assessed at the same time point; Within each outcome, all participants in all groups were measured using the same tools, etc.; 2. Roland‐Morris Disability Questionnaire (for disability) and Numeric Rating Scale (for pain) are well‐validated tools in the context of low back pain.
Other bias	Low risk	Powered for non‐inferiority; had to adjust for baseline Roland‐Morris Disability Questionnaire