| Study characteristics |
| Methods |
Study design: RCT
Setting: USA, mixed
Exercise groups: 1
Comparison groups: 1 |
| Participants |
Number of participants: 90 (E1 = 43, C1 = 47)
Chronic LBP duration: Not specified (long)
Neurological/radicular symptoms: No participants
Mean age (years): 48
Sex (female): 77% |
| Interventions |
Exercise Group 1 (E1): Iyengar yoga; type = yoga; duration = 24 weeks; dose = high; design = standardised; delivery = group; additional intervention = none
Comparison Group 1 (C1): Usual care/no treatment (control group: continued with normal activity and treatment) |
| Outcomes |
Core outcomes reported: Pain (Visual Analogue Scale); function (Oswestry Disability Index)
Follow‐up time periods available for syntheses: 24 weeks (moderate); 50 weeks (long) |
| Notes |
Conflicts of interest: None to declare
Funding source: National Institutes of Health’s National Center for Complementary and Alternative Medicine grant (no.1 R21 AT001679‐01A2)
Other: Information modified for author contact; SDs imputed |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Eligible participants were given envelopes with randomly generated group assignment and enrolled in one of four cohorts of 20 to 28 participants each. |
| Allocation concealment (selection bias) |
Low risk |
Author contact: changed to yes; they used envelopes |
| Blinding of participants and personnel (performance bias)
All outcomes |
High risk |
Not described |
| Blinding of care provider (performance bias) |
High risk |
Not described |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
Participants were asked to return at 12 (midway), 24 (immediately after), and 48 weeks (six‐month follow‐up) after the start of the intervention. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Sixteen participants (12 from the yoga group) did not complete the 24‐week protocol. |
| Participants analysed in group allocated (attrition bias) |
Low risk |
For intention‐to‐treat analyses, missing baseline data were replaced by group means while missing data at 12 and 24 weeks were replaced. |
| Selective reporting (reporting bias) |
Low risk |
Support for judgement was not available. |
| Groups similar at baseline (selection bias) |
Low risk |
More African‐Americans were enrolled in the yoga versus control groups. |
| Co‐interventions avoided or similar (performance bias) |
Low risk |
Agreed to not get chiropractic treatment, massage therapy, Pilates, or acupuncture or to participate in any other yoga programme |
| Compliance acceptable in all groups (performance bias) |
Low risk |
On average, yoga completers attended 88.5% of classes and 87.1% completed home practice. |
| Timing of outcome assessment similar in all groups (detection bias) |
Low risk |
Support for judgement was not available. |
