Michalsen 2016.

Study characteristics
Methods	Study design: RCT (DRKS00000373) Setting: Germany, general population Exercise groups: 1 Comparison groups: 1
Participants	Number of participants: 68 (E1 = 36, C1 = 32) Chronic LBP duration: 11.5 years (long) Neurological/radicular symptoms: Not specified Mean age (years): 55 Sex (female): 76%
Interventions	Exercise Group 1 (E1): Home‐based exercise programme: booklet containing education on low back pain and exercises that focussed on stretching, strengthening, and joint mobilisation exercises; type = mixed; duration = 8 weeks; dose = low; design = standardised; delivery = independent; additional intervention = advice/education Comparison Group 1 (C1): Other conservative treatment (relaxation)
Outcomes	Core outcomes reported: Pain (Visual Analogue Scale); function (Roland‐Morris Disability Questionnaire); HRQoL (36‐Item Short Form Survey) Follow‐up time periods available for syntheses: 8 weeks (short)
Notes	Conflicts of interest: None to declare Funding source: Else KrönerFresenius‐Stiftung, Germany Other: None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was based on the “ranuni” pseudo‐random number generator of the SAS/Base statistical software, using a nonstratified block‐randomisation with varying block lengths method.
Allocation concealment (selection bias)	Low risk	Patients were randomly allocated to a treatment group by preparing sealed, sequentially numbered opaque envelopes containing the treatment assignments; envelopes were prepared by study biostatistician.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	1. Patients could not be blinded to the intervention due to the nature of the treatment groups; 2. Unlikely that knowledge of the meditation intervention would have significantly altered the way participants in the take‐home exercise group performed the intervention
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 care provider blinding led to deviations from protocols; meditation was practiced in a standard way, and independent exercise group only saw physician once at the start of study.
Blinding of outcome assessment (detection bias) All outcomes	High risk	1. Outcome assessors for outcomes of interest (pain and disability) were participants, who could not be blinded due to the nature of the interventions; 2. Pain and functional questionnaires are subjective, and responses could be altered by awareness of intervention; 3. Possible that either intervention could be considered better with no clear bias in a particular direction
Incomplete outcome data (attrition bias) All outcomes	High risk	1. 16 out of 68 total randomised participants (23.5%) dropped out of the study 2. Dropout rates between treatment groups were not equal, which indicates that there may have been bias in missingness of data between treatment groups; 3. Possible that participants who saw no improvement or worsening of symptoms were more likely to drop out; missingness of outcomes could have been more likely for poorer outcome results; 4. Missingness rates between treatment groups were not equal; 37.5% missing from meditation group, 11% missing from exercise group; 5. Likely that participants who saw no improvement or worsening of symptoms dropped out. Thus, worse outcome results were missing, biasing meditation group to appear better than it truly was.
Participants analysed in group allocated (attrition bias)	Low risk	1. All outcome criteria were analysed by intention‐to‐treat, including all randomised subjects, irrespective of whether or not they adhered to the protocol, or gave a full set of data.
Selective reporting (reporting bias)	Low risk	1. All analyses conducted and reported as described, except global rating of effectiveness, which was only briefly reported in discussion for one treatment group
Groups similar at baseline (selection bias)	Low risk	All relevant baseline characteristics were measured and similar between treatment groups, except there was a higher proportion of females in the meditation group.
Co‐interventions avoided or similar (performance bias)	High risk	Regular analgesic medication should not have been changed in 6 weeks before study start; rescue medication was allowed; use was reduced in 5 subjects of the mediation group and none of exercise group.
Compliance acceptable in all groups (performance bias)	High risk	Study reported "non‐compliance" among some individuals, but none of these individuals completed a post‐intervention assessment, so we considered them dropouts; no other information reported
Timing of outcome assessment similar in all groups (detection bias)	Low risk	1. All participants had outcome assessments at the same time points, and for each outcome; were assessed using the same tools; 2. Visual Analogue Scale (for pain) and Roland‐Morris Disability Questionnaire (for disability) are well‐validated tools in the context of low back pain.
Other bias	Low risk	Appeared free from other sources of bias