Kullich 2003.

Study characteristics
Methods	Study type: randomised using a computer‐based randomisation list (Kullich 2014a [pers comm]) Design: 2‐arm, parallel group design Blinding: single blind; data assessment performed by non‐trial personnel (Kullich 2014a [pers comm])
Participants	Sample: adults with low back pain and sleep difficulties documented by PSQI scores > 5 n: 65 randomised, 65 completed and included in analyses Age: mean age reported by group (range 21–68 years); music group: mean 47.0 (SD 9.7) years, control group: mean 49.7 (SD 7.9) years  Sex: 41 men, 24 women Setting: rehabilitation facility Country: Austria
Interventions	Intervention (n = 32): music group. Participants administered the music intervention themselves. They listened to researcher‐selected music and relaxation instructions through headphones and received TAU. Music characteristics: CD 'Entspannung bei Schmerzen' (Mentalis Verlag, ISBN: 3‐932239‐95‐4). No further information provided Length of sessions: 25 minutes Frequency of sessions: once a day, no time specified Duration of intervention period: 3 weeks ± 2 days Control (n = 33): TAU
Outcomes	Sleep quality (assessed with PSQI) mean at baseline and postintervention. No SD reported scores for components (sleep latency, sleep duration, sleep efficiency, sleep disturbance, sleep medication, daytime dysfunction, subjective sleep quality) Pain (assessed with VAS)a Level of disability (assessed with R‐MDQ)a aOutcome not included in this review
Notes	Trial start and end dates: not provided. Funding sources: supported by the Ludwig Boltzmann Institut (Saalfelden), the Herbert von Karajan Centrum (Wien), Salzburg University, and the Mozart University (Salzburg).  Protocol registration: none found
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Comment: computer‐based randomisation list (Kullich 2014a [pers comm])
Allocation concealment (selection bias)	Low risk	Comment: allocation done by another person (not the doctor) who referred the participant to the trial (Kullich 2014a [pers comm])
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: due to the nature of the intervention, blinding of participants was not possible. It is likely that this affected the subjective measures of sleep. There was no information on the blinding of the personnel at the rehabilitation facility.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: data were assessed by non‐trial personnel (secretary). Data analysis was performed by a researcher who was aware of group allocation, but did not know the patients (Kullich 2014a [pers comm]).
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: no attrition or missing data (Kullich 2014a [pers comm])
Selective reporting (reporting bias)	Low risk	Comment: we found no published protocol on this study, but there was no indication of selective reporting. Measures on sleep quality were reported without SDs in the publication, but these were provided by the first author on request (Kullich 2014b [pers comm]). These data did not alter the conclusions of the trial.
Other bias	Low risk	Comment: no other risk of bias detected