Glombiewski 2010b.

Methods	RCT; 3 arms: CBT + biofeedback; CBT; waiting list control, post‐treatment (WLC assigned to treatment so no WLC at 6‐month follow‐up)
Participants	End of treatment: n = 116 Start of treatment: n = 128 Sex: 77 F, 39 M Mean age: 48.8 (SD 11.7) Source = medical referrals (86%) or response to newspaper advert (14%) Diagnosis = chronic back pain Mean years of pain: 8.1 (SD 8.7)
Interventions	"CBT with biofeedback" "CBT" "waiting list control"
Outcomes	Primary pain outcome: 0 to 10 NRS pain intensity Primary disability outcome: PDI Primary mood outcome: BDI Catastrophising outcome: none Pain intensity 0 to 10 NRS Pain average of 4x daily diary for 1 week Pain Disability Index Beck Depression Inventory Coping Strategies Scale from FESV Health‐Related Life Satisfaction Scale Global treatment change Treatment satisfaction (Adverse events noted from pain intensity and global treatment change) Health care use: doctor visits for pain
Notes	Combined (CBT + biofeedback and CBT) versus WLC: analyses 3.1, 3.2, 3.3 2011 update search Yates quality scale: total quality 24/35, design quality 17/26, design quality 15/26
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation by random number generation
Allocation concealment (selection bias)	Unclear risk	“coordinated by the first author” before study
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Attrition fully reported; statement that dropout data will be reported elsewhere
Selective reporting (reporting bias)	Low risk	Fully reported
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not reported