Smeets 2006.

Methods	RCT; 4 arms; assessed at pre‐treatment, post‐treatment, 1 year
Participants	End of treatment n = 212 Start of treatment n = 223 Sex: 106 F, 117 M Mean age = 41.6 (SD 10.0) Source = pain or rehabilitation clinic Diagnosis = CLBP Mean years of pain = 4/6
Interventions	"Cognitive behavioural therapy + active physical treatment" "Cognitive behavioural therapy" "active physical treatment" "waiting list"
Outcomes	Primary pain outcome: MPQ PRI (follow‐up only) Primary disability outcome: Roland & Morris Disability Scale Primary mood outcome: BDI Catastrophising outcome: process only Roland Morris Disability Questionnaire disability Difficulty with 3 most limited activities: 0 to 100 Visual analogue scale pain Beck Depression Inventory Pain Cognitions List: catastrophising, pain control subscales as process measures Follow‐up only MPQ PRI 6. 5‐minute walk 7. 50‐foot walk 8. timed stand‐to‐sits 9. extended reach 10. stair climb 11. lifting task
Notes	1‐year follow‐up Smeets 2008; December 2009 search CBT plus active PT versus active PT: analyses 1.1, 1.2, 1.3, 2.1, 2,2. 2.3 GA plus problem solving versus WLC: analyses 3.1, 3.2, 3.3 (waiting list not followed up) Yates quality scale: total quality = 28/35, design quality = 23/26, treatment quality = 5/9
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised in blocks by computer‐generated algorithm
Allocation concealment (selection bias)	Low risk	Generated by independent statistician; sealed envelopes
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Attrition fully reported; no test for differences
Selective reporting (reporting bias)	Low risk	Fully reported
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Assessment by blinded research assistants