van der Veek 2013

Methods	RCT. 2 arms. Assessed pre‐treatment, post‐treatment, 6 months, and 12 months follow‐up
Participants	End of treatment n = 92; n = 88 at 12 months follow‐up Start of treatment n = 104 Sex: 24 F, 12 M Mean age 11.9 (SD 2.77) Source = children's hospital Diagnosis = abdominal pain Mean months of pain = 34.01 (SD 37.54)
Interventions	"Cognitive behavior therapy" "Intensive medical care"
Outcomes	Primary pain outcome: Abdominal Pain Index (child report) Primary disability outcome: Functional Disability Inventory (child report) Primary depression outcome: Revised Child Anxiety and Depression Scale ‐ Short Version (child report) Primary anxiety outcome: Revised Child Anxiety and Depression Scale ‐ Short Version (child report) 1. Abdominal pain index (completed by child and parent) 2. Functional disability inventory (completed by child and parent) 3. Revised Child Anxiety and Depression Scale ‐ Short Version (completed by child and parent) 4. KIDSCREEN (quality of life) (completed by child and parent) 5. Satisfaction with treatment and therapist/doctor (completed by child and parent) 6. Pain diary (child report) 7. Health care use (follow‐up only)
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"The first author randomized the children using a computerized randomization program" Comment: probably done, method not described
Allocation concealment (selection bias)	Unclear risk	No description found in text Comment: probably not done
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	"Diary data were entered in SPSS by students who were blinded to treatment." Comment: probably not done but no description given for other measures
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Attrition is described, however significant differences between completers and non‐completers were not described
Selective reporting (reporting bias)	Unclear risk	Data fully reported when requested