Powell 2001

Methods	RCT, 4 parallel arms
Participants	Diagnostic criteria: Oxford Number of participants: N = 148 Gender: 116 (78%) female Age, mean: 33 years Earlier treatment: NS Co‐morbidity: 58 (39%) possible cases of depression (HADS), 27 (18%) used antidepressants Illness duration: 4.3 years Work and employment status: 50 (34%) working, 64 (43%) on disability Setting: secondary/tertiary care Country: UK
Interventions	Group 1: treatment as usual (n = 34) Group 2: exercise therapy + 2 sessions (total 3 hours, n = 37) Group 3: exercise therapy + 7 telephone sessions (total 3.5 hours, n = 39) Group 4: exercise therapy + 7 sessions (total 7 hours, n = 38) Sessions, whether telephone or face‐to‐face, were used to reiterate the treatment rationale and to discuss problems associated with graded exercise
Outcomes	Physical functioning (SF‐36, subscale physical functioning). Clinical improvement at 1 year predetermined as a score ≥ 25 or an increase from baseline of ≥ 10 on the physical functioning scale (score range, 10 to 30) Fatigue (Fatigue Scale, FS; 11 items; scores > 3 indicate excessive fatigue) Anxiety and depression (Hospital Anxiety and Depression Scale, HADS; score range from 0 to 21 worst) Sleep (Jenkins Sleep Scale, 4 items; lower scores indicate better outcomes; score range 0 to 20 worst) Changes in overall health (Global Impression Scale; score between 1 and 7, where 1 = very much better, 4 = no change) Illness beliefs and experience of treatment (simple questionnaire) Outcomes assessed at 3 (end treatment), 6 and 12 months
Notes	Treatment as usual comprised a medical assessment, advice and an information booklet that encouraged graded activity and positive thinking but gave no explanations for symptoms. SF‐36 physical functioning subscale is reported on a 10 to 30 scale. We transformed scores from the 10 to 30 scale to the more common 0 to 100 scale by using the following formula: meannew = (meanold ‐ 10) * 5 and SDnew = 5 * SDold
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomised into four groups by means of a sequence of computer generated random numbers...simple randomisation with stratification for scores on the hospital anxiety and depression scale, 15, using a cut off of 11 to indicate clinical depression"
Allocation concealment (selection bias)	Unclear risk	Quote: "...in sealed numbered envelopes"
Blinding (performance bias and detection bias) of participants and personnel?	High risk	Not possible for this intervention
Blinding (performance bias and detection bias) of outcome assessors?	High risk	Blinding not possible for self‐reported measurements (e.g. FS, SF‐36)
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "We used an intention to treat analysis. For patients who dropped out of treatment, the last values obtained were carried forward. Complete data were obtained for all patients who completed treatment except for three: two did not complete the questionnaire at three months and one did not complete the questionnaire at one year"
Selective reporting (reporting bias)	Unclear risk	All primary outcomes stated under Methods were reported; however, as the trial protocol is not available, we cannot categorically state that the review is free of selective outcome reporting
Other bias	Low risk	We do not suspect other bias