Chappell 2008.

Methods	Six‐month, randomised, double‐blind, placebo‐controlled, clinical trial of duloxetine in fibromyalgia
Participants	Male and female outpatients were eligible for the study if they were ≥ 18 years of age, met criteria for fibromyalgia as defined by the American College of Rheumatology, with or without major depressive disorder No criteria for pain level at entry
Interventions	Duloxetine ‐ variable dose. Started at 60 mg (30 mg run in period over 1 week), randomised increase to 120 mg after 13 weeks if not > 50% reduction in pain on BPI average
Outcomes	BPI‐I at > 12 weeks. No data given for less than 12 weeks although "statistically significant" P values quoted without figures at weeks 1, 2, 4, 6 and 8 BUT NOT 13, then week 18 Short Form Health Survey (SF‐36) Patient Global Impression of Improvement Fibromyalgia Impact Questionnaire (FIQ) Clinical Global Impression ‐ Severity scale (CGI‐S) Multidimensional fatigue inventory Hospital Anxiety and Depression Scale (HADS) Hamilton Depression Rating Scale (HAMD) Beck Depression Inventory –II Sheehan Disability Scale EQ‐5D
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated random sequence within each study centre stratified by major depressive disorder
Allocation concealment (selection bias)	Low risk	Double‐blind
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Participants "blinded", but not clear how the study managed dose escalations and decreases and whether blinding was maintained
Incomplete outcome data (attrition bias) All outcomes	High risk	37.6% to 38.6% discontinuations, significantly different in lack of efficacy only. Investigators used LOCF and MMRM to correct for dropouts
Selective reporting (reporting bias)	Low risk	30% improvement in BPI‐average added post hoc
Other bias	Unclear risk	Lilly sponsored trial Significant unexplained treatment by investigator interaction