Arnold 2005.
| Methods | Randomised, double‐blind, placebo‐controlled, parallel group trial of duloxetine in fibromyalgia | |
| Participants | 354 participants Women only, ≥ 18 years of age who met criteria for primary fibromyalgia as defined by the American College of Rheumatology, and had a score of ≥ 4 on the average pain severity item of the Brief Pain Inventory (BPI) at randomisation |
|
| Interventions | Duloxetine 60 mg daily, duloxetine 60 mg twice daily and placebo for 12 weeks | |
| Outcomes |
|
|
| Notes | Company sponsored and run trial. Fibromyalgia Impact Questionnaire abandoned in favour of BPI | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Random assignment of women who met entry criteria following the screening phase to one of three treatment groups: duloxetine 60 mg daily, duloxetine 60 mg twice daily (forced titration from 60 mg daily for 3 days to 60 mg twice daily), or placebo, with randomisation in a 1:1:1 ratio. Random assignment of the participants to treatment groups occurred within two stratified groups, those with and those without current major depressive disorder |
| Allocation concealment (selection bias) | Unclear risk | Probably low risk of bias as previous trial used an adequate method |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Double‐blind |
| Incomplete outcome data (attrition bias) All outcomes | High risk | High proportion of dropouts: 138 (39%) participants withdrew during the 12‐week therapy phase, 41 (35%) from the duloxetine 60 mg daily group, 45 (39%) from the duloxetine 60 mg twice daily group, and 52 (43%) from the placebo group (P = 0.407). Matched across groups but a high rate of loss "Partial intention to treat analysis". Efficacy analyses include all randomised participants with a baseline and at least one post‐baseline visit with efficacy data, while safety analyses included all randomised participants |
| Selective reporting (reporting bias) | Unclear risk | See incomplete outcome data above |
| Other bias | Low risk | Lilly study. No other bias identified |