Sindrup 2003.
Methods | Double‐blind, placebo‐controlled cross‐over design with 3 x 4‐week periods and 1‐week washout | |
Participants | 40 participants with painful polyneuropathy of at least 6 months' duration. Mean age 56 years (range 31‐69 years). 23 men and 9 women were included in the data analysis. Participants were recruited in 2 Danish hospitals | |
Interventions | Venlafaxine 75 mg/day in week 1, 150 mg/day in week 2, 225 mg/day in weeks 3 and 4, imipramine 50 mg/day in week 1, 100 mg/day in week 2, 150 mg/day in weeks 3 and 4 vs. placebo for 5 weeks | |
Outcomes | Participant‐reported daily rating of 4 aspects of pain were summed (pain paroxysms, constant pain, touch, and pressure‐evoked pain ‐ all on 11‐point VAS). Patient's global impression of pain relief (complete, good, moderate, slight, none). Adverse effects and use of escape medication Complete/good pain relief: 9/29 imipramine; 2/29 placebo; 7/30 venlafaxine. Complete/good/moderate pain relief: 14/29 imipramine; 2/29 placebo; 8/30 venlafaxine. Authors report NNTB of 5.2 for at least moderate pain relief with venlafaxine, but did not provide raw data or confidence intervals. Use of escape medication (paracetamol) not significantly different |
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Notes | 1‐week baseline observations. People with diabetes (15 participants) more likely to gain clinically relevant pain relief than people without diabetes (17 participants). 33/40 participants completed all 3 arms of study. 7 withdrew due to adverse effects (1 imipramine; 2 placebo; 4 venlafaxine). 1 lost to follow‐up | |
Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Random sequence generation (selection bias) | Low risk | Authors stated that 'assignment to one of six possible treatment sequences was random via a computer‐generated randomization code' and that this 'randomization plan was generated by one author who was not involved in the conduct of the trial' |
Allocation concealment (selection bias) | Low risk | Participants were numbered consecutively. Sealed envelopes were employed |
Blinding of participants and personnel (performance bias) All outcomes | Low risk | 'Double dummy technique was employed as venlafaxine, and its corresponding placebo capsules had a different appearance than imipramine and its corresponding placebo tablets' |
Blinding of outcome assessment (detection bias) All outcomes | Low risk | The randomisation plan was generated by an author who was not involved in the conduct of the trial and double‐blinding was maintained throughout |
Incomplete outcome data (attrition bias) All outcomes | Unclear risk | > 10% of participants did not complete the trial. Last observation carried forward analysis was employed |
Size | High risk | < 50 participants per treatment arm |