Diener 2005.
| Study characteristics | ||
| Methods | Randomised, double‐blind, placebo‐controlled, multicentre, parallel‐group study. Treatment study | |
| Participants | 218 patients aged 18 to 65 years, 170 analysed. Migraine with or without aura according to IHS criteria | |
| Interventions | 6.25 mg CO2‐extract (MIG‐99) or placebo 3 times per day for 16 weeks | |
| Outcomes | Primary: total number of migraine attacks within 28 days during the second and third 28‐day treatment period (mean of P2 and P3) compared with baseline Secondary: further outcomes related to frequency and intensity of migraine. Clinical global impression of efficacy. Vital signs and laboratory parameters. Drop‐outs due to inefficacy. Adverse events |
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| Notes | 45 patients randomised without fulfilling IHS criteria, excluded from analysis. Design and conduct of trial as well as data analysis were supported by a grant from the manufacturers of MIG‐99. 4‐week treatment‐free run‐in phase Oxford score: 5/5 |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Randomisation of 4 in centre‐specific blocks on the basis of a randomisation code using a validated program |
| Allocation concealment (selection bias) | Low risk | Random numbers were allocated in consecutive order on enrolment into study |
| Blinding (performance bias and detection bias) All outcomes | Low risk | "All persons active in the study, including the biometrician, remained blinded until the database was locked" "Study medications were identical in appearance, size, weight, taste and smell." |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | 170 of 218 randomised patients completed the study; 45 had been randomised without fulfilling all IHS criteria. This resulted in 170 patients available for efficacy analysis in the ITT sample. Violators of the inclusion criteria did not differ between groups |
| Selective reporting (reporting bias) | Low risk | Relevant outcome measures included; results reported for pre‐defined outcome measures |
| Other bias | Unclear risk | Unclear risk of bias due to sample size (n = 170 evaluated for efficacy) |