Intended for healthcare professionals

Endgames Statistical Question

Meta-analyses I

BMJ 2011; 342 doi: (Published 11 January 2011) Cite this as: BMJ 2011;342:d45
  1. Philip Sedgwick, senior lecturer in medical statistics
  1. 1Section of Medical and Healthcare Education, St George’s, University of London, Tooting, London, UK
  1. p.sedgwick{at}

Researchers undertook a meta-analysis of the effectiveness of parenteral corticosteroids for relief of acute severe migraine headache in adults.1 Seven randomised controlled trials were identified in which single dose parenteral dexamethasone, administered alone or in combination with standard abortive therapy, was compared with placebo or any other standard treatment for acute migraine in adults. For each trial, the relative risk for recurrence of headache within 72 hours for the dexamethasone treatment arm compared with the placebo arm was obtained.

The results of the meta-analyses are presented in the figure. When combined with standard abortive therapy, single dose parental dexamethasone was more effective than placebo in reducing recurrence of headache within 72 hours (relative risk 0.74, 95% confidence interval 0.60 to 0.90).

Forest plot of the effectiveness of dexamethasone compared with placebo in preventing the recurrence of acute severe migraine headache in adults

Which of the following …

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