Journal Club Summary

Landmark Article Series
Methodology Score: 4.5/5 
Usefulness Score: 4.5/5
Colman I, Friedman BW, Brown MD, Innes GD, Grafstein E, Roberts TE, Rowe BH.
BMJ. 2008 Jun 14;336(7657):1359-61
​In this well performed meta-analysis, a single dose of 10mg IV Dexamethasone administered before discharge demonstrated an important reduction in migraine recurrence rates (RR 0.74, 95% CI 0.6-0.9 P < 0.05) with a NNT of 9. The same treatment demonstrated no statistically significant effect on migraine pain scores. JC attendees noted in other publications that the reduced recurrence effect is best demonstrated when administered at times when pain scores are lowest (before discharge home).  
By: Dr. Shawn Mondoux
(Presented May 2013)

Epi lesson

Subgroup analyses in Meta-analysis
Subgroup analyses can be an important source of hypothesis generation. The key element to determine is whether the subgroup analyses were planned a priori. These analyses have greater validity than post hoc analyses which result from searching for statistically significant trends in the data which could be present due to chance and which some have labeled “data dredging”. 
By: Dr. Lisa Calder