Parenteral dexamethasone for acute severe migraine headache: meta-analysis of randomised controlled trials for preventing recurrence
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”.