Problems in conducting economic evaluations alongside clinical trials

Abstract

Retrospective power calculations indicated that the trial could have detected differences of 30% in total cost, but would have required 700 patients per arm to detect a 20% difference in health care costs. Hence this study, which had adequate power to detect clinically meaningful differences, was found to be far too small to detect large differences in costs. Funding agencies increasingly request that clinical trials include economic alongside clinical end-points: these findings may have important lessons for that policy.