Reporting and analysis of open-label extension studies of anti-epileptic drugs.

Open-label extension studies, or follow-on randomised controlled trials (FORCTs) are widely believed to be prone to patient selection biases which may inflate effect estimates. This study investigates the reporting and analysis of efficacy outcomes in FORCTs and critically evaluates the associated underlying assumptions. We propose an alternative method of analysis, in line with that recommended in the analysis of RCTs, the intention to treat (ITT) approach, in which it is assumed that all patients who discontinue treatment are non-responders.