Interpretation of subgroup analyses in medical device clinical trials

One purpose of a clinical trial is to evaluate the safely and effectiveness of a medical treatment or device based an a representative sample of people from the targeted population. An additional issue of interest to many researchers, however; is: for what patient group a given treatment is most beneficial or poses an increased risk. Subgroup analyses are usually performed to attempt to answer these questions. The results of subgroup analyses must be interpreted bearing in mind the conditions under which the clinical trial was designed and analyzed and the limitations associated with such analyses. This article discusses interpretation of subgroup analyses in clinical trials with emphasis on special considerations related to medical devices. The questions of interest are: under what conditions should subgroup analyses be performed and how, should the results be interpreted from a regulatory perspective for medical device clinical trials?