Some Considerations on Design and Analysis Plan on a Nonrandomized Comparative Study Using Propensity Score Methodology for Medical Device Premarket Evaluation

Nonrandomized comparative studies have been widely proposed and conducted in the premarket safety and effectiveness evaluation of medical devices. A typical case is to compare results of a clinical study on an investigational device with those of control, which is formed based on prior studies or some real-world data. Propensity score methodology is often used to mitigate the bias caused by the imbalance of the patient baseline characteristics. To maintain the objectivity of study design and validity of study results, proper procedure of two-stage design needs to be implemented. In this article, considerations of the analysis elements of such studies, such as endpoint analysis, missing data handling, and subgroup analysis, are discussed. An example is provided to illustrate these considerations.