Endpoint selection for noninferiority percutaneous coronary intervention trials: a methodological description.

BACKGROUND: The objective of this review is to provide a practical update on endpoint selection for noninferiority (NI) studies in percutaneous coronary intervention studies. METHODS: A PubMed search was conducted for predefined terms to explore the use of NI designs and intrapatient comparisons to determine their current importance. Sample size calculations for the most frequently used endpoints with NI hypotheses were done to increase statistical awareness. RESULTS: Reported NI trials, with the most frequently chosen clinical endpoint of major adverse cardiac events (MACE), had NI margins ranging from 1.66% to 5.00%, resulting in patient populations of 400-1500 per treatment group. Clinical study endpoints comprising of MACE complemented with rates of bleeding complications and stent thrombosis (ST) are suggested to conduct a statistically and clinically meaningful NI trial. Study designs with surrogate endpoints amenable to intrapatient randomizations, are a very attractive option to reduce the number of necessary patients by about half. Comparative clinical endpoint studies with MACE and ST/bleeding rates to study a shortened dual antiplatelet therapy (DAPT) in coronary stent trials are feasible, whereas ST as the sole primary endpoint is not useful. CONCLUSIONS: Expanded composite clinical endpoints (MACE complemented by ST and bleeding rates and intrapatient randomization for selected surrogate endpoints) may be suitable tools to meet future needs in device approval, recertification and reimbursement.