Understanding Noninferiority Trials: What Stroke Specialists Should Know

Noninferiority trials aim to prove that the efficacy, defined in terms of a key clinical outcome, of a new treatment is not meaningfully worse than that of an established active control. Noninferiority trials are important when other aspects of care can be improved, such as convenience, toxicity, costs, and safety (nonefficacy benefits). While the motivation for a noninferiority trial is straightforward, the design, execution, and interpretation of these trials is not a trivial task. Several safeguards that protect superiority trials from incorrect conclusions do not apply or even work in reverse for noninferiority trials. This review aims to provide stroke clinicians and researchers with a general overview of noninferiority trials and a deeper understanding of 10 pitfalls they should consider when designing and interpreting such trials.