A surrogate endpoint is intended to substitute for a clinical endpoint and is expected to predict the effect of the intervention on clinical endpoints based on epidemiologic, diagnostic, and pathophysiologic evidence. A validated surrogate endpoint can reduce sample size and follow-up duration of clinical trials; hence, the evaluation and validation methods of surrogate endpoints have been discussed for more than 30 years around the world. This paper comprehensively introduced the definition evolution, evaluation, and validation methods of surrogate endpoints, and provided references for future research.
