Adjusted Nelson–Aalen Estimates With Retrospective Matching

原文摘要

In certain situations, randomized trials are not possible, but formal comparison of survival in two or more groups is still desirable. Although no substitute for randomization, application of the matched case-control design to survival studies may minimize the potential bias. Comparable estimates for each treatment group can be obtained by matching or stratifying according to prognostic variables, and weighting each individual to make stratum distributions the same over the treatment groups. Here we develop a weighted Nelson–Aalen estimator and a corresponding survival estimator. When data are closely matched, the stratum effects should be considered as random, leading to additional variance components, and standard asymptotic results do not apply. We derive a variance estimator and show that, asymptotically, the estimator converges to a Gaussian process. Simulations show that the asymptotic results are a good approximation in moderate-sized samples. It should be noted that ignoring the heterogeneity will lead to underestimation of the variance. An application is presented in a clinical study where data on patients receiving standard treatments are obtained for comparison with patients receiving a novel treatment, with retrospective matching to obtain comparable estimates.

摘要来源：OpenAlex 索引摘要（稿件版本未注明）