Dichotomizing a Continuous Baseline Covariate in Randomized Clinical Trials with Binary Outcomes

Abstract

After a randomized clinical trial is conducted, it is often desired to dichotomize a continuous baseline covariate such that a subgroup of patients who may benefit more from the experimental treatment can be identified. We herein propose an approach to dichotomizing a continuous baseline covariate in randomized clinical trials by generalizing an existing likelihood-based approach for one-sample observational studies. Numerical results show that the proposed approach can accurately detect the cutpoint and is less likely to produce estimates that are markedly different from the true cutpoint value compared with the widely adopted minimum p-value approach.

Keywords:

• Baseline covariate
• Binary outcome
• Dichotomization
• Likelihood
• Randomized clinical trial

Mathematics Subject Classification:

• 62N02
• 62P10

Acknowledgment

The authors thank the anonymous reviewers and the Associate Editor for their insightful comments and suggestions, which have led to an improved article.

Notes

^*The authors contributed equally to this work.