USA – FDA Drafts Guidance on Adjusting for Covariates in Randomized Trials

The US Food and Drug Administration (FDA) on Wednesday published draft guidance to provide recommendations on the use of covariates in the primary analysis of randomized clinical trials.

Specifically, the three-page draft offers recommendations for adjusting for covariates in randomized trials “with continuous endpoints that are appropriate for analysis with normal-theory methods, such as the two-sample t-test.”

Building on ICH’s E9 guidance, which deals with the statistical principles for clinical trials, FDA offers a series of recommendations for sponsors and explains how the method of adjusting for covariates is usually referred to as analysis of covariance (ANCOVA).

The agency’s five recommendations include:

  1. “Sponsors can use ANCOVA to adjust for differences between treatment groups in relevant baseline variables to improve the power of significance tests and the precision of estimates of treatment effect…