Statistical adjustment of treatment effect for covariates in clinical trials / 中国临床药理学与治疗学

ABSTRACT

Some non treatment variables that affect the outcome of a disease are often called covariates. These covariables should be considered in the design and analysis of clinical trials to obtain unbias conclusion. To ensure that any observed treatment effect is not influenced by an imbalances in baseline characteristics, both preadjustment and postadjustment are provided in the design stage and analysis stage of the trials respectively. They can improve the credibility of the trial results and increase the statistical efficiency. Based on a few papers published about adjustment for covariates and some documentations of the International Conference on Harmonization (ICH), we review the concepts, methods and procedures for adjustment of treatment effects for the influence of covariates. The statistical issues on the application of adjustment are especially discussed in great depth.