title: Relaxing the independent censoring assumption in the Cox proportional hazards model using multiple imputation.
abstract: The Cox proportional hazards model is frequently used in medical statistics. The standard methods for fitting this model rely on the assumption of independent censoring. Although this is sometimes plausible, we often wish to explore how robust our inferences are as this untestable assumption is relaxed. We describe how this can be carried out in a way that makes the assumptions accessible to all those involved in a research project. Estimation proceeds via multiple imputation, where censored failure times are imputed under user-specified departures from independent censoring. A novel aspect of our method is the use of bootstrapping to generate proper imputations from the Cox model. We illustrate our approach using data from an HIV-prevention trial and discuss how it can be readily adapted and applied in other settings.
authors: MRC Biostatistics Unit, Institute of Public Health, Forvie Site, Robinson Way, Cambridge, CB2 0SR, U.K.
authors: Dan
authors: D
authors: Jackson
authors: Ian R
authors: IR
authors: White
authors: Shaun
authors: S
authors: Seaman
authors: Hannah
authors: H
authors: Evans
authors: Kathy
authors: K
authors: Baisley
authors: James
authors: J
authors: Carpenter
mesh_terms: D000212:Acyclovir; D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents; D015982:Bias; D001699:Biometry / Q000379:methods; D003198:Computer Simulation; D005260:Female; D015658:HIV Infections / Q000517:prevention & control; D006558:Herpes Genitalis / Q000188:drug therapy; D018258:Herpesvirus 2, Human; D006801:Humans; D009010:Monte Carlo Method; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D012044:Regression Analysis; D013636:Tanzania; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D000212:Acyclovir
keywords: Schoenfeld residuals; bootstrapping; informative censoring; multiple imputation; sensitivity analysis; survival analysis