Efficient semiparametric estimation of short-term and long-term hazard ratios with right-censored data.

TitleEfficient semiparametric estimation of short-term and long-term hazard ratios with right-censored data.
Publication TypeJournal Article
Year of Publication2013
AuthorsDiao, Guoqing, Donglin Zeng, and Song Yang
JournalBiometrics
Volume69
Issue4
Pagination840-9
Date Published2013 Dec
ISSN1541-0420
KeywordsAlcoholism, Bias, Data Interpretation, Statistical, Humans, Incidence, Longitudinal Studies, Models, Statistical, Outcome Assessment, Health Care, Proportional Hazards Models, Reproducibility of Results, Risk Assessment, Sensitivity and Specificity, Stomach Neoplasms, Survival Analysis
Abstract

The proportional hazards assumption in the commonly used Cox model for censored failure time data is often violated in scientific studies. Yang and Prentice (2005) proposed a novel semiparametric two-sample model that includes the proportional hazards model and the proportional odds model as sub-models, and accommodates crossing survival curves. The model leaves the baseline hazard unspecified and the two model parameters can be interpreted as the short-term and long-term hazard ratios. Inference procedures were developed based on a pseudo score approach. Although extension to accommodate covariates was mentioned, no formal procedures have been provided or proved. Furthermore, the pseudo score approach may not be asymptotically efficient. We study the extension of the short-term and long-term hazard ratio model of Yang and Prentice (2005) to accommodate potentially time-dependent covariates. We develop efficient likelihood-based estimation and inference procedures. The nonparametric maximum likelihood estimators are shown to be consistent, asymptotically normal, and asymptotically efficient. Extensive simulation studies demonstrate that the proposed methods perform well in practical settings. The proposed method successfully captured the phenomenon of crossing hazards in a cancer clinical trial and identified a genetic marker with significant long-term effect missed by using the proportional hazards model on age-at-onset of alcoholism in a genetic study.

DOI10.1111/biom.12097
Alternate JournalBiometrics
Original PublicationEfficient semiparametric estimation of short-term and long-term hazard ratios with right-censored data.
PubMed ID24328712
PubMed Central IDPMC3868993
Grant ListR01 CA082659 / CA / NCI NIH HHS / United States
R37 GM047845 / GM / NIGMS NIH HHS / United States
R01 GM031575 / GM / NIGMS NIH HHS / United States
R15CA150698 / CA / NCI NIH HHS / United States
R15 CA150698 / CA / NCI NIH HHS / United States
GM31575 / GM / NIGMS NIH HHS / United States
P01 CA142538 / CA / NCI NIH HHS / United States