In many observational longitudinal studies, the outcome of interest presents a skewed distribution, is subject to censoring due to detection limit or other reasons, and is observed at irregular times that may follow a outcome-dependent pattern. In this work, we consider quantile regression modeling of such longitudinal data, because quantile regression is generally robust in handling skewed and...

BACKGROUND The clinical features and the prognostic relevance of vitiligo lesions in melanoma patients are still controversial. This prospective observational study was designed to characterise the clinical features of melanoma-associated vitiligo, to analyse the association with other autoimmune manifestations and to ascertain whether the development of vitiligo lesions carries a prognostic re...

OBJECTIVES Many studies of self-rated health show that it is a reliable predictor of mortality even when controlling for health-related variables and status characteristics. According to previous research, one reason for the consistent finding is that self-ratings of health represent judgments of health trajectories. Although self-ratings of health may be dynamic perceptions of health, relative...

OBJECTIVE To evaluate the effects of metformin use on the survival of inoperable non-small cell lung cancer (NSCLC) patients with diabetes using the Taiwanese National Health Insurance Research Database. RESEARCH DESIGN AND METHODS In total, 7,620 patients were eligible in this study, among them, 3,578 patients were metformin users and 4,042 were non-users. Propensity score matching was used ...

In making inference on the relation between failure and exposure histories in the Cox semiparametric model, the maximum partial likelihood estimator (MPLE) of the finite dimensional odds parameter, and the Breslow estimator of the baseline survival function, are known to achieve full efficiency when data is available for all time on all cohort members, even when the covariates are time dependen...