Early detection of subjects at high risk of developing dementia is essential. By dealing with censoring and competing risk of death, we developed a score for predicting 10-year dementia risk by combining cognitive tests, and we assessedwhether inclusion of cognitive change over the previous year increased its discrimination. Data came from the French prospective cohort study Personnes AgéesQUID...

When testing the null hypothesis that treatment arm-specific survival-time distributions are equal, the log-rank test is asymptotically valid when the distribution of time to censoring is conditionally independent of randomized treatment group given survival time. We introduce a test of the null hypothesis for use when the distribution of time to censoring depends on treatment group and surviva...

Background When trials are subject to departures from randomised treatment, simple statistical methods that aim to estimate treatment efficacy, such as per protocol or as treated analyses, typically introduce selection bias. More appropriate methods to adjust for departure from randomised treatment are rarely employed, primarily due to their complexity and unfamiliarity. We demonstrate the use ...

The accumulation of medical cost over time for each subject is an increasing stochastic process defined up to the instant of death. The stochastic structure of this process is complex. In most applications, the process can only be observed at a limited number of time points. Furthermore, the process is subject to right censoring so that it is unobservable after the censoring time. These special...

This paper investigates the sensitivity of maximum quasi likelihood estimators of the covariate eeects in duration models in the presence of misspeciication due to neglected heterogeneity or misspeciication of the hazard function. We consider linear models for r (T) where T is duration and r is a known, strictly increasing function. This class of models is also referred to as location-scale mod...

Most multiple imputation (MI) methods for censored survival data either ignore patient characteristics when imputing a likely event time, or place quite restrictive modeling assumptions on the survival distributions used for imputation. In this research, we propose a robust MI approach that directly imputes restricted lifetimes over the study period based on a model of the mean restricted life ...

Changes in analytical procedures, and detection limits with sub-detection limit data censoring, can have profound effects on trend analysis and add tedium and uncertainty to the process. Less accurate methods early in the record may produce not only high-biased data but also greater variance. The consequence of this is an artificial induction of a down-trend. In datasets with multiple procedure...

We develop an approach, based on multiple imputation, that estimates the marginal survival distribution in survival analysis using auxiliary variables to recover information for censored observations. To conduct the imputation, we use two working survival models to define a nearest neighbour imputing risk set. One model is for the event times and the other for the censoring times. Based on the ...

The proportional hazards model is commonly used in observational studies to estimate and test a pre-defined measure of association between a variable of interest and the time to some event T . For example, it has been used to investigate the effect of vascular access type in patency among end-stage renal disease patients (Gibson, Gillen, Caps, Kohler, Sherrard & Stehman-Breen 2001). The measure...