Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Medicine and Health Sciences
Additive Hazards Models With Latent Treatment Effectiveness Lag Time, Ying Qing Chen, Charles A. Rohde, Mei-Cheng Wang
Additive Hazards Models With Latent Treatment Effectiveness Lag Time, Ying Qing Chen, Charles A. Rohde, Mei-Cheng Wang
Johns Hopkins University, Dept. of Biostatistics Working Papers
In many clinical trials to evaluate treatment efficacy, it is believed that there may exist latent treatment effectiveness lag times after which medical procedure or chemical compound would be in full effect. In this article, semiparametric regression models are proposed and studied to estimate the treatment effect accounting for such latent lag times. The new models take advantage of the invariance property of the additive hazards model in marginalizing over random effects, so parameters in the models are easy to be estimated and interpreted, while the flexibility without specifying baseline hazard function is kept. Monte Carlo simulation studies demonstrate the …
Estimation And Projection Of Indicence And Prevalence Based On Doubly Truncated Data With Application To Pharmacoepidemiological Databases, Henrik Stovring, Mei-Cheng Wang
Estimation And Projection Of Indicence And Prevalence Based On Doubly Truncated Data With Application To Pharmacoepidemiological Databases, Henrik Stovring, Mei-Cheng Wang
Johns Hopkins University, Dept. of Biostatistics Working Papers
Incidences of disease are of primary interest in any epidemiological analysis of disease spread in general populations. Ordinary estimates obtained from follow-up of an initially non-diseased cohort are costly, and so such estimates are not routinely available. In contrast, routine registers exist for many diseases with data on all detected cases within a given calendar time period, but lacking information on non-diseased. In the present work we show how this type of data supplemented with data on the past birth process can be analyzed to yield age specific incidence estimates as well as lifetime prevalence. A non-parametric model is studied …