Persson, I. 2002. Essays on the Assumption of Proportional Hazards in Cox Regression. Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Social Sciences 110. 36 pp. Uppsala. ISBN 91-554-5208-6. This thesis consists of four papers about the assumption of proportional hazards for the Cox model in survival analysis. The first paper compares the haz...

conclusions by controlling the modifiable risk factors and modality of treatment in our study, physicians can reach more effective treatment. results at the end of the study, long-term graft failure was seen in 27 (10.2%) cases. one-year and 2-year graft survival after diagnosis of cancer were 93.6% and 91.7%, respectively. the univariate analysis showed that the incidence of chronic graft loss...

Survival bias is a potential problem when subjects are lost to follow-up, and this selection issue may arise in a wide range of biomedical studies. Controlling for the bias is difficult because subjects may be lost due to unmeasured factors. This article presents a two-step method that adjusts for survival bias in the proportional hazards model, even when unmeasured factors influence survival. ...

BACKGROUND Randomized Controlled Trials almost invariably utilize the hazard ratio calculated with a Cox proportional hazard model as a treatment efficacy measure. Despite the widespread adoption of HRs, these provide a limited understanding of the treatment effect and may even provide a biased estimate when the assumption of proportional hazards in the Cox model is not verified by the trial da...

The objective of this study was to investigate the impact of social engagement and patterns of change in social engagement over time on mortality in a large population, aged 45 years or older. Data from the Korean Longitudinal Study of Aging from 2006 and 2012 were assessed using longitudinal data analysis. We included 8,234 research subjects at baseline (2006). The primary analysis was based o...

This paper proposes the Additive Risk Model (ARM), first used by Aalen (1980), to explain households’ interpurchase times. Unlike the Proportional Hazard Model (PHM), first proposed by Cox (1972), the ARM incorporates the effects of covariates on the individual hazard function in an additive (as opposed to multiplicative) manner. While a large number of previous studies on interpurchase timing ...

A Simple GMM Estimator for the Semi-Parametric Mixed Proportional Hazard Model Ridder and Woutersen (2003) have shown that under a weak condition on the baseline hazard there exist root-N consistent estimators of the parameters in a semiparametric Mixed Proportional Hazard model with a parametric baseline hazard and unspecified distribution of the unobserved heterogeneity. We extend the Linear ...

The association of hemodialysis dosage with patient survival is controversial. Here, we tested the hypothesis that methods for survival analysis may influence conclusions regarding dialysis dosage and mortality. We analyzed all-cause mortality by proportional hazards and accelerated failure time regression models in a cohort of incident hemodialysis patients who were followed for 9 yr. Both mod...

To ensure the production/output and customer satisfaction in mining sector the estimation of Remaining Useful Life of mining machineries is a prime. In this paper we used the reliability analysis in order to estimate an optimal mining equipment repair/replacement policy by estimating their remaining useful life. The proportional hazard model was used in reliability analysis to be realistic and ...

This paper proposes a discrete-time hazard regression approach based on the relation between hazard rate models and excess over threshold models, which are frequently encountered in extreme value modelling. The proposed duration model employs a exible link function and incorporates the grouped-duration analogue of the wellknown Cox proportional hazards model and the proportional odds model as s...