Methods We analyse survival data reconstructed from two trials publications which reported extreme non-proportional hazards (with respective p-values as 9.19E-13 and 1.344E-24 in non-PH Grambsch-Thernau test). We use the Cox proportional hazards model, flexible parametric model and accelerated failure time model to estimate the time-independent hazard ratio, between-arm difference in restricted...

The Cox proportional hazards regression model has been widely used in the analysis of survival/duration data. It is semiparametric because the model includes a baseline hazard function that is completely unspecified. We study here the statistical inference of the Cox model where some information about the baseline hazard function is available, but it still remains as an infinite dimensional nui...

Up-to-date information about CPR's research projects and other activities is available from our World Wide Web site at www-cpr.maxwell.syr.edu. All recent working papers and Policy Briefs can be read and/or printed from there as well. ABSTRACT In survival analysis, Cox's name is associated with the partial likelihood technique that allows consistent estimation of proportional hazard scale param...

The analysis of event sequence data that contains system failures is becoming increasingly important in the design of service and maintenance policies. This paper presents a systematic methodology to construct a statistical prediction model for failure event based on event sequence data. First, frequent failure signatures, defined as a group of events/errors that repeatedly occur together, are ...

We propose a general framework which can be used for modeling and predicting the popularity of online contents. The aim of our modeling is not inferring the precise popularity value of a content, but inferring the likelihood with which the content will be popular. Our approach is rooted in survival analysis which deals with the survival time until an event of a failure or death. Survival analys...

We introduce the R package CPHshape, which computes the effect parameters and the nonparametric maximum likelihood estimator of a shape constrained baseline hazard in the Cox proportional hazards model. The functionality of the package is illustrated using reproducible examples which are based on simulated data.

Patients with dementia are at increased risk of stroke. Acetylcholinesterase inhibitors (AChEIs) have endothelial function protection effects and anti-inflammatory properties. We investigated the ischemic stroke risk in AChEIs use in dementia patients without stroke history. Using Taiwan National Health Insurance Database from 1999 to 2008, 37,352 dementia patients over 50 years old without str...

BACKGROUND Cox proportional hazard (CPH) model is the most widely used model for survival analysis. When there are unobserved/unmeasured individuals factor, then the results of the Cox proportional hazard model may not be reliable. The purpose of this study was to compare the results of CPH and frailty models in breast cancer (BC) patients. METHODS A historical cohort study was carried out us...