Results 21 to 30 of about 10,758,008 (293)
Testing proportional hazards for specified covariates
Modern Stochastics: Theory and Applications, 2019 Tests for proportional hazards assumption concerning specified covariates or groups of covariates are proposed. The class of alternatives is wide: log-hazard rates under different values of covariates may cross, approach, go away.
Vilijandas Bagdonavičius +1 more
doaj +1 more source
Partial Orders with Respect to Continuous Covariates and Tests for the Proportional Hazards Model [PDF]
, 2008 Several omnibus tests of the proportional hazards assumption have been proposed in the literature. In the two-sample case, tests have also been developed against ordered alternatives like monotone hazard ratio and monotone ratio of cumulative hazards ...
Bhattacharjee, Arnab +1 more
core +1 more source
BMC Medical Research Methodology, 2019 Background Most clinical trials with time-to-event primary outcomes are designed assuming constant event rates and proportional hazards over time. Non-constant event rates and non-proportional hazards are seen increasingly frequently in trials.
Kim Jachno +2 more
doaj +1 more source
Estimating average regression effect under non-proportional hazards [PDF]
Biostatistics, 2000 We present an estimator of average regression effect under a non-proportional hazards model, where the regression effect of the covariates on the log hazard ratio changes with time. In the absence of censoring, the new estimate coincides with the usual partial likelihood estimate, both estimates being consistent for a parameter having an interpretation
Xu, Ronghui, O'Quigley, John
openaire +3 more sources
Weighted Cox Regression Using the R Package coxphw
Journal of Statistical Software, 2018 Cox's regression model for the analysis of survival data relies on the proportional hazards assumption. However, this assumption is often violated in practice and as a consequence the average relative risk may be under- or overestimated.
Daniela Dunkler +3 more
doaj +1 more source
Treating non-responders: pitfalls and implications for cancer immunotherapy trial design
Journal of Hematology & Oncology, 2020 Background Conventional trial design and analysis strategies fail to address the typical challenge of immune-oncology (IO) studies: only a limited percentage of treated patients respond to the experimental treatment.
Zhenzhen Xu +3 more
doaj +1 more source
Analysis of time to event outcomes in randomized controlled trials by generalized additive models. [PDF]
PLoS ONE, 2015 BACKGROUND:Randomized Controlled Trials almost invariably utilize the hazard ratio calculated with a Cox proportional hazard model as a treatment efficacy measure.
Christos Argyropoulos, Mark L Unruh
doaj +1 more source
An exact corrected log-likelihood function for Cox's proportional hazards model under measurement error and some extensions [PDF]
, 2002 This paper studies Cox`s proportional hazards model under covariate measurement error. Nakamura`s (1990) methodology of corrected log-likelihood will be applied to the so called Breslow likelihood, which is, in the absence of measurement error ...
Augustin, Thomas
core +1 more source
Estimation of treatment effects in weighted log-rank tests
Contemporary Clinical Trials Communications, 2017 Non-proportional hazards have been observed in clinical trials. The log-rank test loses power and the standard Cox model generally produces biased estimates under such conditions.
Ray S. Lin, Larry F. León
doaj +1 more source
Which test for crossing survival curves? A user’s guideline
BMC Medical Research Methodology, 2022 Background The exchange of knowledge between statisticians developing new methodology and clinicians, reviewers or authors applying them is fundamental. This is specifically true for clinical trials with time-to-event endpoints.
Ina Dormuth +5 more
doaj +1 more source