Results 1 to 10 of about 10,758,008 (293)

Methods for non-proportional hazards in clinical trials: A systematic review [PDF]

Statistical Methods in Medical Research
For the analysis of time-to-event data, frequently used methods such as the log-rank test or the Cox proportional hazards model are based on the proportional hazards assumption, which is often debatable. Although a wide range of parametric and non-parametric methods for non-proportional hazards has been proposed, there is no consensus on the best ...
Tim Friede, Tobias Fellinger, Andrew C. Hooker   +2 more
exaly   +9 more sources

Survival analysis: coping with non proportional hazards in randomized trials [PDF]

Trials, 2011
Almost all trials with a censored time-to-event outcome are designed, powered and analysed with a target hazard ratio for comparing experimental and control treatments in mind. Differences in survival experience between trial arms are tested with a logrank test and usually illustrated using a Kaplan-Meier plot.
Royston Patrick, Parmar Mahesh KB
doaj   +4 more sources

Comparison of statistical methods for the analysis of recurrent adverse events in the presence of non-proportional hazards and unobserved heterogeneity: a simulation study [PDF]

BMC Medical Research Methodology, 2022
Background In preventive drug trials such as intermittent preventive treatment for malaria prevention during pregnancy (IPTp), where there is repeated treatment administration, recurrence of adverse events (AEs) is expected.
Noel Patson, Mavuto Mukaka, Lawrence Kazembe, Marinus J. C. Eijkemans, Don Mathanga, Miriam K. Laufer, Tobias Chirwa   +6 more
doaj   +2 more sources

Interval-Censored Regression with Non-Proportional Hazards with Applications

Stats, 2023
Proportional hazards models and, in some situations, accelerated failure time models, are not suitable for analyzing data when the failure ratio between two individuals is not constant. We present a Weibull accelerated failure time model with covariables
Fábio Prataviera, Elizabeth M. Hashimoto, Edwin M. M. Ortega, Taciana V. Savian, Gauss M. Cordeiro   +4 more
doaj   +2 more sources

Augmenting the logrank test in the design of clinical trials in which non-proportional hazards of the treatment effect may be anticipated [PDF]

BMC Medical Research Methodology, 2016
Background Most randomized controlled trials with a time-to-event outcome are designed assuming proportional hazards (PH) of the treatment effect. The sample size calculation is based on a logrank test.
Patrick Royston, Mahesh K.B. Parmar
doaj   +2 more sources

Group sequential design for time-to-event outcome with non-proportional hazards using the concept of relative time utilizing two different Weibull distributions [PDF]

Contemporary Clinical Trials Communications
A group sequential design allows investigators to sequentially monitor efficacy and safety as part of interim testing in phase III trials. Literature is well developed in the case of continuous and binary outcomes, however, in case of trials with a time ...
Milind A. Phadnis, Nadeesha Thewarapperuma, Matthew S. Mayo   +2 more
doaj   +2 more sources

Comparison between asymptotic and re-randomisation tests under non-proportional hazards in a randomised controlled trial using the minimisation method [PDF]

BMC Medical Research Methodology
Background Pocock-Simon’s minimisation method has been widely used to balance treatment assignments across prognostic factors in randomised controlled trials (RCTs).
Ryusei Kimura, Shogo Nomura, Kengo Nagashima, Yasunori Sato   +3 more
doaj   +2 more sources

A Bayesian spline-augmented piecewise exponential model with spatial frailty for under-five mortality in Nigeria [PDF]

Frontiers in Epidemiology
IntroductionThe Cox proportional hazards (PH) model is widely used in time-to-event research, but its validity depends on the PH assumption, which can be violated in child mortality studies where hazards vary with age. Piecewise exponential models (PEMs)
Peter Enesi Omaku, Joseph Odunayo Braimah, Fabio Mathias Correa   +2 more
doaj   +2 more sources

Violations of proportional hazard assumption in Cox regression model of transcriptomic data in TCGA pan-cancer cohorts

Computational and Structural Biotechnology Journal, 2022
Background: Cox proportional hazard regression (CPH) model relies on the proportional hazard (PH) assumption: the hazard of variables is independent of time. CPH has been widely used to identify prognostic markers of the transcriptome.
Zihang Zeng, Yanping Gao, Jiali Li, Gong Zhang, Shaoxing Sun, Qiuji Wu, Yan Gong, Conghua Xie   +7 more
doaj   +1 more source

Simulating time-to-event data under the Cox proportional hazards model: assessing the performance of the non-parametric Flexible Hazards Method

Frontiers in Applied Mathematics and Statistics, 2023
Numerous methods and approaches have been developed for generating time-to-event data from the Cox Proportional Hazards (CPH) model; however, they often require specification of a parametric distribution for the baseline hazard even though the CPH model ...
Jennifer L. Delzeit, Devin C. Koestler
doaj   +1 more source