Search results for "Cox model"
showing 4 items of 4 documents
Segmented relationships to model erosion of regression effect in Cox regression
2010
In this article we propose a parsimonious parameterisation to model the so-called erosion of the covariate effect in the Cox model, namely a covariate effect approaching to zero as the follow-up time increases. The proposed parameterisation is based on the segmented relationship where proper constraints are set to accomodate for the erosion. Relevant hypothesis testing is discussed. The approach is illustrated on two historical datasets in the survival analysis literature, and some simulation studies are presented to show how the proposed framework leads to a test for a global effect with good power as compared with alternative procedures. Finally, possible generalisations are also present…
Flexible Bayesian survival models with application in biometric studies
2018
El análisis de supervivencia es una metodología estadística diseñada para analizar datos procedentes de estudios científicos relativos a tiempos de ocurrencia de uno o varios eventos de interés. La duración de estos tiempos suele conocerse como tiempos de supervivencia debido a los particulares orígenes de esta metodología en contextos exclusivamente médicos y demográficos. Durante las últimas décadas, la literatura científica en este campo ha sido muy prolífica y su aplicación se ha extendido a múltiples áreas de conocimiento. Los procedimientos estadísticos propios de esta metodología empezaron a abordarse desde el marco inferencial frecuentista. Sin embargo, en los últimos años la utiliz…
Robust estimation and regression with parametric quantile functions
2022
A new, broad family of quantile-based estimators is described, and theoretical and empirical evidence is provided for their robustness to outliers in the response. The proposed method can be used to estimate all types of parameters, including location, scale, rate and shape parameters, extremes, regression coefficients and hazard ratios, and can be extended to censored and truncated data. The described estimator can be utilized to construct robust versions of common parametric and semiparametric methods, such as linear (Normal) regression, generalized linear models, and proportional hazards models. A variety of significant results and applications is presented to show the flexibility of the…
Dimethyl fumarate vs Teriflunomide: an Italian time-to-event data analysis
2020
The introduction of oral disease-modifying therapies (DMTs) for relapsing-remitting multiple sclerosis (RRMS) changed the therapeutic landscape and algorithms of RRMS treatment (1). In Europe, dimethyl fumarate (DMF) and teriflunomide (TRF) are approved as first-line agents and are often used as the initial therapeutic choice (2, 3). Pivotal trials showed the efficacy of both DMTs on controlling clinical relapses, disability accrual and magnetic resonance imaging (MRI) activity (4-8). Both DMTs had overall good tolerability. There have been no head-to-head randomized trials to compare these two DMTs; however, several real-world evidence (RWE) studies have compared DMF and TRF and provided u…