نتایج جستجو برای: cox hazard function

تعداد نتایج: 1301063  

2003
Juanjuan Fan

Recently Fan and colleagues have proposed two measures of the strength of dependency between failure time variates over a finite region of the sample space; namely, an average relative risk measure and a finite region version of Kendall’s tau. Here, these dependency measures are generalized to accommodate regression effects on marginal hazard functions. Specifically, the dependency measures pre...

Journal: :journal of paramedical sciences 0
nezhat shakeri department of biostatistics, faculty of paramedical sciences, shahid beheshti university of medical sciences fatemeh eskandari prevention of metabolic diseases research center, research institute of endocrine sciences, shahid beheshti university of medical sciences farhad hajsheikholeslami prevention of metabolic diseases research center, research institute of endocrine sciences, shahid beheshti university of medical sciences arash ghanbarian prevention of metabolic diseases research center, research institute of endocrine sciences, shahid beheshti university of medical sciences fereidoun azizi research center of endocrine sciences, research institute of endocrine sciences, shahid beheshti university of medical sciences

abstract         in the increasing population of the elderly in iran, so far no prospective health studies have been undertaken.   this study was conducted to identify the risk factors of survival time of the elderly of ages above 60 years. material and methods: individuals above 60 years old were recruited in the primary phase of the tehran lipid and glucose study (tlgs) during 1998-2001. they...

Journal: :medical journal of islamic republic of iran 0
javad nasseryan department of biostatistics, faculty of medical sciences, tarbiat modares university, tehran, iran. ebrahim hajizadeh department of biostatistics, faculty of medical sciences, tarbiat modares university, tehran, iran. aliakbar rasekhi department of biostatistics, faculty of medical sciences, tarbiat modares university, tehran, iran. hassan ahangar department of heart, faculty of medical sciences, zanjan university of medical sciences, zanjan, iran.

background: the incidence of restenosis in patients suffering from coronary artery disease after undergoing angioplasty is of paramount importance. accordingly, this study aimed to investigate factors affecting the time of the first incidence of restenosis in patients undergone angioplasty in the city of zanjan, iran.   methods: this retrospective cohort study was conducted on 421 patients who ...

Journal: :veterinary research forum 2012
maryam ansari-lari mehdi mohebbi-fani abbas rowshan-ghasrodashti

this study was designed to investigate causes of culling in industrial dairy herds in fars province and to describe the pattern of reason-specific culling with respect to age of animal and interval from calving to culling. a total number of 9 dairy herds were selected for the study and information about culling reasons, birth date, last calving date and culling date was collected for culled cow...

Journal: :Communications in Statistics - Simulation and Computation 2021

The natural direct and indirect effects in causal mediation analysis with survival data having one mediator is addressed by VanderWeele. He derived an approach for (1) accelerated failure time regression model general cases (2) a proportional hazards when the time-to-event outcome rare. If not rare, then VanderWeele did derive simple closed-form expression log-natural because baseline cumulativ...

Journal: :Asian Pacific journal of cancer prevention : APJCP 2011
Alireza Abadi Saeed Saadat Parvin Yavari Chris Bajdik Parvin Jalili

BACKGROUND Regression models for survival data have traditionally been based on the Cox regression model. However, its validity relies heavily on assumption of proportional hazards. Another restriction of the Cox model is insufficiency in dealing with time-varying covariate effects, since the regression coefficients are assumed constant. These weaknesses have generated interest in alternative a...

اسکندری, فاطمه, حاج شیخ الاسلامی, فرهاد, شاکری, نزهت, عزیزی, فریدون, مومنان, امیر عباس,

Background & Objectives: Although the population of elderly is increasing in Iran, few studies carried out on this group. The aim of this study was to identify life expectancy and contributory risk factors for the Tehranian elderly of ages above 60 years. Methods: Individuals above 60 years old whom were recruited in the primary phase of the Tehran Lipid and Glucose Study (TLGS) during 1998-20...

Journal: :Lifetime data analysis 2000
D V Glidden

This paper describes the properties of a two-stage estimator of the dependence parameter in the Clayton-Oakes multivariate failure time model. The parameter is estimated from a likelihood function in which the marginal hazard functions are replaced by estimates. The method extends the approach of Shih and Louis (1995) and Genest, Ghoudi and Rivest (1995) to allow the marginal hazard for failure...

اعتمادی نژاد, سیاوش , روشنی, دائم, محمدپور تهمتن, رضاعلی, مرادی, مسعود, یزدانی چراتی, جمشید,

Abstract Background and purpose: Asthma is one of the most common chronic diseases worldwide and its prevalence has increased over the past decades in industrialized and developing countries. Cox proportional hazards model is one of the main models used in the analysis of survival data. This study was performed to evaluate the Stratified cox model in identifying the factors influencing readm...

ژورنال: پژوهش های ریاضی 2016
Mohammadzadeh , M, Abyar, A, Motarjem , K,

An important issue in survival data analysis is the identification of risk factors. Some of these factors are identifiable and explainable by presence of some covariates in the Cox proportional hazard model, while the others are unidentifiable or even immeasurable. Spatial correlation of censored survival data is one of these sources that are rarely considered in the literatures. In this paper,...

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