نتایج جستجو برای: cox proportional hazards

تعداد نتایج: 124379  

Journal: :iranian journal of public health 0
omid hamidi jalal poorolajal maryam farhadian leili tapak

background: kidney transplantation is the best alternative treatment for end-stage renal disease. several studies have been devoted to investigate predisposing factors of graft rejection. however, there is inconsistency between the results. the objective of the present study was to utilize an intuitive and robust approach for variable selection, random survival forests (rsf), and to identify im...

Journal: :hepatitis monthly 0
bahareh khosravi department of biostatistics, shiraz university of medical sciences, shiraz, ir iran saeedeh pourahmad department of biostatistics, shiraz university of medical sciences, shiraz, ir iran; colorectal research center, shiraz university of medical sciences, shiraz, ir iran; department of biostatistics, shiraz university of medical sciences, p. o. box: 71345-1874, shiraz, ir iran. tel/fax: +98-7132349330 amin bahreini department of organ transplantation, ahvaz university of medical sciences, ahvaz, ir iran saman nikeghbalian department of organ transplantation, shiraz university of medical sciences, shiraz, ir iran goli mehrdad center of namazee hospital organ transplant, shiraz, ir iran

conclusions the present study detected more accurate results for ann method compared to those of cox ph model to analyze the survival of patients with liver transplantation. furthermore, the order of effective factors in patients’ survival after transplantation was clinically more acceptable. the large dataset with a few missing data was the advantage of this study, the fact which makes the res...

ژورنال: Hormozgan Medical Journal 2012
Hosseini Teshnizi, S, Tazhibi, M, Zare, SH,

Introduction: The most important models used in analysis of survival data is proportional hazards models. Applying this model requires establishment of the relevance proportional hazards assumption, otherwise it world lead to incorrect inference. This study aims to evaluate Cox and Weibull models which are used in identification of effective factors on survival time in acute leukemia. Me...

Journal: :iranian red crescent medical journal 0
hoda noorkojuri department of biostatistics, faculty of medical sciences,tarbiat modares university, tarbiat modares university, tehran, ir iran ebrahim hajizadeh department of biostatistics, faculty of medical sciences,tarbiat modares university, tarbiat modares university, tehran, ir iran; tarbiat modares university, jalal ale ahmad highway, tehran, ir iran, tel: +98-2182883810, fax: +98-2182884555 ahmadreza baghestani 2. department of biostatistics, faculty of paramedical sciences, shahid beheshti university of medical sciences, tehran, ir iran mohamadamin pourhoseingholi department of biostatistics, gastroenterology and liver diseases research center, shahid beheshti university of medical sciences, tehran, ir iran

conclusions the use of smoothing methods helps us to eliminate non-linear effects but it is more appropriate to use cox proportional hazards model in medical data because of its’ ease of interpretation and capability of modeling both continuous and discrete covariates. also, cox proportional hazards model and smoothing methods analysis identified that age at diagnosis and tumor size were indepe...

باغستانی, احمد رضا, حاجی زاده, ابراهیم, نور کجوری, هدی, پورحسینقلی, محمد‌امین ,

Background & Objectives: Cox regression model is one of the statistical methods in survival analysis. The use of smoothing techniques in Cox model makes the more accurate estimates for the parameters. Fractional polynomial is one of these techniques in Cox model. The aim of this study was to assess the effects of prognostic factors on survival of patients with gastric cancer using the fractiona...

Journal: :acta medica iranica 0
ramin ravangard department of health management and economics, school of public health, tehran university of medical sciences, tehran, iran. mohamad arab department of health management and economics, school of public health, tehran university of medical sciences, tehran, iran. arash rashidian department of health management and economics, school of public health, tehran university of medical sciences, tehran, iran. ali akbarisari department of health management and economics, school of public health, tehran university of medical sciences, tehran, iran. ali zare department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, tehran, iran. hojjat zeraati department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, tehran, iran.

survival analysis is a set of methods used for analysis of the data which exist until the occurrence of an event. this study aimed to compare the results of the use of the semi-parametric cox model with parametric models to determine the factors influencing the length of stay of patients in the inpatient units of women hospital in tehran, iran. in this historical cohort study all 3421 charts of...

Journal: :Bioinformatics 2009
Insuk Sohn Jinseog Kim Sin-Ho Jung Changyi Park

MOTIVATION There has been an increasing interest in expressing a survival phenotype (e.g. time to cancer recurrence or death) or its distribution in terms of a subset of the expression data of a subset of genes. Due to high dimensionality of gene expression data, however, there is a serious problem of collinearity in fitting a prediction model, e.g. Cox's proportional hazards model. To avoid th...

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