نتایج جستجو برای: Cox proportional hazards model

تعداد نتایج: 2194121  

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...

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...

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...

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: :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: :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...

احمدنژاد, الهام, زراعتی, حجت, هلاکویی نائینی, کورش, کدیور, ملیحه, کندی‌کله, مریم,

  Background & Objectives : The length of stay (LOS) is a useful indicator that can be used according to the objective to improve hospital care performance. The purpose of our study was to find factors affecting infants LOS in NICU at Children's Medical Center, Imam Khomeini Hospital, Tehran University of Medical Sciences, using the Cox multiple hazards regression model.   Methods : This histor...

Journal: :acta medica iranica 0
hojjat zeraati department of epidemiology and biostatistics, tehran university of medical sciences, tehran, iran. zohreh amiri department of basic sciences, shahid beheshti university of medical sciences, tehran, iran.

recently, reports have shown that gastric cancer has high abundance in iran and is at the second level in men, and fourth in total. this study aimed to determine the 5-year survival of gastric cancer patients and to investigate factors affecting the performance, based on tnm-7 staging system. in this study, we investigated 760 patients with gastric cancer since the beginning of 1993 to the end ...

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