نتایج جستجو برای: proportional hazards model

تعداد نتایج: 2169276  

Journal: :iranian journal of public health 0
ali zare dept. of epidemiology and biostatistics, school of public health, tehran university of medical sciences , tehran, iran. mahmood mahmoodi dept. of epidemiology and biostatistics, school of public health, tehran university of medical sciences , tehran, iran. kazem mohammad dept. of epidemiology and biostatistics, school of public health, tehran university of medical sciences , tehran, iran. hojjat zeraati dept. of epidemiology and biostatistics, school of public health, tehran university of medical sciences , tehran, iran. mostafa hosseini dept. of epidemiology and biostatistics, school of public health, tehran university of medical sciences , tehran, iran. kourosh holakouie naieni dept. of epidemiology and biostatistics, school of public health, tehran university of medical sciences , tehran, iran.

gastric cancer is the most prevalent cancer among men and the third most prevalent cancer among women in iran. its most important reason for death is its belated diagnosis at the advanced stages of the disease. various factors can be effective on the survival of these patients after surgery, which are the major concern in this study.data from 330 patients with gastric cancer who had undergone s...

Journal: :iranian red crescent medical journal 0
abbas rahimi foroushani department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, tehran, ir iran mahmoud salesi nephrology and urology research center, baqiyatallah university of medical sciences, tehran, ir iran zohreh rostami nephrology and urology research center, baqiyatallah university of medical sciences, tehran, ir iran ali reza mehrazmay behaviolar sciences research center, baqiyatallah university of medical sciences, tehran, ir iran jamile mohammadi department of psychology, faculty of humanities, tarbiat modares university, tehran, ir iran behzad einollahi nephrology and urology research center, baqiyatallah university of medical sciences, tehran, ir iran

conclusions by controlling the modifiable risk factors and modality of treatment in our study, physicians can reach more effective treatment. results at the end of the study, long-term graft failure was seen in 27 (10.2%) cases. one-year and 2-year graft survival after diagnosis of cancer were 93.6% and 91.7%, respectively. the univariate analysis showed that the incidence of chronic graft loss...

Journal: :iranian red crescent medical journal 0
zohreh amiri department of basic sciences, national nutrition and food technology research institute, faculty of nutrition sciences and food technology, shahid beheshti university of medical sciences, ir iran kazem mohammad department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, ir iran +98-2188989126, [email protected] mahmood mahmoudi department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, ir iran +98-2188989126, [email protected] mahbubeh parsaeian department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, ir iran +98-2188989126, [email protected]

results survival probabilities at different times were determined using the cox proportional hazards and a neural network with three nodes in the hidden layer; the ratios of standard errors with these two methods to the kaplan-meier method were 1.1593 and 1.0071, respectively, revealed a significant difference between cox and kaplan-meier (p < 0.05) and no significant difference between cox and...

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...

1994
Ian W. McKeague Mei-Jie Zhang

Cox's proportional hazards model is often t to grouped survival data, i.e. occurrence/exposure data over given time intervals and covariate strata. We derive a Sheppard correction for the bias in the grouped data analogue of Cox's maximum partial likelihood estimator. This is done via a large sample theory in which the covariate strata and time intervals shrink as the sample size increases.

Journal: :Journal of data science 2021

We fit a Cox proportional hazards (PH) model to interval-censored survival data by first subdividing each individual's failure interval into nonoverlapping sub-intervals. Using the set of all endpoints in set, those that fall are then used as cut points for Each sub-interval has an accompanying weight calculated from parametric Weibull based on current parameter estimates. A weighted PH is with...

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...

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