Often in biomedical research the aim of a study is to compare the outcomes of several treatment arms while adjusting for multiple clinical prognostic factors. In this paper we focus on computation of the direct adjusted survival curves for different treatment groups based on an unstratified or a stratified Cox model. The estimators are constructed by taking the average of the individual predict...

BACKGROUND Chronic inflammation has been regarded as an important mechanism in carcinogenesis. Inflammation-associated genetic variants have been highly associated with cancer risk. Polymorphisms in the gene cyclooxygenase-2 (COX-2), a pro-inflammation factor, have been suggested to alter the risk of multiple tumors, but the findings of various studies are not consistent. METHODS A literature...

Fine and Gray (1999) suggested a Cox model for the subdistribution hazard, which is the hazard attached to the cumulative incidence function of interest in a competing risks setting. They also noted that standard Cox software may be used to fit the model provided that the potential censoring times are known for individuals observed to experience a competing event (‘censoring complete data’) and...

Often in medical studies of time to an event, the treatment effect is not constant over time. In the context of Cox regression modeling, the most frequent solution is to apply a model that assumes the treatment effect is either piecewise constant or varies smoothly over time, i.e., the Cox nonproportional hazards model. This approach has at least two major limitations. First, it is generally di...

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...

Cox regression model serves as a statistical method for analyzing the survival data, which requires some options such as hazard proportionality. In recent decades, artificial neural network model has been increasingly applied to predict survival data. This research was conducted to compare Cox regression and artificial neural network models in prediction of kidney transplant survival. The prese...

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 ...