Factors Influencing Hemodialysis Patients Survival Using Frailty Models

Abstract

Abstract Background and objection: Hemodialysis is the most common renal replacement therapy in patients with End Stage Renal Disease (ESRD). This study investigated the 5-year survival rate of hemodialysis patients admitted to Imam Khomeini and Fatima Zahra Hospitals in Sari. Materials & Methods: This study was performed on 335 patients on hemodialysis referring to Imam Khomeini and Fatima Zahra Hospitals from November 2008 to November 2013. To investigate the factors influencing the patients' survival rate, we used Cox model and Frailty model and compared these models efficiency, we also applied the Akaikie information criterion and the residuals review. All calculations have been performed with SPSS version 20 & STATA version 8 and the significance level was 0.05. Findings: The results of this study showed that applying the Kaplan– Meier method to determine one, three and five year’s survival rates for hemodialysis patients were 74.9%, 53.2% and 20.4%, respectively. The mean survival time was 37.241 months. In the final model, in multivariate analysis of the gamma frailty model, the variables as age, education, marital status, diabetes, Kidney stone & obstructions, the clinic, the mean serum albumin and urea have been identified as the most important predictors in hemodialysis patients' survival (p < 0.05). Conclusion: According to the results of the frailty model fitness, the hemodialysis patients having the same explanatory variables also have different risk of death. Giving the Akaikie information criterion and the residuals review, the Weibull model with gamma frailty is more efficient than the Cox model and it has good fitness to the data.