Factors Associated With Short-Term and Long-Term Survival in Patients Undergoing Hemodialysis Using Semi- Parametric Mixture Cure Models

Abstract

Introduction. Understanding the factors affecting the survival of patients undergoing hemodialysis is the mainstay of care in this population. The present study aims at finding these features using novel cure models that discover factors important in both long term and short-term survival of patients undergoing HD. Methods. Data were retrospectively collected from the database of Shiraz University of Medical Sciences Special Diseases Administration including patients of 34 HD centers during 2011 to 2015. The primary outcome was death. Considering people with no death event as cured, the rest of the patients considered as uncured. To evaluate the factors affecting mortality, we used a mixture cure model (MCM) that model the long-term and short-term survival of patients separately. Results. Of 506 patients, 68.75% of women and 75.0% of men were long-term survivors. The mean (± SD) age of the patients was 57.5 (± 16.5) years and the empirical value of the cure rate was 72.9%. Sex, age, and Kt/Vurea were recognized as important factors in the long-term survival. In other words, lower age, male sex, and Kt/ Vurea ≥ 1.2 significantly increased the odds of being cured. The factors effective in short-term survival were mean corpuscular hemoglobin concentration (MCHC) and serum hemoglobin. The serum hemoglobin between 11 and 12.5 and a high MCHC decreased the risk of death. Conclusion. Using cure model survival analysis, it was found that factors affecting the proportion of the patients with long-term survival might be different from those affecting short-term survival.