Identifying Important Risk Factors for Survival of HIV-infected Patients Using Censored Quantile Regression

Introduction: This study aimed to estimate the effect of potential risk factors on survival of human immunodeficiency virus/acquired immunodeficiency syndrome (AIDS) patients using censored quintile regression model. Material and methods: We used a dataset from a (registry-based) retrospective cohort study conducted in Tehran (from April, 2004 to March, 2018). Demographic information, such as age, sex, marital sta-tus, and educational level as well as behavioral information, including being-in-prison, drug/alcohol abuse and smoking, antiretroviral therapy, co-infection with tuberculosis (TB), and CD4+ cell count, were investigated as potential risk factors for AIDS progression. Censored quintile regression was used to estimate and investigate these factors for AIDS progression. Results: Mean age of patients was 33.93 years. Time to progression ranged from 0.01 to 223.17 months, and mean of time to progression was 40.55 months. A total of 1,249 (50.5%) patients experienced an event by end of the study. Impact of age, gender, prison, being addicted, being infected with tuberculosis, and using highly active antiretroviral therapy (HAART) were significant for most of quintiles (p < 0.05). Conclusions: It was shown that age, being prisoned, TB infection, and HAART were significantly associ-ated with a lower time in AIDS progression. Censored quintile regression could be an appropriate choice for considering time-varying effects and easy interpretation of regression coefficients in analyzing AIDS progression data.