Impact of HIV risk factors on survival in Iranian HIV-infected patients: A Bayesian approach to retrospective cohort

Introduction: Human immunodeficiency virus (HIV) infection is recognized as a human health issue, and its social, cultural, economic, and political consequences lead to an extremely large problem for human health. The aim of this study is to evaluate association between risk factors and HIV-positive patient’s survival time.

Material and methods: In this population-based retrospective cohort study, a total of 245 positive HIV/AIDS infected patients were included. The required information were collected by an interview and blood testing. The interview was conducted by an expert and trained social worker, using a structured questionnaire. The demographic and risk factors of HIV infection factors such as: age, gender, job status, marital status, education attainment, prison status, injection drug user, heterosexual, homosexual, infected mothers, sexually transmitted disease, sex worker status, addiction, disease stage at diagnosis, CD4+ T-cell count, HBV, HCV, and AIDS were collected. The survival time of HIV patients was considered as a main outcome. Since there was a lot of censored data, we applied Gaussian Mixture Model.

Results: The analysis was done based on data of 205 (84%) patients. One hundred and sixty (78%) patients were male and the mean (SD) age of patients was 37.1 (9.3) years, varied from 4 to 65 years. During the study, 43 (21%) deaths were recorded. Median and mean with their 95% confidence intervals for survival time were 50.4 (range, 36.6-64.2) and 44.1 (range, 34.4-53.6) months, respectively, based on posterior distribution. Survival time was significantly correlated with the variables of disease stage at diagnosis time, sexually transmitted disease, CD4+ T-cell count, HBV, and AIDS. According to the sign of regression coefficients, there was strong negative correlation between survival time and disease stage at diagnosis time, sexually transmitted disease, HBV, and AIDS. Furthermore, positive correlation was found between survival times with CD4 level.

Conclusions: Since there are numerous national surveys running in Iran to fill in the information gaps on HIV prevalence and related risky behaviors among most at risk population, it is recommended to implement several integrated bio-behavioral surveillance surveys for hidden and hard-to-reach populations.