Evaluation of Factors Related to Survival Time in HIV-Infected Persons in Mashhad, Iran, Between 1994 - 2014: A Bayesian Joint Model

background: the prevalence of hiv is increasing in iran, so obtaining an estimate of the survival of hiv-infected persons can be helpful to prevent and control this infection. objectives: this research aimed to use the bayesian joint model by which identifies factors associated with the survival and determine the relationship between the trend of cd4+ t cell counts and survival time in hiv-infected persons. methods: in this retrospective cohort study, we collected hiv/aids surveillance data from mashhad’s counseling center of behavioral diseases in the province of khorasan razavi, northeast of iran, during 1994 - 2014. data collection included variables cd4+ t cells count, survival time, and other related factors. we used the bayesian joint model to estimate the survival time and identify the factors associated with survival time in hiv-infected persons. results: the study included 260 individuals, of whom 212 (81.54%) were male. the survival sub-model of the joint model identified gender (95% credible interval (ci): 0.486, 3.197) and antiretroviral treatment (95% ci: -1.935, -0.641) as the variables associated with the patients’ survival. the longitudinal sub-model, which determined the variables associated with the number of cd4+ t-cells included time (95% ci: -0.934, -0.554), age (95% ci: -0.152, -0.011), and antiretroviral treatment (95% ci: -6.193, -3.505).conclusions: using cd4+ t cells as a covariate in the bayesian joint model, the survival time for hiv-infected persons was estimated more precisely than separate model and it can be inferred that at the beginning of antiretroviral treatment, especially in men and controls, the cd4+ t cell counts can increase the survival time of hiv-infected persons.