JOINT MODELING OF TIME TO DEVELOP TUBERCULOSIS AND CHANGE IN CD4 COUNT AMONG HIV PATIENTS UNDER ART IN MEKELLE, ETHIOPIA, 2024

Abstract

Background: In patients with HIV, tuberculosis remains the leading cause of mortality and morbidity. Little is known about the predictors and the median time to develop tuberculosis while considering for the effect of the variation of longitudinal CD4 cell count. Objective: To investigate the time to develop tuberculosis accounting for longitudinal CD4 cell count change and its predictors among HIV patients who are under ART follow-up at Mekelle General Hospital and Ayder Comprehensive Specialized Hospital, Mekelle, Ethiopia, 2024. Methodology: A facility-based retrospective follow-up study was conducted among 449 adult PLHIV under ART follow-up from March 2018 to May 2024. The study participant were selected via a simple random sampling. The secondary data were collected from the patients’ medical records via Kobocollect version 2021.2.4 and exported to STATA version 17.0. The final model was a joint random intercept Cox-proportional hazard model. A model with the lowest Akaike information criterion and Bayesian information criterion was selected. Results: The incidence density of TB disease was 6.77 cases/100 person-years with a restricted mean survival time of 60 months. The joint analysis provided an association parameter alpha with AHR=0.854; 95% CI(0.8-0.91), indicating that for a unit increase in the average √CD4 cell count , the hazard of TB infection decreased by 14.6%, keeping other variables constant. The study also revealed that advanced WHO clinical stage (AHR = 1.024, 95% CI: 1.017–1.033), sex (AHR= 1.62, 95% CI: 1.09,2.4), CPT intake (AHR= 0.55, 95% CI: 0.35,0.89), and adherence (AHR= 0.38, 95% CI: 0.28,0.52) were significantly associated with the time to develop tuberculosis. The random intercept model indicated that greater variation in CD4 counts at baseline contributed strongly to the hazard of tuberculosis. Conclusion and Recommendation: This research highlights that PLHIV with a decreasing trajectory of CD4 count, advanced WHO clinical stage, female sex, history of CPT intake, and poor adherence have a higher risk of tuberculosis. On the basis of these findings, it is strongly recommended that the government and relevant health actors working on TB/HIV should intensify activities that improve patient adherence and a regular CD4 cell measurement.