Time-to-Tuberculosis disease diagnosis after completion of Tuberculosis preventive therapy among people living with HIV on Antiretroviral Therapy in Eastern Uganda: A retrospective cohort study

BackgroundTuberculosis (TB) remains a leading cause of morbidity and mortality among people living with HIV (PLHIV), who face a 12-fold higher risk of active TB reactivation than HIV-negative individuals. TB preventive therapy (TPT) is an effective intervention, yet TB/HIV co-infection persists at 40-45%, raising questions about the durability of a single course of TPT. This study assessed the time from TPT completion to TB diagnosis and predictors of early TB reactivation. MethodsWe conducted a retrospective case-only cohort study using routine data from Ugandas electronic medical record system, TB registers, and patient files at three TASO Centres of Excellence (Soroti, Mbale, Tororo). PLHIV on antiretroviral therapy (ART) diagnosed with TB after completing TPT between 2022-2024 were included. Participant characteristics and time to TB diagnosis were summarised descriptively; predictors of early TB were identified using logistic regression. ResultsAmong 670 participants, most were female (464, 69.3%) with mean age 51.6 years (SD 14.5). Newly diagnosed TB accounted for 638 (95.2%), including bacteriologically confirmed pulmonary TB (535, 79.9%), clinically diagnosed TB (123, 18.4%), and extrapulmonary TB (12, 1.8%). Overall, 548 (82.8%) participants were virally suppressed, with most on Dolutegravir-based regimens (641, 95.7%). Early TB occurred in 144 (21.5%), with average time to diagnosis 2.6 years. Multivariable analysis showed care at TASO Soroti was protective (aOR = 0.104, p < 0.001), while clinically diagnosed TB (aOR = 1.91, p = 0.007), shorter ART duration (<5 years: aOR = 3.07, p = 0.001; 5-10 years: aOR = 1.74, p = 0.018), and viral suppression (aOR = 1.87, p = 0.014) increased odds of early TB. ConclusionsTB can occur soon after TPT completion, with one in five PLHIV developing early disease particularly those with shorter ART duration despite viral suppression. Strengthening TB screening, continuous monitoring, and repeat TPT for high-risk groups may improve prevention.