Incidence and predictors of tuberculosis disease among people living with HIV who completed tuberculosis preventive treatment: a retrospective cohort study at Baylor- Uganda HIV clinic in Uganda

<title>Abstract</title> <p>Background Even with over 80% tuberculosis preventive treatment (TPT) coverage among people living with HIV (PLHIV), 39% of people with tuberculosis (TB) in Uganda are PLHIV. We explored the TB incidence, and predictors of TB disease after completing TPT. Methods We conducted a retrospective cohort study among PLHIV of all ages, comparing TB incidence among PLHIV who completed TPT, with that of PLHIV who did not receive TPT. TB incidence was reported as the number of new TB cases per 1000 person years of follow-up. Poisson regression with robust standard errors was used to assess for the predictors of TB disease after completion of TPT. Time-to-event analysis was done to estimate the median time to TB disease after TPT initiation. Results Of the 9505 PLHIV; majority were female (61%), median age was 22 years (IQR 15, 31), 6014 (79.2%) initiated and completed TPT, and 1907 (20.0%) did not initiate TPT. The TB incidence among PLHIV who completed TPT reduced from 4.34 cases/1000 in 2016 to 1.71 TB cases/1000 person years in 2020, and increased slightly in 2021. Among PLHIV who did not receive TPT, TB incidence increased from 3.21 cases/1000 in 2016, to 84.95 cases/1000 person years in 2021. Among PLHIV who completed TPT, unsuppressed viral load (≥ 1000 copies/mL) significantly increased TB risk (aIRR: 6.19; 95% CI: 2.80–13.69, p &lt; 0.001). The median time to TB disease after initiating TPT was 2.5 years (IQR: 2.3–2.8 years). The PLHIV on ART for 5–9 years had a significantly lower hazard risk of developing TB (HR = 0.30, 95% CI: 0.11–0.81, p = 0.018). Conclusions The TB incidence among PLHIV was high, although this was lower and reduced over the years among PLHIV who completed TPT, but increased among PLHIV who did not receive TPT within the six years. Even after completing TPT, HIV viral non-suppression increases the risk of TB disease by six times, with PLHIV developing TB within two and half years after initiating TPT. This emphasizes need for regular TB screening, and research on benefit of repeat TPT doses and longer-term TB prevention options like vaccines.</p>