Incidence and factors associated with tuberculosis disease among people living with HIV who completed tuberculosis preventive treatment: a retrospective comparative cohort study at Baylor-Uganda HIV Clinic

Abstract

The life-time risk of tuberculosis disease (TB) is higher among people living with HIV (PLHIV) compared to the general population. This study aimed to determine the incidence and factors associated with TB disease among PLHIV after completion of at least one course of TB preventive treatment (TPT). This was a retrospective comparative cohort study among PLHIV of all ages, who initiated and completed TPT, in comparison with PLHIV who did not receive TPT at Baylor-Uganda HIV clinic for the period Jan 2016 to Dec 2021. The incidence of TB disease was reported as the number of new TB cases per 1000person years of follow-up. A multivariable Poisson regression model was used to assess for significant factors associated with TB disease after completion of TPT, adjusting for potential confounders. Of the 9505 PLHIV in care, 6014 (79.2%) initiated and completed TPT, and 1907 (20.0%) did not initiate TPT. Majority of PLHIV were female (61%). The TB incidence among PLHIV who completed TPT reduced over the study period, from 4.34 in 2016 to 1.71 TB cases per 1000person years in 2020, and increased slightly 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<0.001). The overall median survival time to TB disease after completing TPT PLHIV was 2.5 years (IQR: 2.3–2.8 years). The TB incidence is low among PLHIV who complete TPT compared to PLHIV who do not receive TPT. After completing TPT, HIV viral non-suppression increases risk of TB disease by six times. Therefore, TB screening and treatment adherence support should continue after completing TPT. The risk of TB disease after receiving TPT increases after 2.5 years. This calls for research on the need of repeat TPT doses in high-risk groups.