Empiric tuberculosis treatment and 12-month mortality among sputum GeneXpert-negative adults living with HIV in Uganda in the era of widespread Antiretroviral therapy: A prospective cohort study

Background: In sub-Saharan Africa where both tuberculosis (TB) and HIV are prevalent, empiric TB treatment in people living with HIV (PLHIV) persists due to limited sensitivity of sputum-based TB tests. We evaluated mortality among molecular test-negative presumptive TB adult PLHIV in a population where the majority are or have been on antiretroviral therapy (ART), comparing mortality between those who received empiric TB treatment and those who did not. Materials and Methods: From November 2017 to December 2020, Xpert-negative presumptive TB adult PLHIV were recruited at Mulago Referral Hospital and Kisenyi Health Centre-IV in Kampala, Uganda. Clinical data including TB symptoms, chest X-ray, and empiric TB treatment decision were collected. Laboratory investigations included CD4 cell count, serum cryptococcal antigen (CrAg), urine TB-lipoarabinomannan (TB-LAM), microbiological blood cultures, and sputum mycobacterial growth indicator tube (MGIT) cultures. Participants were followed monthly for 12 months to ascertain vital status. Results: Overall, 300 participants were enrolled; 61.3% inpatients, 55.7% female, median age 37 (IQR 29-45) years, 82.3% on ART, median CD4 206 cells/mm3 (IQR 36-507). Of the 300 participants, 68 (22.7%) received empiric TB treatment, of which 53 (77.9%) were inpatients. 12-month mortality was 31.0% (93/300); 91.4% among inpatients, 72% within three months post-enrolment. Mortality was higher among those who received empiric TB treatment (51.5 vs. 30.2 per 1,000 person-months; p=0.013) compared to those who did not. TB cultures were positive in 5.0% (15/300), of whom seven (46.7%) were also TB-LAM positive. CrAg was positive in 12.3% and 3.7% had positive blood culture. Conclusion: We found high mortality among Xpert-negative PLHIV, particularly those who received empiric TB treatment, despite high ART coverage. Cryptococcal antigenemia and bacteremia were not uncommon. In presence of negative Xpert results in PLHIV, clinicians should perform extensive laboratory evaluations to identify possible comorbidities or alternative non-TB diagnosis.