Factors associated with unfavourable treatment outcomes in people with HIV-associated tuberculosis in Armenia, 2015 to 2019

To evaluate factors associated with tuberculosis (TB) treatment outcomes in Human Immunodeficiency Virus-Associated (HIV) TB patients in Armenia, we conducted a nation-wide cohort study using routine programmatic data of all HIV-associated TB patients receiving TB treatment with first- or second-line drugs from 2015 to 2019. Data were obtained from the TB and HIV electronic databases. We analysed occurrence of the combined unfavourable outcome (failure, lost to follow-up, death and not evaluated) and death separately, and factors associated with both outcomes using Cox regression. There were 320 HIV-associated TB patients who contributed a total of 351 episodes of TB treatment. An unfavourable TB treatment outcome was registered in 155 (44.2%) episodes, including 85 (24.2%) due to death, 38 (10.8%) lost to follow up, 13 (3.7%) failure and 19 (5.4%) not evaluated. Multivariable analysis showed that receipt of Antiretroviral Treatment (ART) [ART start before TB treatment: adjusted hazard ratio (aHR)=0.3, 95% confidence interval (CI): 0.2-0.5, ART start within 8 weeks of TB treatment: aHR=0.2, 95% CI: 0.1-0.3; and ART start after 8 weeks: aHR= 0.1, 95% CI: 0.07-0.3] and CD4 count >200cell/ mu L (aHR=0.5, 95% CI: 0.3-0.9) decreased the risk of unfavourable outcome, while TB meningitis (aHR=4.4, 95% CI: 1.6-11.9) increased the risk. The risk of death was affected by the same factors as above in addition to the low Body Mass Index (aHR=2.5, 95% CI: 1.3-.5) and drug resistance (aHR=2.3, 95% CI: 1.0-5.4). In the subsample of episodes receiving ART, history of interruption of ART during TB treatment increased the risk of unfavourable outcome (aHR=2.1, 95% CI: 1.2-3.9), while ART start during TB treatment was associated with lower risk of both unfavourable outcome (within first 8 weeks: aHR: 0.5, 95% CI: 0.3-0.9; after 8 weeks: aHR: 0.4, 95% CI: 0.2-1.0) and death (within first 8 weeks: aHR: 0.2, 95% CI: 0.1-0.4; after 8 weeks: aHR: 0.1, 95% CI: 0.01-0.3). The rates of unfavourable TB treatment outcomes, and death in particular, among HIV-associated TB patients in Armenia are high. Our findings emphasize the protective effect of ART and the importance of proper management of cases complicated by drug resistance or meningitis.