Sustained high fatality during TB therapy amid rapid decline in TB mortality at population level: A retrospective cohort and ecological analysis from Shiselweni, Eswatini

Abstract

Objectives: Despite declining TB notifications in Southern Africa, TB-related deaths remain high. We describe patient- and population-level trends in TB-related deaths in Eswatini over a period of 11 years.

Methods: Patient-level (retrospective cohort, from 2009 to 2019) and population-level (ecological analysis, 2009-2017) predictors and rates of TB-related deaths were analysed in HIV-negative and HIV-coinfected first-line TB treatment cases and the population of the Shiselweni region. Patient-level TB treatment data, and population and HIV prevalence estimates were combined to obtain stratified annual mortality rates. Multivariable Poisson regressions models were fitted to identify patient-level and population-level predictors of deaths.

Results: Of 11,883 TB treatment cases, 1302 (11.0%) patients died during treatment: 210/2798 (7.5%) HIV-negative patients, 984/8443 (11.7%) people living with HIV (PLHIV), and 108/642 (16.8%) patients with unknown HIV-status. The treatment case fatality ratio remained above 10% in most years. At patient-level, fatality risk was higher in PLHIV (aRR 1.74, 1.51-2.02), and for older age and extra-pulmonary TB irrespective of HIV-status. For PLHIV, fatality risk was higher for TB retreatment cases (aRR 1.38, 1.18-1.61) and patients without antiretroviral therapy (aRR 1.70, 1.47-1.97). It decreases with increasing higher CD4 strata and the programmatic availability of TB-LAM testing (aRR 0.65, 0.35-0.90). At population-level, mortality rates decreased 6.4-fold (-147/100,000 population) between 2009 (174/100,000) and 2017 (27/100,000), coinciding with a decline in TB treatment cases (2785 in 2009 to 497 in 2017). Although the absolute decline in mortality rates was most pronounced in PLHIV (-826/100,000 vs. HIV-negative: -23/100,000), the relative population-level mortality risk remained higher in PLHIV (aRR 4.68, 3.25-6.72) compared to the HIV-negative population.

Conclusions: TB-related mortality rapidly decreased at population-level and most pronounced in PLHIV. However, case fatality among TB treatment cases remained high. Further strategies to reduce active TB disease and introduce improved TB therapies are warranted.

Keywords: HIV; TB-related deaths; population-level; trends.