Factors associated with mortality among laboratory-diagnosed drug-resistant tuberculosis patients on treatment, KwaZulu-Natal Province, 2017-2019

Abstract

Introduction: tuberculosis (TB) remains a leading cause of death in South Africa. KwaZulu-Natal (KZN) is one of the provinces with a high burden of TB/drug-resistant TB cases and deaths. We determined predictors for mortality among drug-resistant TB patients on treatment in KZN province.

Methods: we conducted a retrospective cohort study using secondary data from the Electronic Drug-Resistant Tuberculosis Register. We used a modified Poisson regression model with robust standard errors to determine predictors for drug-resistant TB mortality.

Results: of the 7,692 eligible patients, 1,234 (16.0%) died. Males predominated (707, 57.3%) and the median age was 36 years (Interquartlile Range: 29-45 years). The majority (978, 79.2%) were HIV-TB co-infected with 911 (93%) on antiretroviral treatment (ART). The predictors included HIV-TB co-infection without ART (aIRR 3.4; 95% CI: 2.3-5.1), unknown ART status (aIRR: 1.8; 95% CI: 1.4-2.3), aged ≥60 years (aIRR: 2.1; 95% CI: 1.6-2.7), previous drug-resistant TB (aIRR: 1.5; 95% CI: 1.2-1.8) and exposure to second-line drugs (aIRR: 1.7; 95% CI: 1.4-2.0). Other predictors were hospitalization during treatment initiation (aIRR 2.5; 95% CI 2.0-3.1), initiation in other treatment facilities (aIRR: 2.2; 95% CI: 1.6-2.9) and rifampicin-resistant (aIRR: 1.2; 95% CI: 1.1-1.4). Bedaquiline fumarate was a significant protective factor against death (aIRR: 0.5; 95% CI: 0.4-0.5).

Conclusion: older age, HIV co-infection without ART, hospitalization for treatment initiation, exposure to second-line drugs and a previous episode of drug-resistant TB were predictors for DR-TB mortality. Early treatment initiation and provision of antiretroviral treatment for all co-infected patients may reduce DR-TB mortality in the Province.