Risk factors for mortality among adults registered on the routine drug resistant tuberculosis reporting database in the Eastern Cape Province, South Africa, 2011 to 2013

INTRODUCTION: South Africa is among countries with the highest burden of drug resistant tuberculosis (DR-TB). The Eastern Cape Province reported the highest MDR-TB mortality rates in South Africa for the 2010 treatment cohorts. This study aimed to determine risk factors for mortality among adult patients registered for DR-TB treatment in the province. METHODS: We conducted a retrospective cohort study of adult patients treated for laboratory confirmed DR-TB between January 2011 and December 2013. Demographic and clinical characteristics of the patients were obtained from a web-based electronic database of patients treated for DR-TB. We applied modified Poisson regression with robust standard errors to identify risk factors for DR-TB mortality. We also stratified the analyses into multi-drug resistant TB (MDR-TB) and extensively drug resistant (XDR-TB). RESULTS: Among 3,729 patients that met the inclusion criteria, 39% (n = 1,445) died. Of the patients that died, 53% (n = 766) were male, 68% (n = 982) had MDR-TB, 72% (n = 1,038) were HIV co-infected, and median age was 37 years (Interquartile Range [IQR] 30–46). Patients were at higher risk of mortality during DR-TB treatment if they were HIV co-infected not on antiretroviral treatment (ART) (adjusted incidence risk ratio [aIRR] 3.3, 95% confidence interval [CI] 2.9–3.8), were 60 years or older (aIRR 1.7, 95%CI 1.5–2.0), had a diagnosis of XDR-TB (aIRR 1.6, 95%CI 1.5–1.7), or had been hospitalised at treatment start (aIRR 1.7, 95%CI 1.5–1.8). Among MDR-TB patients, risk of mortality was higher if patients were HIV co-infected not on ART (aIRR 3.9, 95%CI 3.3–4.6), were 60 years or older (aIRR 1.9, 95%CI 1.6–2.3), or had been hospitalised at start of MDR-TB treatment (aIRR 1.7, 95%CI 1.5–1.9). Among XDR-TB patients, risk of mortality was higher in patients who were HIV co-infected not on ART (aIRR 1.8, 95%CI 1.5–2.2), or had been hospitalised at the start of XDR-TB treatment (aIRR 1.5, 95%CI 1.3–1.8). CONCLUSION: HIV co-infected not on ART, older age, XDR-TB and hospital admission for DR-TB treatment were independent risk factors for DR-TB mortality. Integration of TB and HIV services, with focus on voluntary HIV testing and counselling of DR-TB patients with unknown HIV status, and provision of ART for all co-infected patients may reduce DR-TB mortality in the Eastern Cape.