Treating drug-resistant tuberculosis in an era of shorter regimens: Insights from rural South Africa

BACKGROUND

Progressive interventions have recently improved programmatic outcomes in drug-resistant tuberculosis (DR-TB) care in South Africa (SA). Amidst these, a shorter regimen was introduced in 2017 with weak evidence, and has shown mixed results. Outcomes still fall short of national targets, and the coronavirus disease 2019 pandemic has undermined progress to date.

OBJECTIVES

To describe the outcomes of participants treated for DR-TB using a shorter, compared with a longer, regimen in a deeply rural SA setting, and to explore other factors affecting these outcomes.

METHODS

This retrospective cohort study describes outcomes in short and long DR-TB treatment regimens, over 5 years, at two rural treatment sites in SA. Characteristics were analysed for outcome correlates using multivariable logistic regression models.

RESULTS

Of 282 treatment episodes, 62% were successful, with higher success in shorter (69%) compared with longer regimens (58%). Mortality was approximately 21% in both groups. Characteristics included high proportions of HIV co-infection (61%). Injectables (adjusted odds ratio (aOR) 3.00, 95% confidence interval (CI) 1.48 - 6.09), bedaquiline (aOR 3.16, 95% CI 1.36 - 7.35), increasing age (aOR 0.97, 95% CI 0.95 - 0.99) and HIV viraemia defined as final HIV-RNA viral load >1 000 copies/mL (aOR 0.16, 95% CI 0.07 - 0.37) were all significantly and independently associated with treatment success. Injectables (aOR 0.22, 95% CI 0.08 - 0.57), bedaquiline (aOR 0.05, 95% CI 0.01 - 0.19), increasing age (aOR 1.09, 95% CI 1.05 - 1.13), extra-pulmonary TB (aOR 8.15, 95% CI 1.62 - 41.03) and HIV viraemia (aOR 9.20, 95% CI 3.22 - 26.24) were all significantly and independently associated with mortality.

CONCLUSION

In a rural context, treating DR-TB amid limited resources and a high burden of HIV co-infection, we found that after considering controls, a short regimen was no different to a longer regimen in terms of success or mortality. Therefore, by alleviating burdens on multiple stakeholders, a short regimen is likely to be favourable for rural patients, clinicians, and healthcare systems. Besides other previously described correlates of outcomes, HIV viraemia emerged as a novel marker for reliably predicting poor outcomes in DR-TB with HIV co-infection, and a pragmatic target for intervention.

Evaluation of a point-of-care blood test for identification of Ebola virus disease at Ebola holding units, Western Area, Sierra Leone, January to February 2015

Current Ebola virus disease (EVD) diagnosis relies on reverse transcription-PCR (RT-PCR) technology, requiring skilled laboratory personnel and technical infrastructure. Lack of laboratory diagnostic capacity has led to diagnostic delays in the current West African EVD outbreak of 2014 and 2015, compromising outbreak control. We evaluated the diagnostic accuracy of the EVD bedside rapid diagnostic antigen test (RDT) developed by the United Kingdom's Defence Science and Technology Laboratory, compared with Ebola virus RT-PCR, in an operational setting for EVD diagnosis of suspected cases admitted to Ebola holding units in the Western Area of Sierra Leone. From 22 January to 16 February 2015, 138 participants were enrolled. EVD prevalence was 11.5%. All EVD cases were identified by a positive RDT with a test line score of 6 or more, giving a sensitivity of 100% (95% confidence interval (CI): 78.2-100). The corresponding specificity was high (96.6%, 95% CI: 91.3-99.1). The positive and negative predictive values for the population prevalence were 79.0% (95% CI: 54.4-93.8) and 100% (95% CI: 96.7-100), respectively. These results, if confirmed in a larger study, suggest that this RDT could be used as a 'rule-out' screening test for EVD to improve rapid case identification and resource allocation.