OPTIMIZING TUBERCULOSIS TREATMENT SUCCESS RATES IN NAMIBIA

ABSTRACT

Tuberculosis (TB) is a leading cause of mortality globally, leading to an annual death rate of 1.8 million. In 2017, over 700 people died from TB in Namibia. Moreover, despite the scale-up of high-quality Directly Observed Treatment Short Course strategy (DOTS) to control TB in Namibia, treatment success rates (TSR) fall short of the global target of 90%. Unsuccessful treatment outcomes are a risk drug resistant TB. Consequently, the study aimed to model the population, patient and drug (pharmacokinetics and pharmacovigilance) level predictors of treatment success, cure and completion rates under the DOTS programme in Namibia.

The study was designed in four phases, population, and patient and drug level models, and an overall conceptual model to optimize TSR. Population-level modeling of the effectiveness of the community based-DOTS on TSR, cure and completion was done using interrupted time-series analysis. Three patient level models of TSR, loss to-folow-up (LTFU) and case fatality rates for a 10-year nationwide cohort, 2004-2016 were conducted using multivariate regression in R. Two drug level studies, i.e. a meta-analysis of the impact of HIV/TB co-infection on serum concentrations (Cmax) of rifampicin, isoniazid, pyrazinamide and ethambutol, as well as a systematic review on the burden of adverse effects were modeled.

First, the CB-DOTS intervention in 2005, immediately increased annual TSR by 12.9% (p