To examine longitudinal trends in drug-resistant tuberculosis treatment outcomes and evaluate how incomplete reporting serves as a signal of health system and governance performance.
Conducted a retrospective analysis of routine aggregated drug-resistant tuberculosis treatment outcomes from two rural Eastern Cape facilities in South Africa between 2020 and 2024.
Categorized outcomes into success, failure, loss to follow-up, death, and 'not evaluated,' estimating proportions with Wilson 95% confidence intervals and evaluating year-to-year shifts using chi-square tests.
Applied bounding analyses to evaluate the sensitivity of treatment success estimates under differing assumptions regarding missing and unevaluated outcome data.
Multidrug-resistant tuberculosis treatment success declined significantly from 80.9% in 2021 to 38.5% in 2024 (p = 0.007).
Outcomes classified as 'not evaluated' rose substantially from 2023 onward, reaching 25.8% for rifampicin-resistant tuberculosis and 30.8% for multidrug-resistant tuberculosis by 2024 (p < 0.001).
Bounding analyses demonstrated that overall treatment success rate estimates were highly sensitive to the high proportion of incomplete outcome reporting.