Systematic differences in TB treatment outcomes across in Brazil by patient- and area-related factors: an analysis of national disease registry data

BackgroundA substantial fraction of individuals initiating tuberculosis (TB) treatment do not successfully complete the regimen. Understanding variation in TB treatment outcomes could reveal opportunities to improve the effectiveness of TB treatment services. MethodsWe extracted data on TB treatment outcomes, patient covariates, and location of residence from Brazils National Disease Notification Information System, for all new TB patients diagnosed during 2015-2018. We analyzed whether or not patients experienced an unsuccessful treatment outcome (any death on treatment, loss to follow-up, or treatment failure). We constructed a statistical model predicting treatment outcome as a function of patient-level covariates, including socio-demographic factors, co-prevalent health conditions, health behaviors, membership of vulnerable populations, and diagnosed form of TB disease. We used this model to decompose state- and municipality-level variation in treatment outcomes into differences attributable to patient-level factors and area-level factors, respectively. ResultsTreatment outcomes data for 259,449 individuals were used for the analysis. Across Brazilian states, variation in unsuccessful treatment due to patient-level factors was substantially less that variation due to area-level factors, with the difference between best and worst performing states 7.1 and 13.3 percentage points for patient-level and area-level factors, respectively. Similar results were estimated at the municipality-level, with 9.3 percentage points separating best and worst performing municipalities according to patient-level factors, and 20.5 percentage points separating best and worst performing municipalities according to area-level factors. Results were similar when we analyzed loss to follow-up as an outcome. ConclusionsThe results of this analysis revealed substantial variation in TB treatment outcomes across states and municipalities in Brazil, which could not be explained by differences in patient-level factors. This area-level variation likely reflects the consequences of differences in health system organization, clinical practices, and other socio-environmental factors not reflected in patient-level data. Further research to reveal the reasons for these differences is urgently needed to identify effective approaches to TB care, reduce geographic disparities in treatment effectiveness across Brazil, and increase the fraction of patients who successfully complete TB treatment.