ABSTRACTBackgroundIt is unclear whether diabetes or prediabetes drives adverse treatment outcomes and death in people with tuberculosis (PWTB).MethodsCulture-confirmed PWTB, enrolled in the Regional Prospective Observational Research in Tuberculosis (RePORT)-Brazil cohort between 2015 and 2019 (n=756) were stratified based on glycemic status by baseline glycated hemoglobin levels. Unfavorable TB outcome was defined as treatment failure or modification, recurrence or death, whereas favorable outcome was cure or treatment completion. We validated the findings using data from PWTB reported to the Brazilian National System of Diseases Notification (SINAN) during 2015-2019 (n=20,989). Stepwise binary multivariable regression analysis models evaluated associations between glycemic status and unfavorable outcomes.ResultsIn both cohorts, in univariate analysis, unfavorable outcomes were more frequently associated with drug resistance and HIV infection. Diabetes was associated with unfavorable outcomes in the RePORT (aOR: 2.85, p=0.001) and in SINAN (aOR: 1.56, p=0.040) cohorts. Furthermore, diabetes was associated with higher risk of death in both, RePORT-Brazil (aOR:3.23, p=0.006) and in the SINAN (aOR:2.75, p= 0.047) cohorts.ConclusionDiabetes was associated with an increased risk of unfavorable outcomes and mortality in Brazilian PWTB. Interventions to improve tuberculosis treatment outcomes in persons with diabetes are needed.40-word summary of the article’s main pointIn a multicenter prospective cohort study from Brazil, diabetes was associated with an increased risk of unfavorable treatment outcomes, including mortality, in pulmonary tuberculosis patients. These observations were validated in the Brazilian National Disease Notification System during the same period.