Diabetes Mellitus in adult patients with active tuberculosis in Canada: Presentation and treatment outcomes

RATIONALE: Evidence supports a bidirectional relationship between tuberculosis (TB) and diabetes mellitus (DM) that may negatively impact TB elimination goals. Data from low TB incidence countries describing this relationship is limited. OBJECTIVES: We evaluated the association between DM and clinical presentation and treatment outcomes in adult patients with active TB in Canada. Our primary outcome was TB mortality. Secondary outcomes included relapse, development of drug resistance, delayed culture conversion and treatment failure (composite outcome). METHODS: A retrospective cohort study was conducted among adults diagnosed with TB between 2007 and 2012 in two Canadian cities. Clinical presentation and outcomes data was collected. Adjusted odds ratios (OR) were used to assess the association between DM and TB treatment outcomes. MEASUREMENTS AND MAIN RESULTS: Of 690 TB patients, 136 (19.7%) had DM. Diabetic patients were more likely to be smear positive (43% vs. 34%) and have cavitary disease (35% vs. 19%). In unadjusted analysis, DM was strongly associated with mortality during TB treatment (OR 2.68, 95% CI 1.42-5.06) and treatment failure (OR 2.81, 95% CI 1.55-5.09). However, after multivariate assessment these associations were no longer significant (mortality OR 1.24, 95% CI 0.61-2.56; treatment failure OR 1.46, 95% CI 0.75-2.81). CONCLUSION: In this cohort of patients treated for active TB in Canada, DM was associated with more extensive disease at presentation. In multivariate analysis DM did not impact treatment outcomes.