Burden of diabetes among patients with tuberculosis: 10-year experience from a tertiary care referral teaching hospital in South India

CONTEXT: Tuberculosis (TB) and diabetes mellitus (DM) are converging epidemics, each worsening the morbidity of the other. A study of the prevalence of DM in TB patients assumes great importance. AIMS: The study aims to evaluate the association between DM and TB over a 10-year period in a tertiary care hospital. SETTINGS AND DESIGN: A retrospective observational study in a southern Indian tertiary care teaching hospital was conducted. MATERIALS AND METHODS: All patients with TB diagnosed and treated during the 10-year study period were identified from the hospital database. All relevant clinical, microbiological, and laboratory results pertaining to diagnosis of DM were collected. The diagnosis of TB and DM was made as per the standard criteria. STATISTICAL ANALYSIS: Categorical variables were analyzed using Chi-square test while continuous variables using independent sample t-test. RESULTS: From 2001 to 2012, we studied 1979 TB patients among whom data on DM were available. The prevalence of DM was 29%, 21%, and 14%, in smear positive, smear negative and extrapulmonary TB respectively (overall 24%). Diabetics were more likely to be men (77.3% vs. 61%; P = 0.001); >40 years of age (81.7% vs. 38.9%; P < 0.001); heavier (59.96 vs. 50.37; P = 0.004); tobacco smokers (16.1% vs. 8.1%; P < 0.001); and alcohol consumers (6.8% vs. 4%; P = 0.02). They were less likely to be HIV coinfected (1.8% vs. 6.1%; P < 0.001). HIV coinfection was seen in 5% of patients and was substantially higher in extrapulmonary TB group (19.4%). Multidrug-resistant TB was lower in DM (11.7%) compared to non-DM (15.9%) (P = 0.02). Overall, 48% of the DM patients were diagnosed at the time of TB diagnosis. Over 10 years, no obvious changes in the trend were evident. CONCLUSIONS: Over a 10-year study period, 24% of the TB patients were diabetic, nearly half were detected at the time of TB diagnosis. There may be a good case for screening all TB patients for DM.