Background: Diabetes mellitus (DM) is recognised as an important risk factor to tuberculosis (TB). India has high TB burden, along with rising DM prevalence. There are inadequate data on prevalence of DM and pre-diabetes among TB cases in India. Aim was to determine diabetes prevalence among a cohort of TB cases registered under Revised National Tuberculosis Control Program in selected TB units in Tamil Nadu, India, and assess pattern of diabetes management amongst known cases.
Methods: 827 among the eligible patients (n = 904) underwent HbA1c and anthropometric measurements. OGTT was done for patients without previous history of DM and diagnosis was based on WHO criteria. Details of current treatment regimen of TB and DM and DM complications, if any, were recorded. A pretested questionnaire was used to collect information on sociodemographics, habitual risk factors, and type of TB.
Findings: DM prevalence was 25.3% (95% CI 22.6-28.5) and that of pre-diabetes 24.5% (95% CI 20.4-27.6). Risk factors associated with DM among TB patients were age (31-35, 36-40, 41-45, 46-50, >50 years vs <30 years) [OR (95% CI) 6.75 (2.36-19.3); 10.46 (3.95-27.7); 18.63 (6.58-52.7); 11.05 (4.31-28.4); 24.7 (9.73-62.7) (p<0.001)], positive family history of DM [3.08 (1.73-5.5) (p<0.001)], sedentary occupation [1.69 (1.10-2.59) (p = 0.016)], and BMI (18.5-22.9, 23-24.9 and ≥25 kg/m(2) vs <18.5 kg/m(2)) [2.03 (1.32-3.12) (p = 0.001); 0.87 (0.31-2.43) (p = 0.78); 1.44 (0.54-3.8) (p = 0.47)]; for pre-diabetes, risk factors were age (36-40, 41-45, 46-50, >50 years vs <30 years) [2.24 (1.1-4.55) (p = 0.026); 6.96 (3.3-14.7); 3.44 (1.83-6.48); 4.3 (2.25-8.2) (p<0.001)], waist circumference [<90 vs. ≥90 cm (men), <80 vs. ≥80 cm (women)] [3.05 (1.35-6.9) (p = 0.007)], smoking [1.92 (1.12-3.28) (p = 0.017)] and monthly income (5000-10,000 INR vs <5000 INR) [0.59 (0.37-0.94) (p = 0.026)]. DM risk was higher among pulmonary TB [3.06 (1.69-5.52) (p<0.001)], especially sputum positive, than non-pulmonary TB.
Interpretation: Nearly 50% of TB patients had either diabetes or pre-diabetes.