Pulmonary tuberculosis and diabetes mellitus: Clinical profile and outcomes

Background: India is endemic for Tuberculosis (TB), contributing to the world's highest number of active cases. Diabetes (DM), with its increasing burden in India, could contribute to adverse outcomes among patients with TB. Methods: Consecutive patients with sputum smear positive pulmonary tuberculosis were included in the study. We defined cases as those patients with diabetes at recruitment. Controls were non diabetics (NDM). Sputum samples for AFB smears, AFB culture and Xpert PCR along with blood samples for glycosylated Haemoglobin and glucose levels were collected at recruitment and at 6 months from patients with sputum positive pulmonary TB. Blood glucose levels and sputum smears were repeated at 2 months and monthly till they tested negative. The primary outcome studied was mortality at 6 month follow-up. The secondary outcomes included the time to conversion of sputum smears and cure rates between cases and controls. Results: We recruited 124 patients of which 68 were cases. Mortality after therapy was 15% in cases and 7% in controls, however, the difference was not statistically significant. Equal proportions in each group (Diabetics: 9% vs. NDM 9%) had persistent smear positivity at 2 months. There was no association between delayed sputum conversion and uncontrolled diabetes. Only about 57% of cases and 50% of controls were documented to have completed treatment or been cured. A significant reduction in HbA1c after 6 months of Antituberculous therapy was noted among the cases. [Mean difference - 1.76, P-value - 0.001, 95% CI of difference - (1.01 - 2.52)]. Conclusions: Diabetes did not have adverse outcomes in the form of increased mortality or delayed sputum conversion rates. The high proportion of loss to follow-up seems to be a trend of concern, which should be addressed emergently.