According to a recent study published in Clinical Infectious Diseases, the presence of diabetes mellitus (DM) increases risk for mortality during tuberculosis treatment, but metformin use may counteract that risk.
In this retrospective cohort study, researchers evaluated 2416 patients ≥13 years of age undergoing treatment for pulmonary tuberculosis. The association of DM and metformin use with mortality during tuberculosis treatment was assessed.
After adjusting for age, sex, chronic kidney disease, cancer, hepatitis C, tobacco use, cavitary disease, and treatment adherence, DM increased the risk for death during treatment compared with the risk for participants without DM (odds ratio [OR] 1.91; 95% CI, 1.51-2.40). Moreover, diabetes also increased the risk for remaining culture positive at 2 months (OR 1.72; 95% CI, 1.25-2.38).
Metformin use in those with DM was associated with a decreased mortality rate during tuberculosis treatment (hazard ratio [HR] 0.56; 95% CI, 0.39-0.82). When compared with patients who did not have DM, patients who received metformin had a similar mortality rate (HR 1.02; 95% CI, 0.72-1.45).
The researchers noted that those with DM who used metformin had similar or lower blood glucose levels compared with people with DM who did not use metformin, indicating that the improved survival associated with metformin may be unrelated to the blood glucose-lowering effects of the drug.
Dr Nicholas Degner, from the Department of Internal Medicine at Stanford University and lead author on the study, discussed the importance of the findings, noting that “studies to date exploring the effect of diabetes on tuberculosis treatment outcomes have not fully controlled for the many comorbidities that accompany diabetes.”
He called the results indicating that metformin may decrease the risk for death “promising,” but concluded that prospective controlled trials would need to be performed first.
Degner NR, Wang J-Y, Golub JE, Karakousis PC. Metformin use reverses the increased mortality associated with diabetes mellitus during tuberculosis treatment [published online September 19, 2017]. Clin Infect Dis. doi: 10.1093/cid/cix819