Association between prior metformin therapy and sepsis in diabetes patients: a nationwide sample cohort study

Purpose There have been no large-scale studies on whether metformin therapy might have a potential benefit for lowering mortality. Thus, this study aimed to investigate the association between prior metformin therapy and the development of sepsis as well as the association between prior metformin therapy and 30-day mortality in sepsis patients. Methods We evaluated adult diabetes patients registered in the 2010 sample cohort database of the National Health Insurance Service in South Korea. Diabetes was identified according to the International Classification of Disease-10 diagnostic system (E10-E14). The cohorts were divided into the metformin user group (i.e., those who had been prescribed continuous oral metformin over a period of >= 90 days) and the control group (i.e., all other individuals). The primary endpoint was the development of sepsis between 2011 and 2015, and the secondary endpoint was 30-day mortality among diabetes patients diagnosed with sepsis. Results In total, 77,337 patients (34,041 in the metformin user group and 43,296 in the control group) were included in the analysis, among whom 2512 patients (3.2%) were diagnosed with sepsis between 2011 and 2015. After propensity score adjustment, metformin use was not significantly associated with both the risk of sepsis (OR: 0.92, 95%CI 0.82-1.03; P = 0.143) and the risk of 30-day mortality after diagnosis of sepsis (OR: 0.94, 95%CI 0.75-1.17; P = 0.571). Conclusions Prior metformin therapy was not significantly associated with the risk of sepsis and 30-day mortality after diagnosis of sepsis among diabetes patients.