Effects of Metformin on COVID-19 Patients with Type 2 Diabetes: A Retrospective Study

Purpose: The pandemic of coronavirus disease 2019 (COVID-19) has highlighted the intricate relationship between underlying conditions and death. We designed this study to determine whether metformin therapy for type 2 diabetes mellitus (T2D) is associated with low in-hospital mortality in patients hospitalized for COVID-19. Materials and Methods: This was a retrospective study including patients with COVID-19 and T2D in Wuhan, from February 4th to April 11th, 2020. Patients were divided into two groups according to metformin exposure. The hazard ratio (HR) of COVID-19-related mortality and invasive mechanical ventilation was estimated using Cox regression. Results: There were 571 T2D patients among the 4330 confirmed COVID-19 patients. Of those patients, 241 received metformin therapy. The in-hospital mortality and invasive mechanical ventilation of metformin group was lower than non-metformin group. In the multivariate model, metformin use was linked to a decreased in-hospital mortality and invasive mechanical ventilation when compared with that of the control group (HR: 0.376 [95% CI 0.154-0.922]; P = 0.033). Conclusion: Our study indicated that metformin therapy was associated with decreased death risk in COVID-19 patients with T2D.