Association of metformin with mortality or ARDS in patients with COVID-19 and type 2 diabetes: a retrospective cohort study

Jiang, Nan; Chen, Zhenyuan; Yin, Xiaoxv; Liu, Li; Yang, Heping; Tan, Xiangping; Wang, Jing; Li, Hui; Tian, Mengge; Lu, Zuxun; Xiong, Nian; Gong, Yanhong

Aims To determine the association between metformin use and mortality and ARDS incidence in patients with COVID-19 and type 2 diabetes. Methods This study was a multi-center retrospective analysis of COVID-19 patients with type 2 diabetes and admitted to four hospitals in Hubei province, China from December 31st, 2019 to March 31st, 2020. Patients were divided into two groups according to their exposure to metformin during hospitalization. The outcomes of interest were 30-day all-cause mortality and incidence of ARDS. We used mixed-effect Cox model and random effect logistic regression to evaluate the associations of metformin use with outcomes, adjusted for baseline characteristics. Results Of 328 patients with COVID-19 and type 2 diabetes included in the study cohort, 30.5% (100/328) were in the metformin group. In the mixed-effected model, metformin use was associated with the lower incidence of ARDS. There was no significant association between metformin use and 30-day all-cause mortality. Propensity score-matched analysis confirmed the results. In the subgroup analysis, metformin use was associated with the lower incidence of ARDS in females. Conclusions Metformin may have potential benefits in reducing the incidence of ARDS in patients with COVID-19 and type 2 diabetes. However, this benefit differs significantly by gender.