Metformin use is associated with a reduced risk of mortality in patients with diabetes hospitalised for COVID-19.
Diabetes & metabolism. 2021;(5):101216
AIMS: Metformin exerts anti-inflammatory and immunosuppressive effects. We addressed the impact of prior metformin use on prognosis in patients with type 2 diabetes hospitalised for COVID-19. METHODS CORONADO is a nationwide observational study that included patients with diabetes hospitalised for COVID-19 between March 10 and April 10, 2020 in 68 French centres. The primary outcome combined tracheal intubation and/or death within 7 days of admission. A Kaplan-Meier survival curve was reported for death up to day 28. The association between metformin use and outcomes was then estimated in a logistic regression analysis after applying a propensity score inverse probability of treatment weighting approach. RESULTS Among the 2449 patients included, 1496 were metformin users and 953 were not. Compared with non-users, metformin users were younger with a lower prevalence of diabetic complications, but had more severe features of COVID-19 on admission. The primary endpoint occurred in 28.0% of metformin users (vs 29.0% in non-users, P = 0.6134) on day 7 and in 32.6% (vs 38.7%, P = 0.0023) on day 28. The mortality rate was lower in metformin users on day 7 (8.2 vs 16.1%, P < 0.0001) and on day 28 (16.0 vs 28.6%, P < 0.0001). After propensity score weighting was applied, the odds ratios for primary outcome and death (OR [95%CI], metformin users vs non-users) were 0.838 [0.649-1.082] and 0.688 [0.470-1.007] on day 7, then 0.783 [0.615-0.996] and 0.710 [0.537-0.938] on day 28, respectively. CONCLUSION Metformin use appeared to be associated with a lower risk of death in patients with diabetes hospitalised for COVID-19.
Metformin and COVID-19: From cellular mechanisms to reduced mortality.
Diabetes & metabolism. 2020;(6):423-426
Type 2 diabetes mellitus (T2DM) is associated with both poorer clinical outcomes during the COVID-19 pandemic and an increased risk of death in such hospitalized patients. While the role of glucose control has been emphasized to improve the prognosis, the impact of different glucose-lowering agents remains largely unknown. Metformin remains the first-line pharmacological choice for the management of hyperglycaemia in T2DM. Because metformin exerts various effects beyond its glucose-lowering action, among which are anti-inflammatory effects, it may be speculated that this biguanide might positively influence the prognosis of patients with T2DM hospitalized for COVID-19. The present concise review summarizes the available data from observational retrospective studies that have shown a reduction in mortality in metformin users compared with non-users, and briefly discusses the potential underlying mechanisms that might perhaps explain this favourable impact. However, given the potential confounders inherently found in observational studies, caution is required before drawing any firm conclusions in the absence of randomized controlled trials.
Mortality and other adverse outcomes in patients with type 2 diabetes mellitus admitted for COVID-19 in association with glucose-lowering drugs: a nationwide cohort study.
BMC medicine. 2020;(1):359
BACKGROUND Limited evidence exists on the role of glucose-lowering drugs in patients with COVID-19. Our main objective was to examine the association between in-hospital death and each routine at-home glucose-lowering drug both individually and in combination with metformin in patients with type 2 diabetes mellitus admitted for COVID-19. We also evaluated their association with the composite outcome of the need for ICU admission, invasive and non-invasive mechanical ventilation, or in-hospital death as well as on the development of in-hospital complications and a long-time hospital stay. METHODS We selected all patients with type 2 diabetes mellitus in the Spanish Society of Internal Medicine's registry of COVID-19 patients (SEMI-COVID-19 Registry). It is an ongoing, observational, multicenter, nationwide cohort of patients admitted for COVID-19 in Spain from March 1, 2020. Each glucose-lowering drug user was matched with a user of other glucose-lowering drugs in a 1:1 manner by propensity scores. In order to assess the adequacy of propensity score matching, we used the standardized mean difference found in patient characteristics after matching. There was considered to be a significant imbalance in the group if a standardized mean difference > 10% was found. To evaluate the association between treatment and study outcomes, both conditional logit and mixed effect logistic regressions were used when the sample size was ≥ 100. RESULTS A total of 2666 patients were found in the SEMI-COVID-19 Registry, 1297 on glucose-lowering drugs in monotherapy and 465 in combination with metformin. After propensity matching, 249 patients on metformin, 105 on dipeptidyl peptidase-4 inhibitors, 129 on insulin, 127 on metformin/dipeptidyl peptidase-4 inhibitors, 34 on metformin/sodium-glucose cotransporter 2 inhibitor, and 67 on metformin/insulin were selected. No at-home glucose-lowering drugs showed a significant association with in-hospital death; the composite outcome of the need of intensive care unit admission, mechanical ventilation, or in-hospital death; in-hospital complications; or long-time hospital stays. CONCLUSIONS In patients with type 2 diabetes mellitus admitted for COVID-19, at-home glucose-lowering drugs showed no significant association with mortality and adverse outcomes. Given the close relationship between diabetes and COVID-19 and the limited evidence on the role of glucose-lowering drugs, prospective studies are needed.