Background: Evidence shows that diabetes raises the probability of contracting COVID-19 and associated complications. We hypothesize that metformin, being pleiotropic, may improve COVID-19 in diabetics.
Methods: A retrospective cohort study was conducted with 421 COVID-19 patients with diabetes, hospitalized between 1st April 2020 and 31st March 2022 in a tertiary-care hospital. Patients with metformin or its combination constituted the study cohort (SC; n = 221), while other antidiabetics constituted the reference cohort (RC; n = 200).
Results: SC and RC were matched for mean age ± SD (SC: 53.3 ± 5.7 vs. RC: 54.3 ± 8.2 years). The mean length of hospitalization (days) was significantly shorter in SC (9.0 ± 5.7) than in RC (12.7 ± 6) (p < 0.02). Metformin use was associated with reduction in mortality risk (OR: 0.106, 95% CI = 0.039-0.287; p < 0.001). Moreover, SC also improved levels of LDH (OR: 0.243, 95% CI = 0.104-0.566; p < 0.001), CRP (OR: 0.281, 95% CI = 0.120-0.659; p < 0.004), and D-dimer (OR: 0.220, 95% CI = 0.089-0.539; p < 0.001) than RC. The calculated number needed to treat for metformin was 3.1.
Conclusion: Metformin users have a decrease in hospital stay and mortality rates and improvement in LDH, CRP, and D-dimer levels. Therefore, metformin might protect against mortality in COVID-19 with diabetes.
Keywords: COVID-19; SARS-CoV-2; diabetes; metformin; mortality.
The study observed that COVID-19 patients with diabetes on metformin had lower CRP levels than those on other antidiabetics.The incidence and mortality risk were significantly found to be reduced in metformin users than in non-metformin users.Improvement in D-dimer, LDH, and CRP levels were also associated with reduced mortality risk in metformin users.The number needed to treat shows three patients would have to receive metformin to prevent one additional death in COVID-19 with diabetes.Therefore, metformin could be beneficial in COVID-19, in addition to its effect on diabetes.