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Metformin Lowers Mortality Risk for Patients who have Diabetes and Covid-19

Apr 27, 2021
 
Editor: David L. Joffe, BSPharm, CDE, FACA

Author: Adrian Gavre, PharmD Candidate, Philadelphia College of Osteopathic Medicine; Oluwatayo Ishola, PharmD Candidate, South College School of Pharmacy; Shalonda Kimble, PharmD Candidate, South College School of Pharmacy

Diabetes patients who were taking metformin before contracting Covid-19 had dramatically different mortality outcomes.

Patients who have diabetes are at a greater risk of contracting Covid-19 and are more likely to die than patients who do not have diabetes. The increased death toll from the virus has been linked to advanced age, racial disparity, and comorbid conditions, including disease states like hypertension, diabetes, heart conditions, and obesity. A recent study published by Frontiers in Endocrinology found that patients with diabetes who received metformin reduced their mortality rates significantly. 

 

The study was designed to identify patient characteristics and factors affecting mortality in COVID-19. This retrospective study analyzed health records from 25,326 individuals who tested positive for Covid-19 between February-June of 2020. The individuals who participated in the study were categorized as COVID-19 positive or negative based on the viral nucleic acid testing in respiratory specimens. The primary outcome was mortality in Covid-19 patients. The study also aimed to establish an association between Covid-19 and mortality based on a patient’s baseline characteristics and comorbidities. 

The study found that the odds ratio of contracting Covid-19 was significantly higher in the following patient populations: Blacks/African Americans (OR 2.6; 95% CI 2.19–3.10; p<0.0001) patients with obesity (OR 1.93; 95% CI 1.64–2.28; p<0.0001), patients with hypertension (OR 2.46; 95% CI 2.07–2.93; p<0.0001) and patients with diabetes (OR 2.11; 95% CI 1.78–2.48; p<0.0001). Patients with diabetes had a significantly higher mortality rate (OR 3.62; 95% CI 2.11–6.2; p<0.0001). Diabetes was found to be an independent risk factor even when correcting for confounding factors. Patients who had diabetes and who were also receiving metformin treatment before contracting Covid-19 were found to have statistically lower mortality rates (OR 0.33; 95% CI 0.13–0.84; p=0.0210). Higher age and male sex were associated with the highest rates of mortality within the diabetes group. There was no significant difference between patients who had type 1 diabetes and type 2 diabetes. Insulin had no considerable effect regarding lowering mortality. 

Overall mortality in the subject group was 11%, with significant variance between subgroups. Roughly 93% of all deaths occurred in patients over 50 years of age, and more than 67% of all deaths occurred in patients with diabetes. However, when patients with diabetes were on metformin therapy before contracting Covid-19, the mortality rate was dramatically lower. Patients with diabetes had a 24% chance of mortality, and patients who had diabetes and were on metformin had an 11% chance of mortality, which is roughly equivalent to the overall mortality. 

The study did have limitations. One of the restrictions was the size of the study.  There was no analysis to incorporate additional subcategories.  Results might have been slightly different if the patients used other diabetic drugs. One unique feature of the study was the diverse community of African Americans. Metformin users did not have lower glucose levels than individuals who did not use metformin. This increased glucose suggested that metabolic control probably did not occur and was not a factor in the improved outcome result observed. 

Practice Pearls: 

  • Metformin can reduce the odds of dying in individuals who have Covid-19 and are on therapy for diabetes treatment.
  • The populations most at risk for contracting Covid-19 include Blacks/African Americans (OR 2.6; 95% CI 2.19–3.10; p<0.0001), patients with obesity (OR 1.93; 95% CI 1.64–2.28; p<0.0001), patients with hypertension (OR 2.46; 95% CI 2.07–2.93; p<0.0001), and patients with diabetes (OR 2.11; 95% CI 1.78–2.48; p<0.0001).
  • Patients who had diabetes and who were also receiving metformin treatment before contracting Covid-19 were found to have statistically lower mortality rates (OR 0.33; 95% CI 0.13–0.84; p=0.0210).

 

Crouse, A., Grimes, T. Metformin use is associated with reduced mortality in a diverse population with covid-19 and diabetes. Frontiers in Endocrinology, December 07, 2020. 

 

Adrian Gavre, PharmD Candidate, Philadelphia College of Osteopathic Medicine  

Oluwatayo Ishola, PharmD Candidate, South College School of Pharmacy 

Shalonda Kimble, PharmD Candidate, South College School of Pharmacy