Metformin and Covid-19: a systematic review of systematic reviews with meta-analysis

Abstract. Introduction: the COVID-19 infection, caused by severe Coronavirus 2 syndrome (Sars-Cov-2),
immediately appeared to be the most tragic global pandemic event of the twentieth century. Right from the
start of the pandemic, diabetic patients treated with metformin experienced a reduction in mortality and
complications from COVID-19 compared to those with different treatments or no treatment. Objective: The
main objective of the study was to observe the effects of metformin in diabetic hospitalized subjects infected
with COVID-19. Specifically, the outcomes of hospitalization in Intensive Care Units or death were examined.
Materials and Methods: A specific research PICOS was developed and the Pubmed, Embase and Scopus
databases were consulted down to April 30, 2022. To estimate the extent of the metformin effect and risk of
severity in SARS-CoV-2 infection, the Odd Ratio (OR) with 95% Confidence Interval (CI) published by
the authors of the selected systematic reviews was used. Results: from five systematic reviews 36 studies were
selected. The final meta-analysis showed that thanks to treatment with metformin, Type II Diabetes (DM2)
patients affected by COVID-19 had protection against risk of disease severity, complications (SE 0.80; CI
95%: 0.61 - 0.78; I2: 70.5%) and mortality (SE 0.69; CI 95%: 0.65 - 0.98; I2: 53,6%). Conclusions: More indepth
studies on the use of metformin, compared to other molecules, may be required to understand the real
protective potential of the drug against negative outcomes caused by COVID-19 infection in DM2 patients.
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