EVALUATING the Effects of Metformin on Glycemic Control and Mortality Rates of Hospitalized COVID-19 Patients with Type 2 Diabetes Mellitus: A Systematic Review and META-ANALYSIS

Abstract

Patients with diabetes mellitus have become direct and incidental prey for COVID-19. The purpose of this study is to summarize multiple observational studies into a single report to show if metformin gives a statistically significant difference in the blood glucose levels and mortality rate of hospitalized COVID-19 patients with type 2 diabetes mellitus. The research performed a systematic search on PubMed, Google Scholar, ProQuest, Cochrane Library, Elsevier, Science Direct, Sage Journals, Springer Link, MDPI, and Wiley Library from 2020-2024. Participants, intervention, comparator, and outcome (PICO) analysis were employed in the study selection. The intervention group was the patients who received metformin during admission in the hospital, and the control group (comparator) was the non-metformin users. The outcomes measured were the blood glucose levels of the patients and the mortality. One hundred nine studies were initially reviewed, however, only six studies met the inclusion criteria and were included in systematic review and meta-analysis. All six studies utilized observational research design, five were retrospective, and one was a prospective cohort. Three studies showed statistically significant differences (p<0.05) in blood glucose levels of the patients between metformin and non-metformin users. In fact, the blood glucose levels were lower in the non-metformin group. Three studies also reported a significant decrease in the mortality rate of the patients. The overall pooled result suggested that metformin may slightly lower the odds of mortality. There was no significant evidence of publication bias in the six studies included. In conclusion, metformin was not able to control and reduce the blood glucose levels of the patients. The mortality rate reduction effect of metformin was similar to non-metformin use.