Effects of pre-existing metformin therapy on platelet count, serum creatinine, and hospitalization in COVID-19 patients with diabetes mellitus

COVID-19 infected individuals with type 2 diabetes mellitus are at higher risk of COVID-19 related complications. Previous studies have yielded varying results regarding the effect of metformin, an antidiabetic drug, on the clinical outcomes of COVID-19 patients. In this retrospective observational study, we aim to assess the impact of pre-existing oral antidiabetic treatment on the clinical outcomes of COVID-19.We analyzed in-patient data from hospital records, enrolling 150 COVID-19 patients with pre-existing diabetes mellitus. Among them, 75 were treated with metformin, while the remaining 75 were not. Exclusion criteria included patients with type I diabetes mellitus and those above 85 years of age. Fisher's exact test, Chi square test and unpaired t-test were used to analyze the data. There were no significant differences between the two groups in terms of age, gender, or drugs prescribed, aside from metformin. However, the metformin-treated group exhibited a significantly higher proportion of moderately ill patients compared to the non-metformin-treated group (P = 0.0011). Nonetheless, no statistically significant differences were observed between the groups regarding oxygen support requirement or duration of hospital stay. Notably, the metformin group showed distinct variations in haematological parameters, including lower serum creatinine levels (P = 0.0049), platelet count (P = 0.02) and HbA1c levels (P = 0.01). In conclusion, pre-existing metformin treatment did not impact the duration of hospital stay or the need for oxygen support in COVID-19 patients. However, the treatment did exert influence on other essential parameters.