Background: The effects of diabetes medications on COVID-19 hospitalization outcomes have not been consistent. We sought to determine the effect of metformin, DPP-4 inhibitors (DPP-4i), and insulin on admission to the intensive care unit (ICU), need for assisted ventilation, development of renal insufficiency, and mortality, in patients admitted with COVID-19 infection after controlling for clinical variables and other relevant diabetes-related medications.
Methods: This was a retrospective study of patients hospitalized with COVID-19 from a single hospital system. Univariate and multivariate analyses were performed. Demographic data, HbA1c, kidney function, smoking status, insurance, type of diabetes, Charlson comorbidity index, number of diabetes medications, use of angiotensin-converting enzyme inhibitors (ACEi) and statin prior to admission, and steroids during admission, were included as variables.
Results: On univariate analysis, hospitalized COVID-19 patients who were on metformin 90 days before admission were less likely to experience mortality (p=0.039). DPP-4i was not associated with any of the outcomes. Patients on insulin were more likely to require assisted ventilation (0.004), experience renal insufficiency (0.016) and be admitted to the ICU (p< 0.001). After multivariate analyses adjusting for factors, the protective association between metformin use and mortality, and the increase in risk of ventilation and development of renal insufficiency with insulin, were no longer found to be significant.
Conclusions: After controlling for multiple variables, metformin no longer had a protective effect on mortality, and insulin retained its association with ICU admission, in patients with diabetes hospitalized with COVID-19. DPP4i had a neutral effect.