ObjectiveThe effects of diabetes medications on COVID-19 hospitalization outcomes have not been consistent. We sought to determine the effect of metformin, dipeptidyl peptidase-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 in patients with type 2 diabetes mellitus (DM). MethodsThis was a retrospective study of patients hospitalized with COVID-19 from a single hospital system. Univariate and multivariate analyses were performed that included demographic data, glycated hemoglobin, kidney function, smoking status, insurance, Charlson comorbidity index, number of diabetes medications, and use of angiotensin-converting enzyme inhibitors and statin prior to admission and glucocorticoids during admission. ResultsA total of 529 patients with type 2 DM were included in our final analysis. Neither metformin nor DPP4i prescription was associated with ICU admission, need for assisted ventilation, or mortality. Insulin prescription was associated with increased ICU admission but not with need for assisted ventilation or mortality. There was no association of any of these medications with development of renal insufficiency. ConclusionsIn this population, limited to type 2 DM and controlled for multiple variables that have not been consistently studied (such as a measure of general health, glycated hemoglobin, and insurance status), insulin prescription was associated with increased ICU admission. Metformin and DPP4i prescriptions did not have an association with the outcomes.