Association Between Diabetes Severity and Risks of COVID-19 Infection and Outcomes

Background Little is known about whether diabetes increases the risk of COVID-19 infection and whether measures of diabetes severity are related to COVID-19 outcomes. Objective Investigate diabetes severity measures as potential risk factors for COVID-19 infection and COVID-19 outcomes. Design, Participants, Measures In integrated healthcare systems in Colorado, Oregon, and Washington, we identified a cohort of adults on February 29, 2020 ( n = 1,086,918) and conducted follow-up through February 28, 2021. Electronic health data and death certificates were used to identify markers of diabetes severity, covariates, and outcomes. Outcomes were COVID-19 infection (positive nucleic acid antigen test, COVID-19 hospitalization, or COVID-19 death) and severe COVID-19 (invasive mechanical ventilation or COVID-19 death). Individuals with diabetes ( n = 142,340) and categories of diabetes severity measures were compared with a referent group with no diabetes ( n = 944,578), adjusting for demographic variables, neighborhood deprivation index, body mass index, and comorbidities. Results Of 30,935 patients with COVID-19 infection, 996 met the criteria for severe COVID-19. Type 1 (odds ratio [OR] 1.41, 95% CI 1.27–1.57) and type 2 diabetes (OR 1.27, 95% CI 1.23–1.31) were associated with increased risk of COVID-19 infection. Insulin treatment was associated with greater COVID-19 infection risk (OR 1.43, 95% CI 1.34–1.52) than treatment with non-insulin drugs (OR 1.26, 95% 1.20–1.33) or no treatment (OR 1.24; 1.18–1.29). The relationship between glycemic control and COVID-19 infection risk was dose-dependent: from an OR of 1.21 (95% CI 1.15–1.26) for hemoglobin A1c (HbA1c) < 7% to an OR of 1.62 (95% CI 1.51–1.75) for HbA1c ≥ 9%. Risk factors for severe COVID-19 were type 1 diabetes (OR 2.87; 95% CI 1.99–4.15), type 2 diabetes (OR 1.80; 95% CI 1.55–2.09), insulin treatment (OR 2.65; 95% CI 2.13–3.28), and HbA1c ≥ 9% (OR 2.61; 95% CI 1.94–3.52). Conclusions Diabetes and greater diabetes severity were associated with increased risks of COVID-19 infection and worse COVID-19 outcomes.