Abstract: Original research Hospitalization and mortality in patients with COVID-­19 with or at risk of type 2 diabetes: data from five health systems in Pennsylvania and Maryland Hsin-­Chieh Yeh ‍ ‍,1 Jennifer L Kraschnewski,2,3 Lan Kong,3 Erik B Lehman,3 Emily S Heilbrunn,2 Pamela Williams,4 Jennifer M Poger,2 Erica Francis,2 Cindy L Bryce5 To cite: Yeh H-­C, Kraschnewski JL, Kong L, et al. Hospitalization and mortality in patients with COVID-­19 with or at risk of type 2 diabetes: data from five health systems in Pennsylvania and Maryland. BMJ Open Diab Res Care 2022;10:e002774. doi:10.1136/ bmjdrc-2022-002774 ► Additional supplemental material is published online only. To view, please visit the journal online (http://d​ x.​doi.​ org/​10.​1136/b​ mjdrc-​2022-​ 002774). Received 18 January 2022 Accepted 16 May 2022 © Author(s) (or their employer(s)) 2022. Re-­use permitted under CC BY-­NC. No commercial re-­use. See rights and permissions. Published by BMJ. For numbered affiliations see end of article. Correspondence to Hsin-­Chieh Yeh; ​hyeh1@​jhmi.e​ du ABSTRACT Objective To identify the demographic and clinical characteristics associated with adverse COVID-­19 outcomes across a 12-­month period in 2020 and 2021. Research design and methods We conducted a retrospective cohort study using electronic health records from five academic health systems in Pennsylvania and Maryland, including patients with COVID-­19 with type 2 diabetes or at risk of type 2 diabetes. Patients were classified based on 30-­day outcomes: (1) no hospitalization; (2) hospitalization only; or (3) a composite measure including admission to the intensive care unit (ICU), intubation, or death. Analyses were conducted in patients with type 2 diabetes and patients at risk of type 2 diabetes separately. Results We included 15 725 patients with COVID-­19 diagnoses between March 2020 and February 2021. Older age and higher Charlson Comorbidity Index scores were associated with higher odds of adverse outcomes, while COVID-­19 diagnoses later in the study period were associated with lower odds of severe outcomes. In patients with type 2 diabetes, individuals on insulin treatment had higher odds for ICU/intubation/death (OR=1.59, 95% CI 1.27 to 1.99), whereas those on metformin had lower odds (OR=0.56, 95% CI 0.45 to 0.71). Compared with non-­Hispanic White patients, Hispanic patients had higher odds of hospitalization in patients with type 2 diabetes (OR=1.73, 95% CI 1.36 to 2.19) or at risk of type 2 diabetes (OR=1.77, 95% CI 1.43 to 2.18.) Conclusions Adults who were older, in racial minority groups, had multiple chronic conditions or were on insulin treatment had higher risks for severe COVID-­19 outcomes. This study reinforced the urgency of preventing COVID-­19 and its complications in vulnerable populations. Trial registration number NCT02788903.