Higher glycated  hemoglobin levels (HbA1c) and insulin use were associated with increased risk of hospitalization, admission to the intensive care unit (ICU), and death in veterans with diabetes and coronavirus disease 2019 (COVID-19), according to research findings published in Diabetes Care.

The study was an analysis of a data repository from the Veterans Health Administration’s integrated electronic medical record, which included a COVID-19 Shared Data Resource comprising veterans who were tested for the novel coronavirus. Researchers focused on veteran enrollees with diabetes and ≥1 positive nasal swab tests s for severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2/COVID-19) collected between March 2020 and March 2021. The investigators evaluated associations between HbA1c  and glucose-lowering treatments with hospitalization, intensive care unit (ICU) admission, and 30-day mortality during a 4.4-month follow-up period (follow-up range, <1–13.1).

A total of 64,892 veterans (mean age, 67.7 years) with diabetes and COVID-19 were included in the analysis. The vast majority of these patients were men, with women representing 6% (n=3872) of the study group. Approximately 52% of patients had an HbA1c <7.0%. During the 30-day period following a COVID-19 diagnosis, 21% of patients were hospitalized, 7% of patients were admitted to the ICU, and 8% of patients died.

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An HbA1c ≥9.0% was significantly associated with higher odds of hospitalization (odds ratio [OR], 1.27; 95% CI, 1.19–1.35), ICU admission (OR, 1.28; 95% CI, 1.15–1.42), and mortality (OR, 1.30; 95% CI, 1.17–1.44) within 30 days among those diagnosed with COVID-19, compared with an HbA1c <7.0%. An HbA1c ≥9.0% vs <7.0% was also associated with a higher risk of death over a 4.4-month follow-up period (hazard ratio [HR], 1.22; 95% CI, 1.12–1.32) Insulin use was also associated with higher odds of hospitalization (OR, 1.12; 95% CI, 1.07–1.18), ICU admission (OR, 1.12; 95% CI, 1.04–1.22), and death (OR, 1.18; 95% CI, 1.09–1.27) within 30 days of a COVID-19 diagnosis, as well as a higher risk of death during the follow-up period (HR, 1.20; 95% CI, 1.13–1.27).

In contrast, the researchers observed lower odds of hospitalization in veterans using sodium–glucose cotransporter 2 inhibitors (SGLT2i; OR, 0.92; 95% CI, 0.85–0.99), glucagon-like peptide-1 receptor agonists (GLP-1RA; OR, 0.88; 95% CI, 0.81–0.96), or angiotensin receptor blockers (OR, 0.94; 95% CI, 0.89–0.99).The use of metformin was also associated with lower odds of death within 30 days of a COVID-19 diagnosis (OR, 0.84; 95% CI, 0.78–0.91) and the risk of death during follow-up (HR, 0.84; 95% CI, 0.79–0.89). The use of SGLT2i was also associated with lower odds of death within 30 days (OR, 0.82; 95% CI, 0.72–0.94) of a COVID-19 diagnosis as well as risk of death during follow-up (HR, 0.82; 95% CI, 0.74–0.92). This lowered risk of complications lasted more than 13 months after a diagnosis of COVID-19.

Limitations of the study included the lack of data on prescriptions, hospitalizations, and COVID-19 diagnoses that occurred outside the Veteran’s Health Administration, which were not captured in the study data. Duration of diabetes and whether patients had type 1 diabetes (T1D) or type 2 diabetes (T2D) were also not accounted for, although it was presumed most veterans had T2D, as people with T1D are not eligible for military service.

The researchers concluded that “future studies are needed to identify risk factors for long-term adverse outcomes after COVID-19 among individuals with diabetes.”


Wander PL, Lowy E, Beste LA, et al. Prior glucose-lowering medication use and 30-day outcomes among 64,892 veterans with diabetes and COVID-19. Diabetes Care. Published online October 6, 2021. doi:10.2337/dc21-1351