Purpose
Diabetes or hyperglycemia at admission are established risk factors for adverse outcomes during hospitalization for COVID-19, but the impact of prior glycemic control is not clear.
Methods
We examined the relationship between clinical predictors including acute and chronic glycemia and clinical outcomes including ICU admission, mechanical ventilation (MV), and mortality among 1,786 individuals with diabetes or hyperglycemia (glucose > 10 mmol/l twice in 24 hrs.) admitted from March 2020 through February 2021 with COVID-19 infection at 5 university hospitals in the eastern U.S.
Results
The cohort was 51.3% male, 53.3% White, 18.8% Black, 29.0% Hispanic, with age = 65.6 ± 14.4 yrs., BMI = 31.5 ± 7.9 kg/m2, glucose = 12.0 ± 7.5 mmol/l [216 ± 135 mg/dl], and HbA1c = 8.07 ± 2.25%. During hospitalization, 38.9% were admitted to the ICU, 22.9% received MV, and 10.6% died. Age (p < 0.001) and admission glucose (p = 0.014) but not HbA1c were associated with increased risk of mortality. Glycemic gap, defined as admission glucose minus estimated average glucose based on HbA1c, was a stronger predictor of mortality than either admission glucose or HbA1c alone (OR = 1.040 [95% CI: 1.019, 1.061] per mmol/l, p < 0.001). In an adjusted multivariable model, glycemic gap, age, BMI, and diabetic ketoacidosis on admission were associated with increased mortality, while higher eGFR and use of any diabetes medication were associated with lower mortality (p < 0.001).
Conclusions
Relative hyperglycemia, as measured by the admission glycemic gap, is an important marker of mortality risk in COVID-19.