Thresholds of Glycemia and the Outcomes of COVID-19 Complicated With Diabetes: A Retrospective Exploratory Study Using Continuous Glucose Monitoring

Objective: Although elevated glucose levels are reported to be associated with adverse outcomes of coronavirus disease 2019 (COVID-19), the optimal range of glucose in patients with COVID-19 and diabetes remains unknown. This study aimed to investigate the threshold of glycemia and its association with the outcomes of COVID-19.

Research design and methods: Glucose levels were assessed via intermittently scanned continuous glucose monitoring in 35 patients with an average period of 10.2 days. The percentages of time above range (TAR), time below range (TBR), time in range (TIR), and coefficient of variation (CV) were calculated. Composite adverse outcomes were defined as either the need for admission to intensive care unit, need for mechanic ventilation, or morbidity with critical illness.

Results: TARs with the threshold from 160 mg/dL - 200 mg/dL were all significantly associated with composite adverse outcomes after adjustment of covariates. Both TBR (<70 mg/dL) and TIR of 70 mg/dL - 160 mg/dL, but not mean sensor glucose level, were significantly associated with composite adverse outcomes and prolonged hospitalization. The multivariate-adjusted odds ratios of the CV of sensor glucose across its tertiles for composite adverse outcomes of COVID-19 were 1.00, 1.18, and 25.2, respectively.

Conclusions: Patients with diabetes and COVID-19 have an increased risk of adverse outcomes with glucose levels over 160 mg/dL, below 70 mg/dL, and a high CV. Therapies that improve these metrics of glycemic control may result in better prognoses for these patients.