Continuous Glucose Monitoring in the Intensive Care Unit: A Multicenter, Retrospective Hospital-Based Analysis

There is limited experience with continuous glucose monitoring (CGM) in intensive care units (ICUs). This study examined CGM accuracy and changes during hemodynamic instability in ICU patients with COVID-19.

We pooled data from three ICUs using CGM within a hybrid protocol combining point-of-care (POC) blood glucose testing with intermittent nonadjunctive CGM use. We compared sensor-meter agreement during lowest oxygen saturation, arterial partial pressure of oxygen (PaO₂), pH, or mean arterial pressure (MAP). Linear mixed models (LMM) were used to estimate the effects of clinical condition on estimates of sensor accuracy.

Of 169 patients, >80% had a history of diabetes, mean age was 61 ± 12 years, and 82%, 93%, and 62% received corticosteroids, mechanical ventilation and vasopressors respectively. The median percent CGM time in range (TIR, 70-180 mg/dL) was 72% (64.9-81.4), 70% (54.0-76.9), and 46% (26.6-68.5) for hospitals A, B, and C. Median time below 70 mg/dL was <0.1% for all hospitals. The absolute relative difference between CGM and POC pairs did not correlate with the lowest PaO₂, oxygen saturation, pH, or mean arterial pressure. In LMM adjusting for within subject and between subject variability, patients on dialysis had higher mean absolute relative difference (MARD, [coefficient = 2.39, P = .05]), while patients on mechanical ventilation had lower MARD ventilation (coefficient = -4.33, P = .05). Of the 6783 pairs 97.3% fell within Clare zones A and B.

These preliminary findings suggest CGM use does not appear to be significantly affected during critical illness. Confirmatory accuracy studies are needed.