Dexcom G7 Accuracy and Reproducibility in the Intensive Care Unit

Objective: To evaluate the accuracy of Dexcom G7 continuous glucose monitor (CGM) in the intensive care unit (ICU) setting. Methods: We performed a prospective, single-center study in patients with known diagnosis of diabetes or stress hyperglycemia and treated with insulin. Two Dexcom G7 sensors were placed on the abdomen and/or upper arm. Blood glucose (BG) measurements obtained according to usual ICU care were paired with sensor glucose values, and accuracy metrics were analyzed. For further comparison, non-ICU patients were also studied. Results: The analyses included 30 participants with mean ± standard deviation age of 55 ± 12 years, with preexisting diabetes in 40% and stress hyperglycemia in 60%. A total of 1515 sensor-BG pairs were analyzed. The mean difference (bias) was -12 mg/dL (median: -6), and the mean relative absolute difference (RAD) was 16% (median: 12%). Mean RAD was 13% (median: 9%) using plasma glucose as the reference and 17% (median: 13%) using capillary glucose. For comparison, in 35 adults with type 2 diabetes in a non-ICU setting, the mean RAD was 15% (median: 13%). No meaningful differences were observed across the duration of time since sensor insertion. No correlation was found between mean RAD and severity of illness. Conclusions: Mean RAD of the Dexcom G7 sensor in the ICU setting was slightly higher than the outpatient use labeling, but was similar to a non-ICU hospital setting. Further studies are needed to determine whether CGM can be used nonadjunctively in an ICU setting for insulin management, including use of glucose trends and alarms for hypoglycemia or hyperglycemia.