Glycemic Gap as a Predictor of Outcome in Critically Ill Patients with Type 2 Diabetes Mellitus

Abstract

Objective: To evaluate the association between glycemic gap and clinical outcomes in critically ill patients with type 2 diabetes mellitus.Material and Methods: This prospective study was conducted at a tertiary care centre in South India. A total of 100 critically ill patients with diabetes mellitus admitted to the intensive care unit (ICU) between February 2021 and October 2022 were included. Admission blood glucose, HbA1c, A1c-derived average glucose (ADAG), glycemic gap, and acute physiology and chronic health evaluation-II (APACHE II) score were recorded. Patients were followed up until hospital discharge or death, and outcomes were analysed.Results: Of the 100 patients, 76 survived and 24 were non-survivors (in-hospital). The mean glycemic gap was significantly higher among non-survivors than survivors (97.3 vs. 67.8 mg/dL; p-value=0.018). Patients with a glycemic gap >56 mg/dL had significantly higher mortality and adverse outcomes compared with those with a lower glycemic gap. The glycemic gap showed better discriminatory ability than HbA1c and admission blood glucose, with area under the characteristic curve (AUCs) of 0.672, 0.556, and 0.539, respectively.Conclusion: A higher glycemic gap was associated with increased mortality and adverse outcomes in critically ill patients with diabetes mellitus. Although its predictive performance was modest, the glycemic gap may serve as a supplementary indicator when used alongside established prognostic scoring systems.