Glycemic Ratio Is a Superior Predictor of Mortality Compared With Stress Hyperglycemia Ratio in Critically Ill Patients

Background: The glycemic ratio (GR), defined as the ratio of mean intensive care unit (ICU) blood glucose (BG) to estimated preadmission BG (EPBG), may provide superior prognostic insight compared with the single admission snapshot represented by the stress hyperglycemia ratio (SHR, the ratio of ICU admission BG to EPAG). Methods: This retrospective study included 4148 patients treated in a university-affiliated medical-surgical ICU from 2019 to 2023 who had >4 ICU BG measurements and a glycated hemoglobin (HbA1c) measured at admission. We compared SHR and GR prognostic ability for mortality, analyzed across prespecified GR and SHR bands, and calculated observed:expected mortality ratios (OEMRs). Results: We observed a more sharply defined J-shaped relationship between GR and mortality compared with that generated by SHR. Mortality in the reference band of 0.8 to <1.0 for GR and SHR mortality was 7.5% vs 10.9%, respectively ( P = .0087), and for the strata ≥1.4, mortality was 25.6% vs 20.5% ( P = .0376). Compared with the reference band, GR < 0.8 and GR > 1.0 had higher OEMR ( P < .0001 for each), but the OEMR for SHR <0.8 and >1.0 compared with the reference band was not significantly different. Conclusions: Glycemic ratio was superior to SHR as a predictor of mortality. This study demonstrates that a mean ICU BG level representing 80% to 100% of the patient’s EPBG was associated with the lowest mortality rate in a heterogeneous cohort of critically ill patients. These results may inform current BG management strategies and should be considered when designing future interventional trials in the critically ill.