An Inverted U-shaped Relationship between Glycemic Variability and Mortality in Patients with Severe Pulmonary...

Hyperglycemia and glycemic variability (GV) are predictors of adverse outcomes in critically ill patients; however, their roles in pulmonary embolism (PE) remain unclear. This study investigated the association between the mean blood glucose (MBG), GV, and mortality in patients with PE.

A retrospective cohort study of patients with PE was conducted using the MIMIC-IV 3.0. GV was quantified using the coefficient of variation (CV). Patients were stratified according to tertiles of MBG and CV. Multivariable logistic regression, restricted cubic splines (RCS), and ROC curves were used to evaluate the associations with ICU and in-hospital mortality, supplemented by the threshold effect, sensitivity, and subgroup analyses.

Among the 1,493 PE patients, the ICU and in-hospital mortality rates were 12.99% and 20.90%, respectively. A higher MBG or CV was significantly associated with an increased risk of ICU mortality and in-hospital mortality. RCS revealed a linear association between MBG and mortality, whereas CV exhibited an inverted U-shaped relationship with inflection points at 38.523% (ICU) and 37.038% (in-hospital). For every 1% increase in CV to the left of the inflection point, the relative risks of ICU and in-hospital mortality increased by 0.035. The combined model (MBG + CV + ERS (European Respiratory Society)) achieved AUCs of 0.735 (ICU) and 0.693 (in-hospital) for mortality prediction.

MBG and CV are independent predictors of mortality in critically ill patients with PE, suggesting that optimal glycemic control may benefit this population.