Association between stress hyperglycemia ratio and 72-hour delirium in critically ill patients: A retrospective cohort study from the MIMIC-IV database.

Background: Stress hyperglycemia, quantified by the stress hyperglycemia ratio (SHR), reflects the acute glycemic response relative to chronic glycemic status. Its association with intensive care unit (ICU)-acquired delirium and the mechanistic pathway linking SHR to mortality remain poorly characterized. Methods: In this retrospective cohort study of 7397 critically ill adults from the MIMIC-IV database, we examined the association between SHR and 72-h delirium using multivariable Cox proportional-hazards regression. Restricted cubic spline analysis was used to characterize the dose-response relationship. Mediation analyses were employed to evaluate whether delirium mediates the effect of SHR on 28-day and 365-day all-cause mortality, with E-value analysis to assess robustness to unmeasured confounding. Results: Overall, 1259 patients developed delirium within 72 h of ICU admission, with a median onset of 11.25 h. Patients in the highest SHR quartile had a significantly higher hazard of delirium than those in the lowest quartile (HR 1.23, 95% CI 1.04-1.45; Conclusions: Elevated SHR is independently associated with an increased risk of ICU-acquired delirium in a linear, dose-dependent manner, and delirium fully mediates the indirect effect of SHR on short- and long-term mortality. These findings support SHR as a readily obtainable biomarker for early delirium risk stratification among critically ill patients.