Association between dysglycemia and mortality in patients with delirium: Based on the MIMIC-IV database.

OBJECTIVE: To investigate the influence of chronic hyperglycemia on the association between acute glycemic metrics and in-hospital mortality in patients with delirium. DESIGN: Observational cohort study. SETTING: Medical Information Mart for Intensive Care (MIMIC-IV) database. PATIENTS OR PARTICIPANTS: 3152 patients with delirium and available HbA1c measurements. INTERVENTIONS: None. MAIN VARIABLES OF INTEREST: Chronic hyperglycemia (categories based on HbA1c: <6.5%, 6.5-7.9%, ≥8.0%); acute glycemic metrics (mean glucose, number of hyperglycemic events, glucose variability, cumulative hyperglycemic dose); in-hospital mortality. RESULTS: Patients with HbA1c 6.5-7.9% showed higher mortality risk compared to the HbA1c <6.5% group (OR = 1.518; P = 0.040). The association between acute hyperglycemia and mortality was modified by chronic glycemic status: mean glucose was associated with mortality only in patients with HbA1c <6.5% (OR = 1.254; P < 0.001) and 6.5-7.9% (OR = 1.190; P = 0.009). The number of hyperglycemic events increased mortality risk only in non-diabetic patients (OR = 1.043; P = 0.005). Glycemic variability and cumulative hyperglycemic dose were associated with mortality exclusively in the HbA1c <6.5% group. CONCLUSIONS: The impact of acute glycemic dysregulation on mortality in delirious patients is moderated by underlying chronic hyperglycemia. Individualized glucose management based on chronic glycemic status may be preferable to uniform strict control.