Relationship between endothelial activation and stress index in delirium patients and seven-day mortality: A retrospective study using inverse probability of treatment weighting.

ObjectiveIn intensive care units (ICUs), delirium frequently occurs as an acute brain dysfunction and is linked to a higher risk of death. The Endothelial Activation and Stress Index (EASIX)-derived from three routine lab tests: lactate dehydrogenase, serum creatinine, and platelet count-has been proposed as a marker of endothelial injury and multi-organ failure. We sought to determine whether the EASIX score is associated with short-term mortality among patients with delirium.MethodsWe conducted a retrospective cohort study using data from the Medical Information Mart for Intensive Care IV database. The analysis included adults diagnosed with delirium. EASIX values were computed from measurements taken within the first 24 hours of ICU admission and then log2-transformed. The primary endpoint was all-cause mortality at 7 days; the secondary endpoint was all-cause mortality at 30 days. To evaluate the association, we used Cox proportional hazards models, restricted cubic splines, subgroup analyses, and inverse probability of treatment weighting (IPTW).ResultsAmong 8,378 delirium patients, 966 (11.53%) died within 7 days, and 1,893 (22.59%) died within 30 days. Higher log2-EASIX was independently associated with increased 7-day mortality (fully adjusted HR = 1.940, 95% CI: 1.574-2.391, p < 0.001) and 30-day mortality (HR = 1.720, 95% CI: 1.485-1.994, p < 0.001). A linear dose-response relationship was observed. Subgroup analyses for the 7-day mortality endpoint showed that the association was stronger in patients aged <60 years and those without sepsis (interaction P < 0.05 for both). The results remained robust after IPTW.ConclusionsEarly EASIX levels are independently associated with 7-day and 30-day mortality in delirium patients. As a simple score derived from routine laboratory parameters, the EASIX may serve as a potential adjunctive marker for risk assessment in this population.