Impact of delirium on clinical outcomes in critically ill patients with acute pancreatitis: A propensity score-matched study

Objective Delirium is an established predictor of adverse outcomes in general ICU populations, but its specific prognostic impact in critically ill patients with acute pancreatitis (AP) remains unclear. This study aimed to evaluate the independent association between ICU-acquired delirium and clinical outcomes in this high-risk population. Methods This retrospective cohort study utilized data from the MIMIC-IV database (2008–2022). Critically ill adults with AP were included and stratified by the presence of ICU-acquired delirium, assessed using the CAM-ICU. The primary outcome was 90-day all-cause mortality. Secondary outcomes included 90-day unplanned readmission, emergency department revisits, and a composite adverse outcome. Propensity score matching (PSM) was performed to balance baseline characteristics, generating 178 matched pairs. Multivariable Cox regression with four sequential models and sensitivity analyses were conducted to assess robustness. Results Among 594 included patients, 44.6% (265/594) developed delirium. After PSM, baseline characteristics were well-balanced. Delirium was independently associated with increased 90-day all-cause mortality (aHR=1.91, 95% CI: 1.04–3.50; P=0.038) and a higher risk of the composite adverse outcome (aHR=1.84, 95% CI: 1.24–2.73; P=0.002). The association with unplanned readmission remained significant after full adjustment (aHR=1.87, 95% CI: 1.20–2.92; P=0.006), while the association with ED revisits did not reach statistical significance. Sensitivity analyses confirmed the robustness of the primary findings. Conclusions In critically ill patients with AP, ICU-acquired delirium was an independent predictor of increased 90-day mortality, unplanned readmission and composite adverse outcomes. These findings highlight delirium as a significant prognostic factor, underscoring the importance of routine screening and targeted management in this vulnerable population.