Age-related vulnerability and clinical outcomes in acute pancreatitis: a stratified cohort study of 1,034 patients

BACKGROUND: Acute pancreatitis (AP) demonstrates substantial heterogeneity across adult age groups; however, the relative contributions of chronological age, baseline vulnerability, acute organ dysfunction, and local disease complexity to short-term outcomes remain incompletely understood. METHODS: This retrospective cohort study included 1,034 adults admitted with AP to the First Affiliated Hospital of Nanchang University between January 2018 and April 2021. Patients were stratified into three age groups (18-40, 41-60, and 61-80 years). Clinical characteristics, organ dysfunction, local complications, interventions, and short-term outcomes were compared across age groups. Organ failure and local complications were defined according to the Revised Atlanta Classification. Multivariable regression analyses were performed to identify factors independently associated with adverse outcomes, ICU admission, and length of hospital stay (LOS). RESULTS: Hypertriglyceridemia predominated in younger adults, whereas biliary pancreatitis was most common in older patients. Older adults demonstrated higher bilirubin, blood urea nitrogen, creatinine, BISAP, and APACHE II scores. Adverse outcomes increased with age; however, after adjustment, chronological age showed only a modest independent association with adverse outcomes (adjusted OR 1.07 per 1-year increase, 95% CI 1.04-1.09). In contrast, acute respiratory failure remained the strongest predictor of adverse outcomes (adjusted OR 15.6, 95% CI 7.69-33.97). ICU admission and prolonged hospitalization were driven primarily by acute organ dysfunction and local disease complexity rather than chronological age alone. CONCLUSION: Acute pancreatitis exhibits clear age-related differences in etiology and clinical presentation. However, short-term adverse outcomes are driven predominantly by acute organ dysfunction and local disease complexity, whereas chronological age may reflect increased baseline vulnerability rather than acting as the primary determinant of disease trajectory. These findings support age-informed assessment and emphasize the importance of early recognition and management of evolving organ dysfunction.