Evaluating the Clinical Characteristics and Outcomes of Idiopathic Acute Pancreatitis

Up to 30% of acute pancreatitis (AP) cases do not have an established etiology (idiopathic AP [IAP]). We evaluated the characteristics and outcomes of hospitalized IAP patients compared with those with established AP cause (non-IAP).A retrospective study of AP patients admitted to a single center from 2008 to 2018 was performed. Patients were divided into IAP and non-IAP groups. Outcomes included mortality, 30-day and 1-year readmission, length of stay (LOS), intensive care unit admissions, and complications.Of 878 AP patients, 338 had IAP and 540 non-IAP (234 gallstone, 178 alcohol). Groups had similar demographics, Charlson Comorbidity Index, and pancreatitis severity. The IAP patients had more 1-year readmissions (0.64 vs 0.55, P = 0.006) but similar 30-day readmissions and mortality. Patients with IAP had shorter LOS (4.98 vs 5.99 days, P = 0.01), and fewer intensive care unit admissions (3.25% vs 6.85%, P = 0.03) and extrapancreatic complications (15.4% vs 25.2%, P = 0.001). There was no difference in pain level between groups.The IAP patients tend to have more readmissions in 1 year, but less severe presentations, shorter LOS, and fewer complications. Readmission rates may be related to lack of defined etiology and treatment to prevent recurrence.