18 Characteristics and 30-Day Outcomes of Acute Pancreatitis Admissions According to Etiology: A Nationwide Analysis

INTRODUCTION: Acute pancreatitis (AP) is a frequent cause of hospitalization in the United States. The major etiologies of AP are alcohol, choledocholithiasis, and drug-induced. We aim to describe demographic, clinical, and admission characteristics of AP hospitalizations according to etiology. In addition, we compared in-hospital and 30 day mortality and readmission outcomes among the three major AP subtypes. METHODS: We performed a retrospective analysis of the 2016 National Readmission Database. Hospital admissions of adults (>18 years of age) with the primary or secondary discharge diagnosis of AP. Specific ICD-10 codes were used to classify AP into biliary pancreatitis (K851), alcoholic pancreatitis (K852), and drug-induced pancreatitis (K853). Patients with nonspecific AP codes were classified as biliary pancreatitis if they had a concomitant diagnosis of cholelithiasis and as alcoholic AP if they had a diagnosis of alcohol abuse. Non-specific AP admissions were excluded. Characteristics and 30-day outcomes of the three groups were compared using the X-square test for categorical variables and the one-way analysis of variance (ANOVA) for continuous variables. RESULTS: A total of 81,382 admissions met the inclusion criteria: 32,459 had biliary AP, 46,438 alcoholic AP, and 2,485 drug-induced AP. Patients with alcoholic AP were more likely to be male (69.1%) and younger (mean age 46.6) compared to the other groups. Patients with biliary AP were more likely to develop cholangitis (1.8%) compared to the other groups (≤0.2%). HIV was more associated with drug-induced pancreatitis (1.4%) compared to the other groups (≤0.4%). Mean length of stay was longest (5.9 days) and mean costs were highest ($15,367) in biliary AP. These were lowest in drug induced AP (4.2 days and $9413, respectively). In-hospital mortality (0.9%) and 30-day mortality (1.3%) was highest in biliary AP compared to the other groups. Thirty day- readmissions were highest in alcoholic AP (14.3%) compared to drug induced AP (11.5%) and biliary AP (10.1%). CONCLUSION: In this large, nationally representative patient sample, drug induced AP had the lowest length of stay and costs, while alcoholic AP had the highest 30-day readmission rates (14.3%). Biliary pancreatitis was associated with the highest in-hospital and 30-day mortality. Knowledge of these findings may allow us to design and target future studies to mitigate the high readmission rates in alcoholic pancreatitis, and the complications and mortality in biliary pancreatitis.