The Epidemiology of Annular Pancreas in the United States: A Population-based Study.

BACKGROUND AND AIMS Annular pancreas is a rare congenital condition where the second part of the duodenum is encircled by pancreatic tissue. There is a scarcity of data on its natural history therefore, we aimed to evaluate the epidemiology of annular pancreas and identify underlying associations using a large database. METHODS A multi-institutional database (Explorys) was surveyed. A cohort of patients with a Systematized Nomenclature of Medicine-Clinical Terms diagnosis of "MRI, CT, EUS and/or ERCP" between April 2015 and April 2020 was identified. Subsequently a cohort of patients with history of "annular pancreas" was identified. RESULTS There were a total of 40,075,980 individuals in the database with 6,162,600 (15.38%) who had an magnetic resonance imaging, computed tomography, endoscopic retrograde cholangiopancreatography, and/or endoscopic ultrasound. There were 210 (3.4/100,000) had a diagnosis of annular pancreas. When compared with the control group, patients with annular pancreas were more likely to have a history of alcohol use, smoking, acute pancreatitis, chronic pancreatitis, gastritis, duodenitis, jaundice, and gastrointestinal outlet obstruction. CONCLUSIONS This is the largest study evaluating the epidemiology of annular pancreas. We found the estimated prevalence rate of annular pancreas to be 3.4/100,000 in those who had abdominal imaging. Annular pancreas was more likely to be diagnosed in patients with symptoms pertaining to acute or chronic pancreatitis, biliary, and gastric outlet obstruction.