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.