Acute pouchitis is the most common complication after a restorative proctocolectomy with ileal pouch–anal anastomosis (IPAA) for ulcerative colitis, affecting 40% of patients within the first year after surgery.1 Although up to 80% of patients can develop pouchitis symptoms,2,3 substantial gaps remain in our understanding of the epidemiology and burden of pouchitis. Administrative claims have been used to advance the knowledge of other areas of inflammatory bowel disease4–6; however, a prerequisite to conducting such studies in pouchitis is a valid, reliable case-finding algorithm. Given concerns that the International Classification of Diseases (ICD) code for pouchitis may not be reliably used by clinicians (resulting in a low sensitivity), the objectives of the study were to (1) develop a series of case-finding definitions for acute pouchitis and (2) compare the performance of these case-finding definitions to that of a single ICD code for pouchitis
