Heterogeneity of definition of upper gastrointestinal tract in different guidelines of Crohn's disease: A scoping review

Crohn's Disease (CD) can affect any part of the gastrointestinal (GI) tract, including the upper GI tract (UGIT). However, the definitions and classifications of upper GI CD (UGICD) vary. We conducted a scoping review to explore how UGIT and UGICD are defined and to assess the heterogeneity of these definitions in published CD guidelines, aiming to inform future initiatives for harmonizing definitions. We conducted a search of MEDLINE and Embase for English-language guidelines on CD that mentioned upper GI-related terms in the titles, abstracts, or keywords from inception until 26 July 2024. Definitions of UGIT and UGICD were summarized descriptively. Of 1132 citations, only 19 records met our inclusion criteria. Only eight were identified as CD guidelines. None of them focuses on UGICD. Among these, five diagnostic guidelines explicitly mentioned "upper GI" in their abstracts. Only the joint European Crohn's and Colitis Organisation and European Society of Gastrointestinal and Abdominal Radiology guidelines clearly defined the UGIT. Most guidelines mentioned UGI terms related to upper endoscopy or biopsy only. It was unclear whether these guidelines typically included the esophagus, stomach, and duodenum in the definition of UGICD while excluding the distal small intestine. Although the latest guideline related to pediatric-onset IBD cited the 2011 Paris classification, none of the three guidelines published after that explicitly mentioned the proposed subdivided location of the upper disease. There is a lack of consistent reporting in defining UGICD according to disease location. It is unclear whether there is a consensus on excluding the small intestine beyond the duodenum. Additionally, there is no indication that the subdivided location of UGIT was considered in CD guideline development. Greater consistency in definitions would aid in diagnosis, clinical care, epidemiological research and inclusion into clinical trials. These findings underscore the need for developing a framework to standardize the classification of UGICD, especially for clinical trials.