Establishing a multiple outcome set for Crohn's disease in real-world evidence studies: results from a Delphi...

Randomized controlled trials (RCTs) provide high-quality evidence but often lack generalizability to real-world populations. Although real-world evidence (RWE) studies help to bridge this gap, retrospective design and heterogeneous outcome measures still limit their standardization in Crohn's disease (CD). Building on the recent ECCO Position Paper, this study aimed to identify the most relevant outcomes for real-world CD studies.

An international panel of inflammatory bowel disease (IBD) specialists participated in a structured two-round Delphi e-survey using the RAND/UCLA Appropriateness Method. Experts rated outcomes across eight domains, including disease activity, patient-reported outcomes, and treatment safety. Agreement was assessed using the Disagreement Index (DI), where DI > 1 indicated disagreement, and DI ≤ 1 indicated agreement or no disagreement. Weighted scoring prioritized key outcomes.

A total of 51/85 experts (60%) completed Round 1 and 48/51 (94%) Round 2. No disagreement was observed (DI < 1) in both rounds. The highest-ranked outcomes were Abscess or Fistula (10.6%), Endoscopic Remission (10.3%), Corticosteroid-Free Clinical Remission (8.9%), Disease Progression (6.7%), and Colorectal Cancer (5.9%). The top 10 outcomes accounted for 61.5% of the weighted score. For combinations, the top four outcomes, Corticosteroid-Free Clinical Remission (16.2%), Endoscopic Remission (15.6%), Disease Progression (14.1%), and Health-Related Quality of Life (11.9%), represented 57.8% of selections. When considering the top five and top six outcomes, the cumulative proportions were 55.4% and 57.6%, respectively.

This expert-driven Delphi study provides a standardized framework for selecting outcomes in CD RWE studies, improving consistency and comparability across future research in this field.