OBJECTIVES: Heterogeneity in clinical outcome measurement between real-world practice and clinical trials in Crohn’s disease (CD) and ulcerative colitis (UC) makes comparisons across these settings challenging. To better understand the similarities and differences in CD and UC clinical endpoints across real-world evidence (RWE) studies and randomised clinical trials (RCTs), we conducted a targeted literature review to collate clinical outcomes.

METHODS: Using a predefined strategy, we performed targeted searches in MEDLINE to identify RCTs and RWE studies including more than 50 patients with CD and UC, published between January 2019 and May 2024. Data on study design, clinical outcomes and treatments were extracted.

RESULTS: Of 1,304 studies identified, 103 (54 RCTs; 49 RWE studies) were selected for full-text review. The most common clinical endpoints were remission and response. From the RCTs, we identified 18 unique definitions of clinical remission or response and 12 definitions for loss of response. Clinical remission and response in RCTs for UC were primarily defined by the Mayo Clinic Score (MCS), with minor differences in score cut-offs. For CD, the definition of remission varied significantly, including the use of Crohn's Disease Activity Index (CDAI) and average daily stool frequency (SF). Among the RWE studies, aside from MCS and CDAI, remission and response were typically defined by the Harvey Bradshaw Index (HBI) and Simple Clinical Colitis Activity Index (SCCAI). Disease activity-related events were also collected as the primary clinical endpoints in RWE studies; these included hospitalisation, disease-related surgeries and change of therapy. Differences in score cut-offs were observed within and across study designs.

CONCLUSIONS: This targeted literature review found wide heterogeneity in definitions of remission and response across RCTs and RWE studies. It is important to establish uniformity to aggregate findings to allow for the combination and comparison of results.