Patient-Reported Outcomes in Clinical Trials of Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

Patient-reported outcomes and outcome measures have increasing prominence in clinical trials for inflammatory bowel disease. This systematic review provides an overview of patient-reported outcome measures used in randomized controlled trials, their placebo outcome rates, effect sizes, and operating properties.

We first searched MEDLINE, Embase and Cochrane CENTRAL up to March 31, 2025, for randomized controlled trials in inflammatory bowel disease using patient-reported outcome measures. In a subsequent search, we searched the databases for studies, regardless of design, reporting on the operating properties of patient-reported outcome measures. In the first part, we summarized the patient-reported outcome measures and outcome definitions. We calculated pooled placebo outcome rates and pooled risk ratios using the DerSimonian-Laird random-effects model. In the second part, we summarized the validity of patient-reported outcome measures.

A total of 132 (71 in Crohn's disease, 61 in ulcerative colitis) randomized controlled trials reported 29 patient-reported outcome measures, most commonly the IBD Questionnaire, PRO-2, the Euro QoL survey, and the 36-item Short Form survey. Outcome definitions and reporting formats were highly heterogeneous. Pooled placebo outcome rates for different patient-reported outcome measures were 25.2% to 43.6%. Although superiority over placebo was demonstrated using different patient-reported outcome measure-based outcomes, effect sizes were smaller compared with the primary endpoint for the same trials. A total of 171 studies evaluated the operating properties of 78 patient-reported outcome measures. A minority of instruments underwent extensive validation. These included IBD Control, IBD Disability Index, and IBD Questionnaire.

There is substantial heterogeneity in patient-reported outcome measure reporting in randomized controlled trials. Placebo rates were high and effect sizes low for patient-reported outcome measures. Only a minority of patient-reported outcome measures were extensively validated; of the latter, none were developed following regulatory recommendations.