Results From a Psychometric Validation Study: Patients With Irritable Bowel Syndrome Report Higher Symptom Burden Using End-of-Day Vs Real-Time Assessment.

Introduction: Real-time assessment of gastrointestinal (GI) symptoms in irritable bowel syndrome (IBS) using the experience sampling method (ESM) is suggested as a more appropriate approach than currently used end-of-day or end-of-week reports. This psychometric evaluation study assesses the validity and reliability of a previously developed ESM-based patient-reported outcome measure (PROM) for real-time GI symptom assessment in IBS.

Methods: This multicenter validation study included 230 Rome IV patients with IBS (80% female; mean age 41.2 years) in 3 European countries. Patients completed the electronic ESM-PROM (up to 10 random moments daily, with a weekly minimum completion rate of 33%) and an end-of-day symptom diary for 7 consecutive days. End-of-week questionnaires (Gastrointestinal Symptom Rating Scale for IBS, IBS Severity Scoring System, Patient Health Questionnaire-9, and Generalized Anxiety Disorder-7) were completed at the end of the 7-day period.

Results: The ESM assessment had a mean completion rate of 71%. Strong and significant correlations (0.651-0.956) with moderate-to-good consistency (intra-class correlation coefficients 0.580-0.779) were observed between ESM and end-of-day scores. However, end-of-day scores were significantly higher (Δ0.790-1.758, P < 0.001) than mean daily ESM scores. Differences with end-of-week scores were more pronounced, with weaker correlations (Pearson's r 0.393-0.802). ESM-PROM exhibited moderate-to-good internal consistency (Cronbach's α 0.585-0.887) across 5 symptom domains. First and second half-week scores demonstrated good-to-excellent consistency (intraclass correlation coefficients 0.871-0.958).

Discussion: Psychometric evaluation demonstrated strong validity and reliability of the ESM-PROM for real-time GI symptom assessment in IBS. In addition, the ESM-PROM provides a precise and reliable ascertainment of individual symptom pattern and trigger interactions, without the bias of peak reporting when compared with retrospective methods. This highlights its potential as a valuable tool for personalized healthcare in monitoring disease course and treatment response in patients with IBS.