Psychometric evaluation of an experience sampling method–based patient‐reported outcome measure in functional dyspepsia

BACKGROUND: Due to important biases, conventional end‐of‐day and end‐of‐week assessment methods of gastrointestinal symptoms in functional dyspepsia (FD) are considered suboptimal. Real‐time symptom assessment based on the experience sampling method (ESM) could be a more accurate measurement method. This study aimed to evaluate validity and reliability of an ESM‐based patient‐reported outcome measure (PROM) for symptom assessment in FD. METHODS: Thirty‐five patients with FD (25 female, mean age 44.7 years) completed the ESM‐based PROM (a maximum of 10 random moments per day) and an end‐of‐day symptom diary for 7 consecutive days. On day 7, end‐of‐week questionnaires were completed including the Nepean Dyspepsia Index (NDI) and Patient Assessment of Gastrointestinal Symptom Severity Index (PAGI‐SYM). KEY RESULTS: Experience sampling method and corresponding end‐of‐day scores for gastrointestinal symptoms were significantly associated (ICCs range 0.770–0.917). However, end‐of‐day scores were significantly higher (Δ0.329–1.031) than mean ESM scores (p < 0.05). Comparing ESM with NDI and PAGI‐SYM scores, correlations were weaker (Pearson's r range 0.467–0.846). Cronbach's α coefficient was good for upper gastrointestinal symptoms (α = 0.842). First half‐week and second half‐week scores showed very good consistency (ICCs range 0.913–0.975). CONCLUSION AND INFERENCES: Good validity and reliability of a novel ESM‐based PROM for assessing gastrointestinal symptoms in FD patients was demonstrated. Moreover, this novel PROM allows to evaluate individual symptom patterns and can evaluate interactions between symptoms and environmental/contextual factors. ESM has the potential to increase patients' disease insight, provide tools for self‐management, and improve shared decision making. Hence, this novel tool may aid in the transition toward personalized health care for FD patients.