Measuring irritable bowel syndrome patient‐reported outcomes with an abdominal pain numeric rating scale

Summary Background Controversy exists on how to measure patient‐reported outcomes in irritable bowel syndrome (IBS) clinical trials effectively. Pain numeric rating scales (NRS) are widely used in the non‐IBS pain literature. The Food and Drug Administration has proposed using the NRS in IBS. Aim To test the psychometrics of an abdominal pain NRS in IBS. Methods We analysed data from a longitudinal cohort of Rome III IBS subjects. At entry, subjects completed a 10‐point NRS, bowel symptoms, IBS severity measurements (IBS‐SSS, FBDSI), health‐related quality of life indices (IBS‐QOL, EQ5D), and the Worker Productivity Activity Index (WPAI). We repeated assessments at 3 months along with a response scale to calculate the minimal clinically important difference. Results There were 277 subjects (82% women; age = 42 ± 15) at baseline and 90 at 3 months. The NRS correlated cross‐sectionally with IBS‐SSS (r = 0.60; P