Figure 1. IBS symptom subgroup classification.
A) Comparison of IBS subtype defined by retrospective questionnaire to percent of days with hard and loose stools from daily diary. B) Comparison of abdominal pain to the ‘Global Severity Index’, which is a measurement of psychological distress. The cluster analyses separate IBS into distinctive symptom phenotypes: 1) constipation, 2) diarrhea + high pain, 3) diarrhea + low pain, and 4) high pain + high psychological distress.