Diarrhea-predominant irritable bowel syndrome: creation of an electronic version of a patient-reported outcome instrument by conversion from a pen-and-paper version and evaluation of their equivalence.

Background: Subjects with diarrhea-predominant irritable bowel syndrome (IBS-D) experience abdominal cramping, bloating, pressure, and pain. Due to an absence of clinical biomarkers for IBS-D severity, evaluation of clinical therapy benefits depends on valid and reliable symptom assessments. A patient-reported outcome (PRO) instrument has been developed, comprising of two questionnaires - the IBS-D Daily Symptom Diary and IBS-D Symptom Event Log - suitable for clinical trials and real-world settings.