Leticia Delgado-Herrera, Benjamin Banderas, Oluwafunke Ojo, Ritesh Kothari, Bernhardt Zeiher

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. This program aimed to support instrument conversion from pen-and-paper to electronic format. Digital technology (Android/iOS) and a traditional mode of administration study in the target population were used to migrate or convert the validated PRO IBS-D pen-and-paper measure to an electronic format. Equivalence interviews, conducted in three waves, each had three parts: 1) conceptual equivalence testing between formats, 2) electronic-version report-history cognitive debriefing, and 3) electronic version usability evaluation. After each inter-view wave, preliminary analyses were conducted and modifications made to the electronic version, before the next wave. Final revisions were based on a full analysis of equivalence interviews. The final analysis evaluated subjects' ability to read, understand, and provide meaningful responses to the instruments across both formats. Responses were classified according to conceptual equivalence between formats and mobile-format usability assessed with a questionnaire and open-ended probes. Equivalence interviews (n=25) demonstrated conceptual equivalence between formats. Mobile-application cognitive debriefing showed some subjects experienced difficulty with font/screen visibility and understanding or reading some report-history charts and summary screens. To address difficulties, minor revisions/modifications were made and landscape orientation and zoom-in/zoom-out features incorporated. This study indicates that the two administration modes are conceptually equivalent. Since both formats are conceptually equivalent, both are psychometrically reliable, as established in the pen-and-paper version. Subjects found both mobile applications (Android/iOS) offered many advantages over the paper version, such as real-time assessment of their experience.