OBJECTIVES:Despite a documented clinical need, no patient reported outcome (PRO) symptom measure
meeting current regulatory requirements for clinically relevant end points is available
for the evaluation of treatment benefit in diarrhea-predominant IBS (IBS-D).METHODS:Patients (N=113) with IBS-D participated in five study phases: (1)
eight concept elicitation focus groups (N=34), from which a 17-item
IBS-D Daily Symptom Diary and four-item IBS-D Symptom Event Log (Diary and Event Log)
were developed; (2) one-on-one cognitive interviews (N=11) to assess the
instrument's comprehensiveness, understandability, appropriateness, and
readability; (3) four data triangulation focus groups (N=32) to confirm
the concepts elicited; (4) two hybrid (concept elicitation and cognitive interview)
focus groups (N=16); and (5) two iterative sets of one-on-one cognitive
interviews (N=20) to further clarify the symptoms of IBS-D and debrief a
revised seven-item Diary and four-item Event Log.RESULTS:Of thirty-six concepts initially identified, 22 were excluded because they were not
saturated, not clinically relevant, not critical symptoms of IBS-D, considered upper GI
symptoms, or too broad or vaguely defined. The remaining concepts were diarrhea,
immediate need (urgency), bloating/pressure, frequency of bowel movements, cramps,
abdominal/stomach pain, gas, completely emptied bowels/incomplete evacuation,
accidents, bubbling in intestines (bowel sounds), rectal burning, stool consistency,
rectal spasm, and pain while wiping. The final instrument included a daily diary with
separate items for abdominal and stomach pain and an event log with four items completed
after each bowel movement as follows: (1) a record of the bowel movement/event and
an assessment of (2) severity of immediacy of need/bowel urgency, (3) incomplete
evacuation, and (4) stool consistency (evaluated using the newly developed Astellas
Stool Form Scale). Based on rounds of interviews and clinical input, items considered
secondary or nonspecific to IBS-D (rectal burning, bubbling in intestines, spasms, and
pain while wiping) were excluded.CONCLUSIONS:The IBS-D Symptom Diary and Event Log represent a rigorously developed PRO instrument
for the measurement of the IBS-D symptom experience from the perspective of the patient.
Its content validity has been supported, and future work should evaluate the
instrument's psychometric properties.