We examined symptom frequency, duration, and severity, as well as episode p
atterns, in 122 adult patients with irritable bowel syndrome in a 12-week s
tudy conducted in the United States, the United Kingdom, and The Netherland
s. Patients used an interactive telephone data entry system daily to report
symptoms. Data from 59 of the patients meeting inclusion criteria are pres
ented, the remainder having been excluded for failing to complete at least
70 days of symptom reporting. The majority of patients experienced at least
one symptom on over 50% of the reported days; however, individual symptoms
were reported on less than 50% of the days, indicating that symptoms somet
imes occurred sequentially rather than always simultaneously. On average, p
atients reported pain/discomfort on 33% of days, bloating on 28% of the day
s, altered stool form or stool passage on 25% and 18% of the days, respecti
vely, and mucus on 7% of the days. The duration of symptoms was relatively
short, with pain/discomfort and bloating lasting the longest, an average of
five days each per episode. All symptoms but one (mucus) were moderately s
evere on the majority of reported days. Patients experienced an "episode" (
defined as a period of days with symptoms bounded by one or more symptom-fr
ee days) on an average of 12.4 times during the study, but the duration of
these episodes varied greatly among patients. These results further establi
sh the chronic nature of irritable bowel syndrome and the burden that this
condition imposes on patients.