Impact of advertisement and clinic populations in symptoms and perception of irritable bowel syndrome

Background: This study assessed the impact of recruitment on irritable bowe l syndrome clinical trials, by determining whether irritable bowel syndrome patients recruited from advertisement or a specialty clinic differ in clin ical and physiologic measures. Methods: We prospectively surveyed 657 irritable bowel syndrome patients wh o either: (i) were referred from a functional bowel disease clinic (52%); o r (ii) responded to advertisement for clinical trials (48%), using question naires about bowel and psychological symptoms, and quality of life. In a su bset of 42 irritable bowel syndrome patients (29 advertisement and 15 clini c patients), rectal discomfort thresholds were measured before and after re petitive sigmoid stimulation. Results: While the advertisement population more commonly consulted primary care physicians, the clinic population more commonly consulted gastroenter ologists. The clinic population reported more prevalent and severe abdomina l pain, and higher psychological symptom scores, while the advertisement po pulation had greater quality of life. In the visceral perception studies, b oth subgroups were hypersensitive to rectal distension. Conclusion: Compared to the clinic population, the advertisement population had less severe abdominal pain and psychological symptoms, better quality of life but similar visceral perception. The differences in clinical self-r eports may have consequences for enrolment of these different patient popul ations into clinical trials.