Background: This study assessed the impact of recruitment on irritable bowel syndrome clinical trials, by determining whether irritable bowel syndrome patients recruited from advertisement or a specialty clinic differ in clinical and physiologic measures.
Methods: We prospectively surveyed 657 irritable bowel syndrome patients who either: (i) were referred from a functional bowel disease clinic (52%); or (ii) responded to advertisement for clinical trials (48%), using questionnaires about bowel and psychological symptoms, and quality of life. In a subset of 42 irritable bowel syndrome patients (29 advertisement and 15 clinic patients), rectal discomfort thresholds were measured before and after repetitive sigmoid stimulation.
Results: While the advertisement population more commonly consulted primary care physicians, the clinic population more commonly consulted gastroenterologists. The clinic population reported more prevalent and severe abdominal pain, and higher psychological symptom scores, while the advertisement population had greater quality of life. In the visceral perception studies, both 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-reports may have consequences for enrolment of these different patient populations into clinical trials.