Background: Variation in the characteristics of irritable bowel syndrome pa
tients recruited for clinical trials from different sources could affect th
eir response and the generalizability of trial results.
Aim: To describe and compare the characteristics of three different groups
of irritable bowel syndrome patients recruited into a 'mock clinical trial.
Methods: We enrolled 245 irritable bowel syndrome patients from three sourc
es: (i) 121 from British primary practitioners; (ii) 72 from California new
spaper advertisements; and (iii) 52 from a California gastroenterologist's
practice. We obtained demographic, clinical, and Hospital Anxiety and Depre
ssion (HAD) Scale data.
Results:Most patients were young to middle-aged women; the majority reporte
d symptoms for > 5 years in all three groups. Subject characteristics varie
d among the groups. Typically, primary care patients were anxious, smokers
and daily alcohol drinkers who had sought care recently for irritable bowel
syndrome and tried antispasmodic drugs. Their symptoms were intermediate i
n severity between those of the other two groups. Advertisement subjects we
re the oldest, most highly educated, most often depressed, and were least l
ikely to have sought care recently for symptoms, which were almost uniforml
y only moderate in severity. Gastroenterologist patients tended to be anxio
us and had nearly all sought care recently for symptoms, which were the mos
t severe and most likely to include all three pain-related Rome I criteria.
Conclusion: Recruitment methodology affects important characteristics of an
irritable bowel syndrome study group.