Clinical Question: How effective are psychologic interventions in patients with irritable bowel syndrome (IBS)?
Setting: Outpatient (any)
Study Design: Randomized controlled trial (single-blinded)
Synopsis: Previous studies of patients with IBS suggest some benefit from behavior interventions, but most of these studies were small, poorly designed, or both. In this study, the authors identified 105 patients who met standard Rome I criteria for IBS; approximately one half of the patients came from a specialty clinic, and the rest were recruited from newspaper advertisements. Patients from the clinic were referred because the gastroenterologist thought they were “appropriate” for the study. Patients were assigned (concealed allocation) to one of three treatment groups: (1) routine clinical care (all patients in all groups had two additional visits with a gastroenterologist), (2) relaxation training (i.e., eight weekly sessions run by a clinical psychologist), and (3) cognitive behavior therapy (i.e., eight weekly sessions run by the same clinical psychologist). The gastroenterologists were blinded to treatment assignment, and the psychologists were blinded to the results of the self-report scales used to assess clinical outcomes.
The primary outcome was the Bowel Symptom Severity Scale (BSSS), which has the patient self-rate eight symptoms on a 6-point scale, in which a higher score is worse. The overall dropout rate in the study was high. A similar number of patients were lost to follow-up in all three groups, but more patients discontinued the intervention in the two therapy groups (13 in relaxation training and 10 in cognitive behavior therapy compared with four in the usual-care group).
All groups had a baseline BSSS score of 20.6 to 21.5, and all ended up with a score of 16.1 to 17 by the end of the 52-week period. Improvement was similar among the groups, but there was no difference in the degree of improvement among the usual-care, relaxation, and cognitive behavior therapy groups. The number of patients who dropped out and the small size of each group raise the possibility of a type II statistical error (i.e., the study may have been too small to detect a clinically meaningful difference if one existed). However, the authors argue that they had adequate power to detect a moderate effect, and that it is unlikely that they missed a clinically meaningful effect given the close similarity in BSSS scores among the groups.
Bottom Line: There is no good evidence that cognitive behavior therapy or relaxation therapy is any more helpful than usual treatment in patients with IBS. (Level of Evidence: 1b–)