Persistence of gastrointestinal symptoms in irritable bowel syndrome and ulcerative colitis: study protocol for a three-arm randomised controlled trial (SOMA.GUT-RCT)

Abstract

Introduction: Ulcerative colitis (UC) and irritable bowel syndrome (IBS) are distressing chronic diseases associated with abdominal pain and altered bowel habits of unknown aetiology. Results from previous studies indicate that, across both diseases, increased levels of illness-related anxiety and dysfunctional symptom expectations contribute to symptom persistence. Thus, comparing both disorders with regard to common and disease-specific factors in the persistence and modification of gastrointestinal symptoms seems justified. Our primary hypothesis is that persistent gastrointestinal symptoms in UC and IBS can be improved by modifying dysfunctional symptom expectations and illness-related anxiety using expectation management strategies.

Methods and analysis: To assess the extent to which persistent somatic symptoms are modifiable in adult patients with UC and IBS, we will conduct an observer-blinded, three-arm randomised controlled trial. A total of 117 patients with UC and 117 patients with IBS will be randomised into three groups of equal size: targeted expectation management aiming to reduce illness-related anxiety and dysfunctional symptom expectations in addition to standard care (SC, intervention 1), non-specific supportive treatment in addition to SC (intervention 2) or SC only (control). Both active intervention groups will comprise three individual online consultation sessions and a booster session after 3 months. The primary outcome is baseline to postinterventional change in gastrointestinal symptom severity.

Ethics and dissemination: The study was approved by the Ethics Committee of the Hamburg Medical Association (2020-10198-BO-ff). The study will shed light onto the efficacy and mechanisms of action of a targeted expectation management intervention for persistent gastrointestinal symptoms in patients with UC and IBS. Furthermore, the detailed analysis of the complex biopsychosocial mechanisms will allow the further advancement of aetiological models and according evidence-based intervention strategies.

Trial registration number: ISRCTN30800023.

Keywords: Functional bowel disorders; Gastroenterology; Inflammatory bowel disease; MENTAL HEALTH.

Figure 1

Commonalities and differences between ulcerative colitis and irritable bowel syndrome.

Figure 2

Hypothetical cross-disease model of pathomechanisms for persistent gastrointestinal symptoms in ulcerative colitis and irritable bowel syndrome. Illness anxiety and dysfunctional expectations as hypothesised mechanisms of action for persistent gastrointestinal symptoms are marked in red.

Figure 3

Study design and outcome assessment. GUT.EXPECT, expectation management intervention; GUT.SUPPORT, supportive intervention. UC, ulcerative colitis; IBS, irritable bowel syndrome

Figure 4

Anticipated flow of participants through the course of the study. *Outcomes after 6 and 12 months are secondary and were not included in the sample size estimation. GUT.EXPECT, expectation management intervention; GUT.SUPPORT, supportive intervention; UC, ulcerative colitis; IBS, irritable bowel syndrome.