Internet-delivered cognitive behavioral therapy and FODMAP diet for adults with irritable bowel syndrome: A four-arm randomized controlled trial.

Background: Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder associated with reduced quality of life and psychological distress. Although several effective self-management interventions exist, patient access is often limited. Internet-delivered interventions may enhance accessibility and scalability. We aimed to evaluate the effectiveness of a CBT-based module, a FODMAP diet module, or their combination, when added to internet-delivered general patient education, compared to general patient education alone, on IBS symptom severity in adults. Methods: In this four-arm randomized controlled trial, 642 adults with IBS were allocated to (1) internet-delivered general patient education alone (control) or with the addition of (2) a CBT-based module, (3) a FODMAP diet module, or (4) both the CBT-based module and the FODMAP diet module. All groups could receive personalized guidance from a clinical dietitian via the platform's asynchronous messaging function. The primary outcome was the proportion of IBS symptom responders at 3 months, defined as a ≥ 50-point reduction on the IBS severity scoring system. Secondary outcomes included IBS-related quality of life, psychological symptoms, module adherence, and treatment satisfaction. Results: Of 557 participants who received their allocated intervention, 373 (67%) completed questionnaires at the primary endpoint at 3 months. Responder rates were comparable across all groups at 3 months ranging from 42.6% to 45.1%, with no significant between-group differences in the primary outcome (OR (95% CI) = 0.97 (0.54 to 1.72), Conclusion: All intervention groups, including internet-delivered general patient education alone and general patient education with an additional CBT-based and/or FODMAP diet module, demonstrated clinically and statistically meaningful improvements in IBS symptoms and IBS-related quality of life. Although no additional benefit of the content-specific modules was observed, this finding should be interpreted in the context of the low adherence to these modules. These findings highlight the value of low-intensity internet-delivered interventions for IBS within resource-constrained health systems and emphasize the importance of addressing adherence and engagement in future research. Trial registration: ClinicalTrials.gov ID: NCT06117865. Registered 31.10.2023.