Predictors of response to a dietary intervention in patients with irritable bowel syndrome.

Background: Different diets have emerged as potential therapeutic options for patients with irritable bowel syndrome (IBS).

Objective: To identify predictors of improvement after a low-FODMAP, low-starch and low-sucrose diet among patients with IBS.

Methods: We performed a descriptive cross-sectional study including patients with IBS according to Rome IV criteria undertaking a social-media based program with a two-week dietary intervention. Patients completed an online survey before and after the intervention including the presence of intestinal and extra-intestinal symptoms, the IBS-SSS (irritable bowel syndrome symptoms severity scale) and the PHQ-9 (patient health questionnaire-9). Clinical improvement was defined as a decrease of at least 50% in IBS-SSS post dietary intervention. Variables associated with symptomatic response were identified with logistic regression analysis. A clinical score to predict response was created and tested with a with a receiver operating characteristic (ROC) curve analysis.

Results: A total of 3583 patients with IBS were included. Mean IBS-SSS before and after dietary intervention was 295.5±52.32 and 240±48.66, respectively (p=0.01); 1178 (32.8%) patients showed clinical improvement. A mean basal IBS-SSS >400 (OR 3.04), chronic headache (OR 1.96), and chronic fatigue (OR 1.81) were significantly associated with symptomatic response. Patients with arthralgia (OR 0.41) and/or fibromyalgia (OR 0.33) were less likely to improve. Each variable received the following individuals scores: IBS-SSS >400: +2, chronic headache: +1.5, chronic fatigue: +1, arthralgia: -1, and fibromyalgia: -1. The ROC curve analysis of the proposed score showed an area under the curve of 0.72 (95% CI 0.69-0.76). A score ≥3 had a sensitivity of 72.64% and specificity of 60.56% for predicting symptomatic improvement.

Conclusions: There are clinical variables that could serve as reliable predictors of response to a low-FODMAP, low-sucrose, low-starch diet among patients with IBS. Further research is needed to understand the link between the presence of extra-intestinal symptoms and clinical improvement after dietary interventions for IBS.