Impact of HADS Anxiety and Depression Scores on the Efficacy of Dietary Interventions for Irritable Bowel Syndrome

Background: Anxiety and depression are associated strongly with irritable bowel syndrome (IBS). Dietary therapies are used increasingly in the management of IBS, but the impact of common mental disorders on response to these has not been well studied. Aims: To examine whether symptoms compatible with common mental disorders influence response to dietary interventions. Methods: Prospective cohort study of adults, with either diarrhoea-predominant or mixed bowel habits, IBS Severity Scoring System [IBS-SSS] score >= 75 points. Participants completed the Hospital Anxiety and Depression score (HADS) and attended initially for British Dietary Association advice for IBS. IBS-SSS was re-checked 3 months later to assess response. If primary endpoint (>= 50 point decrease in IBS-SSS) was not achieved, patients were offered low fermentable oligo-, di- and monosaccharides and polyol diet and repeated IBS-SSS after another 3 months. Secondary endpoints included of change in IBS-SSS and effect of symptom severity on response. Results: In total, 448 patients took part, average age of 42 years and 79.0% were female. 69.9% of participants had HADS-A scores >= 8 and 39.3% with HADS-D scores >= 8. Average IBS-SSS score at baseline was 290 (SD 86). No significant difference was noted in achievement of the primary endpoint according to HADS-A scores (53.4% vs. 62.2% by ITT in those with HADS-A >= 8 vs. HADS-A < 8, p = 0.09). Patients with HADS-D >= 8 were significantly less likely to achieve the primary endpoint compared with those with HADS-D < 8 (43.8% vs. 64.0% by ITT, p < 0.01). Conclusion: Understanding psychological profile of patients can help predicting their response to IBS dietary interventions.