512 THE DOMINO STUDY: DIET OR MEDICATION IN PRIMARY CARE IBS

O In primary care, IBS is a condition that generates high diagnostic and therapeutic uncertainty for general practitioners (GPs), and the efficacy of currently available therapeutic modalities is limited. In Europe, musculotropic agents (eg otilonium bromide, OB) are commonly used. Recently, at the level of specialist care, the low FODMAP diet supervised by an experienced dietician, was shown to provide significant improvement, but the use in primary care remains to be explored. Our aim was to evaluate the effect of a FODMAP lowering diet (D), administered through a smartphone application, vs OB on symptoms, quality of life and psycho-social co-morbidity in primary care IBS. M In this clinical trial, 69 GPs recruited 470 IBS patients who were randomized to OB (60 mg tid) or a FODMAP lowering diet (D). After a treatment period of 8 weeks, followed up continued until 6 months. Patients fulfilling Rome IV criteria were defined as Rome+. The change in IBS Symptom Severity Score (IBS-SSS) was compared between treatment groups both as a numeric score (bootstrapped t-test) and in terms of proportion of responders (≥50 improvement, ChiSquare). Additionally, the impact of treatment was explored for quality of life (IBSQoL), anxiety (GAD), depression and somatization (PHQ15). Finally, parameters predicting response were analyzed in both treatment groups (logistic regression) with effect sizes (OR). R 453 primary care IBS patients (41±15y,76%F,71%Rome+) were randomized to either OB (n=231,41±15y,75%F) or diet app (n=227,41±15y,75%F). The responder rate in the diet group (71%) was significantly higher compared to OB (61%, p=.03) and this was more pronounced in Rome+ (77 vs 62%,p=.005). During the follow-up period, the diet group maintained a significantly higher responder rate (74 vs 58%,p C In primary care IBS, a smartphone app-based diet intervention was superior to standard medical therapy in improving symptom severity, and in achieving clinically significant response, at the end of treatment and during followup. Both treatments improved quality of life and psychosocial co-morbidities. Response to diet is associated with female gender, while OB with high somatization. App-based dietary intervention should be considered the first-line treatment choice for primary care IBS