BACKGROUND: The Dietitian First Gastroenterology Clinic (DFGC) is an initiative that has been established in response to increased gastroenterology clinical demand resulting in increased number of patients waiting outside clinically recommended timeframes for specialist care. In this clinic, a dietitian is the primary contact for eligible patients referred to tertiary gastroenterology services and provides assessment and management strategies for patients under the clinical governance of a gastroenterology consultant. This service has previously been shown to reduce patient wait-times and induce excellent patient satisfaction. Evaluation of models of care need to consider patient health outcomes as a key indicator for overall health service effectiveness. The aim of this study was to determine the impact of DFGC on patient related health outcomes. METHODS: This study utilised a pretest-posttest design of patients seen in the DFGC who met the diagnostic criteria for irritable bowel syndrome using the Rome IV criteria Consenting participants completed the validated symptom-severity (IBS-SSS) and health-related quality of life (IBSQoL) assessments. Paired sample t-tests were used to analyse differences pre- and post-management in the DFGC. Univariate mixed effects analyses were conducted to examine associations between IBS-SSS, IBSQoL and patient demographics. RESULTS: A total of 80 of 122 patients seen in the DFGC were recruited and completed baseline data, with 60 (75%) completing follow up assessments. The average participant age was 35.6 years (75% female), and IBS subtypes; IBS-C 15.0%, IBS-D 38.3%, IBS-M 26.7% and IBS-U 20.0%. Participants experienced significant reductions in symptom severity based on IBS-SSS (300.1 vs 151.7; p < 0.001) independent of IBS subtype, age or gender, with 88% (53/60) experiencing a clinically significant improvement. Quality of life significantly improved for all IBS subtypes (p < 0.001) across all subscales except food avoidance (p = 0.11). There was a moderate negative correlation between the changes in symptom severity and quality of life (R = 0.432, p = 0.001). CONCLUSIONS: Management in the DFGC provided positive patient health outcomes demonstrated by improvements in symptom severity and QoL.