GI dietitians play an important role in the nutrition management of patients with digestive disorders. There are currently no validated, easy to use tools that help patients to identify dietary triggers for their symptoms. From a provider standpoint, a tool which provides insight into the complex relationship between food and GI symptoms would be welcome. To address these unmet needs for a high-resolution measure that examines the relationship between dietary intake and symptoms, we developed the Food and Symptom Tracker (FAST). The goals of this study were to validate FAST and assess the impact of GI dietitian interventions on patients' symptom severity as measured by FAST.
Patients ≥18yo referred to see a GI dietitian at 2 academic medical centers were invited to participate in this two-week pre-post study. The 21-item FAST (higher score = more severe symptoms) was created based on input from 5 GI dietitians and the existing literature and was deployed via the LifeData app. Participants recorded meals daily and answered FAST items 1 hour after each meal. They also completed the Gastrointestinal Symptom Rating Scale (GSRS) and PROMIS Global Health (PROMIS-GH) items 1 day before and 7 days after the visit. We examined convergent validity between the weekly FAST average and GSRS and PROMIS-GH using Pearson's product moment correlation. We then used a linear mixed model repeated measures (LMMRM) analysis to compare scores between the 7 day pre- and post-consultation periods.
104 patients (Table 1) with 3,439 responses were included. Weekly FAST averages correlated (0.58, P < 0.001) with the GSRS, overall, and with its symptom subscales (all >0.50, P < 0.001). FAST also negatively correlated with the PROMIS-GH (higher PROMIS score = better health; physical health, −0.09, P = 0.04; mental health, −0.19, P = 0.05). Mean FAST scores were 5.7 (SD 10.2) in the week before seeing the dietitian, and 4.3 (SD 7.8) in the week after. After adjusting for confounders using the LMMRM, FAST scores were 1.4 points lower (P < 0.001; 95% CI −2.08 to −0.74) in the post-dietitian period. Moreover, 25 subjects had a ≥0.5 SD decrease (correlates with minimal clinically important difference) in mean FAST score after the visit.
FAST displayed convergent validity with legacy measures. We also found that one-fourth of patients had a clinically meaningful decrease in GI symptom severity following meals, as measured by FAST, in the week after consulting with a GI dietitian.