Standardized system and App for continuous patient symptom logging in gastroduodenal disorders: Design, implementation, and validation

Background Functional gastroduodenal disorders include functional dyspepsia, chronic nausea and vomiting syndromes, and gastroparesis. These disorders are common, but their overlapping symptomatology poses challenges to diagnosis, research, and therapy. This study aimed to introduce and validate a standardized patient symptom-logging system and App to aid in the accurate reporting of gastroduodenal symptoms for clinical and research applications. Methods The system was implemented in an iOS App including pictographic symptom illustrations, and two validation studies were conducted. To assess convergent and concurrent validity, a diverse cohort with chronic gastroduodenal symptoms undertook App-based symptom logging for 4 h after a test meal. Individual and total post-prandial symptom scores were averaged and correlated against two previously validated instruments: PAGI-SYM (for convergent validity) and PAGI-QOL (for concurrent validity). To assess face and content validity, semi-structured qualitative interviews were conducted with patients. Key Results App-based symptom reporting demonstrated robust convergent validity with PAGI-SYM measures of nausea (r(S) =0.68), early satiation (r(S) =0.55), bloating (r(S) =0.48), heartburn (r(S) =0.47), upper gut pain (r(S) =0.40), and excessive fullness (r(S) =0.40); all p < 0.001 (n = 79). The total App-reported Gastric Symptom Burden Score correlated positively with PAGI-SYM (r(S) =0.56; convergent validity; p < 0.001), and negatively with PAGI-QOL (r(S) = -0.34; concurrent validity; p = 0.002). Interviews demonstrated that the pictograms had adequate face and content validity. Conclusions and Inferences The continuous patient symptom-logging App demonstrated robust convergent, concurrent, face, and content validity when used within a 4-h post-prandial test protocol. The App will enable standardized symptom reporting and is anticipated to provide utility in both research and clinical practice.