Validation of Dominant Symptom Intensity as a Patient-Reported Outcome Measure in the Evaluation of Esophageal Symptoms

Background: Since gastroesophageal reflux disease (GERD) manifests typical and atypical symptoms of varying frequency and severity, the dominant symptom needs identification and quantification. Goals: We aimed to compare 5-point Likert scales assessing symptom burden to validated GERD questionnaires and outcomes following GERD management. Study: We retrospectively analyzed pooled data from patients undergoing pH-impedance testing for reflux symptoms from 2 centers. Preprocedure questionnaires assessed symptom severity and frequency on 5-point Likert scales (0=not severe, infrequent; 4=extremely severe, multiple daily episodes); the product for the highest scoring symptom constituted the dominant symptom intensity (DSI). DSI was compared against validated instruments global symptom severity (GSS), GERD questionnaire (GERDQ) and reflux symptom index (RSI), and pH-impedance parameters per Lyon Consensus 2.0. DSI change after GERD management was compared against GSS and satisfaction with therapy. Results: Among 808 patients (mean age: 53.8±1.44 y, 65.2% female). DSI significantly correlated with GSS ( R =0.682), GERDQ ( R =0.414), RSI ( R =0.577), acid exposure time (AET) ( R =0.175), total reflux episodes ( R =0.194) and mean nocturnal baseline impedance ( R =−0.157) ( P <0.0001 for each comparison). On ROC analyses, DSI (AUROC=0.60) was noninferior to GSS, GERDQ, and RSI in predicting pathologic AET and total reflux episodes, and conclusive GERD. Percentage DSI improvement after antireflux treatment significantly correlated with GSS change ( R =0.632, P <0.0001) and treatment satisfaction ( R =0.513, P <0.0001) and was an independent predictor of GSS change (β=0.302, P <0.0001), and satisfaction with therapy (β=0.833, P =0.011) on multivariable regression. Conclusions: DSI correlates with validated reflux questionnaires and discriminates abnormal from normal reflux burden. DSI change reflects reflux treatment outcome and satisfaction.