GERD phenotypes from pH‐impedance monitoring predict symptomatic outcomes on prospective evaluation

• Published in: Neurogastroenterology and motility Vol. 28; no. 4; pp. 513 - 521
• Main Authors: Patel, A., Sayuk, G. S., Kushnir, V. M., Chan, W. W., Gyawali, C. P.
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.04.2016
• Subjects: Cohort Studies; Electric Impedance; Esophageal pH Monitoring; Female; Follow-Up Studies; Gastroesophageal Reflux - classification; Gastroesophageal Reflux - diagnosis; Gastroesophageal Reflux - drug therapy; gastroesophageal reflux disease; Humans; Male; Middle Aged; Phenotype; pH‐impedance testing; Prospective Studies; Proton Pump Inhibitors - therapeutic use; strength of reflux evidence; symptom‐reflux association; Treatment Outcome; strength of reflux evidence; symptom-reflux association; gastroesophageal reflux disease; pH-impedance testing
• ISSN: 1350-1925; 1365-2982
• DOI: 10.1111/nmo.12745

Background Combinations of reflux parameters (acid exposure time, AET; symptom association probability, SAP) on pH‐impedance monitoring describe varying confidence in reflux evidence. We compared outcomes between phenotypes with distinct pre‐identified reflux parameters. Methods In this observational cohort study, patients undergoing pH‐impedance testing over a 5‐year period were phenotyped by strength of reflux evidence as strong (abnormal AET, positive SAP), good (abnormal AET, negative SAP), reflux hypersensitivity (RH, normal AET, positive SAP), and equivocal evidence of reflux, and compared to two historical institutional pH monitoring cohorts. Symptom burden (dominant symptom intensity, DSI; global symptom severity, GSS) was assessed by questionnaire at baseline and on prospective follow‐up and compared between phenotypes. Key Results Of 94 patients tested off proton pump inhibitor (PPI) therapy, baseline symptom burden was highest with strong reflux evidence and lowest when equivocal (DSI: p = 0.01; GSS: p = 0.03 across groups). After 3.1 ± 0.2 years follow‐up, symptomatic improvement with surgical or medical therapy was highest with strong or good evidence, and lowest when equivocal (DSI: p = 0.008; GSS: p = 0.005 across groups). This was most pronounced for typical symptoms (DSI: p = 0.001; GSS: 0.016 across groups), but not atypical symptoms (DSI: p = 0.6; GSS: p = 0.2). For testing on PPI therapy, only GSS followed a similar trend (GSS: p = 0.057, DSI: p = 0.3). Compared to historical cohorts with pH monitoring alone, equivocal evidence for reflux was partly replaced by RH, especially off PPI (p < 0.0001). Conclusions & Inferences Phenotyping gastroesophageal reflux disease by the strength of reflux evidence on pH‐impedance testing off PPI efficiently stratifies symptomatic outcome, especially for typical symptoms, and could be useful in planning management. Patients with GERD symptoms can be phenotyped into four distinct categories using a combination of abnormal acid exposure time (AET) and symptom reflux association using symptom association probability (SAP). The phenotypes include strong GERD evidence (abnormal AET, positive SAP), good evidence (abnormal AET, negative SAP), reflux hypersensitivity (normal AET, positive SAP), and equivocal or no GERD evidence (normal AET, negative SAP). By assessing symptom burden (dominant symptom intensity, global symptom severity) at the time of pH impedance monitoring and at follow‐up, we demonstrate that these phenotypes can predict varying grades of symptomatic outcome. View the podcast on this paper at the following sites: iTunes: https://itunes.apple.com/gb/podcast/neurogastroenterology-motility/id1085103798 Youtube: https://www.youtube.com/watch?v=J52NDd7aTw&feature=youtu.be