Characterization of gastroesophageal reflux disease phenotypes using 24-hour multichannel intraluminal impedance–pH monitoring study

Abstract

Backgroud: In contemporary clinical practice, gastroesophageal reflux disease (GERD) is classified into four phenotypes based on upper gastrointestinal endoscopy and 24-hour multichannel intraluminal impedance-pH monitoring: erosive reflux disease (ERD), non-erosive reflux disease (NERD), reflux hypersensitivity (RH), and functional heartburn (FH). Although the prevalence of GERD in Mongolia is high, and certain chronophysiological aspects have been investigated, there remains a significant lack of data regarding GERD phenotypic classification and physiological diagnostic evaluation using impedance-pH monitoring. This knowledge gap provided the rationale for conducting the present study. Aim: To determine the prevalence of GERD phenotypes among adults presenting with heartburn symptoms and to compare selected manometric and pH-impedance parameters among phenotype groups. Materials and Methods: This study analyzed data from 347 adults who presented to Intermed Hospital between 2022 and 2025 with heartburn symptoms and underwent 24-hour multichannel intraluminal impedance-pH monitoring. Statistical analysis was performed using SPSS version 26. Results: Among the study population, 193 patients (55.6%) were diagnosed with ERD, 34 (9.8%) with NERD, 73 (21.0%) with RH, and 47 (13.5%) with FH. Significant differences were observed among the groups in body mass index (BMI), esophageal acid exposure, total reflux episodes, reflux characteristics, and mean nocturnal baseline impedance (MNBI). Type III esophagogastric junction morphology was identified in 78.76% of the ERD group, 64.7% of the NERD group, 56.2% of the RH group, and 42.6% of the FH group, demonstrating statistically significant intergroup differences. Conclusion: ERD was the predominant GERD phenotype among adults with heartburn symptoms, followed by RH, FH, and NERD. Significant differences among GERD phenotypes were observed in BMI, total reflux burden, reflux characteristics, esophageal nocturnal baseline impedance, and esophagogastric junction morphology.