Associations between excessive supragastric belching and esophageal reflux factors in patients with PPI-refractory GERD in Japan

Background: No studies have evaluated the prevalence of supragastric belching (SGB) in Japanese patients with proton pump inhibitor (PPI)-refractory non-erosive reflux disease (NERD) under off-PPI conditions. This study aimed to clarify the association between excessive SGB and esophageal reflux factors. Methods: Seventy-nine patients with PPI-refractory NERD under off-PPI treatment were evaluated using 24-h multichannel intraluminal impedance pH monitoring and high-resolution impedance manometry. Results: The prevalence values of excessive SGB overall and in the true NERD, reflux hypersensitivity, and function heartburn subtypes were 19.0%, 35.7%, 5.3%, and 12.5%, respectively. The monitoring results demonstrated that, compared with those without excessive SGB, patients with excessive SGB had a significantly higher total number of reflux events (63 episodes vs. 39 episodes, p = 0.01) and significantly greater acid exposure time (6.1% vs. 1.35%, p = 0.01). However, bolus exposure did not differ significantly between the groups (p = 0.09). The manometry findings showed no significant differences in lower esophageal sphincter pressure, integrated relaxation pressure, and distal contractile integral between the groups. Regarding gastroesophageal reflux, 22% of the SGB episodes were preceded by reflux, 55% occurred independently, and 23% were followed by reflux. Conclusions: The prevalence of excessive SGB in Japanese patients with PPI-refractory NERD under off-PPI conditions was 19.0% and most commonly observed in patients with true NERD (35.7%). Patients with excessive SGB exhibited increased esophageal acid exposure, and reflux events were sometimes observed before SGB episodes.