Proton Pump Inhibitor Treatment Has Little Effects on Secretion of Saliva in Patients with Proton Pump Inhibitor-Responsive Mild Reflux Esophagitis and Non-Erosive Reflux Disease

Introduction: The secretion of saliva, which is triggered by acid reflux into the esophagus via the esophagosalivary reflex, plays a crucial role in the defensive mechanisms of the esophagus. The volume of saliva secreted in patients with gastroesophageal reflux disease (GERD) is reduced. However, the effects of proton pump inhibitors (PPI) on the secretion of saliva have rarely been reported. Therefore, the present study investigated changes in the volume and pH of saliva after the cessation of PPI. Materials and Methods: We retrospectively reviewed the records of consecutive patients previously diagnosed with mild reflux esophagitis (RE) or non-erosive reflux disease (NERD) controlled with PPI (including vonoprazan) who performed the salivary secretion test before and after a 2-week cessation of PPI. The volume, pH, and pH after acid loading (buffering capacity) of saliva were compared before and after the cessation of PPI. Results: Thirty-two patients (25 NERD, 7 mild RE) were included. The second saliva test was performed a median interval of 14 months [12.0–15.3] after the first test. No significant differences were observed in the volume of saliva secreted before and after the cessation of PPI (before 4.0 mL [2.7–6.0] vs. after 4.0 mL [2.3–5.9], p = 0.894). No significant differences were noted in pH or changes in pH after acid loading before and after the cessation of PPI (pH: before 7.1 ± 0.24 vs. after 7.0 ± 0.24, p = 0.1. Delta pH after acid loading: before 1.0 [0.8–1.2] vs. after 1.0 [0.8–1.2], p = 0.844). Conclusion: The cessation of PPI did not appear to affect the volume, pH, or buffering capacity of saliva in patients with PPI-responsive mild RE and NERD.