Comparison of Proximal Migration of Sensed Reflux Events Among the Different GERD Groups

Abstract

Background: Proximal migration, nadir of pH, and duration have been shown to increase the likelihood of experiencing a sensed reflux event (SRE). Thus far, there are no studies comparing SRE characteristics among the different GERD groups. Aim: To compare the proximal migration characteristics of SRE among the different GERD groups. Methods: Patients with typical heartburn symptoms at least 3 times a week for more than 3 months were recruited to this study. Upper endoscopy and pH testing were used to divide the patients into three groups: erosive esophagitis (EE), nonerosive reflux disease (NERD), and functional heartburn (FH). Patients underwent esophageal pH testing using a 4-sensor pH probe. The most distal pH sensor was positioned 1 cm > LES, and the sensors were located 5 cm apart (6 cm, 11 cm, 16 cm > LES). Results: A total of 22 patients had EE, 15 NERD, and 13 FH (M/F - 20/2, 12/3, 5/8, mean age - 51.5 ± 3.7, 50.1 ± 4.2, 50.3 ± 3.8, respectively). During the pH test, 143 GERD-related symptoms were reported, 112 (78.3%) were correlated with pH < 4 at the very distal pH sensor and thus were considered as SRE. Patients with FH experienced 12, NERD 33 and EE 67 SREs. Of the 112 SREs, 97(86.6%) reached 6 cm > LES, 83(74.1%) - 11 cm > LES, and 59(52.7%) −16 cm > LES. In FH, 75% of the SREs reached 16 cm > LES as compared to 57.6% in the NERD group and 46.3% in EE group (p < 0.01). In contrast, only 28%, 26%, and 26% of the non-SREs of patients with FH, NERD, and EE, respectively, reached 16 cm > LES (P < 0.01). In all groups, duration of SRE 1 cm and 6 cm > LES was significantly higher than duration of non-SRE (5.9 ± 1.1 vs. 3.4 ± 0.5 and 5.2 ± 1.1 vs. 2.2 ± 0.3, respectively, p < 0.001). Additionally, SREs had a significantly lower pH nadir and change in pH at 1 cm>LES then non-SREs (0.96 ± 0.07 vs. 1.4 ± 0.05 and 4.9 ± 0.2 vs. 4.6 ± 0.01, respectively, p < 0.05). Conclusion: Patients with FH demonstrated the highest number of SREs that reach proximal esophagus, as compared to those with EE and NERD. Overall, SREs are more associated with longer duration, pH nadir, and change in pH 1 cm > LES as compared to non-SREs.