Ineffective esophageal motility in Chicago Classification version 4.0 better predicts abnormal acid exposure

The updated Chicago Classification version 4.0 (CCv4.0) establishes a more stringent criteria to diagnose ineffective esophageal motility (IEM). This study aims to investigate the clinical significance of IEM in CCv4.0 in the context of gastroesophageal reflux disease (GERD). A retrospective study was conducted among suspected GERD patients who had heartburn and/or regurgitation as their chief complaints and completed esophageal function tests in our center from 2017 to 2019. Patients were further grouped as “CCv3.0 IEM” and normal motility according to Chicago Classification version 3.0 (CCv3.0), and as “CCv4.0 IEM” and normal motility according to CCv4.0. The clinical characteristics, high-resolution manometry, esophageal reflux monitoring, and proton pump inhibitor (PPI) efficacy were compared between different groups. Multivariate analyses were performed to identify esophageal motility parameters associated with reflux burden and symptom outcome. Of 172 subjects included, 93 patients were identified as CCv3.0 IEM, 69 as CCv4.0 IEM. IEM in either version was concomitant with elevated acid burden and impaired esophageal clearance as compared to normal motility in corresponding diagnostic criteria, while the only presence of IEM in CCv4.0 was predictive to abnormal acid exposure (AET > 6%: OR = 2.66, 95% CI [1.27–5.56], p < 0.01). The presence of “CCv3.0 IEM” and low EGJ-CI (EGJ-CI < 39.1 mmHg·cm) had no added value in predicting increased reflux burden. No interaction effect was found between the presence of IEM and a weakened EGJ. None of the manometric variables was capable of predicting PPI response. Stringent criteria of IEM in CCv4.0 can better predict abnormal acid exposure as compared to CCv3.0.