The Association Between Acidification Time on Wireless Motility Capsule and Gastroesophageal Reflux Disease

Gastric physiological characteristics such as fundus accommodation, gastric distention, emptying/transit time, and basal acid output may contribute to the pathogenesis of gastroesophageal reflux disease (GERD). Wireless motility capsule (WMC) uses pH data to determine gastric transit time but has not been used in the evaluation of GERD. Certain metrics such as acidification time, nadir pH, and gastric transit time may provide insight into the mechanisms of GERD related to gastric physiology, allowing WMC to be a complementary tool in the diagnosis of GERD. We aimed to determine whether pH data and transit time on WMC tests correlated with the presence of GERD on ambulatory reflux testing.

This was a retrospective study of 28 patients who had undergone both WMC and reflux testing via wireless pH or pH/impedance. Acidification time (time from capsule ingestion to pH<2), nadir postprandial pH, and gastric transit time were manually determined from the WMC capsule proprietary software. Spearman correlation was used to compare these metrics with gastric transit time, percent esophageal acid exposure, and DeMeester score.

Acidification time moderately correlated with gastric transit time, R : 0.44, P =0.02, but not nadir pH, percent esophageal acid exposure, or DeMeester score. Patients with an abnormal reflux test had a significantly longer median acidification time (135.5 vs. 78.5 min, P =0.021). After stratifying by patients with normal versus prolonged gastric transit time, there was a trend toward longer acidification time in patients with positive reflux testing in both groups, but this was not statistically significant. Patients with prolonged gastric transit time >300 minutes were not more likely to have a positive reflux test (38% vs. 35%, P =1).

The acidification time on WMC was significantly longer in patients with proven GERD and acidification time positively correlated with gastric transit time. Larger studies are needed to determine whether WMC could be used as a complementary tool in investigating patients with GERD symptoms.