Is the Impedance Baseline Helpful in the Evaluation of Globus Patients?

Background/Aims Gastroesophageal reflux disease (GERD) has been suggested to be responsible for 23-68% of globus cases. The impedance baseline (IB) acquired by 24-hour multichannel intraluminal impedance monitoring has been proven to represent esophageal mucosal integrity. We aimed to investigate whether the IB is helpful for evaluating globus patients. Methods Twenty-four-hour multichannel intraluminal impedance pH tracings (MII-pH) were evaluated in globus patients. Differences in the IB between the acid reflux, non-acid reflux, and no reflux groups were analyzed. Receiver operating characteristic (ROC) curves were obtained to determine the optimal measurement point from the lower esophageal sphincter (LES). Results A total of 62 patients were analyzed. MII-pH showed that acid reflux, non-acid reflux, and no reflux were present in 13, 5, and 44 patients, respectively. The acid reflux group had a significantly lower IB than the other groups at a location 3 cm from the LES. ROC curve analysis revealed that placement at a position 3 cm from the LES resulted in moderate diagnostic accuracy (area under the curve = 0.88). When we set 2500 Omega as the cut-off value for acid reflux at a position 3 cm from the LES, the additional diagnostic yield for acid reflux was increased by 19.4% compared with that obtained by MII-pH. Conclusions IB is complementary to pH findings enabling identification of a subset of patients with co-existing acid reflux. Catheter placement at a location 3 cm from the LES and a cut-off value of 2500 Omega may be reasonable criteria for estimating acid reflux.