Diagnostic accuracy of mean nocturnal basal impedance and other complementary tests for the diagnosis of gastroesophageal reflux disease according to the new Lyon criteria

Aims To determine the diagnostic accuracy of mean nocturnal basal impedance (MNBI), in patients with suspected Gastroesophageal Reflux Disease (GERD), by comparing it to the updated 2023 Lyon Consensus Diagnostic Criteria. Additionally, to identify the optimal MNBI cut-off point for accurate GERD diagnosis. Furthermore, diagnostic accuracy of other complementary tests such as total number of reflux episodes, number of acid reflux episodes, bolus exposure time and DeMeester score for GERD diagnosis were evaluated [1] [2] [3] [4] [5].

Methods A diagnostic test study was conducted based on a retrospective cohort of patients with suspected GERD who were evaluated at the Hospital Universitario San Ignacio in Bogotá, Colombia, between July 2018 and August 2023. These dates were chosen as they span the period between the publication of the first Lyon consensus and its subsequent update in 2023. Patients over 18 years of age with symptoms suggestive of GERD, undergoing impedance-pH monitoring, and not receiving proton pump inhibitor treatment in the 4 weeks prior to the procedure were included. Variables related to endoscopic characteristics were systematically gathered prior to the pH-metry test. MNBI was obtained according to 24 hours impedance-pH monitoring. The diagnosis was made using the updated 2023 Lyon criteria as the gold standard. Sensitivity, specificity and discriminatory ability were evaluated using AUC-ROC. The best cut-off point was determined using Liu's method for MNBI, number of reflux episodes, number of acid reflux episodes, DeMeester score and bolus exposure time. ROC curves were compared using DeLong's method.

Results A total of 55 patients were included in the study. Of these, 26 had a positive and 29 a negative diagnosis of GERD. MNBI discriminative ability for GERD diagnosis was suboptimal (AUC-ROC=0.77; 95% CI 0.64–0.89). The cutoff point with the higher simultaneous sensitivity and specificity was 1590 Ohms (sensitivity=69.2%, specificity=72.4%). MNBI cutoff points of<1500 Ohms and>2500 Ohms showed a sensitivity of 61% and 72.4% and a specificity of 88% and 41.4%, respectively. AUC-ROC, sensitivity and specificity for best cut-off points of other complementary tests were as follows: Total number of reflux episodes (88 reflux episodes), 69%, 72%, 0,80; Acidic reflux episodes (87 reflux episodes), 77%, 83%, 0,85; DeMeester score (15,6 points), 92%, 93%, 0,90; Bolus exposure time (1,6%) 69%, 66%, 0,73. AUC-ROC comparison showed superiority of the DeMeester score over the MNBI (p=0.03). No significant differences in discriminatory ability were found when comparing MNBI with the other complementary tests (p<0.05).

Conclusions MNBI, as well as other complementary tests, showed suboptimal operational characteristics for the diagnosis of GERD. It is suggested to interpret these tests in conjunction with other clinical, endoscopic and pH-metry findings for GERD diagnosis. The DeMeester score seems promising, but future evidence from prospective studies is needed to prove its utility.

Publication History

Article published online:
27 March 2025

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