Effect of aging and obesity on esophageal mucosal integrity as measured by baseline impedance

Abstract

AimLow mean nocturnal baseline impedance (MNBI) values support gastroesophageal reflux disease (GERD) diagnosis. Recent data denote that age and obesity may affect MNBI. We aimed to evaluate diagnostic MNBI cutoffs as also the effect of aging and body mass index (BMI) on MNBI.MethodsIn total 311 patients (M/F: 139/172, mean age: 47 ± 13) referred for typical GERD symptoms that have undertaken both high‐resolution manometry (HRM) and pH‐Impedance studies off PPI were evaluated. MNBI at 3, 5, and 17 cm over lower esophageal sphincter (LES) were evaluated. GERD was diagnosed if acid exposure time (AET) >6%.ResultsMean BMI was 26.6 ± 5.9 kg/cm2. GERD was diagnosed in 39.2% and 13.5% had inconclusive GERD. MNBI was correlated to patients' age, BMI, AET, and the length of LES‐CD separation and at 3 cm also to the total number of reflux and LES hypotension. In the multivariate analysis MNBI at 3 and 5 cm was independently correlated only to age, BMI, and AET. Patients with definite GERD showed lower MNBI at 3 cm compared with inconclusive GERD though both showed lower values when compared with GERD absence. At 3 cm MNBI ability for diagnosing GERD was good (0.815, p < 0.001 95% CI: 0.766–0.863) with an optimal cutoff point of 1281 Ohm.ConclusionAccording to our study findings age and BMI affect independently lower esophageal MNBI values in patients evaluated for GERD. MNBI significantly aids toward GERD diagnosis though in a real‐life setting MNBI values much lower than the one previously proposed should be used.

Mean nocturnal baseline impedance in gastro-esophageal reflux disease diagnosis: Should we strictly follow the Lyon 2 Consensus?

“…The Lyon 2 amendment which lowered the MNBI value used as supportive evidence for GERD diagnosis was a first step in the right direction, as since the publication of the Lyon 1 Consensus, many studies have proved that significantly lower values than 2292 Ohms should be used for GERD diagnosis[ 12 , 13 ]. The proposed cut-offs were based on a pivotal and extremely important publication which unfortunately did not aim to discover MNBI values that could, with the best area under the curve, sensitivity/specificity, diagnose or refute GERD diagnosis, but rather to define the normal values among normal subjects without symptoms[ 14 ].…”

“…It should be noted that several published papers have used receiver operating characteristic (ROC) curve analysis to propose specific MNBI cut-offs for conclusive GERD diagnosis. A previous study from the United Kingdom showed that the best cut-off for conclusive GERD diagnosis was 1278 Ohms, while in a study from China of patients with refractory GERD symptoms, a cut-off of 1941.8 Ohms was shown to refute conclusive GERD[ 11 , 13 ]. Differences in MNBI values in the abovementioned studies can be explained by the same pivotal study by Sifrim et al [ 14 ] which proved that regional MNBI differences exist.…”