Distal Mean Nocturnal Baseline Impedance Predicts Pathological Reflux of Isolated Laryngopharyngeal Reflux Symptoms

Background/Aims Diagnosis of isolated laryngopharyngeal reflux symptoms (ILPRS), ie, without concomitant typical reflux symptoms (CTRS), remains difficult. Mean nocturnal baseline impedance (MNBI) reflects impaired mucosal integrity. We determined whether esophageal MNBI could predict pathological esophagopharyngeal reflux (pH+) in patients with ILPRS. Methods In this cross-sectional study conducted in Taiwan, non-erosive or low-grade esophagitis patients with predominant laryngopharyngeal reflux symptoms underwent combined hypopharyngeal multichannel intraluminal impedance-pH monitoring when off acid suppressants. Participants were divided into the ILPRS (n = 94) and CTRS (n = 63) groups. Asymptomatic subjects without esophagitis (n = 25) served as healthy controls. The MNBI values at 3 cm and 5 cm above the lower esophageal sphincter (LES) and the proximal esophagus were measured. Results Distal but not proximal esophageal median MNBI values were significantly lower in patients with pH+ than in those with pH- (ILPRS in pH+ vs pH-: 1607 omega vs 2709 omega and 1885 omega vs 2563 omega at 3 cm and 5 cm above LES, respectively; CTRS in pH+ vs pH-: 1476 vs 2307 omega and 1500 vs 2301 omega at 3 cm and 5 cm above LES, respectively, P < 0.05 for all). No significant differences of any MNBI exist between any pH- subgroups and healthy controls. The areas under the receiver operating characteristic curve in the ILPRS group were 0.75 and 0.80, compared to the pH- subgroup and healthy controls (P < 0.001 for both), respectively. Interobserver reproducibility was good (Spearman correlation 0.93, P < 0.0001). Conclusion Distal esophageal MNBI predicts pathological reflux in patients with ILPRS. (J Neurogastroenterol Motil 2023;29:174-182)