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 Ω vs 2709 Ω and 1885 Ω vs 2563 Ω at 3 cm and 5 cm above LES, respectively; CTRS in pH+ vs pH–: 1476 vs 2307 Ω and 1500 vs 2301 Ω 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.