Mean Nocturnal Baseline Impedance (MNBI) Provides Evidence for Standardized Management Algorithms of Nonacid Gastroesophageal Reflux-Induced Chronic Cough

BACKGROUND: The clinical management of nonacid gastroesophageal reflux-induced chronic cough (GERC) is challenging, and patient response to standard antireflux therapy (omeprazole 20 mg twice daily plus mosapride 10 mg thrice daily) is suboptimal. This study aimed to identify predictors of standard antireflux therapy efficacy and provide evidence for standardized management algorithms of nonacid GERC. METHODS: A total of 115 nonacid GERC patients who underwent multichannel intraluminal impedance-pH monitoring (MII-pH) were enrolled between March 2017 and March 2021. Retrospective analysis of general information and MII-pH indications were used to establish a regression analysis model for multiple factors affecting standard antireflux therapy efficacy. RESULTS: 90 patients met the inclusion criteria, and the overall response rate to standard antireflux therapy was 55.5% (50/90). The mean nocturnal baseline impedance (MNBI) (1817.75 ± 259.26 vs. 2369.93 ± 326.35, P = 0.030) and proximal MNBI (1833.39 ± 92.16 vs. 2742.57 ± 204.64, P ≤ 0.001) of responders were lower than those of nonresponders. Weakly acid reflux (56.00 (31.70, 86.00) vs. 14.00 (14.00, 44.20), P = 0.022), nonacid reflux (61.35 (15.90.86.50) vs. 21.60 (0.00, 52.50), P = 0.008), and proximal extent (19.00 (5.04, 24.00) vs. 5.50 (2.56, 11.13), P = 0.011) were markedly higher in responders than nonresponders. Proximal MNBI (OR = 0.997, P = 0.042, and optimal cutoff = 2140 Ω) and weakly acid reflux (OR = 1.051, P = 0.029, and optimal cutoff = 45) were independent predictors of standard antireflux therapy efficacy. The combination predictive value did not show better results than either individual predictor. CONCLUSIONS: Proximal MNBI < 2140 Ω may be used to screen patients with nonacid GERC suitable for standard antireflux therapy and in standardized management algorithms for nonacid GERC. In the absence of MNBI, weakly acid reflux > 45 can be used as an auxiliary indicator.