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 refux-induced chronic cough (GERC) is challenging, and patient response to standard antirefux therapy (omeprazole 20 mg twice daily plus mosapride 10 mg thrice daily) is suboptimal. This study aimed to identify predictors of standard antirefux 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 antirefux therapy efficacy. Results. 90 patients met the inclusion criteria, and the overall response rate to standard antirefux 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 refux (56.00 (31.70, 86.00) vs. 14.00 (14.00, 44.20), P = 0.022), nonacid refux (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 Omega) and weakly acid refux (OR = 1.051, P = 0.029, and optimal cutoff = 45) were independent predictors of standard antirefux therapy efficacy. The combination predictive value did not show better results than either individual predictor. Conclusions. Proximal MNBI < 2140 Omega may be used to screen patients with nonacid GERC suitable for standard antirefux therapy and in standardized management algorithms for nonacid GERC. In the absence of MNBI, weakly acid refux > 45 can be used as an auxiliary indicator.