The role of continuous 48 h oropharyngeal pH monitoring in the diagnosis of laryngopharyngeal reflux disease

Abstract

Objective: To investigate the daily variation of LPR and the significance of 48-hour oropharyngeal pH monitoring in the diagnosis of LPRD. Methods: 72 subjects with suspected LPRD who were treated in our department from June 2018 to June 2021 were included. All patients were hospitalized to complete continuous 48-hour oropharyngeal Dx-pH monitoring. The consistency of Ryan index and W index and the correlation of various reflux parameters between the first and second 24-hour were compared. SPSS 24.0 was used for statistical analysis. Results: All 72 subjects successfully completed 48-hour oropharyngeal Dx-pH monitoring. Ryan index was positive in 11 cases (15.2%) in the first 24-hour, in 17 cases (23.6%) in the second 24-hour, in 5 cases (6.9%) both first and second, and in 23 cases (31.9%) in either 24-hour, Kappa=0.211 (P=0.064), 18 cases (25%) had inconsistent results of the first 24-hour and the second 24-hour, and there was no significant difference in the positive rate between the first and second (P=0.234). The number of positive cases in 48-hour monitoring increased by 109.1% compared with 24-hour monitoring.For W index, 49 cases (68.1%) were positive in the first 24-hourf 53 cases (73.6%) were positive in the second 24-hour, 42 cases (58.3%) were positive both first and second, and 58 cases (80.6%) were positive in either 24-hour, Kappa=0.477 (P<0.001), 16 cases (22.2%) had inconsistent results of the first and second, and there was no significant difference in the positive rate between the first and second (P=0.804). The number of positive cases in 48-hour monitoring increased by 18.4% compared with 24-hour monitoring. There was no significant difference in all the reflux parameters of first and second (P>0.05). The correlation comparison showed that the correlation of various reflux parameters in the upright position was lower than that in the supine position. Conclusion: Laryngeal reflux has daily variability. Extending the monitoring time of Dx-pH to 48-hour can help reduce the missed diagnosis caused by daily variability; the use of W index can reduce the influence of daily variability on the diagnostic results of LPRD.