Abstract

OBJECTIVE: Pepsin detection in throat sputum has been posited as a reliable biological marker of laryngopharyngeal reflux disease (LPRD). This study was designed to further correlate pepsin concentration with symptoms and signs of LPRD.

STUDY DESIGN: Cross-sectional study.

SETTING: Nanfang Hospital of Southern Medical University.

SUBJECTS AND METHODS: Fifty-six laryngitis patients were divided into a reflux laryngitis group and a chronic laryngitis group based on the reflux symptom index (RSI), reflux finding score (RFS), and proton pump inhibitor treatment for two weeks. Oral and hypopharyngeal secretions from the study patients and from 15 healthy subjects were collected. Thirty-six obstructive sleep apnea (OSA) patients were divided into a mild-moderate group and a severe group by the apnea-hypopnea index (AHI). Bedtime and first-morning oral secretions were collected. Enzyme-linked immunosorbent assay was used to measure the pepsin concentration.

RESULTS: In laryngitis patients, the total score of RSI and RFS (P < 0.05), and the symptoms, including clearing throat often, coughing, and sensing a lump in the throat (P < 0.006), were more severe in the pepsin-positive group. No significant differences were found between the oral and hypopharyngeal secretions. In OSA, pepsin levels in the first-morning oral secretions were correlated with AHI, mean SaO₂, and mini SaO₂ (P < 0.01). However, RSIs were not significantly correlated with these indicators.

CONCLUSION: Higher levels of pepsin in sputum were associated with higher RSI and RFS in cases of laryngitis. There was no relationship between pepsin levels and RSI in cases of OSA. There were no differences of pepsin concentration in sputum collection methods or in collection timing.