AUTHOR=Su Yiliang , Shen Li , Zhang Fen , Jiang Xing , Jin Xiaofeng , Zhang Yuan , Hu Yang , Zhou Ying , Li Qiuhong , Li Huiping 

TITLE=Laryngopharyngeal pH Monitoring in Patients With Idiopathic Pulmonary Fibrosis

JOURNAL=Frontiers in Pharmacology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2021.724286

DOI=10.3389/fphar.2021.724286

ISSN=1663-9812

ABSTRACT=Background: Patients with idiopathic pulmonary fibrosis (IPF) often have irritating persistent dry cough. Possible correlations between dry cough and laryngopharyngeal reflux (LPR) remain unclear.
Methods: 44 patients with IPF and 30 healthy individuals underwent 24-hour laryngopharyngeal pH monitoring. Ryan index score was calculated. Patients’ demographic and clinical data were collected.
Results: 44 patients with IPF and 30 healthy individuals were included. The proportions of men and smokers were significantly higher in IPF group than control group (All P<0.01). The average laryngopharyngeal pH value for 24 hours was similar in the IPF (7.11 ± 0.08) group and control group (7.09 ± 0.06). According to the percentage duration of pH<6.5, pH6.5-7.5, and pH>7.5 in the overall measure duration, the patients were classified into three pH groups. In entire pH monitoring duration, the proportion of pH>7.5 group in IPF patients was higher than control group; at upright position, the proportion of pH>7.5 group in IPF patients was higher than control group; at supine position, the proportion of pH<6.5 group in IPF patients was higher than control group (All P<0.01). Seven patients had Ryan index score>9.41 at upright position. All patients had Ryan index score<6.79 at supine position. Four patients showed significantly higher and one patient had significantly lower average pH at coughing than the overall average pH (All P<0.05).
Conclusions: Patients with IPF may have LPR. Basic and acidic LPR may likely occur at upright and supine position, respectively. Ryan index may not accurately reflect LPR in patients with IPF.