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 h 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 h 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.
Keywords: cough; idiopathic pulmonary fibrosis; interstitial lung diseases; laryngopharyngeal reflux; ryan index.
Copyright © 2021 Su, Shen, Zhang, Jiang, Jin, Zhang, Hu, Zhou, Li and Li.