Background: Interstitial lung disease is a heterogeneous entity, which encompasses a large number of pulmonary disorders, including idiopathic pulmonary fibrosis. Gastro-oesophageal reflux appears to be more prevalent in idiopathic pulmonary fibrosis than in controls and in patients with secondary pulmonary fibrosis, but its contribution to interstitial lung disease remains unsettled.
Aims: To prospectively evaluate gastro-oesophageal reflux in patients with interstitial lung disease and to define acid reflux patterns in patients with idiopathic and secondary forms of pulmonary fibrosis.
Materials and methods: Twenty-eight patients (15M, median age 66 years, interquartile range 60-71) were studied by history taking, pulmonary function tests, high resolution computed tomography, oesophageal manometry and 24h oesophago-gastric pH monitoring.
Results: Sixteen patients (57%) had typical reflux symptoms. All patients completed 24h pH metry and 14 underwent oesophageal manometry. An abnormal oesophageal acid exposure was observed in 19 patients (68%), 13 of which complained of predominant typical reflux symptoms. A diagnosis of idiopathic pulmonary fibrosis was made in 18 patients, while the remaining 10 patients were classified as secondary pulmonary fibrosis. Secondary pulmonary fibrosis patients had more restrictive lung defect, as expressed as Tiffeneau index (p<0.05) and greater acid reflux at nighttime (p<0.05) than idiopathic pulmonary fibrosis patients.
Conclusions: The prevalence of abnormal acid reflux in interstitial lung disease patients is high and, in particular, patients with secondary pulmonary fibrosis show higher oesophageal acid exposure than those with idiopathic form.