Impact of gastroesophageal reflux and proton pump inhibitors in fibrotic interstitial lung disease

INTRODUCTION: The role of gastroesophageal reflux disease (GERD) and proton pump inhibitors (PPI) in fibrotic interstitial lung disease (fILD) remains unclear. We evaluated the association of GERD and PPI use with cough severity and major pulmonary outcomes in patients with fibrotic ILD. METHODS: This retrospective analysis of a prospective cohort study consisted of patients with fibrotic ILD enrolled in the CAnadian REgistry for Pulmonary Fibrosis. Patients were categorized by the presence of GERD and PPI use based on patient self-report and verified by review of the medical record. We evaluated the unadjusted and adjusted association of GERD and PPI use with cough severity visual analog scale (VAS), change in lung function, and mortality. RESULTS: 2238 patients with fILD were included, of whom 731 had idiopathic pulmonary fibrosis. GERD was present in 777 patients (35%), with 494 (64%) of these reporting PPI use. GERD was associated with worse baseline cough severity VAS [36 mm (21-59) vs 30 mm (17-55), p = 0.007), with no difference between PPI users and non-users (p = 0.89). There was no consistent association of GERD or PPI use with change in lung function or transplant-free survival, with PPI use tending to be associated with worse outcomes only upon adjustment for age, sex, body mass index, and smoking pack-years (HR 1.31, 95%CI 1.02-1.67, p = 0.03). CONCLUSIONS: GERD is associated with worse cough severity in fILD, but PPI use is not associated with less cough. Neither GERD nor PPI use was consistently associated with change in lung function or transplant-free survival.