Can Gastroesophageal Reflux Disease (GERD) cause Pulmonary Fibrosis?

Relationship Between GERD and Pulmonary Fibrosis

GERD is associated with pulmonary fibrosis, but there is insufficient evidence to establish a clear causal relationship. 1

Association Between GERD and Pulmonary Fibrosis

• GERD is recognized as a possible extraesophageal manifestation of gastroesophageal reflux disease according to the American Gastroenterological Association's 2023 clinical practice update 1
• Pulmonary fibrosis is specifically listed among the potential extraesophageal manifestations of GERD in clinical guidelines 1
• The relationship between GERD and pulmonary fibrosis is complex, with evidence suggesting association rather than clear causation 1, 2
• Meta-analysis data indicates GERD is associated with idiopathic pulmonary fibrosis (IPF) with an odds ratio of 2.94, but this association may be confounded by factors such as smoking 3

Pathophysiological Mechanisms

• Abnormal acid gastroesophageal reflux is highly prevalent in patients with IPF, with up to half of these patients being asymptomatic 1
• The proposed mechanism involves micro-aspiration of gastric contents leading to repeated subclinical lung injury, which may contribute to pulmonary fibrosis 4, 2
• Reflux may exacerbate inflammatory conditions via acid or non-acid mechanisms, including micro-aspiration of digestive fluids 1
• The relationship may be bidirectional - IPF might increase negative intrathoracic pressure, which could potentially worsen GERD 2, 5

Clinical Evidence and Guidelines

• The 2011 ATS/ERS/JRS/ALAT guidelines for IPF recommend treating asymptomatic GERD in IPF patients (weak recommendation, very low-quality evidence) 1
• This recommendation was based on retrospective case series showing stabilization of pulmonary function and oxygen requirements with medical and surgical management of gastroesophageal reflux 1
• More recent studies have questioned this relationship, with some suggesting that while GERD is more common in IPF patients compared to the general population, it may be less common than in patients with other interstitial lung diseases 6

Treatment Implications

• Despite the uncertain causal relationship, some evidence suggests that proton pump inhibitor (PPI) use for at least 4 months may have a protective effect against IPF-related mortality 4
• The 2011 IPF guidelines recommend medical treatment of asymptomatic GERD in most patients with IPF, though this is a weak recommendation based on very low-quality evidence 1
• More recent studies have raised concerns that PPI use might be associated with increased risk of lung infections and potentially negative outcomes in some patients 2

Multidisciplinary Approach

• A multidisciplinary approach involving pulmonology, gastroenterology, and other specialties is recommended for patients with both conditions 1
• Diagnostic testing should include thorough evaluation of both conditions, with results from various specialties (bronchoscopy, thoracic imaging, laryngoscopy) taken into consideration 1

Pitfalls and Caveats

• Causation versus association is difficult to establish as many conditions thought to be related to extraesophageal reflux are associated with a higher incidence of acid reflux 1
• The relationship between GERD and IPF may be confounded by common risk factors, particularly smoking 3
• Patients with IPF and GERD may not complain of typical reflux symptoms such as heartburn or regurgitation, making diagnosis challenging 1
• The evidence supporting treatment of GERD in IPF is of very low quality, and more recent studies have questioned the benefit of this approach 1, 2