The Lung Disease of Rheumatoid Arthritis

Lung disease is a major morbidity of rheumatoid arthritis (RA). Lung involvement is heterogeneous, and may occur in some form in over 50% of patients with RA. Clinically apparent interstitial lung disease (ILD) affects about 8 % of patients, most commonly usual interstitial pneumonitis. Pulmonary disease is a major cause of death in patients with RA; patients with ILD have a median survival of 2.6 years following diagnosis of the lung disease, lowest in patients with diffuse alveolar damage. Risk factors for RA related lung disease include male sex, older age, smoking, and more severe RA with erosive joint and other extraarticular involvement. Drugs used in management of RA may be associated with pulmonary toxicity, including methotrexate, leflunomide and some biologics. In ILD, lung function studies show a restrictive pattern, with low DLC0 a sensitive parameter of early ILD. High resolution chest computed tomography is sensitive for demonstrating ILD. Treatment of RA associated lung disease is guided by the type of pulmonary disease, recognizing that control of the underlying RA is critical to reducing the impact of disease related comorbidities. Much remains to be done to better understand the pathogenesis and management of this disease manifestation.