Prevalence of Airway and Parenchymal Abnormalities in Newly Diagnosed Rheumatoid Arthritis

Background: Pulmonary disease is a well recognised and important extra-articular manifestation of rheumatoid arthritis (RA). The objective of this study was to determine the prevalence of airway and parenchymal abnormalities in newly diagnosed patients with RA and to correlate these with clinical measures of RA severity and laboratory tests.

Methods: 60 patients with a new (symptom duration <12 months) diagnosis of RA (43 females, 42 European, mean age 54, 33 ever smoker, (17 current) underwent lung function testing and high resolution computed tomography (HRCT) scored by two independent radiologists.

Results: Eighteen (30%) patients reported respiratory symptoms: dyspnoea (11), cough (11), and wheeze (8). Twelve (20%) patients had physiologic evidence of airflow obstruction and 24 (40%) had reduced gas transfer. The prevalence of HRCT abnormalities (in any lobe) was as follows: decreased attenuation 67%, bronchiectasis 35%, bronchial wall thickening 50%, ground glass opacification 18%, reticular changes 12%. All abnormalities were more common in the lower lobes. With the exception of reduced DLCO, there were no significant differences in the prevalence of HRCT patterns or lung function parameters between smokers and non smokers. Anti-CCP antibodies and rheumatoid factor (RF) correlated strongly with DLCO and variably with other physiologic measures but poorly with radiologic abnormalities.

Conclusion: Patients with newly diagnosed RA have a moderate prevalence of airway and parenchymal abnormalities on HRCT and lower than predicted lung function parameters which cannot entirely be explained by smoking. These data suggest that pulmonary involvement is present early in the disease course in RA.