Airways involvement in rheumatoid arthritis: clinical, functional, and HRCT findings

Abstract

The aim of the present study was to assess the prevalence and characteristics of airways involvement in rheumatoid arthritis (RA) patients in the absence of interstitial lung disease. We prospectively evaluated, with high-resolution computed tomography (HRCT) and pulmonary function tests (PFTs), 50 patients with RA (nine males and 41 females; mean age: 57.8 yr), including 39 nonsmokers and 11 smokers (mean cigarette consumption: 15.3 pack-yr) without radiographic evidence of RA-related lung changes. PFTs demonstrated airway obstruction (i.e., reduced FEV1/VC) in nine patients (18%) and small airways disease (SAD) (i.e., decreased FEF(25-75), defined as exceeding the predicted value by 1.64 residual SD [RSD] or more, and/or an increased phase III slope > 2 SD by single breath nitrogen washout) in four patients (8%). HRCT demonstrated bronchial and/or lung abnormalities in 35 cases (70%), consisting of air trapping (n = 16; 32%), cylindral bronchiectasis (n = 15; 30%), mild heterogeneity in lung attenuation (n = 10; 20%), and/or centrilobular areas of high attenuation (n = 3; 6%). Airway obstruction and SAD were correlated with the presence of bronchiectasis and bronchial-wall thickening (p = 0.003), and with bronchial infection (p = 0.01), but were unrelated to rheumatologic data. FEF(25-75) was reduced and the slope of phase III was increased in patients with airway changes on HRCT scans, whereas no PFT abnormalities were found in 13 of 15 patients with normal HRCT scans. HRCT depicted features of SAD in 20 of the 33 patients with normal PFTs. HRCT findings were unrelated to rheumatologic data. A high prevalence of airway abnormalities as assessed with HRCT and/or PFTs was observed in our RA population. HRCT appears to be more sensitive than PFTs for detecting small airways disease.