Airways abnormalities in a prospective cohort of patients with rheumatoid arthritis

Abstract

Rheumatoid arthritis (RA) affects roughly 1% of the population and commonly involves the lungs. Of lung involvement in RA, interstitial lung disease (ILD) is well-known; however, airways disease in RA is relatively understudied. What are the baseline airways abnormalities in a prospective cohort of patients with RA based on pulmonary function tests (PFT), high-resolution CT scans (HRCT) and computational imaging analysis and are there associations between these abnormalities and respiratory symptoms? In this single-center study, 188 patients with RA without a clinical diagnosis of ILD underwent HRCT and PFT. Radiologists assessed HRCTs for airway abnormalities. Computational imaging via VIDA Vision software and in-house quantitative CT (qCT) analysis was applied to 147 HRCTs to quantify airway abnormalities. Airways obstruction (FEV1/FVC ratio < 0.7) was present in 20.7% of patients, and associated with older age, male sex and higher smoking rate. Radiologists identified airway abnormalities in 61% of patients-55% had bronchial wall thickening, 12% bronchiectasis, and 5% mosaic attenuation; these airways findings were associated with older age, male sex, lower FEV1, FVC, FEV1/FVC ratios, and higher rates of rheumatoid factor positivity. Prespecified qCT metrics (wall thickening % and emphysema %) correlated with PFT obstruction and more severe respiratory symptoms including shortness of breath and cough. There were high rates of airways abnormalities in this prospective RA cohort based on three methods of detection. There were significant associations between qCT measures and respiratory symptoms. Airways disease may be an under-recognized extra-articular manifestation of RA and qCT may be a sensitive method to detect the clinical impact on respiratory symptoms.