Background Rheumatoid arthritis (RA) is a systemic inflammatory disease that affects joints and various organs including the lung. The pulmonary involvement is critical for prognosis of the patients and decision of the treatment. Moreover, the pulmonary involvement showed various abnormalities such as interstitial pneumonia (ILD) and airway disease (AD). Importantly, a pulmonary abnormality coexists with other ones in RA patients. There have been large numbers of studies on the prevalence of pulmonary abnormalities and clinical features of patients with these lesions. However, it remains to be elucidated what existence pattern of pulmonary abnormalities RA patients have.
Objectives To reveal the existence pattern of the pulmonary abnormalities in RA patients using cluster analysis, and to clarify the clinical features of patients with multiple pulmonary abnormalities.
Methods Subjects were consecutive 208 RA patients who were treated with bDMARDs as the first one from Feb. 2004 to Sep. 2015 in our department and received HRCT scan before and after the therapy. Pulmonary abnormalities were classified into 4 categories (ILD, nodular lesions, AD and other) and 20 lesions such as ground-glass opacity, reticular pattern, bronchiolitis and bronchiectasis and were examined their existence and distribution. Cluster analysis was conducted according to the existence of the lesions by Ward method. Clinical features were analyzed through reviewing medical records.
Results Subjects were 208 RA cases (M/F; 64/144, mean age 59.2 year-old, disease duration 13.1 years). Pulmonary lesions were found in 146 (70.2%) of RA patients before treatment Imaging findings were 81of ILD (39%),45 of nodular lesion (21.6%) and 115 of AD (55%). Cluster analysis showed 6 clustered (Fig.), 1; no pulmonary lesions, 2; AD without bronchoectasia, 3; AD with bronchoectasia, 4; AD with curved linear opacities, 5; AD with nodular lesions, and 6; reticular pattern with AD.
AD was common abnormalities and coexisted with other pulmonary lesions in RA. AD was found in 79%, 78% and 71% of patients with pulmonary abnormalities, ILD and nodular lesions, respectively. AD alone, AD with ILD, and AD with nodular pattern were found in 16.3%, 8.6% and 28.9%, respectively, while patients without pulmonary lesions were 29.8% in RA. AD was frequently associated with ILD and nodule compare to non-AD.
No differences were found in gender, smoking history, disease duration and disease activity between patients with and without AD. New emergence or exacerbation of pulmonary abnormalities developed in AD patients compared to those without pulmonary abnormalities or AD. No significant differences were found in clinical features, among AD alone, AD with ILD and AD with nodules.
Conclusions Pulmonary abnormalities were found in 70% in RA. AD was found in 55% of RA patients and coexisted with other pulmonary lesions such as ILD and nodular lesions. Patients with AD frequently showed newly emerging or worsening pulmonary lesions, regardless of the coexistence of other pulmonary lesions. Thus, AD is shared and critical pulmonary abnormality in RA.
Disclosure of Interest None declared