A Novel screening protocol for early detection of lung involvement in seropositive and ACPA positive rheumatoid arthritis

Background: Seropositive rheumatoid arthritis (RA) is associated with significant cardiovascular and pulmonary morbidity. However, screening for early detection of pulmonary involvement especially interstitial lung disease (ILD) is not established in RA. Methods: We used a non-invasive radiation-free approach to screen for pulmonary, pleural, or vascular disease manifestation using a pulmonary function test (PFT), a cardiopulmonary exercise test (CPET), echocardiography (ECG), and pleuro-pulmonary transthoracic ultrasound (LUS). We included patients with confirmed diagnosis of seropositive RA according to ACR criteria, but without symptoms for or known cardiopulmonary disease. Results: We included 67 consecutive patients (78% female, mean age 61±12 years, 48% active or previous smokers), who fulfilled the inclusion criteria and gave written informed consent. We found 48% of patients with suspected changes in PFT with a diffusion capacity (DLCOc-SB) ≤ 80% among them 7% with forced vital capacity (FVC) ≤ 80%. In 40% of patients, we found noticeable changes in LUS, 24% with an ILD compatible pattern. ILD was suspected when LUS abnormalities and additional PFT changes were present, which was found in 16% of cases. Other findings included obstructive lung disease (n=11), subpleural consolidation (n=6) including one confirmed lung cancer, minimal pleural effusion (n=6), severe aortic stenosis in bicuspid aortic valve (n=1), and ischemic cardiac disease (n=2). None of the patients showed signs of pulmonary vascular involvement on ECG or CPET. Conclusions: Screening of asymptomatic RA patients for pulmonary involvement detects a variety of cardiopulmonary comorbidities. ILD was suspected in 16% of cases. Trial registration: German Register of Clinical Studies (DRKS00028871).