Pulmonary Function Test in Rheumatoid Arthritis Patients

Lung disease is a common and important contributor to morbidity and mortality in rheumatoid arthritis (RA) patients. Studies have shown that diagnostic methods can reveal hidden pulmonary diseases even in RA patients with no respiratory symptoms. In this study, we assessed pulmonary function tests (PFTs) and chest radiographs (CXRs) in RA patients with more than three years of illness to find a suitable instrument for prospecting RA-induced lung diseases. We conducted a prospective cross-sectional study on 57 RA patients. Demographic, clinical, and CXR data were recorded. Residual volume (RV), total lung capacity (TLC), forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), and FEV1/FVC ratio was assessed. According to the FEV1/FVC ratio, patients were divided into three groups: FEV1/FVC below 70% (obstructive pattern) in 5% and between 70% and 85% (normal) in 50%, and above 85% (restrictive lung disease) in 45% of RA patients. Normal X-ray was the most common finding in CXR, and only cystic changes and reticular changes were found in 5% of patients. Analysis showed a significant relationship between abnormal chest images and the duration of disease (P=0.025), but PFT data did not result in any significance. Respiratory symptoms or clinical examinations are positive findings in the evaluation of asymptomatic patients, and using PFT is more rational than CXR. Our data show that there is no correlation between the disease duration and PFT data; hence, asymptomatic patients with a variety of risk factors should undergo further investigation.