Frequency and Associated Factors of Lung Involvement in Early Rheumatoid Arthritis / 대한류마티스학회지

ABSTRACT

OBJECTIVE: To determine the frequency and associated factors of physiologic abnormalities indicative of lung disease in early rheumatoid arthritis (RA). METHODS: Thirty-six early RA patients(mean age 43+/-12 years, 30 females, disease durations less than 12 months, mean duration 5+/-3 months), who had not been treated with disease modifying antirheumatic drugs (DMARDs), were studied. Clinical, laboratoy and radiologic variables such as age, sex, smoking history, past lung disease history, drug medication history, rheumatoid factor positivity, erythrocyte sedimentation rate (ESR), CRP and chest radiography, were undertaken. Pulmonary function tests (PFTs) were performed in all patients and results for PFTs were expressed as percentage of predicted values for each individual adjusted for age, sex, and height. Lung disease was defined as one or more of the followings should be present, 1) forced vital capacity (FVC) <80% for predicted, 2) diffusing capacity of carbon monoxide (DLCO) <80% for predicted, 3) forced expiratory flow from 25% and 75% of vital capacity (FEF 25-75%) <80% for predicted. Statistical comparisons were made using Student? t test or chi-square test as appropriate. RESULTS: All patients had normal chest radiography. Rheumatoid factor was positive in 21 patients (58%), smokers were 5 patients (14%), ESR and CRP were increased in 16 (44%) and 17 patients (47%). Ten patients (28%) had lung disease and included FVC <80% in 4, DLCO <80% in 4 and FEF 25-75% <80% in 6 patients. There was no significant predictor of lung disease. CONCLUSION: The frequency of lung disease in early RA by PFTs was 28% and there was no significant predictor of lung disease.