Pulmonary involvement in lifelong non-smoking patients with rheumatoid arthritis and ankylosing spondylitis without respiratory symptoms

Abstract

Pulmonary involvement seen in rheumatoid arthritis (RA) and ankylosing spondylitis (AS) has been detected increasingly by using highly sensitive diagnostic techniques such as high-resolution computed tomography (HRCT). However, HRCT findings in healthy controls and the effects of smoking and drugs have not been well studied. The aim of this controlled study was to evaluate the relationships between disease-specific clinical, laboratory, HRCT and pulmonary function test (PFT) findings in 20 RA patients using methotrexate (MTX) and 20 AS patients using sulphasalazine who were non-smokers and exhibited asymptomatic respiratory signs. For this purpose, a total of 60 persons (40 patients and 20 healthy controls) were included in this study. A restrictive pattern on PFT was detected in four patients (20%) with AS, one patient with RA and one control (p<0.05). Fourteen patients (70%) with RA and ten patients (50%) with AS had positive HRCT findings. Only one patient (5%) in the control group had abnormal HRCT findings (p<0.05). Interstitial lung disease (ILD) was the most frequently seen HRCT finding in both the RA (35%) and AS (20%) groups. The chest expansion measurement, the score of the visual analogue scale (VAS) for pain and C-reactive protein (CRP) levels were statistically significantly better in patients with AS having normal HRCT than in those with abnormal findings (p<0.05). There was no correlation detected between HRCT and duration of disease, disease activity markers, functional indexes and PFT in patients with RA and AS. HRCT is a sensitive tool in detecting ILD in patients with RA and AS with no signs and symptoms of pulmonary involvement and may be an integral part of such work-up. However, future prospective studies are needed to better determine if HRCT is in fact a predictor of subsequent MTX toxicity.