Clinical and high resolution computed tomography characteristics of patients with rheumatoid arthritis lung disease.

Introduction: Rheumatoid arthritis (RA) is a systemic disease of unknown cause. A variety of pulmonary disorders have been described in association with RA. Among the most common are interstitial lung disease (ILD) and bronchiectasis.

Objectives: This study aims to determine the characteristics of RA patients with lung disease in relation to clinical characteristics, pulmonary function test (PFT) and high resolution computed tomography (HRCT) thorax.

Method: This is a 6-months cross-sectional study involving 63 consecutive RA patients in an outpatient rheumatology clinic. Patients had a mean disease duration of 5 years and above. Disease activity and severity was assessed by Disease Activity Score 28 (DAS28), Health Assessment Questionnaire (HAQ) and Rheumatoid Arthritis Articular Damage (RAAD) score. Full pulmonary function test (PFT) and HRCT of thorax were performed.

Conclusions: The prevalence of RA-ILD is 44% and 67% of patients are asymptomatic. There was significant higher proportion (68%) in patients of Chinese ethnicity who have ILD. Diffusion capacity of carbon monoxide was abnormal in all patients and forced expiratory flow (FEF)(25-75%) was low in 16%. Restrictive pattern was 66.7% by PFT. The most common HRCT findings were reticulation (46%) followed by ground glass opacities (38.1%) and bronchiectasis (28.6%). There was no association between ILD and male gender, duration of the disease, smoking, rheumatoid factor, extra-articular manifestations, disease activity or severity.