Lung ultrasound is a promising screening tool to rule out interstitial lung disease in patients with rheumatoid arthritis.

Abstract

It is still controversial how to screen for interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA). We aimed to evaluate the performance of lung ultrasound (LUS) as a screening tool for RA-ILD and to compare it with the performance of chest auscultation, chest x-ray and pulmonary function tests (PFTs). Cross-sectional study of consecutive RA patients evaluated at a Rheumatology Clinic in Buenos Aires between January and December 2022. High-resolution computed tomography (HRCT) was the gold standard for diagnosing ILD and was performed within 30 days of the LUS, chest x-ray and PFTs. Investigators were blinded to HRCT results and patients' clinical data. LUS was performed by exploring 14 areas and was considered positive when the sum of B lines was ≥5. Performance for the diagnosis of ILD was reported for each diagnostic test. One hundred and six patients were included; 87 (82%) were women. Median age was 60.9 (±9.5) years-old. A total of 32 (30.2%, 95% CI: 21.6%-39.9%) had ILD. The sensitivity and negative predictive value of LUS were 90.6% (95% CI 75.0%-98.0%) and 94.7% (95% CI 85.4%-98.9%), respectively. LUS performance was superior to that of the other evaluated diagnostic tests for screening ILD. Given that the US is a low-cost point-of-care tool with a high negative predictive value, it is emerging as a valuable tool for ruling out ILD in patients with RA.