Lung ultrasound helps rule out ILD in patients with RA

Lung ultrasound (LUS), a low-cost tool with a high negative predictive value, can be a useful instrument for dismissing the presence of interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA), suggests a study.

A total of 106 consecutive RA patients (median age 60.9 years, 82 percent women) evaluated at a Rheumatology Clinic in Buenos Aires, Argentina, between January and December 2022 were included in this cross-sectional study.

The gold standard for ILD diagnosis was high-resolution computed tomography (HRCT), which was carried out within 30 days of the LUS, chest x-ray, and pulmonary function tests (PFTs). The investigators were blinded to the HRCT results and patients’ clinical data.

LUS explored 14 areas and was deemed positive when the sum of B lines was ≥5. The investigators reported the performance for ILD diagnosis for each diagnostic test.

Of the patients, 32 (30.2 percent, 95 percent confidence interval [CI], 21.6‒39.9) had ILD. LUS had a sensitivity of 90.6 percent (95 percent CI, 75.0‒98.0) and a negative predictive value of 94.7 percent (95 percent CI, 85.4‒98.9). The performance of LUS was superior to that of other diagnostic tests performed 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,” the investigators said.