Performance of Lung Ultrasound as a Screening Tool for Subclinical Rheumatoid Arthritis-Associated Interstitial Lung Disease: a Multicenter Study.

Background: The screening strategy for interstitial lung disease (ILD) in rheumatoid arthritis patients is currently debated. While high-resolution computed tomography (HRCT) is the gold standard for diagnosing ILD, its systematic use as a screening tool is not yet recommended. The role of lung ultrasound (LUS) in assessing ILD has been previously explored.

Research question: What is the performance of LUS for ILD diagnosis in asymptomatic rheumatoid arthritis patients?

Study design and methods: We conducted a multicenter, cross-sectional study involving 203 asymptomatic rheumatoid arthritis patients from outpatient clinics in Argentina, Greece, France, and Mexico. Participants underwent clinical evaluations, pulmonary function tests, and lung ultrasound. HRCT scan was performed on each patient within 30 days of the lung ultrasound. Statistical analyses included sensitivity, specificity, and predictive values for LUS and pulmonary function tests.

Results: Of the participants, 26% were diagnosed with ILD. The median age was 63 years (52-89), with 161 patients (79.3%) women. The median duration from rheumatoid arthritis diagnosis to inclusion was 7 years (range: 2-16). LUS demonstrated a sensitivity of 83% (95% CI 70.2%-91.9%) and specificity of 81.2% (95% CI 74.2%-87.2%), with a negative predictive value of 93.1% (95% CI 87.4%-96.8%) and a positive predictive value of 61.1% (95% CI 58.9%-72.4%). LUS outperformed pulmonary function tests, underscoring its potential as a primary screening tool.

Interpretation: LUS is a promising tool for ILD screening in asymptomatic rheumatoid arthritis patients, offering high sensitivity and negative predictive value. Its incorporation into routine clinical practice could optimise ILD screening strategies and enhance patient outcomes through early detection and intervention.