Thoracic ultrasound to detect interstitial lung disease associated with rheumatoid arthritis: comparing three protocols

Interstitial lung disease associated with rheumatoid arthritis (RA-ILD) has a high mortality. Thoracic ultrasound (TUS) is a promising screening tool. We compared three protocols to determine an optimal approach. 116 adult patients with RA, fulfilling the ACR/EULAR criteria, were included at the outpatient rheumatology clinic. 92 patients received TUS, high-resolution CT (HRCT), and questionnaires including the Modified Medical Research Council (mMRC) dyspnea scale and Visual Analogue Scale (VAS) for Cough. TUS was scored by the number of B-lines in 72, 14 and 9 intercostal spaces (IS; Figure 1). An expert pulmonologist scored the HRCT for the presence of ILD. We performed sensitivity-specificity analyses for ILD presence with different cut-offs: 10 B-lines for 72 IS, 5 for 14 IS, 5 and 1 for 9 IS. AUROC was done to detect ILD for TUS, mMRC, and VAS cough. 61% of patients were female, 82% were seropositive. 55% were ever-smokers, 14% current smokers. Median age was 62y (IQR 19) with median RA duration of 9y (IQR 17) and median DAS28CRP of 2.2 (IQR 1.3). 36% experienced cough, 32.6% dyspnea. Median mMRC was 0 (IQR 1) and median VAS cough 1 (IQR 20). 9% had a clinically relevant ILD. Test statistics and AUROC curves are shown in Figure 1. All three TUS-based protocols had good AUCs (>0.8), with an excellent AUC (>0.9) for 72 IS. Contrarely, mMRC and VAS Cough performed poorly (AUC 0.6-0.7). <fig><object-id>erj;64/suppl_68/PA3405/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>