LAUSR

Background: Cartilage damage in rheumatoid arthritis (RA) has been evaluated by joint space narrowing (JSN) in X-ray, despite the fact that it is not a direct evaluation of cartilage. We have recently reported that direct evaluation of finger joint cartilage thickness evaluated by ultrasound (US) is valid and useful for patients with RA1). Objectives: In this study, we aimed to examine the progression of cartilage damage in RA patients. Methods: Forty-six patients with RA who had completed the US evaluation of finger joint cartilage thickness at baseline and after 1 year were included in this study. The cartilage thickness of metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints of 2nd to 5th fingers were bilaterally visualized and measured at the middle portion of MCP and PIP joints from a longitudinal dorsal view, with approximately 90 degrees flexion. Cartilage thickness was measured from the base of the cartilage to the interface artefact at the cartilage surface by calculating the pixel counts on DICOM images. Results: In patients, 78% were female, the median age was 68 years and the median disease duration of the patients was 6 years. The median DAS28-CRP at baseline was 2.6. The sum of total cartilage thickness from 16 joints per patient ranged from 3.1 to 9.1 mm (median 6.4 mm) at baseline, and it was significantly correlated with disease duration (ρ=-0.423, p=0.003). A significant decrease from the baseline in the cartilage thickness (median -1.6%) was observed after 1 year (p=0.041). Furthermore, patients with persistently moderate/high disease activity for 1 year by DAS28-CRP (n=9) showed a greater decrease in the cartilage thickness than the remaining patients with controlled disease activity (n=37) (median -5.9% versus -1.5%, respectively, p=0.029). Conclusion: This study further supported the validity and usefulness of joint cartilage thickness evaluation by US in patients with RA. References: [1]Ogura T, et al. Arthritis Care Res 2019 Oct 25. Disclosure of Interests: Takehisa Ogura: None declared, Ayako Hirata: None declared, Sayaka Takenaka: None declared, Yuki Inoue: None declared, Takaharu Kagtagiri: None declared, Yuto Takakura: None declared, Hideki Ito: None declared, Hideto Kameda Grant/research support from: Abbvie, Asahi-Kasei, Chugai, Eisai, Mitsubishi-Tanabe and Novartis, Consultant of: Abbvie, Boehringer, Celgene, Eli Lilly, Janssen, Novartis, Sanofi, UCB, Speakers bureau: Abbvie, Asahi-Kasei, BMS, Chugai, Eisai, Eli Lilly, Janssen, Mitsubishi-Tanabe, Novartis and Pfizer