POS0403 RISK FACTORS FOR PROGRESSION OF RHEUMATOID ARTHRITIS-ASSOCIATED INTERSTITIAL LUNG DISEASE: REASSURING IMPACT OF METHOTREXATE

Background: Factors associated with rheumatoid arthritis-associated interstitial lung disease (RA-ILD) progression and prognosis are not well identified, especially the impact of methotrexate. Objectives: Identify risk factors of ILD progression in RA-ILD patients in a longitudinal study. Methods: RA patients with ILD confirmed in 2 high resolution computed tomography (HRCT) chest scans spaced at least 6 months apart (T0: date of the first HRCT chest scan describing ILD; Tx: date of the last HRCT chest scan available) were consecutively included in this retrospective multi-centric study from 2010 to 2020. HRCT chest scans were analyzed for each patient at T0 and Tx by 2 independent radiologists to determinate ILD pattern (definite UIP, probable UIP, indeterminate UIP, non-UIP) and progression during the follow-up including variation of the fibrosis score (aggravated or non-aggravated). Characteristics of patients (demographic-clinical-biological findings, respiratory function tests, and treatments exposure) at ILD diagnosis and during the follow-up (T0-Tx) were analyzed as potential determinants of ILD progression through multivariable logistic regression analysis. Overall survival was analyzed using Kaplan-Meier method. Results: 74 RA-ILD patients were included. During a mean duration between T0-Tx of 2.8 years ± 2.4, 26 patients (35%) had ILD progression. Thirty-three patients (45%) were treated by methotrexate at ILD diagnosis (T0) and 29 of them (39%) continued methotrexate during T0-Tx. Logistic regression in multivariate analysis revealed that a treatment by methotrexate at ILD diagnosis was protective against ILD progression (OR=0.14 [0.04-0.52]; p=0.0031). Non-UIP pattern at ILD diagnosis was also protective against ILD progression (OR=0.09 [0.02-0.36]; p=0.0005). The follow-up for survival analysis was 5.1 years ± 2.9. Thirty-three patients (31%) died, and the 3-year survival rate was 80%. Survival was better for non-aggravated ILD patients (HR=3.5 [1.46-8.4]; p=0.004) and for patients treated by methotrexate during T0-Tx (HR= 0.36 [0.15-0.84]; p=0.018) and worse for definite UIP patterns (HR=2.570 [1.078-6.128]; p=0.0332). Conclusion: In RA-ILD patients, non-UIP pattern and methotrexate treatment are associated with better ILD evolution and prognosis. Disclosure of Interests: None declared