SAT0101 ABATACEPT IN RHEUMATOID ARTHRITIS ASSOCIATED-INTERSTITIAL LUNG DISEASE: SHORT TERM OUTCOME AND PROGNOSTIC FACTORS

Abstract

Background: The prevalence of interstitial lung disease (ILD) in rheumatoid arthritis (RA) varies in the medical literature from 1% to 67% and is a major cause of mortality. Previous works have identified increased age, smoking and anticytrullinated protein antibodies (ACPA) titre as risk factors for RA-ILD (RA-ILD). Conventional treatments for RA may lead to a new onset or worsening of RA-ILD, so treatment should be identified to prevent the onset or exacerbation of RA-ILD. Studies have shown that abatacept (ABA) may improve the outcome of RA-ILD. Objectives: The aim of our study is to evaluate ABA effectiveness and safety in patients with RA-ILD. Methods: We enrolled RA-ILD patients who started treatment with ABA. All patients underwent thoracic high-resolution computed tomography (HRCT) at the beginning of ABA treatment and after 18 months of therapy. HRCT abnormalities were evaluated using a a computer-aided method (CaM). At each visit clinical, laboratory and respiratory function characteristics were collected and the Clinical Disease Activity Index (CDAI) and the Health Assessment Questionnaire Disability Index (HAQ-DI) for disease activity and functional disability were measured. The cohort was divided into three groups based on the CaM-HRCT results: patients with a lung fibrosis progression of 15% or more were defined as “worsened”, those with a reduction of 15% or more were defined as “improved”, all other patients were defined as “stable”. The 15% threshold of change, derived from the CaM assessment, results from the determination of the standard deviation of the mean value change after 18 months of follow-up of the cohort. The multivariate regression model was used to assess the strength of the association between RA characteristics and HRCT response to ABA. Results: Forty-four patients (81% women) with a mean age of 59.1±8.0 years and a mean duration of the disease of 7.5±3.1 years were recruited. Twenty-three (52.3%) patients were positive for ACPA and 28 (63.6%) for rheumatoid factor. Five patients (11.4%) showed deterioration of ILD, 31 (70.6%) were in the “stable” group, and 7 patients (16.0%) experienced improvement over a mean follow-up period of 18 months. The factors related to ILD deterioration were use of methotrexate (MTX) (p=0.0078), and current smoking habit (p=0.0054), according to multivariate regression analysis (Table). Conclusion: Treatment with ABA is associated with an RA-ILD stability or improvement rate of 86.6% of patients, while the worsening rate is 11.4%. Concomitant treatment with MTX and current smoking habit are factors associated with RA-ILD worsening. MTX discontinuation and smoking cessation should be strongly promoted in patients with RA-ILD.