SAT0582 RISK OF INTERSTITIAL LUNG DISEASE IN SYSTEMIC AUTOIMMUNE RHEUMATIC DISEASES: A NATIONWIDE, POPULATION-BASED COHORT STUDY

Abstract

Background: To date, very few studies had investigated the epidemiology of interstitial lung disease (ILD) among patients with systemic autoimmune rheumatic disease (SARD). Objectives: To study the risk of interstitial lung disease (ILD) among patients with various systemic autoimmune rheumatic diseases (SARDs) including rheumatoid arthritis (RA), dermatomyositis (DMtis), polymyositis (PM), systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and primary Sjogren's syndrome (pSS). Methods: Using 1997-2013 claims data from the Taiwanese National Health Insurance Research Database, we identified 63,277 newly diagnosed patients with various SARDs after excluding those with overlapping SARD diagnoses from 2001-2013 and randomly selected 253,108 non-SARD subjects matching (1:4) SARD patients for SARD diagnosis, age, sex and the year of the index date. We calculated the incidence rates (IRs) of ILD (ICD-9 code 515) in various SARD groups and the corresponding non-SARD comparison groups and estimated the IR ratios (IRRs) with 95% confidence intervals (CI) of ILD development. Using multivariable cox regression analyses, we estimated hazard ratios (HRs) with 95% CIs of ILD in various SARD groups compared with their comparison groups after adjusting for age, sex, Charlson comorbidity index, amiodarone use and methotrexate use. Sensitivity analyses were conducted by using a narrow definition of ILD. Results: As shown in Table 1, the IRs of ILD were greatest in SSc patients (2,523 per 105 years), followed by patients with DMtis (2,463 per 105 years), PM (1,956 per 105 years), SS (601 per 105 years), RA (279 per 105 years), and SLE (276 per 105 years). Multivariable analyses showed that the risks of ILD were significantly increased in patients with SSc (HR, 66.01; 95% CI, 32.73-133.13), DMtis (128.74, 95% CI, 40.19-412.47), PM (HR, 30.39; 95% CI, 11.24-82.15), pSS (HR, 8.76; 95% CI, 7.03-10.90), RA (HR, 4.22; 95% CI, 3.51-5.08), and SLE (HR, 13.98; 95% CI, 9.25-21.14). Conclusion: This nationwide, population-based, matched cohort study demonstrated that the risks of ILD were significantly increased in patients with SARDs.