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 Sjögren’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 105years), followed by patients with DMtis (2,463 per 105years), PM (1,956 per 105years), SS (601 per 105years), RA (279 per 105years), and SLE (276 per 105years). 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.References:[1]Su R, Bennett M, Jacobs S, Hunter T, Bailey C, Krishnan E, et al. An analysis of connective tissue disease-associated interstitial lung disease at a US Tertiary Care Center: better survival in patients with systemic sclerosis. The Journal of rheumatology. 2011;38(4):693-701.[2]Hu Y, Wang LS, Wei YR, Du SS, Du YK, He X, et al. Clinical Characteristics of Connective Tissue Disease-Associated Interstitial Lung Disease in 1,044 Chinese Patients. Chest. 2016;149(1):201-8.Araki T, Putman RK, Hatabu H, Gao W, Dupuis J, Latourelle JC, et al. Development and Progression of Interstitial Lung Abnormalities in the Framingham Heart Study. Am J Respir Crit Care Med 2016;194:1514-1522.Disclosure of Interests:None declared
Progression and mortality of interstitial lung disease in mixed connective tissue disease: a long-term observational nationwide cohort study