FRI0067 ALL-CAUSE AND CAUSE-SPECIFIC MORTALITY OF PATIENTS WITH RHEUMATOID ARTHRITIS IN KOREA: A NATION-WIDE POPULATION-BASED STUDY
Authors: E. Lee, A. Shin, J. Lee, Y. J. Ha, Y. J. Lee, E. B. Lee, Y. W. Song, E. H. Kang
Journal: Annals of the Rheumatic Diseases (2020)

Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with excess mortality. Objectives: To compare all-cause and cause-specific mortality between RA patients versus general population, using a nationally representative cohort from Korea National Health Insurance Service database (KNHIS). Methods: Patients with RA aged ≥ 40 years were identified from 2010-2016 KNHIS database and their annual cohorts were constructed per each calendar year. RA patients of each cohort were required to have prevalent RA on January 1 st of the given calendar year. The KNHIS were linked with Korea national mortality data to obtain cause of death information and to estimate expected deaths of RA patients in reference to mortality data of the general population in Korea. Standardized mortality ratio (SMR) with a 95% confidence interval (CI) was calculated to compare mortality of RA patients and general population. Results: A total of 6,404 deaths occurred among 79,440 RA patients during 2011-2016 period, showing all-cause SMR (95% CI) of 1.45 (1.42-1.49) compared to general population. The SMR was 1.72 (1.59-1.85) for biologics users and 1.43 (1.39-1.46) for non-users, versus general population. The annual SMR of RA patients showed a growing trend of mortality over time particularly among biologics users (Table 1). The SMRs for common causes of death among RA patients showed approximately tripled risk of dying due to pulmonary and infectious causes compared to general population (Table 2). There was approximately 20% increased risk of cardiovascular deaths but 8% decreased risk of cancer-related deaths among RA patients compared to general population (Table 2). Table 1. Annual all-cause SMR of RA patients compared to 2010 general population Calendar year 1 RA patients Biologics users Biologics non-users 2011 1.00 (0.92−1.07) 1.13 (0.87−1.39) 0.98 (0.90−1.06) 2012 1.13 (1.06−1.21) 0.98 (0.75−1.22) 1.15 (1.07−1.23) 2013 1.22 (1.14−1.30) 1.29 (1.04−1.54) 1.21 (1.13−1.29) 2014 1.30 (1.23−1.38) 1.53 (1.26−1.79) 1.28 (1.20−1.36) 2015 1.45 (1.38−1.53) 1.81 (1.53−2.09) 1.41 (1.33−1.50) 2016 1.45 (1.37−1.52) 1.94 (1.66−2.22) 1.39 (1.31−1.47) CI, confidence interval; RA, rheumatoid arthritis; SMR, standardized mortality ratio 1 2010 data were used to identify RA diagnosis dates but were not included for SMR estimation since diagnosis dates of RA were unclear for those who had RA in 2010. Table 2. Cause-specific SMR comparing RA patients versus general population Cause of death RA patients Biologics users Biologics non-users Infection 3.12 (2.93−3.13) 4.12 (3.36−4.88) 3.03 (2.83−3.23) Cancer 0.92 (0.87−0.97) 0.98 (0.81−1.14) 0.91 (0.85−0.96) Respiratory 1 3.14 (2.97−3.32) 4.64 (3.89−5.38) 3.01 (2.83−3.19) Cardiovascular 2 1.18 (1.12−1.25) 1.26 (1.03−1.50) 1.18 (1.11−1.25) CI, confidence interval; RA, rheumatoid arthritis; SMR, standardized mortality ratio 1 Includes pulmonary infections and chronic lung diseases (J00-J98, U04); 2 Includes atherosclerotic and non-atherosclerotic deaths (I00-I99). Conclusion: The all-cause mortality of RA patients during 2011-2016 was overall 45% greater than that of general Korean population, which increased annually over the study period. The increased mortality was more prominent among biologics users than non-users. The risk of infectious and respiratory deaths were tripled among RA patients compared to general population. References: [1]Sokka T, et al. Mortality in rheumatoid arthritis: 2008 update. Clin Exp Rheumatol. 2008;26(5 Suppl 51):S35-61. Acknowledgments: None Disclosure of Interests: None declared