An increased disease burden of autoimmune inflammatory rheumatic diseases in Korea

To estimate the prevalence, medical utilization, and recent changes in the economic burden of autoimmune rheumatic diseases (AIRDs) in Korea.

Using a nationwide claims database that includes all medical claims made by approximately 50 million Korean residents, the prevalences of seropositive rheumatoid arthritis (RA), ankylosing spondylitis (AS), systemic lupus erythematosus (SLE), and others between 2012 and 2016 were calculated. Changes in medical utilization and the direct medical costs of each AIRD from 2012 to 2016 were also evaluated.

Based on the data for 2016, seropositive RA was the most common AIRD in Korea with 96,330 cases (188.5/100,000 population), followed by AS (30,006, 58.7/100,000 population), SLE (19,441, 38.0/100,000 population), Behçet's disease (BD, 14,943, 29.2/100,000 population), primary Sjögren syndrome (pSS, 12,018, 23.5/100,000 population), and systemic sclerosis (SSc, 3606, 7.1/100,000 population). In terms of medical utilization, patients with eosinophilic granulomatosis with polyangiitis visited outpatient clinics the most frequently (9.8 times/year/patient), while hospitalization was most frequent in microscopic polyangiitis patients (1.0 time/year/patient). Total medical costs for all AIRDs increased from $154,348,011 in 2012 to $262,481,974 in 2016. The annual medical cost per patient in 2016 was the highest in microscopic polyangiitis ($6223/year), followed by psoriatic arthritis ($3,362/year), and granulomatosis with polyangiitis ($2823/year).

In Korea, the most prevalent AIRD is seropositive RA, followed by AS, SLE, BD, pSS, and SSc. The economic burden of AIRDs has risen substantially in the last 5 years due not only to an increase in their prevalence but also to an increase in medical costs per patient.