Background Psoriatic arthritis (PsA) is a chronic inflammatory condition featuring arthritis/periarthrits that is well known to accompany comorbidities such as metabolic syndrome, obesity and cardiovascular illness. In Korea, the spondylitis subset has been recognized as the most common feature of PsA in tertiary medical facilities1. However, there is no data of the true prevalence or incidence of PsA in Korea to date, and it is likely to be under-appreciated. Studies based on nationwide data are in need to better understand the characteristics of PsA in Korea.
Objectives To study the prevalence and baseline characteristics of Korean PsA patients using National Health Insurance claims data
Methods Four identification algorithms for defining patients with PsA were established by using electronic medical records and clinical database at SMG-SNU Boramae Medical Center. The first step was to obtain a pool of patients with the International Classification of Diseases (ICD-10) diagnostic code for PsA (M07.0-M07.3, L40.5). The next step was to select patients that have been prescribed with medications for PsA: biologic disease modifying anti-rheumatic drugs (DMARD), non-steroidal anti-inflammatory drugs (NSAID) and/or non-biologic DMARDs. The best performing algorithm was chosen to identify PsA patients in then nationwide data (2008-2012) provided by the Korean Health Insurance Review and Assessment Service (HIRA). The five-year data included 85,168 patients linked with information including age, gender, ICD-10 codes, and prescribed medications. Descriptive analysis was performed to present PsA patient characteristics for each year.
Results Among the four algorithms, the one defining PsA patients first by biologic DMARD use, secondly by non-biologic DMARD plus NSAID use was validated to be the best option (sensitivity 95%, specificity 99.8%, accuracy 99.8%). With the HIRA data, the baseline demographic of Korean PsA patients each year was as follows (Table). The overall prevalence of PsA in 2012 was 0.13%. Biologic DMARDs use in PsA has been covered by the National Health Insurance only after 2010 in Korea. Between 2010-2012, approximately 3% of PsA patients were registered in the Korean National Rare Disease Registry.
Conclusions This is the first study to analyze the prevalence and baseline characteristics of PsA patients in Korea. Values of basic parameters have been rather consistent during 2008-2012, yet the proportion of patients visiting secondary or tertiary hospitals has increased by year, coinciding with the time point when biologic DMARDs became available for PsA patients in Korea.
Beak HJ, Yoo CD, Shin K, et al. Spondylitis is the most common pattern of psoriatic arthritis in Korea. Rheumatol Int. 2000;19(3):89-94.
Acknowledgements We would like to thank Mr. Seung Won Yu and Ms. Hae-Kyung Park at HIRA for aiding data analysis.
Disclosure of Interest None declared