International descriptive study for comparison of treatment patterns in patients with knee osteoarthritis between Korea and Japan using claims data.

Aim: To compare medication prescriptions for patients with knee osteoarthritis (KOA) in the real world in Korea and Japan.
Methods: This retrospective and descriptive population-based study was conducted using claims data provided by Health Insurance Review and Assessment in Korea and JMDC Inc in Japan. We defined individuals as KOA patients if they had an International Classification of Diseases 10 (ICD10) code for gonarthrosis (M17) and were ≥50 years old in 2012. Korean and Japanese patients were matched for age and sex using frequency matching. Patients were observed for 1 year from the first month of the ICD10 code M17 in 2012. We described baseline characteristics including prevalence of comorbidities, and use of medication for KOA during the observational period.
Results: The median age was 59 and the percentage of women was 61.4 in both countries (N = 1 133 138 in Korea, N = 10 498 in Japan). The prevalence of nonsteroidal anti-inflammatory drug (NSAID) usage in Japan (74.7%) was significantly higher than that in Korea (59.0%). Analgesics such as acetaminophen and symptomatic slow-acting drugs for OA (SYSADOA) were significantly more frequently used in Korea (25.8%) than in Japan (9.4%). Intra-articular injection (IAI) of corticosteroids or hyaluronic acid was performed more frequently in Japanese patients (57.3%) than Korean patients (30.5%).
Conclusions: Medication patterns for KOA in Korea and Japan are described for the first time. Use of NSAIDs and IAI were more common in Japan, while other pain killers and SYSADOA were more commonly prescribed in Korea.
(© 2019 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)