Prevalence of patients with rheumatoid arthritis and age‐stratified trends in clinical characteristics and treatment, based on the National Database of Health Insurance Claims and Specific Health Checkups of Japan. (5th October 2020) - Nakajima, Ayako
Abstract: Aim: To estimate the prevalence and age‐stratified treatment trends and clinical characteristics of rheumatoid arthritis (RA) in Japan. Method: Using 7 RA definitions, the prevalence of RA in those aged ≥16 years was estimated using the National Database of Health Insurance Claims and Specific Health Checkups of Japan in the fiscal year 2017. We analyzed age‐stratified trends in characteristics and treatments. Results: Of 1 116 122 patients aged ≥16 years with at least 1 RA‐related International Classification of Diseases‐10 code, 825.7 thousand patients (women, 76.3%) were assessed as having RA with an estimated prevalence of 0.65%. The highest age‐stratified prevalence was 1.63% in patients aged 70‐79 years. Overall, 60.8% and 7.0% of patients with RA were aged ≥65 years and ≥85 years, respectively. Methotrexate use was most frequent in patients aged 50‐59 years (73.0%) and least frequent in patients aged ≥85 years (38.2%). Biologic disease‐modifying antirheumatic drugs use was 50.9% in patients aged 16‐19 years and decreased to 13.7% in those aged ≥85 years. Preference for the use of tumor necrosis factor inhibitors versus abatacept decreased from 24.0:1 to 1.7:1 in patients aged 16‐19 years and ≥85 years, respectively. The prevalence of cardiovascular disease was 3.5% in patients aged 60‐69 years and 12.1% in those aged ≥85 years. Overall RA‐related orthopedic surgeries were most prevalent in patients aged 70‐79 years. Conclusion: The estimated prevalence of patients with RA in Japan was 0.65%. Age‐stratified treatment trends and clinical characteristics have been described in a super‐aged society for the first time.