Trends in Prevalence of Non-Valvular Atrial Fibrillation and Anticoagulation Therapy in a Japanese Region　― Analysis Using the National Health Insurance Database

Background:Direct oral anticoagulants (DOACs) are effective in reducing thromboembolism events in patients with non-valvular atrial fibrillation (NVAF). However, little is known about trends in NVAF prevalence and DOAC prescriptions in daily clinical practice. This study investigated the current status and trends in NVAF prevalence and DOAC prescriptions in a region of Japan.Methods and Results:Annual data for the 4 years from May 2014 to May 2017 in the Tsugaru region of Aomori Prefecture, Japan, were obtained for analysis from the Japanese National Health Insurance database (“Kokuho” database [KDB]). The prevalence of NVAF in subjects aged 40–74 years increased gradually over the 4-year study period (1,094/57,452 [1.90%] in 2014, 1,055/56,018 [1.88%] in 2015, 1,072/54,256 [1.98%] in 2016, and 1,154/52,341 [2.20%] in 2017). The proportion of NVAF patients prescribed warfarin decreased (42%, 33%, 24%, and 21% in 2014, 2015, 2016, and 2017, respectively), the proportion of those prescribed DOACs increased (30%, 42%, 50%, and 57%, respectively), and the proportion not prescribed an oral anticoagulant (OAC) decreased (28%, 25%, 26%, and 22%, respectively). However, 17% of patients with a CHADS2score ≥2 were not prescribed an OAC in 2017.Conclusions:By using the KDB we found that the prevalence of NVAF has increased gradually from 2014 to 2017. In the Tsugaru region in Japan, DOACs prescriptions increased and warfarin prescriptions decreased over the 4-year period.