Stroke risk reduction with oral anticoagulation using CHA2DS2-VASc in a Japanese AF population: A modeling analysis

BackgroundCurrent clinical guidelines recommend that risk stratification for ischaemic stroke in patients with nonvalvular AF (NVAF) should be performed using the CHA2DS2-VASc score (Congestive heart failure, Hypertension, Age ≥ 75 years [double], Diabetes mellitus, previous thromboembolism [double], Vascular disease, Age 65-74 years, and female gender) to aid decision making for antithrombotic treatment, with a preference for Non-Vitamin K Oral Anticoagulants (NOACs) in those with CHA2DS2-VASc score ≥ 1. However, CHA2DS2-VASc score is not recommended in the 2014 Japanese Circulation Society (JCS) guidelines for patients with NVAF.MethodsTo assess the impact of the JCS approach to stroke prevention in AF, and model the impact of using a CHA2DS2-VASc based 2-step decision making strategy, we calculated the incidence of ischaemic stroke in NVAF patients without OAC on basis of the CHADS2 and CHA2DS2-VASc scores using published Japanese data, and estimated the preventable number of stroke events.ResultsUsing a CHA2DS2-VASc-based approach, the potential annual stroke events based on the estimated total number of NVAF patients in Japan was 889,000, as follows: 4369 for dabigatran 150 mg, 6049 for dabigatran 110 mg, 5918 for rivaroxaban (intention-to-treat; ITT), 5302 for apixaban, 5843 for edoxaban 60 mg (ITT), and 7598 for edoxaban 30 mg (ITT), respectively. Using a CHADS2 score-based approach, the number of potential stroke events was much greater for each agent.ConclusionOur modelling analysis has shown that when considering antithrombotic treatment for Japanese NVAF patients, using a CHA2DS2-VASc-based approach would allow greater opportunities for stroke prevention.