Direct Oral Anticoagulant (DOAC) in Patients with Non-valvular Atrial Fibrillation for Secondary Stroke Prevention: A 4-year prescription trend.

L. Fu1, W.M. Ng1, I.F. Tan1, S.R. Fam2, Y.T. Lim3, Sanchalika Acharyya 4, W.X.L. Khong3, L.Y. Goh Li1, D.C.T. Oh1, T.M. Tu1.
1National Neuroscience Institute, Neurology Department, Singapore.
2National Neuroscience Institute, Neuroradiology Department, Singapore.
3Tan Tock Seng Hospital, Pharmacy, Singapore.
4Duke-National University of Singapore Medical School, Centre for quantitative medicine, Singapore

Background
Anticoagulant therapy is the treatment of choice for stroke prevention in patients with Atrial Fibrillation (AF). Warfarin has been the main oral anticoagulant prescribed. Since the availability of Direct Oral Anticoagulants (DOAC), there has been an increase use of DOAC but the choice of DOAC use remains varied.

Aim
The aim of our study is to compare the prescription trends among DOACs (dabigatran, rivaroxaban and apixaban) and warfarin, specifically in ischemic stroke patients with non-valvular AF from 2014 to 2017.

Methods
We performed a retrospective review of all DOAC and warfarin prescription records of all ischemic stroke patients admitted to our Neurology Service. We included patients whom had new prescriptions of DOAC or warfarin for non-valvular AF between January 2014 to October 2017. We calculated the incidence rate ratios to determine the prescription trend of each drug and compared the trends of each anticoagulant prescribed over time.

Results
A total of 264 patients were newly initiated on DOAC throughout the study period. Apixaban was the most commonly initiated DOAC (n=176, 66.7%) followed by Rivaroxaban (75, 28.4%) and Dabigatran (13, 4.9%). In contrast, a total of 284 patients were prescribed warfarin. The incidence rate ratios suggested significantly increasing trend of prescribing Apixaban over the study period (p value <0.001) and a significant increasing trend compared to warfarin prescription across the years (p value for trend <0.001). Among all the three DOAC, there was no significant difference in their prescribing trends.

Conclusion
Apixaban was the most common DOAC prescribed in our institution and was significantly more compared to warfarin. However, there is no increase in trend over time compared to Dabigatran and Rivaroxaban.

TRENDS IN USE OF DIRECT ORAL ANTICOAGULANT (DOAC) IN PATIENTS WITH NON-VALVULAR ATRIAL FIBRILLATION FOR SECONDARY STROKE PREVENTION