Oral antithrombotic prescription patterns among hospitalized adult patients with non-valvular atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background Oral anticoagulant (OAC) therapy reduces stroke risk in patients with atrial fibrillation. Despite extensive recommendations regarding the use of non-vitamin K antagonist oral anticoagulants (NOACs), available data shows that they remain underutilized. Additionally, data on OAC prescription patterns in relation to stroke and bleeding risk scores are scarce; more so in low to middle income countries. The aim of this study was to describe the antithrombotic prescription patterns among Filipino patients with non-valvular AF. Methods This retrospective, cross-sectional study included adult patients with non-valvular AF admitted from January to December 2019 in a single center. The antithrombotic therapy prescribed was reviewed for patterns according to the CHA2DS2-VASc and HAS-BLED risk scores. Creatinine clearance was also calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation to determine the dose appropriateness of prescribed NOACs. Results We reviewed the records of 503 patients, and 302 were included in the study. Of these, 143 (47.35%), 61 (20.19%), 78 (25.83%) and 20 (6.62%) patients were on anticoagulant therapy alone, antiplatelet therapy alone, combination therapy, and no therapy, respectively. A total of 210 (69.54%) patients were prescribed with NOACs, of which 52.8% were dosed appropriately and 41.43% were underdosed. Among patients with high stroke risk but with low bleeding risk, only 39.63% were prescribed with an appropriately dosed NOAC. Thirty-three percent were given an underdosed NOAC while 16.28% received only antiplatelets and 4.65% received no antithrombotic therapy. Patients with low bleeding risk accounted for the majority of NOAC underdosage rates. Furthermore, 59 (20.48%) patients were prescribed with antiplatelets alone despite being stratified as having a high stroke risk. Warfarin use was also documented in 11 (3.64%) patients. Although accounting for only a minority, overdosed NOACs were observed among patients with high bleeding risk. Conclusion Over two-thirds of the patients with non-valvular AF were initiated on NOACs but only one-half received the appropriate dose. Rivaroxaban monotherapy or in combination with clopidogrel were the most frequently used agents. Antiplatelet therapy and underdosed NOACs constituted one-half of the antithrombotic therapy prescribed in high risk patients. The prescription patterns observed show that although the rate of NOAC use was high, a significant proportion of patients were still given suboptimal antithrombotic treatment. Abstract Figure. Baseline characteristics  Abstract Figure. Antothrombotic therapy