Factors associated with antithrombotic treatment decisions for stroke prevention in atrial fibrillation in the Stockholm region after the introduction of NOACs

Abstract

Purpose: The purpose of this study was to investigate the influence of patient characteristics such as age and stroke and bleeding risks on decisions for antithrombotic treatment in patients with atrial fibrillation (AF). Methods: This was a retrospective, population-based study including AF patients initiated with either warfarin, dabigatran, rivaroxaban, apixaban, or low-dose aspirin (ASA) between March 2015 and February 2016. Multivariate models were used to calculate adjusted odds ratios (aOR) for factors associated with treatment decisions. Results: A total of 6765 newly initiated patients were included, most with apixaban (46.4%) and least with ASA (6.7%). There were more comorbidities in patients initiated with ASA or warfarin compared to the cohort average. Patients with high stroke risks had higher chances of receiving ASA (CHA2DS2-VASc ≥5 vs 0; aOR 2.01; 95% confidence interval (CI) 1.12–3.33). Among patients receiving oral anticoagulants, patients with high bleeding risks more often received warfarin (ATRIA score 5–10 vs 0–3; aOR 1.40; CI 1.20–1.64). Among NOACs, apixaban was preferred for patients with higher stroke risks (aOR 1.78; CI 1.31–2.41), high bleeding risks (aOR 1.54; CI 1.26–1.88) and high age (age group ≥85 vs 0–65; aOR 1.84; CI 1.44–2.35). Conversely, dabigatran treatment was associated with lower ages and lower risks. Conclusions: High stroke and bleeding risks favored choices of warfarin or ASA. Among patients receiving NOACs, apixaban was favored for elderly and high-risk patients whereas dabigatran was used in lower risk patients. The inadvertent use of ASA, especially among those with high stroke risks, should be further discouraged.