Impacts of off-label dosing noacs on clinical outcomes in very elderly patients with atrial fibrillation

Abstract

Abstract Background Studies about the comparisons of on-label and off-label dosing non-vitamin K antagonist oral anticoagulants (NOACs) regarding the risks of clinical outcomes among atrial fibrillation (AF) patients have been published. However, data among the very elderly AF patients were limited. In the present study, we aimed to investigate the impacts of inappropriate dosing of NOACs on clinical outcomes in AF patients aged ≥85 years of age. Methods We used medical data from a multi-center healthcare system in Taiwan enrolling 1,836 and 268 AF patients aged ≥85 years treated with NOACs and warfarin, respectively. Among 1,836 patients receiving NOACs, underdosing, overdosing and on-label dosing NOACs were prescribed in 248, 149 and 1439 patients, respectively. The risks of ischemic stroke/systemic embolism (IS/SE) and major bleeding were compared between warfarin and NOACs in different dosing groups. Also, the risks of clinical events of underdosing and overdosing NOACs were comapred to on-labeling dosing. Results Compared to warfarin, underdosing NOACs were associated with a higher risk of IS/SE (aHR 2.39; p=0.048) without a lower risk of major bleeding; while overdosing NOACs were not associated with a lower risk of IS/SE (aHR 0.74, p=0.604) (Figure 1). Compared to on-label dosing NOACs, underdosing NOACs were associated with a higher risk of IS/SE, while the risk was not lower for overdoing NOACs (Figure 2). Conclusions Even for very elderly AF patients aged ≥85 years, NOACs should still be prescribed at the dosing following the criteria defined in clinical trials and guideline recommendations. Funding Acknowledgement Type of funding sources: None. Figure 1Figure 2