Beyer-Westendorf Jan, Fay Matthew, Amara Walid
Thrombosis Research Unit, Division Hematology, Department of Medicine I, University Hospital "Carl Gustav Carus" Dresden, Dresden, Germany.
Department of Haematology, Kings Thrombosis Service, Kings College London, United Kingdom.
TH Open. 2021 Aug 23;5(3):e353-e362. doi: 10.1055/s-0041-1731777. eCollection 2021 Jul.
Preventing thromboembolic events, while minimizing bleeding risks, remains challenging when managing patients with atrial fibrillation (AF). Several factors contribute to current dosing patterns of nonvitamin K antagonist oral anticoagulants (NOACs), including patient characteristics, comorbidities, and physician judgment. Application of NOAC doses inconsistent with the drug labels may cause patients to receive either subtherapeutic (increasing stroke risk) or supratherapeutic (increasing bleeding risk) anticoagulant levels. In clinical practice, under- or over-dosing of NOACs in patients with AF is not uncommon. This analysis of prospective and retrospective registry and database studies on NOAC use in patients with AF (with at least 250 patients in each treatment arm) showed that under-dosing may be associated with reduced effectiveness for stroke prevention, with similar or even increased bleeding than with the standard dose. This may reflect underlying conditions and patient factors that increase bleeding despite NOAC dose reduction. Such factors could drive the observed overuse of reduced NOAC dosages, often making the prescription of reduced-dose NOAC an intentional label deviation. In contrast, over-dosing more likely occurs accidentally; instead of providing benefits, it may be associated with worse safety outcomes than the standard dose, including increased bleeding risk and higher all-cause mortality rates. This review summarizes the main findings on NOAC doses usually prescribed to patients with AF in clinical practice.
在管理心房颤动（AF）患者时，预防血栓栓塞事件同时将出血风险降至最低仍然具有挑战性。非维生素K拮抗剂口服抗凝药（NOACs）目前的给药模式受多种因素影响，包括患者特征、合并症和医生判断。应用与药品标签不一致的NOAC剂量可能导致患者接受的抗凝水平低于治疗剂量（增加中风风险）或高于治疗剂量（增加出血风险）。在临床实践中，房颤患者NOAC剂量不足或过量的情况并不少见。这项对房颤患者使用NOAC的前瞻性和回顾性登记及数据库研究（每个治疗组至少250例患者）的分析表明，剂量不足可能与预防中风的有效性降低有关，出血情况与标准剂量相似甚至增加。这可能反映了尽管降低了NOAC剂量但仍会增加出血风险的潜在病情和患者因素。这些因素可能导致观察到的NOAC低剂量过度使用情况，常常使低剂量NOAC的处方成为有意的标签偏离。相比之下，过量用药更可能是意外发生；它非但不会带来益处，反而可能与比标准剂量更差的安全结果相关，包括出血风险增加和全因死亡率升高。本综述总结临床实践中通常开给房颤患者的NOAC剂量的主要研究结果。
