Department of Medicine Stanford University School of Medicine Stanford CA.
Center for Digital Health Stanford University School of Medicine Stanford CA.
J Am Heart Assoc. 2021 Dec 7;10(23):e020904. doi: 10.1161/JAHA.121.020904. Epub 2021 Nov 15.
Background Reduced time in international normalized ratio therapeutic range (TTR) limits warfarin safety and effectiveness. In patients switched from warfarin to direct oral anticoagulants (DOACs), patient factors associated with low TTR could also increase risk of DOAC nonadherence. We investigated the relationship between warfarin TTR and DOAC adherence in warfarin-treated patients with atrial fibrillation switched to DOAC. Methods and Results Using data from the Veterans Health Administration, we identified patients with atrial fibrillation switched from warfarin to DOAC (switchers) or treated with warfarin alone (non-switchers). Logistic regression was used to evaluate association between warfarin TTR and DOAC adherence. We analyzed 128 605 patients (age, 71±9; 1.6% women; CHADS-VASc 3.5±1.6); 32 377 switchers and 96 228 non-switchers. In 8016 switchers with international normalized ratio data to calculate 180-day TTR before switch, TTR was low (median 0.45; IQR, 0.26-0.64). Patients with TTR <0.5 were more likely to be switched to DOAC (odds ratio [OR],1.68 [95% CI,1.62-1.74], <0.0001), as were those with TTR <0.6 or TTR <0.7. Proportion of days covered ≥0.8 was achieved by 76% of switchers at 365 days. In low-TTR individuals, proportion of days covered ≥0.8 was achieved by 70%, 72%, and 73% of switchers with TTR <0.5, 0.6, and 0.7, respectively. After multivariable adjustment, TTR <0.5 decreased odds of achieving 365-day proportion of days covered ≥0.8 (OR, 0.49; 0.43-0.57, <0.0001), with similar relationships for TTR <0.6 and TTR <0.7. In non-switchers with TTR <0.5, long-term TTR remained low. Conclusions In patients with atrial fibrillation switched from warfarin to DOAC, most achieved adequate DOAC adherence despite low pre-switch TTRs. However, TTR trajectories remained low in non-switchers. Patients with low warfarin TTR more consistently achieved treatment targets after switching to DOACs, although adherence-oriented interventions may be beneficial.
国际标准化比值治疗范围（TTR）时间缩短会限制华法林的安全性和有效性。在从华法林转为直接口服抗凝剂（DOAC）的患者中，与 TTR 较低相关的患者因素也可能增加 DOAC 不依从的风险。我们研究了房颤患者从华法林转为 DOAC 治疗后华法林 TTR 与 DOAC 依从性之间的关系。
我们利用退伍军人事务部的数据，确定了从华法林转为 DOAC（转换者）或单独接受华法林治疗（非转换者）的房颤患者。使用逻辑回归评估华法林 TTR 与 DOAC 依从性之间的关系。我们分析了 128605 名患者（年龄 71±9 岁；1.6%为女性；CHA2DS2-VASc 评分为 3.5±1.6）；32377 名转换者和 96228 名非转换者。在 8016 名转换者中，有国际标准化比值数据可计算转换前 180 天的 TTR，TTR 较低（中位数 0.45；IQR，0.26-0.64）。TTR<0.5 的患者更有可能转为 DOAC（比值比[OR]，1.68[95%CI，1.62-1.74]，<0.0001），TTR<0.6 或 TTR<0.7 的患者也是如此。在 365 天时，76%的转换者达到了覆盖率≥0.8 的天数。在 TTR 较低的患者中，TTR<0.5、0.6 和 0.7 的转换者达到覆盖率≥0.8 的天数比例分别为 70%、72%和 73%。在多变量调整后，TTR<0.5 降低了达到 365 天覆盖率≥0.8 的天数比例的可能性（OR，0.49；0.43-0.57，<0.0001），TTR<0.6 和 TTR<0.7 也存在类似的关系。在 TTR<0.5 的非转换者中，长期 TTR 仍然较低。
在从华法林转为 DOAC 的房颤患者中，尽管 TTR 较低，但大多数患者仍能达到足够的 DOAC 依从性。然而，非转换者的 TTR 轨迹仍然较低。尽管以治疗为导向的干预可能是有益的，但转为 DOAC 后，TTR 较低的患者更能持续达到治疗目标。
