General Practice Research Database, Medicines and Healthcare products Regulatory Agency, London, UK.
Thromb Haemost. 2011 Nov;106(5):968-77. doi: 10.1160/TH11-05-0353. Epub 2011 Sep 8.
Atrial fibrillation (AF) carries an increased risk of ischaemic stroke, and oral anticoagulation with warfarin can reduce this risk. The objective of this study was to evaluate the association between time in therapeutic International Normalised Ratio (INR) range when receiving warfarin and the risk of stroke and mortality. The study cohort included AF patients aged 40 years and older included in the UK General Practice Research Database. For patients treated with warfarin we computed the percentage of follow-up time spent within therapeutic range. Cox regression was used to assess the association between INR and outcomes while controlling for patient demographics, health status and concomitant medication. The study population included 27,458 warfarin-treated (with at least 3 INR measurements) and 10,449 patients not treated with antithrombotic therapy. Overall the warfarin users spent 63% of their time within therapeutic range (TTR). This percentage did not vary substantially by age, sex and CHA2DS2-VASc score. Patients who spent at least 70% of time within therapeutic range had a 79% reduced risk of stroke compared to patients with ≤30% of time in range (adjusted relative rate of 0.21; 95% confidence interval 0.18-0.25). Mortality rates were also significantly lower with at least 70% of time spent within therapeutic range. In conclusion, good anticoagulation control was associated with a reduction in the risk of stroke.
心房颤动（AF）会增加缺血性中风的风险，口服抗凝剂华法林可以降低这种风险。本研究的目的是评估接受华法林治疗时国际标准化比值（INR）治疗范围内的时间与中风和死亡率风险之间的关系。该研究队列包括年龄在 40 岁及以上的英国普通实践研究数据库中的 AF 患者。对于接受华法林治疗的患者，我们计算了治疗范围内的随访时间百分比。Cox 回归用于评估 INR 与结果之间的关联，同时控制患者的人口统计学、健康状况和伴随用药。研究人群包括 27458 名接受华法林治疗（至少有 3 次 INR 测量）和 10449 名未接受抗血栓治疗的患者。总体而言，华法林使用者有 63%的时间处于治疗范围内（TTR）。这个百分比在年龄、性别和 CHA2DS2-VASc 评分方面没有显著差异。与处于治疗范围内时间≤30%的患者相比，至少有 70%的时间处于治疗范围内的患者中风风险降低了 79%（调整后的相对风险率为 0.21；95%置信区间为 0.18-0.25）。死亡率也随着至少 70%的时间处于治疗范围内而显著降低。总之，良好的抗凝控制与降低中风风险有关。
