Department of Pharmacy Practice, University of Illinois at Chicago College of Pharmacy, 833 S. Wood St, Room 164, Chicago, IL 60612-7230, USA.
J Thromb Thrombolysis. 2009 May;27(4):430-7. doi: 10.1007/s11239-008-0236-8. Epub 2008 Jun 19.
We sought to identify contributors to unstable anticoagulation in African Americans.
Sixty African Americans on warfarin were enrolled. Cytochrome P450 2C9 and vitamin K epoxide reductase genotypes and vitamin K intake were assessed, and clinical and dietary data during the 12 months prior to enrollment were collected. Data were compared between stable and unstable patients, classified based on the proportion of international normalized ratio (INR) values outside the therapeutic range.
The median proportion of out-of-range INRs among study participants was 44%; 28 patients had a higher proportion of INRs out-of-range and were included in the unstable group, with the remaining constituting the stable group. The median (IQR) number of clinic visits/year was higher among unstable versus stable patients [18 (15-22) vs. 16 (13-19); P = 0.03]. Higher warfarin doses, lower adherence, vomiting or diarrhea, and use of antiinfective agents were more common among unstable patients. Genotype was not associated with anticoagulation stability. After regression analysis, only poor adherence and gastrointestinal illness remained predictive of unstable anticoagulation. In a control group of Caucasians of similar age and sex distribution, poor adherence, but not gastrointestinal illness, was associated with unstable anticoagulation.
We conclude that poor warfarin adherence and gastrointestinal illness are major contributors to unstable anticoagulation in African Americans. Our data suggest that, similar to Caucasians, improving warfarin adherence rates may be an important mean to improve anticoagulation control in African Americans. In addition, close monitoring during acute illness may be particularly important in this population.
我们试图确定非裔美国人抗凝治疗不稳定的原因。
共纳入 60 名服用华法林的非裔美国人。评估细胞色素 P450 2C9 和维生素 K 环氧化物还原酶基因型和维生素 K 摄入量，并收集入组前 12 个月的临床和饮食数据。将稳定和不稳定患者的数据进行比较，根据国际标准化比值（INR）值超出治疗范围的比例进行分类。
研究参与者的 INR 超出范围的中位数比例为 44%；28 名患者 INR 超出范围的比例较高，被纳入不稳定组，其余患者构成稳定组。不稳定组与稳定组相比，中位数（IQR）年就诊次数[18（15-22）次比 16（13-19）次；P=0.03]更高。不稳定患者的华法林剂量更高、服药依从性更低、呕吐或腹泻以及使用抗感染药物更为常见。基因型与抗凝稳定性无关。回归分析后，只有较差的依从性和胃肠道疾病仍然与抗凝不稳定相关。在年龄和性别分布相似的白种人对照组中，较差的依从性，但无胃肠道疾病，与抗凝不稳定相关。
我们的结论是，较差的华法林依从性和胃肠道疾病是导致非裔美国人抗凝治疗不稳定的主要原因。我们的数据表明，与白种人相似，提高华法林的依从率可能是改善非裔美国人抗凝控制的重要手段。此外，在急性疾病期间密切监测可能在该人群中尤为重要。
