Schapkaitz Elise, Sithole Johanna
Department of Molecular Medicine and Hematology, Charlotte Maxeke Johannesburg Academic Hospital, National Health Laboratory Service, Anticoagulation Clinic and University of Witwatersrand, Johannesburg, South Africa.
Department of Molecular Medicine and Hematology, Charlotte Maxeke Johannesburg Academic Hospital, National Health Laboratory Service, Anticoagulation Clinic and University of Witwatersrand, Johannesburg, South Africa.
J Vasc Nurs. 2017 Mar;35(1):27-30. doi: 10.1016/j.jvn.2016.05.002.
Warfarin is the most common oral anticoagulant for the treatment and prevention of thromboembolic disease. However, it has a wide interpatient variability in dose requirements due to various genetic and clinical factors.
This study investigated the effect of clinical and genetic factors on the variability of warfarin dose requirements in 147 South African patients (81 white and 66 black). The study was performed at a University Hospital Anticoagulation Clinic managed by nursing sisters at the Charlotte Maxeke Johannesburg Academic Hospital.
The most common indication for anticoagulation was atrial fibrillation (n = 55, 37.4%). The mean warfarin dose was significantly higher in black patients as compared to white patients (5.4 ± 2.9 mg/day and 3.8 ± 2.1 mg/day, respectively; P < 0.001). Older age was significantly associated with a lower maintenance warfarin dose (P < 0.001). Drugs which decreased the international normalized ratio (INR) were significantly associated with a higher maintenance warfarin dose of 6.4 ± 3.4 mg/day (P < 0.034). In contrast, there was no significant difference in warfarin dosage requirements in the presence of CYP2C9 and VKORC1 variant alleles (P > 0.05). Patients, however, homozygous for CYP2C9 *1,*3, and VKORC1 required less than 5 mg/day of warfarin to maintain the INR within the therapeutic range.
In conclusion, this study indicates that clinical characteristics including; age, ethnic group, and drugs which decrease the INR might help to predict better dose requirements in this population group and thereby reduce the risk of bleeding and thrombotic complications.
华法林是治疗和预防血栓栓塞性疾病最常用的口服抗凝剂。然而，由于各种遗传和临床因素，其剂量需求在患者间存在很大差异。
本研究调查了147名南非患者（81名白人，66名黑人）的临床和遗传因素对华法林剂量需求变异性的影响。该研究在夏洛特·马克西克约翰内斯堡学术医院由护士管理的大学医院抗凝门诊进行。
抗凝最常见的适应症是心房颤动（n = 55，37.4%）。黑人患者的平均华法林剂量显著高于白人患者（分别为5.4±2.9毫克/天和3.8±2.1毫克/天；P < 0.001）。年龄较大与较低的华法林维持剂量显著相关（P < 0.001）。降低国际标准化比值（INR）的药物与较高的华法林维持剂量6.4±3.4毫克/天显著相关（P < 0.034）。相比之下，存在CYP2C9和VKORC1变异等位基因时，华法林剂量需求无显著差异（P > 0.05）。然而，CYP2C9 *1、*3和VKORC1纯合子患者维持INR在治疗范围内所需的华法林剂量低于5毫克/天。
总之，本研究表明包括年龄、种族和降低INR的药物等临床特征可能有助于更好地预测该人群的剂量需求，从而降低出血和血栓并发症的风险。
