Lubetsky A, Dekel-Stern E, Chetrit A, Lubin F, Halkin H
Anticoagulation Clinic, Department of Medicine, Sheba Medical Center, Tel-Hashomer, and Sackler School of Medicine, Tel-Aviv University, Israel.
Thromb Haemost. 1999 Mar;81(3):396-9.
The effect of dietary vitamin K intake on warfarin sensitivity is known only from case reports and few small clinical studies. We followed 50 patients commencing warfarin and consuming their regular diets (for 8 weeks) to study this relationship. A one-week recall dietary questionnaire was completed at weeks 2 and 8. Daily intake of nutrients and vitamin K was calculated from standard tables. Warfarin sensitivity index (WSI) was defined as final INR/final warfarin dose (mg/day/m2 of body surface area) (week 8). Vitamin K intake was 17-974 (median: 179) microg/day. Median WSI was 0.82 (0.31-4.47). A WSI value of 1.1 significantly separated excess (>250 microg/day) from normal (<250 microg/day) vitamin K consumers (16/18 vs. 15/32, respectively, p <0.01). The former had lower day 5 INR (median: 1.9 vs. 3.0, p <0.001), needed more warfarin to achieve INR > or =2.0 (32.0+/-9.2 mg vs. 25.4+/-6.4 mg, p = 0.009) and required a higher maintenance steady state warfarin dose (5.7+/-1.7 mg/day vs. 3.5+/-1.0 mg/day, p <0.001). We conclude that in 32% (16/50) of anticoagulated patients under usual dietary conditions sensitivity to warfarin is decreased by vitamin K intake > or =250 microg/day.
饮食中维生素K摄入量对华法林敏感性的影响仅来自病例报告和少数小型临床研究。我们对50名开始服用华法林并维持日常饮食（为期8周）的患者进行了跟踪研究，以探讨这种关系。在第2周和第8周完成了一份为期一周的回顾性饮食调查问卷。根据标准表格计算营养素和维生素K的每日摄入量。华法林敏感性指数（WSI）定义为末次国际标准化比值（INR）/末次华法林剂量（mg/天/体表面积m2）（第8周）。维生素K摄入量为17 - 974（中位数：179）μg/天。WSI中位数为0.82（0.31 - 4.47）。WSI值为1.1时，显著区分了维生素K摄入量超过正常水平（>250μg/天）和正常水平（<250μg/天）的人群（分别为16/18和15/32，p<0.01）。前者在第5天的INR较低（中位数：1.9对3.0，p<0.001），达到INR≥2.0需要更多的华法林（32.0±9.2mg对25.4±6.4mg，p = 0.009），并且维持华法林稳态剂量更高（5.7±1.7mg/天对3.5±1.0mg/天，p<0.001）。我们得出结论，在日常饮食条件下，32%（16/50）接受抗凝治疗的患者中，维生素K摄入量≥250μg/天会降低对华法林的敏感性。
