Department of Pharmacy, Singapore General Hospital, Singapore.
J Thromb Haemost. 2014;12(3):349-54. doi: 10.1111/jth.12496.
Anticoagulation with warfarin is influenced by dietary changes but the effect of fasting on warfarin therapy is unknown.
To study changes in international normalized ratio (INR) and the percentage of time within therapeutic range (%TTR) before, during and after the Muslim fasting month (Ramadan) in stable warfarinised Muslim patients.
METHODS/PATIENTS: In this prospective study, weekly INR readings were taken at home visits from participating patients during three study periods: before, during and after Ramadan. Readings were blinded to patients and their primary physicians except for when pre-set study endpoints were reached.
Among 32 participating patients, mean INR increased by 0.23 (P = 0.006) during Ramadan from the pre-Ramadan month and decreased by 0.28 (P < 0.001) after Ramadan. There was no significant difference (P = 1.000) in mean INR between the non-Ramadan months. %TTR declined from 80.99% before Ramadan to 69.56% during Ramadan (P = 0.453). The first out-of-range INR was seen around 12.1 days (95% CI, 9.0-15.1) after the start of fasting and returned to range at about 10.8 days (95% CI, 7.9-13.7) after Ramadan. Time above range increased from 10.80% pre-Ramadan to 29.87% during Ramadan (P = 0.027), while time below range increased from 0.57% during Ramadan to 15.49% post-Ramadan (P = 0.006). No bleeding or thrombotic events were recorded.
Fasting significantly increases the mean INR of medically stable patients taking warfarin and the likelihood of having an INR above therapeutic targets. For patients maintained at the higher end of INR target ranges or at increased risk of bleeding, closer monitoring or dosage adjustment may be necessary during fasting.
华法林抗凝作用受饮食变化影响，但禁食对华法林治疗的影响尚不清楚。
研究在稳定服用华法林的穆斯林患者中，在穆斯林斋戒月（斋月）前后，国际标准化比值（INR）和治疗范围内时间百分比（%TTR）的变化。
方法/患者：在这项前瞻性研究中，每周在家访时从参与患者中采集 INR 读数，共分为三个研究阶段：斋月前、斋月中和斋月后。读数对患者及其主治医生保密，除非达到预设的研究终点。
在 32 名参与患者中，与斋月前一个月相比，斋月期间 INR 平均增加 0.23（P=0.006），斋月后平均降低 0.28（P<0.001）。非斋月期间的平均 INR 无显著差异（P=1.000）。%TTR 从斋月前的 80.99%下降到斋月期间的 69.56%（P=0.453）。首次出现超出范围的 INR 时间约在禁食开始后 12.1 天（95%CI，9.0-15.1），之后在斋月后约 10.8 天（95%CI，7.9-13.7）恢复到范围内。在斋月期间，超出范围的时间从 10.80%增加到 29.87%（P=0.027），而低于范围的时间从 0.57%增加到 15.49%（P=0.006）。没有记录到出血或血栓形成事件。
禁食会显著增加服用华法林的稳定患者的平均 INR 值，增加 INR 超出治疗目标的可能性。对于维持在 INR 目标范围较高端或出血风险增加的患者，在禁食期间可能需要更密切的监测或剂量调整。
