Tellor Katie B, Nguyen Steffany N, Bultas Amanda C, Armbruster Anastasia L, Greenwald Nicholas A, Yancey Abigail M
Department of Pharmacy Practice, St Louis College of Pharmacy, 4588 Parkview Place, St Louis, MO 63110, USA.
Memorial Hermann, Texas Medical Center, Houston, TX, USA.
Ther Adv Cardiovasc Dis. 2018 Aug;12(8):207-216. doi: 10.1177/1753944718781295. Epub 2018 Jun 19.
Despite well established empiric dose adjustments for drug and disease-state interactions, the impact of body mass index (BM) on warfarin remains unclear. The objective of this study is to evaluate warfarin requirements in hospitalized patients, stratified by BMI.
This retrospective review included two cohorts of patients: cohort A (patients admitted with a therapeutic international normalized ratio (INR)) and cohort B (newly initiated on warfarin during hospitalization). Exclusion criteria included: age under 18 years, pregnancy, INR (goal 2.5-3.5), and warfarin thromboprophylaxis post orthopedic surgery. The primary outcome was mean total weekly dose (TWD) of warfarin based on weight classification: underweight (BMI <18 kg/m), normal/overweight (BMI 18-29.9 kg/m), obese (BMI 30-39.9 kg/m), and morbidly obese (BMI ⩾ 40 kg/m). Data were extracted from two community hospitals in reverse chronologic order during July 2015-June 2013 until both study institutions evaluated 100 patients per cohort in each BMI classification or until all patients had been evaluated within the prespecified timeframe.
A total of 585 patients were included in cohort A (26 underweight, 200 normal/overweight, 200 obese, 159 morbidly obese). There was a statistically significant difference in TWD as determined by one-way analysis of variance ( p < 0.05). A Tukey post hoc test revealed a statistically significantly higher TWD in morbidly obese (41.5 mg) compared with underweight (25.6 mg, p < 0.05), normal/overweight (28.8 mg, p < 0.05) and obese patients (32.4 mg, p < 0.05). In cohort B, 379 patients were evaluated (9 underweight, 166 normal/overweight, 152 obese, 52 morbidly obese). Overall, 191 patients had a therapeutic INR on discharge (88.9% underweight, 52.4% normal/overweight, 44.1% obese, 55.8% morbidly obese, p = 0.035). Of those, there was a statistically significant difference in TWD ( p = 0.021) with a higher TWD in the morbidly obese (41 mg) compared with underweight patients (24.4 mg, p = 0.017).
Based on the results of this study, morbidly obese patients may require higher TWD to obtain and maintain a therapeutic INR.
尽管针对药物与疾病状态相互作用已有成熟的经验性剂量调整方法，但体重指数（BMI）对华法林的影响仍不明确。本研究的目的是评估按BMI分层的住院患者对华法林的需求量。
这项回顾性研究纳入了两组患者：队列A（国际标准化比值（INR）处于治疗范围的入院患者）和队列B（住院期间开始使用华法林的新患者）。排除标准包括：年龄低于18岁、妊娠、INR（目标值2.5 - 3.5）以及骨科手术后使用华法林进行血栓预防。主要结局是根据体重分类确定的华法林平均每周总剂量（TWD）：体重过轻（BMI <18 kg/m²）、正常/超重（BMI 18 - 29.9 kg/m²）、肥胖（BMI 30 - 39.9 kg/m²）和病态肥胖（BMI⩾40 kg/m²）。数据从两家社区医院按倒序时间顺序提取，时间跨度为2015年7月至2013年6月，直至每个研究机构在每个BMI分类中评估完每组100例患者，或在预定时间范围内评估完所有患者。
队列A共纳入585例患者（26例体重过轻、200例正常/超重、200例肥胖、159例病态肥胖）。通过单因素方差分析确定，TWD存在统计学显著差异（p < 0.05）。Tukey事后检验显示，病态肥胖患者的TWD（41.5 mg）显著高于体重过轻患者（25.6 mg，p < 0.05）、正常/超重患者（28.8 mg，p < 0.05）和肥胖患者（32.4 mg，p < 0.05）。在队列B中，评估了379例患者（9例体重过轻、166例正常/超重、152例肥胖、52例病态肥胖）。总体而言，191例患者出院时INR处于治疗范围（体重过轻患者占88.9%，正常/超重患者占52.4%）
