title: Evaluation of 16 genotype-guided Warfarin Dosing Algorithms in 310 Korean Patients Receiving Warfarin Treatment: Poor Prediction Performance in VKORC1 1173C Carriers.
abstract: The purpose of this study was to evaluate the performance of 16 previously published warfarin dosing algorithms in Korean patients.
  
  
  
  The 16 algorithms were selected through a literature search and evaluated using a cohort of 310 Korean patients with atrial fibrillation or cerebral infarction who were receiving warfarin therapy.
  
  
  
  A large interindividual variation (up to 11-fold) in warfarin dose was observed (median, 25 mg/wk; range, 7-77 mg/wk). Estimated dose and actual maintenance dose correlated well overall (r range, 0.52-0.73). Mean absolute error (MAE) of the 16 algorithms ranged from -1.2 to -20.1 mg/wk. The percentage of patients whose estimated dose fell within 20% of the actual dose ranged from 1.0% to 49%. All algorithms showed poor accuracy with increased MAE in a higher dose range. Performance of the dosing algorithms was worse in patients with VKORC1 1173TC or CC than in total (r range, 0.38-0.61 vs 0.52-0.73; MAE range, -2.6 to -28.0 mg/wk vs -1.2 to -20.1 mg/wk).
  
  
  
  The algorithms had comparable prediction abilities but showed limited accuracy depending on ethnicity, warfarin dose, and VKORC1 genotype. Further studies are needed to develop genotype-guided warfarin dosing algorithms with greater accuracy in the Korean population.
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Mina
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Rihwa
authors.initials: R
authors.lastname: Choi
authors.affiliation: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: June Soo
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Young Keun
authors.initials: YK
authors.lastname: On
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Oh Young
authors.initials: OY
authors.lastname: Bang
authors.affiliation: Departments of Laboratory Medicine, Konyang University Hospital, College of Medicine Konyang University, Daejon, Republic of Korea.
authors.forename: Hyun-Jung
authors.initials: HJ
authors.lastname: Cho
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Clinical Pharmacology & Therapeutics, Samsung Medical Center, Seoul, Republic of Korea. Electronic address: sy117.lee@samsung.com.
authors.forename: Soo-Youn
authors.initials: SY
authors.lastname: Lee
mesh_terms: D000328:Adult; D000465:Algorithms; D000925:Anticoagulants / Q000008:administration & dosage*; D044466:Asian People; D001281:Atrial Fibrillation / Q000188:drug therapy; D020520:Brain Infarction / Q000188:drug therapy; D065729:Cytochrome P-450 CYP2C9 / Q000235:genetics; D005260:Female; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008297:Male; D064417:Vitamin K Epoxide Reductases / Q000235:genetics*; D014859:Warfarin / Q000008:administration & dosage*
chemical_list: D000925:Anticoagulants; D014859:Warfarin; D065729:Cytochrome P-450 CYP2C9; C578523:VKORC1 protein, human; D064417:Vitamin K Epoxide Reductases
keywords: CYP2C9; VKORC1; genotype-guided algorithm; warfarin