title: Comparison of dosing algorithms for acenocoumarol and phenprocoumon using clinical factors with the standard care in the Netherlands.
abstract: BACKGROUND
  It has not been investigated how much the use of clinical factors in a dosing algorithm improves the percentage of time in therapeutic range (TTR). The present study aimed to compare the effect of dosing algorithms for acenocoumarol and phenprocoumon including clinical patient characteristics with standard care in the Netherlands.
  
  
  METHODS
  The pre-EU-PACT study, an observational study in the Netherlands, was used to obtain standard care data. Data from the Dutch patients in the EU-PACT trial (comparing the use of a clinical algorithm with and without genetic information) was used for the clinical dosing algorithm.
  
  
  METHODS
  For both acenocoumarol and phenprocoumon, the percentage of time in, below and above therapeutic International Normalized Ratio (INR) range during 12weeks after treatment initiation were assessed in both studies.
  
  
  RESULTS
  During the weeks 2-12, the clinical dosing algorithm of acenocoumarol (80 patients) led to a higher TTR (74.3% versus 68.0% in range 2.0-3.5, 95% Confidence interval [CI] difference: 0.5% to 11.8%), and a reduced percentage of time below INR 2 and above INR 3.5, compared with standard care (272 patients). For phenprocoumon, compared with standard care (484 patients), 80 patients treated by the dosing algorithm did not obtained a significantly higher TTR in range 2.0-3.5 or a lower percentage of time above 3.5, however, they spent more time with INR below 2.
  
  
  CONCLUSIONS
  The use of a clinical dosing algorithm for acenocoumarol seemed to improve the quality of anticoagulation therapy during the treatment of initial 2-12 weeks. For phenprocoumon, there was no statistically difference in anticoagulation control.
authors.affiliation: Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands.
authors.forename: Yumao
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands.
authors.forename: Anthonius
authors.initials: A
authors.lastname: de Boer
authors.affiliation: Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands; Department of Applied Health Research, University College London, London, UK.
authors.forename: Talitha I
authors.initials: TI
authors.lastname: Verhoef
authors.affiliation: Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Felix J M
authors.initials: FJ
authors.lastname: van der Meer
authors.affiliation: Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, Leiden, The Netherlands; Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Saskia
authors.initials: S
authors.lastname: Le Cessie
authors.affiliation: Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands. Electronic address: a.h.maitland@uu.nl.
authors.forename: Anke H
authors.initials: AH
authors.lastname: Maitland-van der Zee
mesh_terms: D000074:Acenocoumarol / Q000008:administration & dosage / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use*; D001777:Blood Coagulation / Q000187:drug effects; D015331:Cohort Studies; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D010644:Phenprocoumon / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D000074:Acenocoumarol; D010644:Phenprocoumon
keywords: Acenocoumarol; Clinical dosing algorithm; Coumarins; International Normalized Ratio; Phenprocoumon