title: Comparison of control and stability of oral anticoagulant therapy using acenocoumarol versus phenprocoumon.
abstract: Variability in the control of oral anticoagulant therapy has been associated with a heightened risk of complications. We compared control of anticoagulation between two commonly used coumarins, phenprocoumon and acenocoumarol, and among anticoagulation clinics. All qualifying patients were managed at six regional anticoagulation clinics in the Netherlands. This retrospective cohort study compiled data during a three-year period from a computerised dosing and management system. Anticoagulation control was expressed as the percent of time within the therapeutic range and stability expressed as the time-weighted variance in the international normalised ratio (INR). Data were available for 22,178 patients of whom 72% were treated with acenocoumarol. INRs of patients who received phenprocoumon were within the therapeutic range 50% of the time compared with 43% for acenocoumarol (OR 1.32, 95% CI 1.24-1.41). Moreover, patients on phenprocoumon required 15% fewer monitoring visits and had more stable INR values. These observations were consistent for all six clinics. There were also sizable differences between the clinics with respect to control and stability of anticoagulation that were stable from year-to-year and were unrelated to the drug used. With its longer half-life of three to five days, phenprocoumon produces more stable anticoagulation than acenocoumarol and should generally be the drug of choice when these are the available choices. The differences observed among clinics suggest that certain clinics employ policies and practices resulting in better control of anticoagulation.
authors.affiliation: Northwest Health Services Research Center of Excellence, Veterans Affairs Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, USA. sfihn@u.washington.edu
authors.forename: Stephan D
authors.initials: SD
authors.lastname: Fihn
authors.forename: Alain A P
authors.initials: AA
authors.lastname: Gadisseur
authors.forename: Edwin
authors.initials: E
authors.lastname: Pasterkamp
authors.forename: Felix J M
authors.initials: FJ
authors.lastname: van der Meer
authors.forename: W G Mimi
authors.initials: WG
authors.lastname: Breukink-Engbers
authors.forename: Lya M
authors.initials: LM
authors.lastname: Geven-Boere
authors.forename: Erik
authors.initials: E
authors.lastname: van Meegen
authors.forename: Hanneke
authors.initials: H
authors.lastname: de Vries-Goldschmeding
authors.forename: Irma
authors.initials: I
authors.lastname: Antheunissen-Anneveld
authors.forename: Annelies R
authors.initials: AR
authors.lastname: van't Hoff
authors.forename: Derk
authors.initials: D
authors.lastname: Harderman
authors.forename: Margriet
authors.initials: M
authors.lastname: Smink
authors.forename: Frits R
authors.initials: FR
authors.lastname: Rosendaal
mesh_terms: D000074:Acenocoumarol / Q000008:administration & dosage* / Q000737:chemistry; D000284:Administration, Oral; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage* / Q000737:chemistry; D015331:Cohort Studies; D005260:Female; D006207:Half-Life; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010644:Phenprocoumon / Q000008:administration & dosage* / Q000737:chemistry; D012189:Retrospective Studies
chemical_list: D000925:Anticoagulants; D000074:Acenocoumarol; D010644:Phenprocoumon