title: The use of warfarin for DVT prophylaxis following hip and knee arthroplasty: how often are patients within their target INR range?
abstract: The purpose of this study was to determine the percentage of time that patients are therapeutic when prescribed warfarin for chemical thromboprophylaxis following a hip or knee arthroplasty procedure. One hundred eighty-four patients receiving warfarin for 4weeks postoperatively, dosed using a Web-application accounting for patient demographics, INR levels, and concomitant medication use, were included. Patients with a target INR range between 1.7 and 2.7 were therapeutic for only 54.4% of the time (32.5% subtherapeutic, 13.0% supratherapeutic) while patients with a target INR range between 2.0 and 3.0 were therapeutic for only 45.9% of the time (39.2% subtherapeutic, 14.8% supratherapeutic). Patients receiving warfarin for chemical thromboprophylaxis are within their targeted INR range for only a limited period of time during their postoperative course.
authors.affiliation: Washington University School of Medicine/Barnes-Jewish Hospital, Department of Orthopedic Surgery, St. Louis, Missouri.
authors.forename: Denis
authors.initials: D
authors.lastname: Nam
authors.affiliation: Washington University School of Medicine/Barnes-Jewish Hospital, Department of Orthopedic Surgery, St. Louis, Missouri.
authors.forename: Anita
authors.initials: A
authors.lastname: Sadhu
authors.affiliation: Washington University School of Medicine/Barnes-Jewish Hospital, Department of Orthopedic Surgery, St. Louis, Missouri.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Hirsh
authors.affiliation: Washington University School of Medicine/Barnes-Jewish Hospital, Department of Orthopedic Surgery, St. Louis, Missouri.
authors.forename: James A
authors.initials: JA
authors.lastname: Keeney
authors.affiliation: Washington University School of Medicine/Barnes-Jewish Hospital, Department of Orthopedic Surgery, St. Louis, Missouri.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Nunley
authors.affiliation: Washington University School of Medicine/Barnes-Jewish Hospital, Department of Orthopedic Surgery, St. Louis, Missouri.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Barrack
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D016903:Drug Monitoring; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020246:Venous Thrombosis / Q000209:etiology / Q000517:prevention & control*; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: coumadin; thromboprophylaxis; total knee arthroplasty; venous thromboembolism; warfarin