The Effectiveness of Warfarin Dosing from a Nomogram Compared with House Staff Dosing

Abstract The purpose of this study is to address the safety and efficacy of a warfarin dosing nomogram. Patients undergoing hip or knee arthroplasty were randomized to warfarin dosed by nomogram (n = 106) or by house staff (n = 110) during their hospital stay. The average daily dose of warfarin was 4.14 mg for the nomogram group and 4.18 mg for the house staff group. On postoperative day 4, the average international normalized ratio was 1.55 in the nomogram group compared with 1.59 in the house staff group. On postoperative day 4, 19.1% of the patients in the nomogram group had a therapeutic international normalized ratio, compared with 14.7% in the house staff group. There were no differences in bleeding or thrombotic complications in the 2 groups. This nomogram appears to be both safe and effective.