Efficacy of computer-aided dosing of warfarin among patients in a rehabilitation hospital

Am J Phys Med Rehabil. 2005 Jun;84(6):423-7. doi: 10.1097/01.phm.0000163716.00164.23.


Objective: To determine whether computer-aided dosing of warfarin is superior to physician dosing to maintain a patient in a rehabilitation hospital within a target international normalized ratio goal.

Design: Randomized, double-blinded, clinical trial in an inpatient rehabilitation hospital. A total of 30 consecutive patients admitted receiving warfarin were randomized to either clinician dosing or computer-aided warfarin dosing for the duration of their hospitalization. The main outcome measures included the percentage of days in a therapeutic anticoagulation range and the number of blood draws. Exclusion criteria included short length of stay (n=110, 39%) and a physician declared international normalized ratio target range of <2.0 (n=67, 23%). A total of 73 patients were excluded because of heme-positive stools at admission, recent gastrointestinal bleed, early discharge or consent refusal. Dawn AC software was used to determine warfarin dosage and frequency of blood draws to maintain a target international normalized ratio of 2.0-3.0 for the computer-dosed group (n=14). Several physicians recommended warfarin dosages for the second group (n=16). Two were dropped from the computer model secondary to lost data files for these two patients.

Results: Computer-aided dosing of warfarin resulted in 61.7% of days within the therapeutic range (international normalized ratio, 2-3), whereas clinician dosing resulted in only 44.1%. There were no significant differences in the number of blood draws or demographic variables between the two groups.

Conclusion: Computers were significantly better at maintaining patients within a therapeutic international normalized ratio range than physicians. There were no significant differences in the number of recommended blood draws.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Anticoagulants / administration & dosage*
  • Atrial Fibrillation / drug therapy
  • Boston
  • Double-Blind Method
  • Drug Monitoring / methods
  • Drug Therapy, Computer-Assisted / methods*
  • Female
  • Humans
  • International Normalized Ratio
  • Length of Stay
  • Male
  • New York
  • Outcome and Process Assessment, Health Care
  • Rehabilitation Centers
  • Stroke / drug therapy
  • Vascular Diseases / drug therapy*
  • Vascular Diseases / rehabilitation
  • Venous Thrombosis / drug therapy
  • Warfarin / administration & dosage*


  • Anticoagulants
  • Warfarin