Initiation of warfarin therapy: comparison of physician dosing with computer-assisted dosing

J Gen Intern Med. 1987 May-Jun;2(3):141-8. doi: 10.1007/BF02596140.


In a prospective, randomized study at two university hospitals, the authors examined how effectively housestaff physicians (n = 36) managed the initiation of warfarin therapy compared with a computer-assisted dosing regimen (n = 39) using the software program Warfcalc, which was managed by one of the authors. Target prothrombin time ratios were selected by the physicians. Study endpoints included: the time to reach a therapeutic prothrombin ratio, the time to reach a stable therapeutic dose, the number of patients transiently overanticoagulated, the number of bleeding complications, and the accuracy of the predicted maintenance dose, which was assessed at steady-state 10-14 days later. Computer-assisted dosing consistently out-performed the physicians: a stable therapeutic dose was achieved 3.7 days earlier (p = 0.002), fewer patients were overanticoagulated (10% versus 41%), and the predicted maintenance dose was in the therapeutic range in 85% of the computer-dosed patients versus 42% of the physician group (p less than 0.002). For physicians who did not routinely manage warfarin therapy, computer-assisted dosing improved the accuracy of dosing and shortened the time required to achieve a stable therapeutic dose.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Clinical Trials as Topic
  • Drug Therapy, Computer-Assisted*
  • Follow-Up Studies
  • Humans
  • Middle Aged
  • Physicians*
  • Prothrombin Time
  • Random Allocation
  • Therapy, Computer-Assisted*
  • Time Factors
  • Warfarin / administration & dosage*


  • Warfarin