An international multicenter randomized study of computer-assisted oral anticoagulant dosage vs. medical staff dosage

Research output: Contribution to journalArticle


  • L Poller
  • M Keown
  • S Ibrahim
  • G Lowe
  • M Moia
  • AG Turpie
  • C Roberts
  • AMHP Van den Besselaar
  • FJM Van der Meer
  • A Tripodi
  • G Palareti
  • C Shiach
  • M Samama
  • M Burgess-Wilson
  • A Heagerty
  • P Maccallum
  • D Wright
  • J Jespersen


Background: Increased demand for oral anticoagulants is overwhelming facilities worldwide, resulting in increasing use of computer assistance. A multicenter clinical endpoint study has been performed to compare the safety and effectiveness of computer-assisted dosage with dosage by experienced medical staff at the same centers. Methods: A randomized study of dosage of two commercial computer-assisted dosage programs (PARMA 5 and DAWN AC) vs. manual dosage at 32 centers with an established interest in oral anticoagulation in 13 countries. The aim was to recruit a minimum of 16 000 patient-years randomized to medical staff or computer-assisted dosage. In total, 13 219 patients participated, 6503 patients being randomized to medical staff and 6716 to computer-assisted dosage. The safety and effectiveness of computer-assisted dosage were compared with those of medical staff dosage. Results: In total, 13 052 patients were recruited (18 617 patient-years). International Normalized Ratio (INR) tests numbered 193 890 with manual dosage and 193 424 with computer-assisted dosage. The number of clinical events with computer-assisted dosage was lower (P = 0.1), but in the 3209 patients with deep vein thrombosis/pulmonary embolism, they were reduced by 37 (24%, P = 0.001). Time in target INR range was significantly improved by computer assistance as compared with medical staff dosage at the majority of centers (P <0.001). Conclusions: The safety and effectiveness of computer-assisted dosage has been demonstrated using two different marketed programs in comparison with experienced medical staff dosage at the centers with established interest in anticoagulation. Significant prevention of clinical events in patients with deep vein thrombosis/pulmonary embolism and the achievement of target INR in all clinical groups has been observed. The reliability and safety of other marketed computer-assisted dosage programs need to be established.


Original languageEnglish
Pages (from-to)935-943
Number of pages9
JournalJournal of Thrombosis and Haemostasis
Issue number6
Publication statusPublished - 1 Jun 2008


  • safety, effectiveness, INR, clinical events, computer-assisted dosage