Quality of Vitamin K Antagonist Control and 1-Year Outcomes in Patients with Atrial Fibrillation: A Global Perspective from the GARFIELD-AF Registry Academic Article uri icon

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  • AIMS: Vitamin K antagonists (VKAs) need to be individually dosed. International guidelines recommend a target range of international normalised ratio (INR) of 2.0-3.0 for stroke prevention in atrial fibrillation (AF). We analysed the time in this therapeutic range (TTR) of VKA-treated patients with newly diagnosed AF in the ongoing, global, observational registry GARFIELD-AF. Taking TTR as a measure of the quality of patient management, we analysed its relationship with 1-year outcomes, including stroke/systemic embolism (SE), major bleeding, and all-cause mortality. METHODS AND RESULTS: TTR was calculated for 9934 patients using 136,082 INR measurements during 1-year follow-up. The mean TTR was 55.0%; values were similar for different VKAs. 5851 (58.9%) patients had TTR<65%; 4083 (41.1%) TTR≥65%. The proportion of patients with TTR≥65% varied from 16.7% in Asia to 49.4% in Europe. There was a 2.6-fold increase in the risk of stroke/SE, 1.5-fold increase in the risk of major bleeding, and 2.4-fold increase in the risk of all-cause mortality with TTR<65% versus ≥65% after adjusting for potential confounders. The population attributable fraction, i.e. the proportion of events attributable to suboptimal anticoagulation among VKA users, was 47.7% for stroke/SE, 16.7% for major bleeding, and 45.4% for all-cause mortality. In patients with TTR<65%, the risk of first stroke/SE was highest in the first 4 months and decreased thereafter (test for trend, p = 0.021). In these patients, the risk of first major bleed declined during follow-up (p = 0.005), whereas in patients with TTR≥65%, the risk increased over time (p = 0.027). CONCLUSION: A large proportion of patients with AF had poor VKA control and these patients had higher risks of stroke/SE, major bleeding, and all-cause mortality. Our data suggest that there is room for improvement of VKA control in routine clinical practice and that this could substantially reduce adverse outcomes. TRIAL REGISTRATION: ClinicalTrials.gov NCT01090362.


  • Connolly, Stuart
  • Eikelboom, John
  • Haas, Sylvia
  • ten Cate, Hugo
  • Accetta, Gabriele
  • Angchaisuksiri, Pantep
  • Bassand, Jean-Pierre
  • Camm, A John
  • Corbalan, Ramon
  • Darius, Harald
  • Fitzmaurice, David A
  • Goldhaber, Samuel Z
  • Goto, Shinya
  • Jacobson, Barry
  • Kayani, Gloria
  • Mantovani, Lorenzo G
  • Misselwitz, Frank
  • Pieper, Karen
  • Schellong, Sebastian M
  • Stepinska, Janina
  • Turpie, Alexander Graham Gri
  • van Eickels, Martin
  • Kakkar, Ajay K

publication date

  • 2016