Adequacy of anticoagulation in patients with atrial fibrillation coming to a hospital

Pharmacotherapy. 2000 Sep;20(9):1060-5. doi: 10.1592/phco.20.13.1060.35038.


Study objective: To evaluate the adequacy of anticoagulation in patients with atrial fibrillation (AF) coming to a hospital.

Design: Retrospective medical record review.

Setting: Tertiary care hospital.

Patients: Consecutive patients with a history of AF who had been prescribed warfarin and who had the international normalized ratio (INR) measured when they arrived at the hospital. Those who developed AF as a complication during hospitalization were excluded.

Measurements and main results: Of 1085 patients, 375 (mean age 73 yrs, 56.3% men) were eligible for further evaluation. Most had nonvalvular AF; in 44.5% the INR was subtherapeutic, in 36.5% it was therapeutic, and in 18.9% it was supratherapeutic. Patients admitted for any thromboembolic event and for ischemic stroke were significantly more likely to have subtherapeutic INRs.

Conclusion: It is well documented in the literature that warfarin is underprescribed, but our results suggest that even in treated patients, about half are inadequately protected from thromboembolism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Analysis of Variance
  • Anticoagulants / administration & dosage*
  • Atrial Fibrillation / drug therapy*
  • Chi-Square Distribution
  • Female
  • Humans
  • International Normalized Ratio / statistics & numerical data*
  • Male
  • Middle Aged
  • Patients / statistics & numerical data
  • Retrospective Studies
  • Stroke / prevention & control*
  • Thromboembolism / prevention & control*
  • Warfarin / administration & dosage*


  • Anticoagulants
  • Warfarin