Why and how should the international normalized ratio (INR) be adjusted for anticoagulation therapy with warfarin in patients with atrial fibrillation (Afib) (AF)?

Updated: Nov 18, 2019
  • Author: Lawrence Rosenthal, MD, PhD, FACC, FHRS; Chief Editor: Jeffrey N Rottman, MD  more...
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Anticoagulation therapy with warfarin is significantly more effective than antiplatelet therapy (relative risk of 40%) if the international normalized ratio (INR) is adjusted. The INR goal in AF is usually between 2 and 3, except in patients who are at a significant risk for stroke (eg, patients with artificial valves, those with rheumatic heart disease, and those at a high risk for AF with recurrent prior strokes), in whom the INR should be maintained between 2.5 and 3.5. A lower INR goal (1.8-2) may be considered in elderly patients who are at high risk for a fall.

Anticoagulation clinics have shown more success and a lower complication rate than primary care physicians in controlling patients’ INR. In addition, one study reported that patients who used an Internet-based program for patient self-management of oral anticoagulant therapy achieved a higher mean time in the therapeutic range than patients whose INR was controlled by an established anticoagulation clinic. [72] Similar programs alone or in combination with regular care provided by anticoagulation clinics may improve the mean time that patients are in the therapeutic range and may further reduce the risk of stroke.

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