Table 1.

Causes of warfarin underutilization.

(1) Risk of bleeding (perceived or real)

(a) Intracranial hemorrhage

(b) Gastrointestinal bleeding

(c) Other major bleeds (retroperitoneal, hematuria, etc.)

(2) Perceived Fall Risk (and associated bleeding risk)

(3) Difficulty with INR monitoring

(a) Geographical barriers

(b) Lack of insurance/primary care physician

(4) Non-compliance

(5) Patient preference

(6) Physician unawareness (such as need in paroxysmal AF*)

(7) Pharmacokinetic interference

(a) Drug interaction

(b) Dietary interference

(8) Ethnic and gender disparities

*AF: atrial fibrillation.