Adequacy of anticoagulation in patients with atrial fibrillation coming toa hospital

Study Objective. To evaluate the adequacy of anticoagulation in patients wi th 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 whe n they arrived at the hospital. Those who developed AF as a complication du ring 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% i t was supratherapeutic. Patients admitted for any thromboembolic event and for ischemic stroke were significantly more likely to have subtherapeutic I NRs. Conclusion. It is well documented in the literature that warfarin is underp rescribed, but our results suggest that even in treated patients, about hal f are inadequately protected from thromboembolism.