WARFARIN USE AMONG PATIENTS WITH ATRIAL-FIBRILLATION

Background and Purpose Warfarin reduces the rate of stroke among patie nts with atrial fibrillation. We sought to determine warfarin use with in a population sample of elderly patients with atrial fibrillation. M ethods The Connecticut Peer Review Organization conducted a chart revi ew of Medicare patients aged greater than or equal to 65 years with a history of atrial fibrillation before a hospitalization during the fir st 6 months of 1994. Results Among 488 patients (308 women; 457 white; 173 aged greater than or equal to 85 years), 38% (184/488) had a rela tive contraindication to anticoagulation (history of bleeding, dementi a, alcohol use, fails, cancer, or the need for nonsteroidal anti-infla mmatory drugs). Among the remaining patients (with known atrial fibril lation, but without a contraindication), only 38% (117/304) had been p rescribed warfarin. Of those not prescribed warfarin, 63% (117/187) we re also not taking aspirin. There were 272 patients with at least one additional vascular risk factor and no contraindication to anticoagula tion. Among these patients at moderate to high risk for stroke, antico agulation had been prescribed in 48% (109/272). Overall, among those n ot prescribed warfarin, 58% (95/163) were not taking aspirin. Patients admitted with a stroke were more likely to be significantly underanti coagulated (with international normalized ratio < 1.5) (43.5% versus 2 0.9% for those without stroke; P < .005). Anticoagulation was most eff ective for those with an international normalized ratio greater than o r equal to 2.0. Conclusions Warfarin anticoagulation with atrial fibri llation, even among ''ideal'' candidates, appears dramatically underut ilized. In addition, among those prescribed warfarin, patients are oft en undertreated, increased warfarin use among patients with atrial fib rillation represents an excellent opportunity for stroke prevention in the elderly.