the Center for Medical Education, Kaiser Permanente Medical Center, Los Angel

We evaluated a multiethnic cohort of subjects with nonrheumatic atrial fibrillation hospitalized over a 6-year period to determine the racial and ethnic differences in the risk of intracranial hemorrhage (ICH) and the effect of warfarin treatment on ICH risk. Treatment with warfarin was associated with a 2-fold greater risk of ICH in whites, a 4- to 5-fold greater risk in both blacks and Hispanics, and a 15-fold greater risk in Asians. After adjusting for established stroke risk factors and warfarin use, Asians were 4 times as likely as whites to have ICH, whereas blacks and Hispanics were twice as likely.