RESUMEN
Objective To study the individualized dose of warfarin in treating atrial fibrillation in elderly patients. Methods Forty-one elderly in-patients with atrial fibrillation were recruited.Warfarin was used tO start anti-coagulation therapy with the target INR value 1.6-2.5.The data of demographic variables,concomitant diseases,medications and laboratory values were collected,then correlated these factors with the maintenance dose of warfarin. Results Warfarin dose requirements were significantly associated with age(r=-0.535,P＜0.01),sex(r=-0.494,P＜0.01),height (r=0.484,P＜0.01),weight(r=0.453,P＜0.01),body surface area(r=0.388,P＜0.05),concomitant use of a sulfonylurea medication(r=-0.446,P＜0.01)and serum albumin level(r=0.520,P＜0.01).The multivariate regression model includedthe variables of age,sex,serum albumin level and concomitant use of a sulfonylurea medication.This algorithm explained 65.4%of the variance in the maintenance dose of warfarin(R=0.808,R2=65.4%). Conclusions The warfarin dose in treating atrial fibrillation in elderly patients can be estimated from demographic,clinical and laboratory factors that can be obtained at the time of warfarin initiation.