Clinical Study Of Warfarin In Treating Atrial Fibrillation In The Old Patients

Objective: To study the individualized dose of warfarin and to explore a simple blood coagulation monitoring method in treating atrial fibrillation in the old patients.Methods: 41 senile in-patients with atrial fibrillation were recruited. Warfarin was used to start anti-coagulation therapy with the target INR value 1.6-2.5.We collected demographic variables, concomitant diseases and medications,laboratory values and correlated these factors with the maintenance warfarin dose. Then, we combined factors that were independently associated with the warfarin dose into the dosing algorithm.Results:1. Warfarin dose requirements varied significantly between different age groups (t=3.70, P=0.001),different gender groups (t=3.11, P=0.003),different albumin concentration groups (t=-2.35, P=0.024 ) and different states of concomitant a sulfonylurea medication use (t=3.54, P=0.001).2.Warfarin dose requirements were significantly associated with age ( r=-0.535,P=0.000 ),sex ( r_s=-0.494,P=0.001 ),height ( r=0.484, P=0.001),weight (r=0.453,P=0.003),body surface area (r=0.388,P =0.012 ),concomitant use of a sulfonylurea medication (r_s=-0.446, P =0.003) and serum albumin concentration (r=0.520, P=0.000) ;The multivariate regression model including the variables of age, sex, concomitant use of a sulfonylurea medication and serum albumin concentration.This algorithm explained 65.4% of the variance in the warfarin dose(R=0.808, R~2=65.4%).3.41 patients reached the target INR range from the second day to the tenth day.10 patients reached the target INR value in the first three days (24.4% ) , 21 patients reached the target INR value in the fourth day and the fifth day, (51.2%) 10 patients reached the target INR value in the succedent days (24.4% ) . The times were significantly associated with the warfarin dose (r_b=0.777, P=0.000) .Conclusions:1. Warfarin dose requirements varied significantly between different age groups,different gender groups,different albumin concentration groups and groups of when treating atrial fibrillation in the old patients.2.The warfarin dose in treating atrial fibrillation in the old patients can be estimated from age,gender,concomitant use of a sulfonylurea medication and serum albumin concentration that can be obtained at the time of warfarin initiation.3. During the early stage of warfarin therapy in treating atrial fibrillation in the old patients,it is safe and effective to monitor INR every other day.