ABSTRACT
Objective To investigate the effectiveness and safety of low-intensity warfarin anticoagulation in over 80-year-old patients with nonvascular atrial fibrillation (NVAF). Methods The 180 NVAF patients aged over 80 years were randomly assigned into 2 groups: 90 patients in lowintensity warfarin anticoagulation group (target value of INR 1.6-2.0), the other 90 patients in standard-intensity warfarin anticoagulation group (target value of INR 2. 0-3.0). All patients were followed up in outpatient-department for one year. Main outcome measures included the incidence rates of bleeding and thromboembolic events, and secondary outcome measures included the warfarin dosage and times of INR＞3.0. Results The incidence rate of thromboembolic events was 4.4% (4/90) in low-intensity group and 3.3% (3/90) in standard-intensity group with no statistically significant difference between these two groups (P＞0. 05). However, the incidence rate of hemorrhage was significantly lower in low-intensity group than in standard-intensity group [5.6% (5/90) vs. 16.7%(15/90), P＜0. 05]. Meanwhile the warfarin dosage was significantly lower in low-intensity group than in standard-intensity group [(1. 55±0. 63) mg vs. (2.31±0.57) mg, P＜0.05]. The times of INR＞3.0 were less in low-intensity group than in standard-intensity group (P＜0. 05). Conclusions Therapy with low-intensity warfarin anticoagulation in NVAF patients aged over 80 years may be equally effective as, but safer than that with standard-intensity warfarin.