Use of anticoagulants in stroke prevention in elderly Chinese with atrial fibrillation

Abstract

Atrial fibrillation (AF) is well recognized as an important risk factor for stroke in elderly people. Even in the absence of rheumatic heart disease, there is a sixfold increase in thromboembolic phenomena, and AF accounts for up to 36% of all strokes in elderly people. Various trials from the West have shown that warfarin has clinically important effect in the primary and secondary prevention of stroke in patients with atrial fibrillation. However, many doctors remain reluctant to prescribe warfarin for their elderly patients with atrial fibrillation because of fear of haemorrhagic complications. We have been running a stroke clinic since 1994. One of the objectives of such a clinic is to reduce strokes by risk factor modification. Elderly patients with atrial fibrillation and without contraindications to anticoagulants are put on warfarin and closely monitored. We reviewed the outpatient records of such patients from 1994 to 1999. The rates of major bleeding and new strokes among these elderly patients over the past 5 years are reported. The study revealed that warfarin maintenance doses required for prevention of stroke in atrial fibrillation are lower among Chinese patients compared with Caucasian patients: the average daily warfarin doses required to achieve a mean target INR of 2.2 among Chinese patients was found to be 2 mg, 2.5 mg, and 4 mg for patients aged >75 years, <75 years, and <40 years, respectively.