Objectives Adjusted-dose warfarin and aspirin reduce stroke in patients with atrial fibrillation, and warfarin is substantially more efficacious than aspirin. But patients especially in Chinese population with genetic variants of vitamin K epoxide reductase (VKORC1), who received warfarin had more than as many haemorrhages than those who received aspirin.

Objective To compare between aspirin combined BNC versus adjusted-dose warfarin in more than 65 years of age patients with high-risk non-valvular atrial fibrillation (NVAF) and genetic variants of VKORC1.

Methods 151 patients with NVAF and the allelic mutation of VKORC1 gene-1639G>A and a CHADS₂ score of 2 and above were randomly divided into two groups. One group was warfarin maintenance dosing adjustment nomogram for INR goal of 2–3, the other group was aspirin (100 mg/d) combined BNC (1.6 g thrice daily) as antithrombotic drug. All drugs were taken at least 1 year and clinical events (ischaemic stroke, haemorrhage, death) were followed up.

Results Baseline clinical data were similar in both groups. Ischaemic stroke and the all-cause death did not significant difference between two groups. The serious bleeding rate of the combined group was less than that of the adjusted-dose warfarin group (0% vs 7.9%, OR=0.921, 95% CI 0.862 to 0.984, p=0.028).

Conclusions Aspirin combined BNC and the adjusted-dose warfarin was equally effective in elderly patients with NVAF for prevention of ischaemic stroke. The combination therapy could reduce the risk of the antithrombotic drug therapy-associated bleeding.