Randomized controlled trial of genotype-guided warfarin anticoagulation in Chinese elderly patients with nonvalvular atrial fibrillation

What is known and objective Warfarin is an oral anticoagulant which has been widely used to treat and prevent thromboembolic events. Managing warfarin therapy requires careful monitoring and dose titration. This randomized controlled study was designed to assess the effect of genotype-guided warfarin anticoagulation in Chinese elderly patients with nonvalvular atrial fibrillation. Methods 507 adults were randomized to receive initial dosing as determined by an algorithm containing genetic (VKORC1andCYP2C9) plus clinical information or only clinical information. The primary endpoint was the time in therapeutic range (TTR) over 90 days. Secondary end points included haemorrhagic events, thrombotic events and mortality. Results The TTR was significantly different between genetic group and control group. The average TTR was (70.80 +/- 24.39) % in the genotype-guided group as compared with (53.44 +/- 26.73) % in the control group. This represents a difference of 17.36% (95% CI, 11.82 to 22.89,P < .001). The cumulative incidence of total haemorrhagic events, minor haemorrhagic events, gastrointestinal bleeding and intracerebral bleeding events was not significantly different between two groups (P > .05). Follow-up showed that the cumulative incidence of ischaemic stroke events occurred in the genetic group was significantly lower than that in the control group (2.39% vs 6.82%), and the genetic group had a significant lower risk than control group in cumulative incidence of ischaemic stroke events [HR 0.22, (95% CI 0.065 to 0.77),P < .05]. What is new and conclusion Genotype-guided dosing could improve the average TTR, and follow-up result showed that genotype-guided therapy resulted in a significantly lower risk of ischaemic stroke events. Further research is required to focus on the clinical benefit of genotype-guided dosing.