Efficacy and Safety of Apixaban Compared with Warfarin at Different Levels of Predicted INR Control for Stroke Prevention in Atrial Fibrillation

In the ARISTOTLE trial apixaban compared with warfarin reduced stroke, systemic embolism, major bleeding, and mortality. This subgroup analysis of the study found that the benefit of apixaban over warfarin was similar regardless of centre and patient predicted quality of INR control.

It is known that the efficacy and safety of vitamin K antagonists for stroke prevention in patients with atrial fibrillation (AF) is strongly dependent upon the percentage of time in the therapeutic range (TTR), with maximum benefit when the TTR is 70% or greater. It has been suggested that the beneficial effect of the newer oral anticoagulant drugs could be simply due to the sub-optimal control of the INR in the warfarin arms of the trials.

 

In this post-hoc subgroup analysis of the ARISTOTLE trial, the authors sought to address this issue and concluded that in patients with AF and at least one additional risk factor for stroke, apixaban seems to be a more effective and safer treatment than warfarin across a broad range of quality of warfarin management.

 

NICE technology appraisal 275 recommends apixaban as an option for preventing stroke and systemic embolism in people with non valvular atrial fibrillation with 1 or more risk factors such as:

• Prior stroke or transient ischaemic attack

• Age 75 years or older

• Hypertension

• Diabetes mellitus

• Symptomatic heart failure

 

The post-hoc subgroup analysis of ARISTOTLE therefore supports the recommendation of NICE in NICE technology appraisal 275.