1142 Population-based study of temporal trends in atrial fibrillation related incident ischaemic stroke: evidence of substantial failure of primary prevention

Background Greater awareness of the importance of stroke prevention in AF, greater screening, and the availability of warfarin for primary prevention over the past 2 decades should have reduced the incidence of AF-related ischaemic stroke despite the ageing population. Methods We studied all AF-related incident ischaemic strokes (IIS) from 2002 to 2008 in the Oxford Vascular Study (OXVASC) and compared our findings with results from a previous population-based study in the same population in 1981–1986 (Oxford Community Stroke Project; OCSP). Results AF-related stroke accounted for 29.4% (210/715) of IIS in OXVASC (mean/SD age=79.8/9.9) vs 17.9% (85/474) in OCSP (77.3/9.0): relative rate =1.64 (1.32–2.04, p<0.0001). However, after adjustment for ageing of the underlying population between the studies the rates were similar (1.19, 0.96–1.48, p=0.109). Of the 154 OXVASC patients with incident ischaemic stroke and prior AF, 116 had a CHADS2 score of ≥2, of whom only 19 (16.4%) had been on warfarin for primary prevention. Conclusions There has been no reduction in age-adjusted incidence of AF-related ischaemic stroke in Oxfordshire over the last 25 years and absolute numbers have increased substantially. Underuse of anticoagulation in primary prevention in eligible patients is a major barrier to effective stroke prevention in the face of an ageing population with high rates of AF.