Stroke in people with atrial fibrillation: Is the treatment gap improving?.

Abstract

Objectives: Atrial fibrillation (AF) is a major risk factor for stroke. The proportion of AF-related stroke is likely to grow as the population ages. We aimed to determine the treatment gap of AF over time in two large population-based studies of stroke. Method(s): We used data from the North East Melbourne Stroke Incidence Study, NEMESIS, 1996-99; and Adelaide Stroke Incidence Study, ASIS, 2009-10 to determine the change in proportion of strokes attributable to previously known and newly diagnosed AF. In those with previously known AF we also determined the CHADS2 score (a score >=2 is indicative of a high risk of stroke, and warfarin is recommended), and the proportion on antithrombotic treatment. Result(s): In total, 411 (27%) of 1511 people in NEMESIS had stroke attributable to AF, and 92 (33%) of 275 in ASIS (p = 0.03). In those with previously known AF, warfarin therapy rose from 13% to 44% (p < 0.001), but many had an INR <2 on admission (37% in NEMESIS and 44% in ASIS). Few with known AF were on adequate anticoagulant therapy with INR >=2 (8% in NEMESIS and 25% in ASIS). The proportion of patients with known AF on antiplatelet agents rose from 46% to 94% over time (p < 0.001), with most having a CHADS2 score >=2 (94% in NEMESIS; 100% in ASIS). This demonstrates a large treatment gap. Conclusion(s): A large proportion of patients with AF were on inadequate therapy. Reducing the treatment gap in AF is essential to reduce the occurrence of stroke, particularly as the population ages.