Abstract P285: Pattern of Atrial Fibrillation and Risk of Outcomes: The Loire Valley Atrial Fibrillation Project

Abstract

Background: The risk of stroke and thromboembolism (TE) in patients with non-valvular atrial fibrillation (NVAF) can be classified in commonly-used stroke risk stratification scores. The role of the pattern of atrial fibrillation in risk prediction is unclear in contemporary ‘real world’ cohorts. Methods: Patients diagnosed with NVAF in a four-hospital-institution between 2000 and 2010 were identified and included. Event rates of stroke/TE were calculated according to pattern of AF, i.e. paroxysmal, persistent and permanent, defined by consensus guidelines. Independent risk factors of stroke/TE were investigated by Cox regression. Results: Among 7156 patients with NVAF, 4176 (58.4%) patients with paroxysmal, 376 (5.3%) with persistent and 2604 (36.3%) with permanent NVAF patterns were included. In non-anticoagulated patients, the overall stroke/TE event rate per 100 person-years was 1.29 (95% CI 1.13–1.47). Paroxysmal NVAF patients were more likely to be female (p<0.001). Persistent NVAF patients were less likely to have prior history of stroke (p–0.002) and vascular disease (p<0.001), and more likely to have hypertension (p<0.001) and vitamin K antagonist therapy (p<0.001). Permanent NVAF patients were more likely to have diabetes (p<0.001), heart failure therapy (p<0.001) and less likely to have dyslipidaemia (p<0.001). Compared with paroxysmal NVAF, rates of stroke/TE (p=0.001), bleeding (p<0.001) and all-cause mortality (p<0.001) were significantly higher in permanent NVAF patients but not in persistent NVAF patients. In multivariate analyses, only previous stroke (hazard ratio, HR 2.58, 95% CI 2.08–3.21), vascular disease (HR 1.34,1.12–1.61), heart failure (HR 1.20,1.00–1.44), age≥75 years (HR 2.75, 2.16–3.50) and age 65–74 years (HR 1.60,1.22–2.09) increased stroke/TE risk, but persistent (HR1.13, 0.76–1.70) and permanent (HR 1.44,0.96–2.16) patterns of NVAF did not. Conclusion: In this large ‘real world’ cohort of NVAF patients, there were significant differences in rates of stroke, TE, death and bleeding between patterns of NVAF, however only previous stroke, age, heart failure and vascular disease (not pattern of NVAF) independently increased the risk of stroke/TE, death and bleeding in multivariate analyses. Therefore, the risk of stroke is similar across all patterns of NVAF and antithrombotic therapy should be based on clinical risk factors not NVAF pattern.