Abstract 11324: Post-Discharge Stroke in Patients With Atrial Fibrillation: A Follow-Up Study in Major Cities of China

Abstract

Introduction: Atrial fibrillation (AF) is a key risk factor for stroke. However, little is known about the stroke incidence among patients with AF. The purpose of this study is to estimate the post-discharge stroke incidence in AF patients hospitalized in major cities of China.

Methods: On the basis of a random representative sample of hospital records between 2003 and 2008, of patients with a primary diagnosis of AF from six tertiary hospitals located in Beijing, Shanghai and Guangzhou in China, patients without stroke on inpatient record were followed up to collect post-discharge information regarding the stroke event, the time to event, as well as demographics, clinical characteristics and post-discharge antithrombotic treatments. A survival analysis was performed to estimate the stroke incidence. A Cox regression analysis was conducted to examine the potential risk factors of post-discharge stroke.

Results: Among 1037 patients identified for follow-up, a total of 705 patients (response rate of 68%) were interviewed over the phone in 2011. Among the 705 patients, 61% were males, average age was 69 years (40% were ≥75 years), 13% had valvular AF, 81% had non-valvular AF, and the remaining 6% had an unidentified type of AF, and 41% had a CHADS₂ score of 2+. By July 2011, a total of 2302 person-years were followed up with a mean follow-up period of 3.3 years. During the follow-up period, 56% of patients received warfarin therapy and 65 (9.2%) suffered ischemic stroke events. The survival analysis showed that the post-discharge stroke incidence rate was 2.8 per 100 person-years. The Cox regression analysis showed a significant protective effect of post-discharge warfarin use on stroke risk (hazard ratio=0.38, 95% CI 0.20-0.70), but a non-significant effect of age, gender, AF type and CHADS₂ score.

Conclusion: This study showed recent data on stroke risk among hospitalized AF patients during an average of about three years of follow-up in China, and also demonstrated the importance of anticoagulation therapy on stroke prevention.