Risk factors associated with stroke/systemic embolic events in elderly non-valvular atrial fibrillation patients in the ANAFIE registry, the largest real-world elderly AF registry
Authors: Inoue H , Yamashita T 
Published: November 2020

Abstract

Background
Since prevalence of atrial fibrillation (AF) is increasing by aging, AF in elderly has been recognized as a big burden to keep long lasting healthy life worldwide. CHADS2 and CHA2DS2-VASc scores are commonly used for stroke risk assessment for AF, but predictors for elderly was not well elucidated, especially for very elderly (≥85 years old) patients.

Purpose
All Nippon AF In the Elderly (ANAFIE) registry was designed to evaluate a real-world treatment status of elderly (≥75 years old) non-valvular AF (NVAF) patients, including anticoagulant therapy and outcomes. The present analysis aimed to identify factors for stroke/systemic embolic events (SEE) of elderly NVAF patients using the dataset of ANAFIE registry, which was conducted in Japan.

Methods
Total of 32,099 patients aged ≥75 years with NVAF were enrolled in ANAFIE registry, and followed for 2 years. Incidence of stroke/SEE for total population, &lt;85 years old group and ≥85 years old group was estimated using Kaplan-Meier method. Cox proportional hazards model was used to determine independent predictors of stroke/SEE. The factors included in the model were selected by backward elimination procedure.

Results
Mean age was 81.5 years. 23,738 (74%) was &lt;85 years old and 8,361 (26%) was ≥85 years old. Women were more prevalent in ≥85 years old than in &lt;85 years old group (53.2 vs 39.0%). Mean CHADS2 and CHA2DS2-VASc scores in the ≥85 years group were 3.0 and 4.7, and 2.8 and 4.4 in the &lt;85 years group, respectively. 92.5% of whole population used anti-coagulants including warfarin (27.6%) or direct oral anticoagulants (DOACs) (72.3%). Stroke/SEE occurred in 396 patients at 12 month with 256 in &lt;85 years old and 140 in ≥85 years old group. The cumulative incidence rate of stroke/SEE by Kaplan-Meier method at 12 months was 1.2% in the whole patients, and was higher in ≥85 years than in &lt;85 years old group (1.7% vs 1.1%). In the multivariate analysis using the whole patients, age ≥85 years (hazard ratio [HR]: 1.27), history of major bleeding (HR: 1.93), persistent AF (HR: 1.64), longstanding persistent and permanent AF (HR: 1.61), high systolic blood pressure (130-&lt;140 [HR: 1.43], ≥140 [HR: 1.44]), prior stroke (HR: 2.09), dementia (HR: 1.34), creatinine clearance &lt;30 mL/min (HR: 1.82) emerged as independent predictors. Independent predictors for stroke/SEE were almost similar between &lt;85 and ≥85 years old group except hypertension and diabetes. High blood pressure was associated with stroke/SEE only in patients aged &lt;85 years, and high blood sugar was only associated in patients aged ≥85 years.

Conclusion
Among elderly NVAF patients in the era of DOACs, higher age (≥85 years), type of AF, prior major bleeding, high blood pressure, prior stroke, dementia, and low creatinine clearance were identified as independent predictors of stroke/SEE. The blood pressure and blood sugar control differently affected &lt;85 years vs ≥85 years old group.

Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Daiichi Sankyo Co., Ltd.