Clinical phenotypes of older adults with non-valvular atrial fibrillation not treated with oral anticoagulants by hierarchical cluster analysis in the ANAFIE registry

Abstract

Abstract Background and purpose The All Nippon AF In the Elderly (ANAFIE) registry evaluated the current status of anticoagulant therapy in older adult patients (aged ≥75 years) with non-valvular atrial fibrillation (NVAF) in Japan. Although older adult NVAF patients requires anticoagulation therapy, some of them do not receive it and the reasons would be diverse. Therefore, we aimed to identify the phenotypes of older adult NVAF patients not treated with oral anticoagulants using data from the ANAFIE registry. Methods In this sub-analysis of the ANAFIE registry, the phenotypes of patients who were not receiving anticoagulants at baseline were evaluated by cluster analysis using Ward's linkage hierarchical algorithm. We used 20 categorical variables and 6 continuous variables for the cluster analysis which were used as the risk factors in the main analysis of the ANAFIE registry [1]. Results Of 33,275 enrolled patients, 2445 (7.3%) were not receiving anticoagulants. Two clusters were identified: (1) elderly paroxysmal AF (PAF) patients with a low prevalence of comorbidities (58%) and (2) very elderly patients with a high previous major bleeding prevalence (42%). For each cluster, mean ages were 79.9 and 85.7 years, mean CHADS2 scores were 2.3 and 3.1, PAF prevalences were 83% and 54%, heart failure prevalences were 18% and 48%, the proportions of patients with a history of major bleeding were 0% and 25%, the proportions of patients with a history of catheter ablation were 21% and 8%, respectively. Annual incidence rates of each cluster were 2.62% and 9.08% for all-cause death, 1.72% and 5.83% for major adverse cardiovascular or neurological events, 1.22% and 3.14% for stroke or systemic embolism, and 0.53% and 1.43% for major bleeding. Conclusions In this cohort of elderly NVAF patients not receiving anticoagulants, more than half (∼60%) were PAF patients and had a low incidence of adverse outcomes. The remaining ∼40% were characterized as very elderly patients with a high prevalence of previous major bleeding and a high incidence of adverse outcomes. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Daiichi Sankyo Co., Ltd.