Background characteristics and anticoagulant usage patterns of elderly non-valvular atrial fibrillation patients in the ANAFIE registry: a prospective, multicentre, observational cohort study in Japan

Objective: To explore anticoagulant usage patterns stratified by stroke and bleeding risk in elderly patients with non-valvular atrial fibrillation (NVAF).

Design: Prospective, multicentre, observational cohort study.

Setting: The real-world All Nippon AF In the Elderly (ANAFIE) registry.

Participants: Japanese patients aged ≥75 years with NVAF (n=32 726).

Outcome measures: The distribution of stroke and bleeding risk scores, and the selection of anticoagulant regimen for patients at high stroke and bleeding risk.

Results: Overall, 18 185 (55.6%) patients had a high risk of stroke (CHADS₂ score ≥3). Of these, 12 561 (38.4% of the total ANAFIE population) had a low bleeding risk (HAS-BLED ≤2) and 5624 (17.2%) had a high bleeding risk (HAS-BLED ≥3). Significant differences were noted between the high versus low bleeding risk groups in sex, height, weight, systolic blood pressure and rates of abnormality of lipid metabolism, gastrointestinal disease, cerebrovascular disorders, chronic kidney disease, angina pectoris, respiratory disease, primary malignant tumour, dementia and fall history within the past year (all p<0.0001). Patients with high stroke and bleeding risks had a lower anticoagulant usage rate versus the low bleeding risk group, and 8.7% and 5.8%, respectively, were not receiving any anticoagulant (p<0.0001). Patients in the high bleeding risk group had a higher usage of warfarin versus the low bleeding risk group (p<0.0001); more patients (14.0%) in the high bleeding risk group receiving warfarin had time in the therapeutic range <40%, versus those in the low bleeding risk group (11.6%, p=0.0146). Direct-acting oral anticoagulants (DOACs) were used less in the high bleeding risk group, without notable differences in the DOAC dose distribution between the two groups.

Conclusions: In elderly NVAF patients at high stroke risk, significant demographic and clinical differences were observed according to bleeding risk. Administration of low-dose DOACs was frequent, but the dose distribution was unaffected by bleeding risk.

Trial registration number: UMIN000024006 (http://www.umin.ac.jp/).