Factors associated with refusal of anticoagulation in patients with atrial fibrillation: findings from the global GARFIELD-AF registry

Conference:

SAPC ASM 2020 - cancelled due to pandemic

Talk Code:

D.1

Presenter:

Patricia Apenteng, University of Warwick

Twitter:

@p_apenteng

Co-authors:

David Fitzmaurice1, Saverio Virdone2, A. John Camm3, Keith A. A. Fox4, Jean-Pierre Bassand 2,5, Samuel Z. Goldhaber6, Shinya Goto7, Sylvia Haas8, Alexander G.G. Turpie9, Freek W.A. Verheugt10, Frank Misselwitz11, Gloria Kayani2, Karen S. Pieper2, Ajay K. Kakkar2,12 for the GARFIELD-AF Investigators

Author institutions:

1. Univ. of Warwick, UK 2. Thrombosis Research Institute, UK 3. St. George’s Univ. of London, UK 4. Univ. of Edinburgh, UK 5. Univ. of Besançon, France 6. Harvard Medical School, USA 7. Tokai Univ. School of Medicine, Japan 8. Technical Univ. of Munich, Germany 9. McMaster Univ. Canada 10. Onze Lieve Vrouwe Gasthuis (OLVG), The Netherlands 11.Bayer AG, Germany 12. Univ.College London, UK

Problem

There is a substantial incidence of stroke in patients with atrial fibrillation (AF) not receiving anticoagulation. Reasons for patients with AF not receiving anticoagulation are generally attributed to the clinician decision, however in practice some patients refuse anticoagulation. The aim of our study was to investigate the rate of refusal of anticoagulation in patients with AF and the factors associated with patient refusal of anticoagulation.

Approach

The Global Anticoagulant Registry in the FIELD (GARFIELD-AF) was an international prospective observational study of patients≥ 18 years with newly diagnosed AF and ≥1 investigator determined risk factor for stroke. Participants were consecutively enrolled in ≥1000 centres in 35 countries and followed up for a minimum of 2 years. A logistic regression was developed with predictors of patient anticoagulation refusal identified by least absolute shrinkage and selection operator (LASSO) methodology. The following information were considered as potential predictors: demographics (sex, age, ethnicity), medical and cardiovascular history, lifestyle factors (smoking and alcohol consumption), vital signs (BMI, pulse, systolic and diastolic blood pressure), type of AF and care setting at diagnosis. Patient refusal of anticoagulation was defined as patients with AF at high risk of stroke (CHA2DS2VASc ≥2) who refused anticoagulation.

Findings

Out of 43,154, 13,283 (30.8%) participants at high risk of stroke did not receive anticoagulation at baseline. The reason for not receiving anticoagulation was unavailable for 38.7% (5146/13283); of the patients with a known reason for not receiving anticoagulation, 12.5% (1014/8137) refused anticoagulation. The median (Q1; Q3) age of participants who refused anticoagulation was 72 (65; 78) years, and 48.3% were female. CHA2DS2VASc score was 3.0 (3.0; 5.0) in patients who refused anticoagulation and HAS-BLED score was 1.0 (1.0; 2.0). The strongest determinant of anticoagulation refusal was care setting at diagnosis, with patients diagnosed in primary care/GP having a higher likelihood of refusing anticoagulation compared to patients diagnosed in cardiology. After care setting, other determinants were ethnicity, vascular disease, type of AF, pulse, care setting location, age, diastolic and systolic blood pressure, history of venous thromboembolism, prior bleeding and prior stroke/TIA/systemic embolism.

Consequences

In this global real-world prospective study of patients with newly diagnosed AF, the overall rate of patient refusal of anticoagulation was low (2.3% of patients at high risk of stroke), though patient refusal accounted for 12.5% of patients at high risk of stroke and not receiving anticoagulation. Diagnosis in primary care/GP, Asian ethnicity and presence of vascular disease were strongly associated with a higher risk of patient refusal of anticoagulation. While patient refusal of anticoagulation is an acceptable outcome of shared decision-making, clinically it is a missed opportunity to prevent AF related stroke. Patients’ reasons for refusing anticoagulation need to be explored.

Submitted by:

Patricia Apenteng

Funding acknowledgement:

The GARFIELD-AF registry is funded by an unrestricted research grant from Bayer AG.