The importance of time in therapeutic range in switching from vitamin K antagonist to non-vitamin K antagonist oral anticoagulants in atrial fibrillation.

Abstract

AIMS:

Patients with non-valvular atrial fibrillation (NVAF) receiving vitamin K antagonists (VKAs) with time in therapeutic international normalized ratio (INR) range (TTR) <70%, despite good adherence, are by guidelines recommended to switch to non-VKA oral anticoagulants (NOACs). The aim was to assess if patients are switched from VKA to NOAC when TTR is <70% in a real-world setting.

METHODS AND RESULTS:

Non-valvular atrial fibrillation patients receiving VKA (1 January 2010 to 31 December 2012) were identified in nationwide registries. Time in therapeutic range was calculated by the Rosendaal method by a minimum of three INR values. Time in therapeutic range of patients continuing VKA (non-switchers) were compared with patients switched from VKA to dabigatran or rivaroxaban (switchers), the only NOACs available at that time. Factors associated with switching were analysed in a multivariable logistic regression model. 7276 patients with NVAF receiving VKA were included; of these, 6437 (88.5%) patients continued VKA [57.9% male, median age 76.7 years (Q1-Q3 68.9-83.5)] and 839 (11.5%) switched to NOAC [54.0% male, median age 76.5 years (Q1-Q3 68.4-83.6)]. No significant differences in CHA2DS2-VASc and HAS-BLED scores were seen between the groups. The mean TTR for non-switchers was 64.0 [standard deviation (SD) 27.8] and 52.9 (SD 28.1) for switchers. Among non-switchers, 51% had a TTR <70% vs. 69% among switchers. 85% of patients with TTR <70%, were not switched contrary to recommendations. Time in therapeutic range <70% was associated with the switch [odds ratio 2.28, 95% confidence interval (1.92-2.72)].

CONCLUSION:

A TTR below 70% was associated with switching from VKA to NOAC, yet by guidelines, most patients were still not switched.

• Authors: Naja Emborg Vinding, Anders Nissen Bonde, Rasmus Rørth, Morten Lamberts, Jonas Bjerring Olesen, Gunnar Hilmar Gislason, Christian Torp-Pedersen, Lars Køber, Emil Loldrup Fosbøl
• Journal: Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology (Europace) Vol. 21 Issue 4 Pg. 572-580 (Apr 01 2019) ISSN: 1532-2092 [Electronic] England
• PMID: 30508073 (Publication Type: Journal Article)
• Copyright: Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: [email protected].

Chemical References

• Anticoagulants
• Antithrombins
• Factor Xa Inhibitors
• Warfarin
• Rivaroxaban
• Dabigatran

Topics

• Aged
• Aged, 80 and over
• Anticoagulants (therapeutic use)
• Antithrombins (therapeutic use)
• Atrial Fibrillation (complications, drug therapy)
• Dabigatran (therapeutic use)
• Drug Monitoring
• Drug Substitution (statistics & numerical data)
• Factor Xa Inhibitors (therapeutic use)
• Female
• Guideline Adherence (statistics & numerical data)
• Humans
• International Normalized Ratio
• Logistic Models
• Male
• Multivariate Analysis
• Practice Guidelines as Topic
• Rivaroxaban (therapeutic use)
• Stroke (etiology, prevention & control)
• Time Factors
• Warfarin (therapeutic use)