Comparison of international normalized ratio audit parameters in patients enrolled in GARFIELD-AF and treated with vitamin K antagonists
Date
2016
Authors
Fitzmaurice, David
Accetta, G
Haas, Sylvia
Kayani, Gloria
Luciardi, H
Misselwitz, F
Pieper, K
ten Cate, Hugo
Turpie, Alexander
Kakkar, Ajay
Journal Title
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Volume Title
Publisher
Blackwell Publishing Ltd
Abstract
Vitamin K antagonist (VKA) therapy for stroke prevention in atrial fibrillation (AF) requires monitoring of the international normalized ratio (INR).
We evaluated the agreement between two INR audit parameters, frequency
in range (FIR) and proportion of time in the therapeutic range (TTR),
using data from a global population of patients with newly diagnosed nonvalvular AF, the Global Anticoagulant Registry in the FIELD–Atrial Fibrillation (GARFIELD-AF). Among 17 168 patients with 1-year follow-up data
available at the time of the analysis, 8445 received VKA therapy
( antiplatelet therapy) at enrolment, and of these patients, 5066 with ≥3
INR readings and for whom both FIR and TTR could be calculated were
included in the analysis. In total, 70 905 INRs were analysed. At the patient
level, TTR showed higher values than FIR (mean, 560% vs 498%; median,
597% vs 500%). Although patient-level FIR and TTR values were highly
correlated (Pearson correlation coefficient [95% confidence interval; CI],
0860 [0852–0867]), estimates from individuals showed widespread disagreement and variability (Lin’s concordance coefficient [95% CI], 0829
[0821–0837]). The difference between FIR and TTR explained 174% of the total
variability of measurements. These results suggest that FIR and TTR are not equivalent and cannot be used interchangeably.
Description
Keywords
atrial fibrillation, frequency in range, international normalized ratio, time in therapeutic range, vitamin K antagonists
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Source
British Journal of Haematology
Type
Journal article
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Restricted until
2099-12-31