Key result
In patients with non-valvular AF on VKA therapy, TTR yielded higher values than FIR (mean 56.0% vs 49.8%), showing widespread disagreement (Lin's concordance coefficient 0.829; 95% CI 0.821-0.837).
Why the study?
Are frequency in range (FIR) and proportion of time in the therapeutic range (TTR) equivalent for monitoring INR in patients with non-valvular AF on VKA therapy?
Population
5,066 patients with newly diagnosed non-valvular atrial fibrillation receiving vitamin K antagonist therapy…
Design
Cohort
Follow-up
1 year
Authors
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TTR and FIR disagree substantially and should not be used interchangeably for VKA monitoring; leaves open which metric better predicts outcomes.
Observational (n=5,066)
Yes
Are frequency in range (FIR) and proportion of time in the therapeutic range (TTR) equivalent for monitoring INR in patients with non-valvular AF on VKA therapy?
Effect estimate: Lin's concordance coefficient 0.829 (95% CI 0.821-0.837)
Absolute Event Rate: 56% vs 49.8%
Frequency in range (FIR) and proportion of time in the therapeutic range (TTR) are not equivalent and cannot be used interchangeably for assessing INR control in patients on VKA therapy.
Fitzmaurice et al. (2016) conducted an observational in newly diagnosed non-valvular atrial fibrillation (n=5,066). Proportion of time in the therapeutic range (TTR) vs. Frequency in range (FIR) was evaluated on Agreement between frequency in range (FIR) and proportion of time in the therapeutic range (TTR) (Lin's concordance coefficient 0.829, 95% CI 0.821-0.837). In patients with non-valvular AF on VKA therapy, TTR yielded higher values than FIR (mean 56.0% vs 49.8%), showing widespread disagreement (Lin's concordance coefficient 0.829; 95% CI 0.821-0.837).
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