In:
British Journal of Haematology, Wiley, Vol. 174, No. 4 ( 2016-08), p. 610-623
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 non‐valvular 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 INR s were analysed. At the patient level, TTR showed higher values than FIR (mean, 56·0% vs 49·8%; median, 59·7% vs 50·0%). Although patient‐level FIR and TTR values were highly correlated (Pearson correlation coefficient [95% confidence interval; CI ], 0·860 [0·852–0·867] ), estimates from individuals showed widespread disagreement and variability (Lin's concordance coefficient [95% CI ], 0·829 [0·821–0·837] ). The difference between FIR and TTR explained 17·4% of the total variability of measurements. These results suggest that FIR and TTR are not equivalent and cannot be used interchangeably.
Type of Medium:
Online Resource
ISSN:
0007-1048
,
1365-2141
DOI:
10.1111/bjh.2016.174.issue-4
Language:
English
Publisher:
Wiley
Publication Date:
2016
detail.hit.zdb_id:
1475751-5
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