TY - JOUR
T1 - Comparison of international normalized ratio audit parameters in patients enrolled in GARFIELD-AF and treated with vitamin K antagonists
AU - the GARFIELD-AF Investigators
AU - Fitzmaurice, David A.
AU - Accetta, Gabriele
AU - Haas, Sylvia
AU - Kayani, Gloria
AU - Lucas Luciardi, Hector
AU - Misselwitz, Frank
AU - Pieper, Karen
AU - ten Cate, Hugo
AU - Turpie, Alexander G.G.
AU - Kakkar, Ajay K.
N1 - Publisher Copyright:
© 2016 John Wiley & Sons Ltd
PY - 2016/8/1
Y1 - 2016/8/1
N2 - 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 INRs 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.
AB - 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 INRs 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.
KW - atrial fibrillation
KW - frequency in range
KW - international normalized ratio
KW - time in therapeutic range
KW - vitamin K antagonists
UR - http://www.scopus.com/inward/record.url?scp=84982915243&partnerID=8YFLogxK
U2 - 10.1111/bjh.14084
DO - 10.1111/bjh.14084
M3 - Article
C2 - 27071942
AN - SCOPUS:84982915243
SN - 0007-1048
VL - 174
SP - 610
EP - 623
JO - British Journal of Haematology
JF - British Journal of Haematology
IS - 4
ER -