International normalized ratio control and subsequent clinical outcomes in patients with atrial fibrillation using warfarin
SourceJournal of Thrombosis and Thrombolysis, 48, 1, (2019), pp. 27-34
Article / Letter to editor
Display more detailsDisplay less details
Journal of Thrombosis and Thrombolysis
SubjectRadboudumc 16: Vascular damage RIHS: Radboud Institute for Health Sciences
We explored associations between INR measures and clinical outcomes in patients with AF using warfarin, and whether INR history predicted future INR measurements. We included patients in ARISTOTLE who were randomized to and received warfarin. Among patients who had events, we included those with >/= 3 INR values in the 180 days prior to the event, with the most recent </= 60 days prior to the event, who were on warfarin at the time of event (n = 545). Non-event patients were included in the control group if they had >/= 180 days of warfarin exposure with >/= 3 INR measurements (n = 7259). The median (25th, 75th) number of INR values per patient was 29 (21, 38) over a median follow-up of 1.8 years. A total of 87% had at least one INR value < 1.5; 49% had at least one value > 4.0. The last INRs before events (median 14 [24, 7] days) were < 3.0 for at least 75% of patients with major bleeding and > 2.0 for half of patients with ischemic stroke. Historic time in therapeutic range (TTR) was weakly associated with future TTR (R(2) = 0.212). Historic TTR >/= 80% had limited predictive ability to discriminate future TTR >/= 80% (C index 0.61). In patients with AF receiving warfarin, most bleeding events may not have been preventable despite careful INR control. Our findings suggest that INRs collected through routine management are not sufficiently predictive to provide reassurance about future time in therapeutic range or to prevent subsequent outcomes, and might be over-interpreted in clinical practice.
Upload full text
Use your RU credentials (u/z-number and password) to log in with SURFconext to upload a file for processing by the repository team.