Hypoprothrombinemia Clinical Trial
Official title:
A Single-site, Randomized Controlled Feasibility Trial of the Fearon Algorithm to Improve Management of Patients With Unstable Warfarin Effect.
Patients on warfarin but with unstable international normalized ratio (INR) will be recruited to a randomized trial comparing dosing based on an algorithm (Fearon algorithm, named after the mathematician Michael Fearon), which uses historical data to estimate patients' sensitivity to warfarin and to dose changes as well as the lag time until a dose adjustment takes effect, or to the investigators standard management Main outcome is improvement in time in therapeutic range.
Patients with very variable INRs resulting in a low proportion of time in therapeutic range
(TTR) have a higher risk of both bleeding complications and thromboembolic events. A good TTR
is generally considered to be over 60% and "excellent TTR" is above 72% of time in range. The
investigators will recruit patients with a TTR below 50%.
The Fearon algorithm provides a more thorough understanding of the individual responses to
changes in warfarin dose and with a personalized nomogram for dose adjustments and timing of
laboratory tests the investigators have an opportunity to improve the TTR and on a larger
scale to reduce clinically important adverse events. Before embarking on a large randomized
trial with this revised Fearon algorithm-derived nomogram this pilot study with a randomized,
open-label design will be performed to demonstrate proof of principle.
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