Aim: To perform a randomized, open-label comparison of average time in therapeutic range (TTR) of international normalized ratio (INR) using two approaches to initial warfarin dosing during hospitalization: the standard method and the one using individual patient characteristics (clinical algorithm - the studied approach).
Materials and methods: We randomly assigned 60 patients with different indications for vitamin K antagonist therapy to the studied approach (n=31, intervention group) or to the standard method (n=29, control group). А target INR range for all patients was 2.0 to 3.0.
Results: The average TTR and portions of INR values within target range during the whole time of drug dosing turned out to be small. TTR was 22.4% with standard method and 21.4% with clinical algorithm, which was well below desired 60%.
Conclusion: The opportunities for achieving target INR in inpatient settings, regardless of warfarin dosing regimen, are limited.
Keywords: SAMe-TT2R2 score; international normalized ratio (INR); stable INR; time in therapeutic range (TTR); warfarin; warfarin dosing.