Randomized Comparison of Two Approaches to Initial Warfarin Dosing: Time in Therapeutic Range of International Normalized Ratio During Hospitalization

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.

варфарин, подбор дозы варфарина, международное нормализованное отношение (МНО), стабильное МНО, время нахождения значений МНО в терапевтическом диапазоне (Time in Theraupeutical Range - TTR), шкала SAMe-TT2R2, warfarin, warfarin dosing, international normalized ratio (INR), stable INR, time in therapeutic range (TTR), SAMe-TT₂R₂ score

1. Kimmel S. E., French B., Kasner S. E. et al. A Pharmacogenetic versus a Clinical Algorithm for Warfarin Dosing. N Engl J Med 2013;369 (24):2283-2293.

2. Pirmohamed M., Burnside G., Eriksson N. et al. A randomized trial of genotype-guided dosing of warfarin. N Engl J Med 2013;369 (24):2294-2303.

3. Mishhenko L. N., Averkov O. V., Gordeev I. G. et al. Randomized comparison of two approaches to warfarin dosage in cardiovascular hospital section. Russian Journal of Cardiology 2015;8 (124):111-122. Russian (Мищенко Л. Н., Аверков О. В., Гордеев И. Г. и др. Рандомизированное сравнение двух подходов к дозированию варфарина в условиях кардиологического стационара. Российский кардиологический журнал 2015;8 (124):111-122).

4. Rosendaal F. R., Cannegieter S. C., van der Meer F.J., Briet E. A method to determine the optimal intensity of oral anticoagulant therapy. Thromb Haemost 1993;69 (3):236-239.

5. Apostolakis S., Sullivan R. M., Olshansky B. et al. Factors Affecting Quality of Anticoagulation Control Among Patients With Atrial Fibrillation on Warfarin: ^e SAMe-'n'2R2 Score. Chest 2013;144 (5):1555-1563.

6. Anderson J. L., Horne B. D., Stevens S. M. et al. A randomized and clinical effectiveness trial comparing two pharmacogenetic algorithms and standard care for individualizing warfarin dosing (CoumaGen-II) Circulation 2012;125 (16):1997-2005.

7. Connolly S.J., Ezekowitz M. D., Yusuf S. et al. Dabigatran versus Warfarin in Patients with Atrial Fibrillation. N Engl J Med 2009;361 (12):1139-1151.

8. Singer D. E., Hellkamp A. S., Piccini J. P. et al. Impact of Global Geographic Region on Time in ^erapeutic Range on Warfarin Anticoagulant Therapy: Data From the ROCKET AF Clinical Trial. Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease 2013;2 (1):e000067. doi:10.1161 /JAHA. 112.000067

9. Al-Khatib M. L., Thomas L., Wallentin L. et al. Outcomes of apixaban vs. warfarin by type and duration of atrial fibrillation: results from the ARISTOTLE trial. Eur Heart J 2013;34:2464-2471.

10. Burmester J. K., Berg R. L., Yale S. H. et al. A randomized controlled trial of genotype-based Coumadin initiation. Genet Med 2011;13 (6):509-518.