Efficacy and safety of warfarin therapy in patients with atrial fibrillation using genotype-guided dosing method

Abstract

The aim. To evaluate the efficacy and safety of warfarin (WF) therapy in patients with atrial fibrillation (AF) using pharmacogenetic dosing method at an anticoagulant monitoring office according to the results of a one-year prospective follow-up. Materials and methods. The study involved 110 patients with AF (mean age 68.72 ± 0.79; men – 57, women – 53). By the method of stratified randomization, the patients with AF were divided into two groups: the main group – 50 patients with AF and genotype-guided dosing method, the control group – 60 patients with AF and clinical dosing method. The outcomes were examined after the one-year follow-up: excessive hypocoagulation episodes (INR > 4) and bleeding. CYP2C9, CYP4F2, VKORC1 gene polymorphisms were determined using multiplex real time polymerase chain reaction; INR was controlled monthly; CHA2DS2-VASC, HAS-BLED, SAMe-TT2R2 scale scores were evaluated; TTR was calculated using the Rosendaal method. Results. The distribution of CYP2C9, CYP4F2, VKORC1 genotypes in the main and control groups were in accordance with the Hardy–Weinberg equilibrium. In patients with AF and genotype-guided dosing, the frequency and risk of excessive hypocoagulation episodes (χ2 = 5.11; P < 0.05; RR = 0.50 (CI 0.27; 0.94)) and bleeding (χ2 = 9.57; P < 0.05; RR = 0.41 (CI 0.22; 0.77)) were significantly lower. However, the groups did not differ in TTR. The validity of genetic-guided dosing was confirmed by the comparability of the medians and the direct correlation between the calculated and therapeutic WF doses (r = +0.57; P < 0.05). There were no relationships between TTR, excessive hypocoagulation episodes, hemorrhagic complications and clinical and genetic factors in the main group. Conclusions. In patients with AF, the use of genotype-guided dosing method in the anticoagulant monitoring office helped to reduce the frequency and risk of excessive hypocoagulation episodes and bleeding as well as eliminate the influence of endogenous and exogenous factors in the personalized management of patients.