A pharmacogenetics-based warfarin maintenance dosing algorithm from Northern Chinese patients.
ABSTRACT: Inconsistent associations with warfarin dose were observed in genetic variants except VKORC1 haplotype and CYP2C9*3 in Chinese people, and few studies on warfarin dose algorithm was performed in a large Chinese Han population lived in Northern China. Of 787 consenting patients with heart-valve replacements who were receiving long-term warfarin maintenance therapy, 20 related Single nucleotide polymorphisms were genotyped. Only VKORC1 and CYP2C9 SNPs were observed to be significantly associated with warfarin dose. In the derivation cohort (n?=?551), warfarin dose variability was influenced, in decreasing order, by VKORC1 rs7294 (27.3%), CYP2C9*3(7.0%), body surface area(4.2%), age(2.7%), target INR(1.4%), CYP4F2 rs2108622 (0.7%), amiodarone use(0.6%), diabetes mellitus(0.6%), and digoxin use(0.5%), which account for 45.1% of the warfarin dose variability. In the validation cohort (n?=?236), the actual maintenance dose was significantly correlated with predicted dose (r?=?0.609, P<0.001). Our algorithm could improve the personalized management of warfarin use in Northern Chinese patients.
Project description:OBJECTIVES:As the most frequently prescribed anticoagulant, warfarin has large inter-individual variability in dosage. Genetic polymorphisms could largely explain the differences in dosage requirement. rs9923231 (VKORC1), rs7294 (VKORC1), rs1057910 (CYP2C9), rs2108622 (CYP4F2), and rs699664 (GGCX) involved in the warfarin action mechanism and the circulatory vitamin K were selected to investigate their polymorphism characteristics and their effects on the pharmacodynamics and pharmacokinetics of warfarin in Chinese population. METHODS:220 patients with cardiac valve replacement were recruited. International normalized ratio and plasma warfarin concentrations were determined. The five genetic polymorphisms were genotyping by pyro-sequencing. The relationships of maintenance dose, plasma warfarin concentration and INR were assessed among groups categorized by genotypes. RESULTS:rs9923231 and rs7294 in VKORC1 had the analogous genotype frequencies (D': 0.969). 158 of 220 recruited individuals had the target INR (1.5-2.5). Patients with AA of rs9923231 and CC of rs7294 required a significantly lower maintenance dose and plasma concentration than those with AG and TC, respectively. The mean weekly maintenance dose was also significantly lower in CYP2C9 rs1057910 mutated heterozygote than in patients with the wild homozygote. Eliminating the influence from environment factors (age, body weight and gender), rs9923231 and rs1057910 could explain about 32.0% of the variability in warfarin maintenance dose; rs7294 could explain 26.7% of the variability in plasma concentration. For patients with allele G of rs9923231 and allele T of rs7294, higher plasma concentration was needed to achieve the similar goal INR. CONCLUSIONS:A better understanding of the genetic variants in individuals can be the foundation of warfarin dosing algorithm and facilitate the reasonable and effective use of warfarin in Chinese.
Project description:The aim of this study was to investigate whether the VKORC1*3 (rs7294/9041 G?>?A), VKORC1*4 (rs17708472/6009 C?>?T), and CYP4F2 (rs2108622/1347 C?>?T) polymorphisms were associated with elevated warfarin maintenance dose requirements in patients with myocardial infarction (n = 105) from the Warfarin Aspirin Reinfarction Study (WARIS-II). We found significant associations between elevated warfarin dose requirements and VKORC1*3 and VKORC1*4 polymorphisms (P = .001 and P = .004, resp.), whereas CYP4F2 (1347 C?>?T) showed a weak association on higher warfarin dose requirements (P = .09). However, analysing these variant alleles in a regression analysis together with our previously reported data on VKORC1*2, CYP2C9*2 and CYP2C9*3 polymorphisms, gave no significant associations for neither VKORC1*3, VKORC1*4 nor CYP4F2 (1347 C?>?T). In conclusion, in patients with myocardial infarction, the individual contribution to warfarin dose requirements from VKORC1*3, VKORC1*4, and CYP4F2 (1347 C?>?T) polymorphisms was negligible. Our results indicate that pharmacogenetic testing for VKORC1*2, CYP2C9*2 and CYP2C9*3 is more informative regarding warfarin dose requirements than testing for VKORC1*3, VKORC1*4, and CYP4F2 (1347 C?>?T) polymorphisms.
Project description:WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT * Genetic polymorphisms of VKORC1 and CYP2C9 are known to influence warfarin dosage. * Recent studies among Caucasians showed that polymorphisms of CYP4F2 also play a role in warfarin pharmacogenetics. * The contribution of CYP4F2 variants to the variability inwarfarin dose requirement in Chinese subjects remains to be investigated. WHAT THIS STUDY ADDS * This research was to study the effect of CYP4F2 variants on warfarin requirements in the Han Chinese population. * This study developed a multiple regression model including CYP2C9, VKORC1 3673G>A, CYP4F2 genotypes and age, weight, combination use of amiodarone which could explain 56.1% of the individual variability in warfarin dose CYP4F2 could explain 4% of the variance in warfarin dose. * We found that one novel genotypic polymorphism 5417G>T for Asp36Tyr, which was identified as an important marker of warfarin resistance, was absent in the Han Chinese population in our study. AIMS The objective of this study was to assess the effect of the CYP4F2 on the daily stable warfarin dose requirement in Han Chinese patients with mechanical heart valve replacement (MHVR). METHODS From March 2007 to November 2008, 222 Han Chinese MHVR patients were recruited in our study. VKORC1 3673G>A, 5417G>T, CYP2C9*3 and CYP4F2 rs2108622 were genotyped by using the polymerase chain reaction restriction fragment length polymorphism method (PCR-RFLP). Polymorphisms of VKORC1 9041G>A were detected by direct sequencing. Multiple linear regression analysis was used to investigate the contribution of CYP4F2. RESULTS The CYP4F2 rs2108622 CT/TT group took a significantly higher stable warfarin dose (3.2 mg day(-1)) than the CC group (2.9 mg day(-1), 95% CI 0.2, 1.0, P= 0.033). The multiple linear regression model included VKORC1 3673G>A, CYP2C9, CYP4F2 genotypes and clinical characteristics. The model could explain 56.1% of the variance in stable warfarin dose in Han Chinese patients with MHVR. CYP4F2 contributed about 4% to the variance in the warfarin dose. There was no variation in the SNPs of VKORC1 5417G>T. CONCLUSION CYP4F2 is a minor significant factor of individual variability in the stable warfarin dose in Han Chinese patients with MHVR. The effect of CYP2C9 and VKORC1 genotypes on variability in the stable warfarin dose had also been confirmed.
Project description:The effects of genetic variants on warfarin dosing vary among different ethnic groups, especially in the Chinese population. The objective of this study was to recruit patients through a rigorous experimental design and to perform a comprehensive screen to identify gene polymorphisms that may influence warfarin dosing in northern Han Chinese patients with mechanical heart valve replacement. Consenting patients (n?=?183) with a stable warfarin dose were included in this study. Ninety-six single nucleotide polymorphisms (SNPs) in 30 genes involved in warfarin pharmacological pathways were genotyped using the Illumina SNP GoldenGate Assay, and their associations with warfarin dosing were assessed using univariate regression analysis with post hoc comparison using least significant difference analysis. Multiple linear regression was performed by incorporating patients' clinical and genetic data to create a new algorithm for warfarin dosing. From the 96 SNPs analyzed, VKORC1 rs9923231, CYP1A2 rs2069514, CYP3A4 rs28371759, and APOE rs7412 were associated with higher average warfarin maintenance doses, whereas CYP2C9 rs1057910, EPHX1 rs2260863, and CYP4F2 rs2189784 were associated with lower warfarin doses (P?<?0.05). Multiple linear regression analysis could estimate 44.4% of warfarin dose variability consisting of, in decreasing order, VKORC1 rs9923231 (14.2%), CYP2C9*3 (9.6%), body surface area (6.7%), CYP1A2 rs2069514 (3.7%), age (2.7%), CYP3A4 rs28371759 (2.5%), CYP4F2 rs2108622 (1.9%), APOE rs7412 (1.7%), and VKORC1 rs2884737 (1.4%). In the dosing algorithm we developed, we confirmed the strongest effects of VKORC1, CYP2C9 on warfarin dosing. In the limited sample set, we also found that novel genetic predictors (CYP1A2, CYP3A4, APOE, EPHX1, CYP4F2, and VKORC1 rs2884737) may be associated with warfarin dosing. Further validation is needed to assess our results in larger independent northern Chinese samples.
Project description:The aim of this study was to investigate the contributions of non-genetic and genetic factors on the variability of stable warfarin doses in Thai patients.A total of 250 Thai patients with stable warfarin doses were enrolled in the study. Demographics and clinical data, e.g., age, body mass index, indications for warfarin and concomitant medications, were documented. Four single nucleotide polymorphisms in the VKORC1 - 1639G > A, CYP2C9*3, CYP4F2 rs2108622, and UGT1A1 rs887829 genes were detected from gDNA using TaqMan allelic discrimination assays.The patients with variant genotypes of VKORC1 - 1639G > A required significantly lower warfarin stable weekly doses (SWDs) than those with wild-type genotype (p < 0.001). Similarly, the patients with CYP2C9*3 variant allele required significantly lower warfarin SWDs than those with homozygous wild-type (p = 0.006). In contrast, there were no significant differences in the SWDs between the patients who carried variant alleles of CYP4F2 rs2108622 and UGT1A1 rs887829 as compared to wild-type allele carriers. Multivariate analysis, however, showed that CYP4F2 rs2108622 TT genotype accounted for a modest part of warfarin dose variability (1.2%). In contrast, VKORC1 - 1639G > A, CYP2C9*3, CYP4F2 rs2108622 genotypes and non-genetic factors accounted for 51.3% of dose variability.VKORC1 - 1639G > A, CYP2C9*3, and CYP4F2 rs2108622 polymorphisms together with age, body mass index, antiplatelet drug use, amiodarone use, and current smoker status explained 51.3% of individual variability in stable warfarin doses. In contrast, the UGT1A1 rs887829 polymorphism did not contribute to dose variability.
Project description:AIM:To determine whether VKORC1 rs9923231, CYP2C9 rs1057910, CYP4F2 rs2108622 and ORM1 rs17650 genotypes contribute to warfarin therapy in patients during initiation and maintenance anticoagulation treatment after heart valve surgery. METHODS:287 Chinese patients with warfarin treatment more than three month after heart valve replacement operations were enrolled. Blood was collected from each subject for DNA extraction and genotyping. Analyzing the relationship between genotypes and warfarin curative effect. RESULTS:Their mean age was 48.0 ± 10.5 years old. During the initiation phase, the growth rate of INR was partial correlated with VKORC1 rs9923231, CYP2C9 rs1057910 and ORM1 rs17650, respectively. Compared with AG or GG genotypes of VKORC1 c.-1639 carriers, patients with VKORC1 c.-1639AA reached target INR therapeutic range faster (P<0.001) and has a high risk of overanticoagulation (P<0.001). Carriers of at least one CYP2C9 *3 allele reached the target INR therapeutic range and supra-therapeutic INR were faster than CYP2C9 wild-type carriers (P=0.032, P=0.032, respectively). CYP4F2 rs2108622 could significantly influence on time to the target INR therapeutic range and time to INR above 3.0 after hierarchical analysis with VKORC1, CYP2C9 and ORM1 (P=0.011, P=0.044, respectively). VKORC1 rs9923231, CYP2C9 rs1057910 and ORM1 rs17650 were significantly influence the %TTR in three months (P=0.031, P=0.008, P=0.001, respectively). During the maintenance phase, VKORC1 c.-1639AA carriers spent more time at supra-therapeutic INRs (P<0.001). CYP2C9 rs1057910, CYP4F2 rs2108622 and ORM1 rs17650 gene variants did not affect outcome parameters in maintenance phase. CONCLUSIONS:This study found that genetic factors could significantly affected on warfarin therapy in Chinese. Meanwhile, genetic variations play a more important role in the initial phase than did in maintenance phase of warfarin therapy.
Project description:Background:Vitamin K antagonists (VKA) are used as prophylaxis for thromboembolic events in patients with cardiovascular diseases. The most common VKA are warfarin and acenocoumarol. These drugs have a narrow therapeutic margin and high inter-individual response variability due to clinical and pharmacogenetic variables. Objective:The authors aim to develop an algorithm comprised of clinical and genetic factors to explain the variability in the therapeutic dose of acenocoumarol among Chilean patients. Methodology:DNA was obtained from 304 patients as a discovery cohort with an international normalized ratio (INR) range of 2.0-3.0. The non-genetic (demographic and clinical) variables were also recorded. Genotype analyses were performed using real-time PCR for VKORC1 (rs9923231), VKORC1 (rs7294), GGCx (rs11676382), CYP4F2 (rs2108622), ABCB1 (rs1045642), CYP2C9*2 (rs1799853), ApoE (rs429358), and CYP2C9*3 (rs1057910). Results:The clinical variables that significantly influenced the weekly therapeutic dose of VKA were age, sex, body mass index (BMI), and initial INR, collectively accounting for 19% of the variability, and the genetic variables with a significant impact were VKORC1 (rs9923231), CYP2C9*2 (rs1799853), and CYP2C9*3 (rs1057910), explaining for another 37% of the variability. Conclusion:We developed an algorithm that explains 49.99% of the variability in therapeutic VKA dosage in the Chilean population studied. Factors that significantly affected the dosage included VKORC1, CYP2C9*2, and CYP2C9*3 polymorphisms, as well as age, sex, BMI, and initial INR.
Project description:CYP2C9 and VKORC1 are two major genetic factors associated with inter-individual variability in warfarin dose. Additionally, genes in the warfarin metabolism pathway have also been associated with dose variance. We analyzed Single Nucleotide Polymorphisms (SNPs) in these genes to identify genetic factors that might confer warfarin sensitivity in Indonesian patients.Direct sequencing method was used to identify SNPs in CYP2C9, VKORC1, CYP4F2, EPHX1, PROC and GGCX genes in warfarin-treated patients. Multiple linear regressions were performed to model the relationship warfarin daily dose requirement with genetic and non-genetic variables measured and used to develop a novel algorithm for warfarin dosing.From the 40 SNPs analyzed, CYP2C9 rs17847036 and VKORC1 rs9923231 showed significant association with warfarin sensitivity. In our study population, no significant correlation could be detected between CYP2C9*3, CYP2C9C-65 (rs9332127), CYP4F2 rs2108622, GGCX rs12714145, EPHX1 rs4653436 and PROC rs1799809 with warfarin sensitivity.VKORC1 rs9923231 AA and CYP2C9 rs17847036 GG genotypes were associated with low dosage requirements of most patients (2.05 ± 0.77 mg/day and 2.09 ± 0.70 mg/day, respectively). CYP2C9 and VKORC1 genetic variants as well as non-genetic factors such as age, body weight and body height account for 15.4% of variance in warfarin dose among our study population. Additional analysis of this combination could allow for personalized warfarin treatment in ethnic Indonesians.
Project description:BACKGROUND:The anticoagulation of atrial fibrillation catheter ablation during the perioperative stage does matter and should be treated with discretion. We aimed to assess impact of three important genes participating in vitamin K cycle (i.e. VKORC1 rs9923231, CYP4F2 rs2108622 and NQO1 rs1800566) on the daily stable warfarin dose requirement in Sichuan Han Chinese patients with catheter ablation of atrial fibrillation. METHODS:A total of 222 atrial fibrillation patients taking stable warfarin therapy after catheter ablation operation were enrolled in this study. The study population included had high (?2) risk according to the CHA2DS2-VASc risk score. Genotypes of VKORC1 rs9923231, CYP4F2 rs2108622 and NQO1 rs1800566 were analyzed by using the polymerase chain reaction restriction fragment length polymorphism method (PCR-RFLP). Multiple linear regression analysis was applied to depict the impact of VKORC1 rs9923231, CYP4F2 rs2108622 and NQO1 rs1800566 on the daily stable warfarin dose requirement. RESULTS:Carriers of VKORC1 rs9923231 AG/GG genotypes required significantly higher warfarin dose (3.03?±?0.28 mg/day, 7.19 mg/day, respectively) than AA carriers (2.52?±?0.07 mg/day; P <?0.001). Carriers of CYP4F2 rs2108622 CT/TT genotypes required significantly higher warfarin dose (3.38?±?0.22 mg/day, 2.79?±?0.19 mg/day, respectively) than CC carriers (2.41?±?0.08 mg/day; P?<?0.001). However, the warfarin dose for carriers of NQO1 rs1800566 CT/TT genotypes (2.46?±?0.24 mg/day, 3.01?±?0.27 mg/day, respectively) was not significantly higher than that for the CC carriers (2.33?±?0.1 mg/day). The multiple linear regression model including genotypes and demographic characteristics, could explain 20.1% of individual variations in the daily stable warfarin dose in Sichuan Han Chinese. VKORC1 rs9923231 contributed most (15%) to the individual variations in daily stable warfarin dose, while CYP4F2 rs2108622 contributed least (3%). CONCLUSION:NQO1 rs1800566 is not a significant genetic factor of warfarin dose for Han Chinese, whereas VKORC1 rs9923231 and CYP4F2 rs2108622 are significant genetic factors, which could explain 15% and approximately 3% of individual variations in the daily stable warfarin dose respectively.
Project description:Despite the development of new oral agents over the last decade, vitamin K antagonists (VKAs) remain the most widely used anticoagulants for treating and preventing thromboembolism worldwide. In Chile, the Ministry of Health indicates that acenocoumarol should be used in preference to any other coumarin. Complications of inappropriate dosing are among the most frequently reported adverse events associated with this medication. It is well known that polymorphisms in pharmacokinetic and pharmacodynamic proteins related to coumarins (especially warfarin) influence response to these drugs. This work analyzed the impact of CYP2C19*2 (rs4244285), CYP1A2*1F (rs762551), GGCx (rs11676382), CYP2C9*2 (rs1799853), CYP2C9*3 (rs1057910), CYP4F2 (rs2108622), VKORC1 (rs9923231), VKORC1 (rs7294), CYP3A4*1B (rs2740574), and ABCB1 (rs1045642) polymorphisms on time to therapeutic range for oral anticoagulants in 304 Chilean patients. CYP2C9*3 polymorphisms were associated with time to therapeutic range for acenocoumarol in Chilean patients, and the CYP4F2 TT genotype, MDR1 A allele, CYP1A2 A allele, and CYP3A4T allele are promising variants that merit further analysis. The presence of polymorphisms explained only 4.1% of time to therapeutic range for acenocoumarol in a multivariate linear model. These results improve our understanding of the basis of ethnic variations in drug metabolism and response to oral anticoagulant therapy. We hope that these findings will contribute to developing an algorithm for VKA dose adjustment in the Chilean population in the near future, decreasing the frequency of stroke, systemic embolism, and bleeding-related adverse events.