Non-genetic factors and polymorphisms in genes CYP2C9 and VKORC1: predictive algorithms for TTR in Brazilian patients on warfarin

Quality of Oral Anticoagulation Control with Warfarin According to Sex: A Cross-Sectional Study

Evidence indicates a difference between men and women in oral anticoagulation control, but the results were discrepant. This study investigated the association of sex with oral anticoagulation control in patients on warfarin assisted by anticoagulation clinics (ACs) in Brazil. The cross-sectional study included patients on warfarin recruited at three public ACs in southeast Brazil (2014-2015). The quality of oral anticoagulation was estimated by the time in therapeutic range (TTR). Univariable and multivariable linear regression models were built to examine the association of sociodemographic, behavior, clinical, and drug therapy variables with TTR. Overall, 801 participants were studied (455; 56.8% women), with a mean age of 65.0 (13.4) years. The female sex was associated with lower TTR than the male sex (Beta (95% CI) = -17.01 (-30.25; -3.76), p = 0.012), however, this difference decreased with increasing age, becoming null after age 60. Smoking patients had a lower TTR than non-smokers (-5.18 (-10.02; -0.34), p = 0.036). The results showed that the association of sex with oral anticoagulation control is dependent on age. Women have lower TTR than men, but this difference is null in older patients. Knowledge of these factors may be useful for developing strategies to improve care for these patients.

Assessment of the relationship between the level of patient knowledge on warfarin therapy and the quality of oral anticoagulation: A systematic review and meta-analysis

The present study aimed to investigate the relationship between the level of patient knowledge on warfarin therapy and the quality of oral anticoagulation. This is a systematic review and meta-analysis written on the basis of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Searches at MEDLINE, EMBASE, Scopus and LILACS electronic databases were carried out on February 13, 2023, using the descriptors "Patient Medication Knowledge", "Patient Education as Topic", "Health Education", "Patient Education" and Warfarin. The steps of selection, data extraction and quality analysis of articles were performed independently by two reviewers. The analysis was performed considering patient knowledge as a possible modifier of time in therapeutic range (TTR). The meta-analysis included studies that reported the correlation coefficient (Pearson or Spearman) between patient knowledge and TTR. A subgroup analysis was performed according to questionnaires employed to measure patient knowledge. Twelve studies were selected with an overall sample size of 7634 participants and mean age 58.2 (standard deviation (SD)±12,8) years. Eleven (92.0%) cross-sectional studies. The mean TTR was 57.8% (SD±11,3%) and the average level of knowledge was 60.4%. The meta-analysis indicated that patient level of knowledge on warfarin therapy was moderately associated with TTR (rs = 0.435; 95% confidence interval (CI) = 0.163-0.645; I2 = 96%). Subgroup analysis indicated association between knowledge level and TTR in studies employing the OAK test (rs = 0.617; 95% CI = 0.192-0.847; I2 = 97%) and the AKA (rs = 0.269; 95% CI = 0.002 to 0.501; I2 = 94%). However, the subgroup analysis presented no significant difference between them (p = 0.14). The meta-regression showed a non-significant negative effect of age on the correlation (estimate = -0.028, 95% CI = -0.073 to 0.016, p = 0.207). No publication bias was noted (p = 0.881). To our knowledge, this is the first systematic review and meta-analysis gathering evidence about the relationship between the level of patient knowledge on oral anticoagulation with warfarin and TTR. The implementation of structured and patient-centered educational interventions is essential to effectively increase the level of patient knowledge and, thus, to improve the quality and safety of warfarin therapy. Systematic review registration number: PROSPERO CRD42023398030.

Construction and Validation of a Protocol Targeting Patients on Oral Anticoagulation with Warfarin

BACKGROUND

Warfarin is an oral anticoagulant that is very useful in preventing thromboembolism, though it is considered a drug with a high risk of causing adverse events. Considering the practical challenges in controlling oral anticoagulation, the patients on warfarin could benefit from educational strategies aimed at behavioral changes, active participation in self-care, and adherence to drug therapy.

OBJECTIVE

The aim was to construct and validate the EmpoderACO protocol for behavioral changes in warfarin patients.

METHODS

The methodological steps were: definition of concepts and domains of self-care, identification of objectives, construction and selection of items, assessment of content validity, and pre-test in the target population.

RESULTS

Relevance, adequacy, clarity, and internal reliability of the instrument's items were assessed by a multidisciplinary judges committee (JC) through the E-surv web platform, obtaining an average agreement of ≥0.91. The understanding of the instrument measured by the target population revealed adequate clarity with a coefficient average of 0.96.

CONCLUSION

EmpoderACO can aid in qualifying the communication process between medical professionals and patients, as well as in improving adherence to both treatment and clinical outcomes, and can be replicated in healthcare settings.

Integrated analysis of clinical and genetic factors on the interindividual variation of warfarin anticoagulation efficacy in clinical practice

AIM

The anticoagulation effect of warfarin is usually evaluated by percentage of time in therapeutic range (PTTR), which is negatively correlated with the risk of warfarin adverse reactions. This study aimed to explore the effects of genetic and nongenetic factors on anticoagulation efficacy of warfarin during different therapeutic range.

METHODS

We conducted an observational retrospective study aiming at evaluating the impact of clinical and genetic factors on PTTR from initial to more than six months treatment. This analysis included patients with heart valve replace (HVR) surgery who underwent long-term or life-long time treatment with standard-dose warfarin for anticoagulation control in Second Xiangya Hospital. All patients were followed for at least 6 months. We genotyped single nucleotide polymorphisms in VKORC1 and CYP2C9 associated with altered warfarin dose requirements and tested their associations with PTTR.

RESULTS

A total of 629 patients with intact clinical data and available genotype data were enrolled in this study, and only 38.63% patients achieved good anticoagulation control (PTTR > 0.6). Clinical factors, including male gender, older age, overweight, AVR surgery and stroke history, were associated with higher PTTR. Patients with VKORC1 -1639AA genotype had significantly higher PTTR level compared with GA/GG genotype carriers only in the first month of treatment. Patients with CYP2C9*3 allele had higher PTTR compared with CYP2C9*1*1 carriers. Moreover, compared with VKORC1 -1639 AG/GG carriers, INR > 4 was more likely to be present in patients with AA genotype. The frequency of CYP2C9*1*3 in patients with INR > 4 was significantly higher than these without INR > 4.

CONCLUSION

We confirmed the relevant factors of warfarin anticoagulation control, including genetic factors (VKORC1 -1639G > A and CYP2C9*3 polymorphisms) and clinical factors (male gender, older age, overweight, AVR surgery and stroke history), which could be helpful to individualize warfarin dosage and improve warfarin anticoagulation control during different treatment period.

Seasonal diet-based resistance to anticoagulant rodenticides in the fossorial water vole (Arvicola amphibius)

Anticoagulant rodenticides (AR) resistance has been defined as "a major loss of efficacy due to the presence of a strain of rodent with a heritable and commensurately reduced sensitivity to the anticoagulant". The mechanism that supports this resistance has been identified as based on mutations in the Vkorc1 gene leading to severe resistance in rats and mice. This study evaluates the validity of this definition in the fossorial water vole and explores the possibility of a non-genetic diet-based resistance in a strict herbivorous rodent species. Genetic support was explored by sequencing the Vkorc1 gene and the diet-based resistance was explored by the dosing of vitamins K in liver of voles according to seasons. From a sample of 300 voles, only 2 coding mutations, G71R and S149I, were detected in the Vkorc1 gene in the heterozygous state with low allele frequencies (0.5-1%). These mutations did not modify the sensitivity to AR, suggesting an absence of genetic Vkorc1-based resistance in the water vole. On the contrary, vitamin K1 was shown to be 5 times more abundant in the liver of the water vole compared to rats. This liver concentration was shown to seasonally vary, with a trough in late winter and a peak in late spring/early summer related to the growth profile of grass. This increase in concentration might be responsible for the increased resistance of water voles to AR. This study highlights a non-genetic, diet-related resistance mechanism in rodents to AR. This diet-based resistance might explain the different evolution of the Vkorc1 gene in the fossorial water vole compared to rats and mice.

Cardiovascular Pharmacogenomics: An Update on Clinical Studies of Antithrombotic Drugs in Brazilian Patients

Anticoagulant and antiplatelet drugs effectively prevent thrombotic events in patients with cardiovascular diseases, ischemic stroke, peripheral vascular diseases, and other thromboembolic diseases. However, genetic and non-genetic factors affect the response to antithrombotic therapy and can increase the risk of adverse events. This narrative review discusses pharmacogenomic studies on antithrombotic drugs commonly prescribed in Brazil. Multiple Brazilian studies assessed the impact of pharmacokinetic (PK) and pharmacodynamic (PD) gene variants on warfarin response. The reduced function alleles CYP2C9*2 and CYP2C9*3, and VKORC1 rs9923231 (c.-1639G>A) are associated with increased sensitivity to warfarin and a low dose requirement to prevent bleeding episodes, whereas CYP4F2 rs2108622 (p.Val433Met) carriers have higher dose requirements (warfarin resistance). These deleterious variants and non-genetic factors (age, gender, body weight, co-administered drugs, food interactions, and others) account for up to 63% of the warfarin dose variability. Few pharmacogenomics studies have explored antiplatelet drugs in Brazilian cohorts, finding associations between CYP2C19*2, PON1 rs662 and ABCC3 rs757421 genotypes and platelet responsiveness or clopidogrel PK in subjects with coronary artery disease (CAD) or acute coronary syndrome (ACS), whereas ITGB3 contributes to aspirin PK but not platelet responsiveness in diabetic patients. Brazilian guidelines on anticoagulants and antiplatelets recommend the use of a platelet aggregation test or genotyping only in selected cases of ACS subjects without ST-segment elevation taking clopidogrel, and also suggest CYP2C9 and VKORC1 genotyping before starting warfarin therapy to assess the risk of bleeding episodes or warfarin resistance.

Genetic Associations With Stable Warfarin Dose Requirements in Han Chinese Patients

ABSTRACT

Warfarin is a commonly prescribed anticoagulant for valvular heart disease that plays an important role in clinical management to prevent thrombotic events. In this study, we aim to perform a comprehensive study to investigate the genetic biomarkers of stable warfarin dose in the Han Chinese population. We performed an integrative study on 211 Han Chinese patients with valvular heart disease. A total of 40 single nucleotide polymorphisms (SNPs) in 10 important genes (CYP2C9, VKORC1, ABCB1, CYP4F2, APOE, PROC, GGCX, EPHX1, CALU, and SETD1A) which are involved in the warfarin metabolic pathway and equilibrium of coagulation and anticoagulation were selected. We applied MassARRAY technology to genotype the 40 SNPs identified in these Han Chinese patients. Our results showed that 13 SNPs on 6 genes (CYP2C9, VKORC1, ABCB1, PROC, EPHX1, and SETD1A) were associated with the individual stable warfarin dose. Two VKORC1 SNPs (rs9934438 and rs2359612) were the strongest genetic factors determining warfarin dose requirements (P = 8 × 10-6 and 9 × 10-6, respectively). Rs4889599 in SETD1A was first reported to be associated with warfarin dose at a significant level of 0.001 in our study (Padjust = 0.040 after Bonferroni correction). We discovered that genetic variants in CYP2C9, VKORC1, ABCB1, PROC, EPHX1, and SETD1A may affect the stable warfarin dose requirement in Han Chinese patients with valvular disease. The discovery of these potential genetic markers will facilitate the development of advanced personalized anticoagulation therapy in Han Chinese patients.

Sex-influence on the time in therapeutic range (TTR) during oral anticoagulation with coumarin derivatives: Systematic review and meta-analysis

AIMS

We sought to investigate the association between sex and oral anticoagulation control employing coumarin derivatives.

METHODS

Electronic sources were MEDLINE, Biblioteca Virtual em Saúde (BVS), The Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE, Cochrane Central and Web of Science. Inclusion criteria were: observational and experimental studies; age ≥18 years; both sexes; treatment with any coumarin derivative for ≥3 months; any indication of long-term use; quality of oral anticoagulation measured by time in therapeutic range (TTR). The meta-analysis was developed with odds ratios (OR) for binary variables and mean differences (MD) for continuous variables, using random-effects models (DerSimonian and Laird) with 95% confidence intervals (CI).

RESULTS

Overall, 22 articles were selected, comprising 16 cohort studies, four cross-sectional studies and two clinical trials. The number of participants ranged from 110 to 104 505 (183 612; women: 45%). The main indication of oral anticoagulation was atrial fibrillation. Most studies reported the use of warfarin. In the meta-analysis, 15 studies were analysed using TTR as a binary variable (OR = 0.87; 95% CI = 0.78, 0.96; z = -2.75; P = .006.; I²  = 67%) and seven studies as a continuous variable (MD = -2.97; 95% CI = -4.80, -1.14; z = -3.19; P = .0014; I²  = 75%). The pooled estimates indicated that women were associated with lower TTR than men.

CONCLUSIONS

Our findings revealed an association between female sex and worse oral anticoagulation control. Further studies are needed with primary design to investigate sex-related factors influencing oral anticoagulation control with coumarin derivatives. Innovative strategies focused on women's health may be useful to improve patient-centred care.