Interrelation of hyperhomocysteinemia and inherited risk factors for venous thromboembolism. Results from the E.D.I.TH. study: a hospital-based case-control study

Risk of venous thromboembolism in association with factor V leiden in cancer patients - The EDITH case-control study

Background

Cancer and factor V Leiden mutation are both risk factors for venous thromboembolism (VTE). Cancer critically increases the thrombotic risk whereas Factor V Leiden is the most common pro-thrombotic mutation. The impact of the factor V Leiden on the risk of VTE in cancer patients remains uncertain.

Objective

To assess the impact of factor V Leiden mutation in cancer-associated thrombosis.

Methods

The EDITH hospital-based case-control study enrolled 182 patients with cancer and VTE as well as 182 control patients with cancer, matched for gender, age and cancer location, between 2000 and 2012, in the University Hospital of Brest. All cases and controls were genotyped for the factor V Leiden mutation and interviewed with a standardized questionnaire.

Results

Twenty one of 182 (11.5%) patients with cancer-associated thrombosis carried the factor V Leiden mutation and 4 of 182 (2.2%) controls with cancer but no venous thrombosis. In multivariate analysis including cancer stage and family history of VTE, cancer patients with factor V Leiden mutation had a seven-fold increased risk of venous thromboembolism (adjusted odds ratio [OR], 7.04; 95% CI, 2.01–24.63).

Conclusion

The pro-thrombotic Factor V Leiden mutation was found to be an independent additional risk factor for venous thromboembolism in cancer patients and might therefore be considered in the individual thrombotic risk assessment.

Risk of venous thromboembolism associated with single and combined effects of Factor V Leiden, Prothrombin 20210A and Methylenetethraydrofolate reductase C677T: a meta-analysis involving over 11,000 cases and 21,000 controls

Genetic and environmental factors interact in determining the risk of venous thromboembolism (VTE). The risk associated with the polymorphic variants G1691A of factor V (Factor V Leiden, FVL), G20210A of prothrombin (PT20210A) and C677T of methylentetrahydrofolate reductase (C677T MTHFR) genes has been investigated in many studies. We performed a pooled analysis of case-control and cohort studies investigating in adults the association between each variant and VTE, published on Pubmed, Embase or Google through January 2010. Authors of eligible papers, were invited to provide all available individual data for the pooling. The Odds Ratio (OR) for first VTE associated with each variant, individually and combined with the others, were calculated with a random effect model, in heterozygotes and homozygotes (dominant model for FVL and PT20210A; recessive for C677T MTHFR). We analysed 31 databases, including 11,239 cases and 21,521 controls. No significant association with VTE was found for homozygous C677T MTHFR (OR: 1.38; 95 % confidence intervals [CI]: 0.98-1.93), whereas the risk was increased in carriers of either heterozygous FVL or PT20210 (OR = 4.22; 95 % CI: 3.35-5.32; and OR = 2.79;95 % CI: 2.25-3.46, respectively), in double heterozygotes (OR = 3.42; 95 %CI 1.64-7.13), and in homozygous FVL or PT20210A (OR = 11.45; 95 %CI: 6.79-19.29; and OR: 6.74 (CI 95 % 2.19-20.72), respectively). The stratified analyses showed a stronger effect of FVL on individuals ≤ 45 years (p value for interaction = 0.036) and of PT20210A in women using oral contraceptives (p-value for interaction = 0.045). In this large pooled analysis, inclusive of large studies like MEGA, no effect was found for C677T MTHFR on VTE; FVL and PT20210A were confirmed to be moderate risk factors. Notably, double carriers of the two genetic variants produced an impact on VTE risk significantly increased but weaker than previously thought.

Risk of venous thromboembolism during treatment with antipsychotic agents

The evidence to date on the relation between the risk of venous thromboembolic disease (VTE) and antipsychotic agents derives primarily from observational and case history studies. While an increased risk of VTE has been associated with first-generation low-potency antipsychotic agents, particularly clozapine, there appears to be a growing number of reports on the occurrence of this adverse reaction during the use of second-generation antipsychotics, such as risperidone and olanzapine. The highest risk of pathological blood clotting emerges during the first 3 months after initiation of treatment with the product. Potential etiopathogenetic factors leading to VTE during treatment with antipsychotic agents include sedation, obesity, elevation of antiphospholipid antibodies, increased platelet activation and aggregation, hyperhomocysteinemia, and hyperprolactinemia. Diagnoses of schizophrenia and/or bipolar affective disorder, as well as hospitalization or stress with sympathetic activation and elevation of catecholamine levels, have been reported as known prothrombogenic factors. The present article contains the new version of the guideline for the prevention of VTE in psychiatric patients with limited mobility. Further prospective studies are necessary to elucidate the biological mechanisms of the relations between antipsychotic agents and VTE.

Vitamin K epoxide reductase genetic polymorphism is associated with venous thromboembolism: results from the EDITH Study

BACKGROUND

The vitamin K epoxide reductase complex subunit 1 (VKORC1) recycles endogenous vitamin K, a cofactor for vitamin K-dependent coagulation factor synthesis. Common polymorphisms in VKORC1, the gene coding for VKORC1, have been found to affect the dose response to vitamin K antagonists, and to confer an increased risk of vascular diseases in a Chinese population. The aim of this study was to evaluate the association between the VKORC1 1173C > T polymorphism and venous thromboembolism (VTE).

METHODS

We report the results of a case-control study designed to evaluate interactions between acquired and inherited risk factors of VTE. We studied 439 cases hospitalized with a first venous thromboembolic event that was not related to a major acquired risk factor for VTE, and 439 matched controls. The VKORC1 1173C > T polymorphism was selected for genotyping as the tagging single-nucleotide polymorphism for previously identified VKORC1 haplotypes.

RESULTS

The relationship between VTE and the VKORCI 1173C > T polymorphism was consistent with a recessive model. The frequency of the VKORCI TT genotype was lower in cases than in controls. The odds ratio (OR) (95% CI) was 0.62 (0.41-0.94) for the TT genotype as compared to CT/CC genotypes. Adjustment on cardiovascular diseases, body mass index, factor V (FV) and prothrombin gene mutations did not alter the results.

CONCLUSIONS

In this case-control study, the frequency of the VKORCI TT genotype was lower in patients with VTE than in matched controls. The clinical consequence of these results remains to be determined, but gives new perspectives for exploration of the role of VKORCI polymorphism in the pathogenesis of VTE.