The risk of venous thromboembolism in oral contraceptive users: the role of genetic factors-a prospective cohort study of 240,000 women in the UK Biobank

BACKGROUND

More than 150 million women worldwide use oral contraceptives. Women with inherited thrombophilia and carriers of certain thrombophilia gene variants, such as factor V Leiden and the prothrombin, are at an increased risk for venous thromboembolism, especially when combined with oral contraceptive use. Venous thromboembolism is a complex disorder involving many genetic risk factors, and recently, polygenic risk scores have been proposed to capture a significant proportion of the genetic risk of venous thromboembolism.

OBJECTIVE

The aim of this study was to estimate the risk for developing venous thromboembolism when initiating oral contraceptive use (first 2 years) and during continued use among women with a high genetic liability.

STUDY DESIGN

We used a prospective study design in which 244,420 participants from the UK Biobank were followed from birth. The effect of oral contraceptive use during the first 2 years and in the remaining years of oral contraceptive use on the risk of developing venous thromboembolism was estimated using a Cox regression with a time-dependent exposure variable. Women were stratified according to their polygenic risk scores and whether they were carriers of factor V Leiden and/or prothrombin variants.

RESULTS

When genetic risk was not considered, an increased risk for venous thromboembolism was observed during the first 2 years of oral contraceptive use (hazard ratio, 3.09; 95% confidence interval, 3.00-3.20) but not during continued use (hazard ratio, 0.92; 95% confidence interval, 0.80-1.05). However, when genetic risk was considered, women in the highest polygenic risk score category had a more pronounced risk of developing a venous thromboembolism during the first 2 years of oral contraceptive use (hazard ratio, 6.35; 95% confidence interval, 4.98-8.09), and a high risk was also observed among factor V Leiden (hazard ratio, 5.73; 95% confidence interval, 5.31-6.17) and prothrombin variant carriers (hazard ratio, 5.23; 95% confidence interval, 4.67 - 5.87). A high polygenic risk score in combination with being a factor V Leiden and prothrombin variant carrier conferred the highest risk for developing a venous thromboembolism during the first 2 years of oral contraceptive use (hazard ratio, 14.8; 95% confidence interval, 9.28-23.6). Women with a high genetic liability also had an increased risk during continued use but it was less pronounced, and the highest risk was conferred to carriers of both factor V Leiden and the prothrombin variant (hazard ratio, 4.93; 95% confidence interval, 3.16-7.7).

CONCLUSION

Evaluating polygenic risk can identify additional venous thromboembolism risk that is not captured in the commonly investigated genes for inherited thrombophilia. Our results indicate that oral contraceptive use is associated with an increased risk for developing a venous thromboembolism, particularly among women with a high genetic predisposition, and that oral contraceptive use dramatically increases the risk thereof short after initiation of use, which decreases with continued use. This suggests that the polygenic risk score could be used to identify women who are at high risk for developing a venous thromboembolism and advise them on alternative methods of contraception.

Do we need more guidance on thrombophilia testing? Challenges and special considerations

INTRODUCTION

Thrombophilia testing (TT) is a laboratory procedure designed to detect the risk factors involved in the pathogenesis of vascular occlusions. The role of TT is also controversial because it has a limited impact on the choice and duration of antithrombotic treatments.

AREAS COVERED

We reviewed, by examining MEDLINE up to October 2023. Accepted and not accepted thrombophilia markers are discussed along with the appropriateness or not of prescribing TT in several conditions such as: provoked and unprovoked venous thromboembolism (VTE), women who are planning a pregnancy whose relatives had VTE or have a hereditary thrombophilia, before assumption of estro-progestins, after multiple pregnant loss, arterial thrombosis, retinal vein occlusion, and splanchnic vein thrombosis.

EXPERT OPINION

TT is not essential in the management of VTE, but it may be useful for limiting adverse events in case of thrombophilia. We expose our criticism of items afforded by other guidelines by presenting our opinion based on both the scientific evidence and clinical practice. We also deal with common mistakes in prescribing and interpretations of TT hoping to purpose an educational approach on this topic. Finally, we emphasize the creation of the expert in hemostasis and thrombosis who should be present in every hospital.

Congenital thrombophilia in East-Asian venous thromboembolism population: a systematic review and meta-analysis

Background

Various inherited traits contribute to the overall risk of venous thromboembolism (VTE). In addition, the epidemiology of thrombophilia in the East-Asian VTE population remains unclear; thus, we aimed to assess the proportion of hereditary thrombophilia via a meta-analysis.

Methods

Publications from PubMed, EMBASE, web of science, and Cochrane before December 30, 2022, were searched. Studies from Japan, Korea, China, Hong Kong, Taiwan, Singapore, Thailand, Vietnam, Myanmar, and Cambodia were included. Congenital thrombophilia was described as diseases including protein C (PC) deficiency, protein S (PS) deficiency, antithrombin (AT) deficiency, factor (F)V Leiden (FVL), and prothrombin G20210A mutations. Studies were selected by 2 reviewers for methodological quality analysis. A random-effects model was used for the meta-analysis, assuming that estimated effects in the different studies are not identical.

Results

Forty-four studies involving 6453 patients from 7 counties/regions were included in the meta-analysis. The prevalence of PC, PS, and AT deficiencies were 7.1%, 8.3%, and 3.8%, respectively. Among 2924 patients from 22 studies, 5 patients were carriers of FVL mutation. Among 2196 patients from 10 studies, 2 patients were carriers of prothrombin G20210A mutation in a Thailand study.

Conclusion

The prevalence of PC, PS, and AT deficiencies was relatively high, while a much lower prevalence of FVL and prothrombin G20210A mutations were identified in East-Asian patients with VTE. Our data stress the relative higher prevalence of PC, PS, and AT deficiencies for thrombophilia in the East-Asian VTE population.

Acute Myocardial Infarction in Patients with Hereditary Thrombophilia-A Focus on Factor V Leiden and Prothrombin G20210A

Factor V (FV) Leiden and prothrombin G20210A are the most common hereditary thrombophilias. While their role in venous thromboembolism is well known, there are still uncertainties regarding their relationship with arterial thrombotic events, especially coronary ones. Our research, based on an in-depth analysis of the available literature, provides up-to-date information on the relationship between FV Leiden and prothrombin G20210A and acute myocardial infarction. FV Leiden and prothrombin G20210A screening should be implemented only in select cases, such as acute coronary syndrome in young individuals and/or in the absence of traditional cardiovascular risk factors and/or in the absence of significant coronary artery stenosis at angiography. Their identification should be followed by the implementation of optimal control of modifiable traditional cardiovascular risk factors to reduce the risk of recurrent events and genotyping and genetic counseling of all family members of affected cases for proper prophylaxis. An extended dual antiplatelet therapy (DAPT) may be considered, given the lower risk of bleeding under DAPT conferred by FV Leiden.

Prevalence of positive factor V Leiden and prothrombin mutations in samples tested for thrombophilia in Saudi Arabia

Venous thromboembolism (VTE) is a multifactorial disease that results from the interaction of both inherited and acquired risk factors. The complications of these risk factors often lead to significant morbidity and mortality. There are many inherited thrombophilia risk factors, such as factor V Leiden (FVL) and prothrombin gene mutation (PT). The prevalence of these mutations varies among geographical locations and ethnic groups.

OBJECTIVES

This is a retrospective analysis of laboratory data aimed to estimate the laboratory-based frequency of FVL and PT mutations and assess the concordance between the coagulation assay and FVL molecular test.

METHODS

The study reviewed the frequency of positive blood samples tested by molecular and functional-based techniques. The demographic and laboratory data of patients tested in molecular and coagulation laboratories at the Institute for Thrombophilia were reviewed and analyzed.

RESULTS

A total of 1524 samples were tested for FVL, 1023 for PT, and 1057 for APCR. Results showed that 90 (5.9%) patients were positive for FVL, 30 (2.93%) for PT mutations, and 95 (8.99%) had low APCR, while 38 (3.69%) patients had low APCR with no FVL mutation.

CONCLUSION

This study reports high positive results among patients tested as part of thrombophilia workup or screening for other clinical conditions associated with the increased risk of thrombosis. The limitation of this study was that it had minimal clinical correlation because the data were collected retrospectively from laboratory records.

Association of venous thromboembolism and myocardial infarction with Factor V Leiden and Factor II gene mutations among Libyan patients

Factor V Leiden G1691A (FVL) and Factor II prothrombin G20210A (PGM) mutations are the leading causes of thrombophilia. In this study, we have investigated the prevalence of the FVL G1691A and PGM G20210A single nucleotide polymorphisms (SNPs) among Libyan deep vein thrombosis (DVT) and myocardial infarction (MI) patients. SNP genotyping was performed using high-resolution melt analysis (HRM) and DNA sequencing. Biochemical parameters conducted on 112 males and 93 females showed no significant difference in means between the control group and the deep vein thrombosis and myocardial infarction groups. For Factor V Leiden, 40 samples were genotyped. Of the 40 samples, 6 (15.0%) of them were heterozygous and no one was homozygous. As for Factor II SNP, 59 samples were genotyped and only 2 (3.3%) were heterozygous. All the heterozygous samples showed 100% concordance between the HRM-PCR and DNA sequence analysis. Our study showed, for the first time, that both the FVL and PGM mutations are present among Libyan DVT and MI patients and that the FVL mutation is significantly associated with DVT but not with MI. However, our results do not support the association of PGM G20210A mutation with DVT or MI.

ABO Blood Groups and Thrombophilia Markers in Patients With Unstimulated Thrombosis in Kurdistan Region of Iraq

Thromboembolism (TE) is a complex disease caused by various acquired and inherited factors. The common mutations; factor V Leiden G1691A (FVL G1691A), prothrombin G20210A (PTG20210A), and methylene tetrahydrofolate reductase C677T (MTHFR C677T) are important inherited causes in both venous and arterial thrombosis. The association between ABO blood groups and thrombophilia has been noted by researchers. We aimed to determine the frequency and association of ABO blood groups as a risk factor along with 3 thrombophilia mutations and another 3 thrombophilia markers in a group of patients with unstimulated thrombosis. In a prospective case-control study, we focused on 100 samples, 50 patients with documented thrombosis as well as 50 healthy age-matched controls. Multiplex polymerase chain reaction and reverse hybridization to oligonucleotide particular probes were employed to detect FVL G1691A, PT G20210A, and MTHFR C677T mutations. Analysis of other thrombophilia markers including protein C (PC), protein S (PS), and antithrombin (AT) assays was also performed. ABO blood group typing was done according to standard methods. Non-O blood group was significantly more frequent among cases than controls (76% vs 54%) with high odds of TE (odds ratio [OR] = 2.69). Positivity for at least 1 thrombophilia marker was more in cases (60%) than controls (34%; OR = 2.9). The combined effect of non-O blood group and thrombophilia markers raised the risk of TE (OR = 4.16, P = .001), particularly FVL (OR = 6.76). This study illustrates that harboring the non-O blood group poses an additive effect with other thrombophilia markers in the causation of TE.

Inherited Thrombophilia in a Lebanese Family of Four Generations: A Case Report of Recurrent Miscarriage

Introduction

Factor V Leiden (G1691A), prothrombin (G20210A) and MTHFR (C677T) gene mutations were investigated in many studies for their association with Deep Venous Thrombosis.

Case Presentation

A North Lebanese family has been examined, from an index case, a 40-year-old woman, who had a history of venous thrombosis with unexplained recurrent miscarriage. The index case was found to be heterozygous for factor V Leiden G1691A, prothrombin G20210A, and methylenetetrahydrofolate reductase C677T gene variants. Her family members were heterozygous for at least two of the three-point mutations, and multiple risk factors associated with thrombophilia were identified.

Conclusion

Our findings emphasize the need for clarifying the utility and futility of thrombophilia testing in the era of molecular diagnostics.

Searching for genetic variants associated with thrombophilia

Thrombotic states are inherited or acquired predisposition for thrombosis in the human vascular system. Nowadays Leiden mutation and mutation in prothrombin G20210A contributing to congenital thrombophilia are routinely tested. These mutations have a high prevalence in the population. Congenital deficiencies of protein S, protein C and antithrombin III are rare thrombophilia with lower population frequency, but higher risk of thromboembolic event. The genetic causes are mutations in the genes, which encode these proteins. The choice of proper molecular genetic testing depends on the difference in the detection of well-known single nucleotide polymorphism or unknown/rare variant. For the detection of causative variant FV Leiden and prothrombin G20210A are mostly used PCR-RFLP, reverse Strip Assay®, allele-specific PCR, TaqMan real-time PCR and SNaPshot®. Precise patient selection should precede the genetic testing of rare variants in anticoagulant proteins. It is appropriate to use methodology of massive parallel sequencing supplemented by a methodology for the detection of larger gene rearrangements - MLPA. We are successfully employing this approach in our institute. This methodology is faster with larger analytic capacity compared to commonly used direct sequencing by Sanger method.

Association of retinal vein occlusion, homocysteine, and the thrombophilic mutations in a Turkish population: A case-control study

PURPOSE

To compare homocysteine and thrombophilic mutations for the methylenetetrahydrofolate reductase (MTHFR) C677T, factor V Leiden, and prothrombin G20210A between retinal vein occlusion (RVO) and healthy controls in a Turkish population.

MATERIALS AND METHODS

Forty-nine subjects with RVO were compared for homocysteine status and the MTHFR C677T, prothrombin G20210A, and factor V Leiden mutations with those of 68 healthy controls. Then, the groups were subdivided into two subgroups according to age (less than 50 years old, equal to or more than 50 years old) and were further compared.

RESULTS

Mean plasma level of homocysteine was similar, but the frequency of hyperhomocysteinemia was significantly higher in the RVO group when compared with the control group (22.5% and 8.8%, respectively, p = 0.037). The frequency of all thrombophilic mutations was similar between the groups (p > 0.05). The frequency of all thrombophilic mutations and homocysteine levels was also similar between age subgroups (p > 0.05). Only hyperhomocysteinemia was significantly different between subgroups (p = 0.037); the frequency of hyperhomocysteinemia was significantly different in RVO patients less than 50 years old (22.7%) from that in healthy controls less than 50 years old (11.1%). Two RVO patients (4.1%) with bilateral involvement had MTHFR C677T mutation.

CONCLUSIONS

Screening for thrombophilic mutations such as MTHFR C677T, factor V Leiden, and prothrombin G20210A in RVO patients at all ages seems to be unnecessary and not cost-effective. However, thrombophilic disorders should be screened selectively, focusing on young individuals, especially with bilateral involvement, without additional cardiovascular risk factors, or a family history of thrombosis.

Seeing through thick and through thin: Retinal manifestations of thrombophilic and hyperviscosity syndromes

The presence of retinal vasculopathy in the absence of typical predisposing factors should suggest a possible underlying hematologic abnormality. In such cases, a systemic investigation may reveal a potentially fatal hypercoagulability or hyperviscosity syndrome. Retinal vein occlusion is the most commonly encountered ophthalmic finding in such syndromes; however, abnormalities of the arterial system, the choroid, and the macula are also possible. Visual symptoms may be the only manifestation of the underlying process, making timely diagnosis by the ophthalmologist critical for both treatment and thrombotic prophylaxis. Moreover, as newer ophthalmic diagnostic technologies arise, there is an increasingly important role for eye physicians in the management of such syndromes.

A Multiplex Allele Specific Polymerase Chain Reaction (MAS-PCR) for the Detection of Factor V Leiden and Prothrombin G20210A

INTRODUCTION

In order to determine the frequencies of factor V Leiden and prothrombin G20210A point mutations in the Iranian population with Azeri Turkish origin.

MATERIAL AND METHODS

120 unrelated individuals from general population randomly selected and were examined for factor V Leiden and prothrombin G20210A mutations using a multiplex allele specific polymerase chain reaction (MAS-PCR) assayOutcomes: The frequency of prothrombin G20210A mutation was 2.08%, which means 5 chromosomes out of 240 chromosomes had prothrombin G20210A mutation. The distribution of prothrombin 20210 GG, GA, AA genotypes and prothrombin 20210A allele were 37(92.5%), 3(7.5%), 0(0%) and 3(3.75%) in males and 78(97.5%), 2(2.5%), 0(0%) and 2(1.25%) in females, respectively. Factor V Leiden was not found in our tested group (zero chromosomes out of 240 chromosomes). Analysis of the observed frequencies in the studied groups indicates that there is no statistically significant difference between females and males, regarding prothrombin G20210A mutation (p value>0.05).

CONCLUSIONS

This is the first study in its own kind in this population and implies that the frequency of Factor V Leiden G1691A (R506Q, FV-Leiden) allele is extremely low but the prothrombin G20210A mutation is more frequent in the tested group.

Is thrombophilia a major risk factor for deep vein thrombosis of the lower extremities among Lebanese patients?

Aim

Factor V Leiden (R506Q) mutation is the most commonly observed inherited genetic abnormality related to vein thrombosis. Lebanon has one of the highest frequencies of this mutation in the world with a prevalence of 14.4% in the general population. The aim of this study is to define risk factors including inherited genetic abnormalities among Lebanese patients with lower extremity deep vein thrombosis. We report the clinical outcome of patients with thrombophilia.

Methods

From January 1998 to January 2008, 162 patients (61 males and 101 females) were diagnosed with lower extremity deep vein thrombosis. Mean age was 61 years (range: 21 to 95 years).

Results

The most frequent risk factors for vein thrombosis were surgery, advanced age, obesity, and cancer. Twenty-five patients had thrombophilia, 16 patients had factor V Leiden (R506Q) mutation, and seven patients had MTHFR C677T mutation. Ninety-two percent of patients screened for thrombophilia were positive. Screening was requested in young patients (16), patients with recurrent (11), spontaneous (8), and extensive (5) venous thrombosis, familial history (5), pregnancy (4), estroprogestative treatment (3), and air travel (1). Nine patients had one, 11 patients had two, and five had three of these conditions. Follow-up (6 to 120 months) of these 25 patients treated with antivitamin K did not reveal recurrences or complications related to venous thromboembolism.

Conclusion

Factor V Leiden mutation followed by MTHFR mutation are the most commonly observed genetic abnormalities in these series. Defining risk factors and screening for thrombophilia when indicated reduce recurrence rate and complications. Recommendations for thrombophilia screening will be proposed.