Self-reported family history in estimating the risk of hormone, surgery and cast related VTE in women

Oral contraceptives and hormone replacement therapy: How strong a risk factor for venous thromboembolism?

Exogenous hormone therapies, such as combined oral contraceptives (COC) and hormone replacement therapy (HRT), cause blood hypercoagulability and are a risk factor for venous thromboembolism (VTE). There is controversy on how strong this "provoking" risk factor is, and how other risk factors may synergise VTE risk. We aim to review the latest literature on the risk of initial and recurrent VTE with COC and HRT use to provide guidance for decision-making about duration of anticoagulation, and guide future research efforts.

Venous thromboembolism in women: new challenges for an old disease

In countries that have controlled classic causes of maternal death, such as eclampsia and hemorrhage, venous thromboembolism (VTE) has become the major concern. Prevention of VTE during pregnancy and postpartum by applying guidelines and implementing pharmacoprophylaxis is still the best strategy to reduce occurrence of this complication. Hormonal contraceptives and hormone replacement therapy also increase the risk of VTE, but women cannot be deprived of their benefits, which increase their freedom at childbearing age and reduce their symptoms at menopause. Both indiscriminate use and unmotivated prohibition are inappropriate. Contraceptive and hormone replacement methods should be chosen with care, evaluating the patients’ contraindications, eligibility criteria, and autonomy. This article presents a nonsystematic review of recent literature with the aim of evaluating and summarizing the associations between VTE and clinical situations peculiar to women.

Preventing venous thromboembolism during pregnancy and postpartum: crossing the threshold

When should a patient with a known thrombophilia or prior venous thromboembolism (VTE) receive low-molecular-weight heparin (LMWH) prophylaxis during pregnancy and/or the postpartum period? Accurately predicting thrombotic and bleeding risks and knowing what to do with this information is at the heart of decision-making in these challenging scenarios. This article will explore the concept of a risk threshold from clinician and patient perspectives and provide guidance for the use of antepartum and postpartum LMWH prophylaxis in women with a known thrombophilia or prior VTE. Advice for the management of LMWH prophylaxis use around labor and delivery is also reviewed.

Family history of venous thromboembolism as a risk factor and genetic research tool

Familial clustering of venous thromboembolism (VTE) was described as far back as 1905 by Briggs. Although Egeberg discovered inherited deficiency of antithrombin in 1965, it was not until Dahlback discovered resistance to activated protein C in 1993 that it became clear that genetic factors are common risk factors of VTE. Several genes have been linked to familial aggregation of VTE and genome-wide association studies have found several novel gene loci. Still, it has been estimated that much of the heritability for VTE remains to be discovered. Family history (FH) of VTE is therefore still important to determine whether a patient has an increased genetic risk of VTE. FH has the potential to represent the sum of effects and interactions between environmental and genetic factors. In this article the design, methodology, results, clinical and genetic implications of FH studies of VTE are reviewed. FH in first-degree relatives (siblings and/or parents) is associated with a 2–3 times increased familial relative risk (FRR). However, the FRR is dependent on age, number of affected relatives, and presentation of VTE (provoked/unprovoked). Especially high familial risks are observed in individuals with two or more affected siblings (FFR> 50). However, the familial risk for recurrent VTE is much lower or non-significant. Moreover, FH of VTE appears mainly to be important for venous diseases (i. e. VTE and varicose veins). The familial associations with other diseases are weaker. In conclusion, FH of VTE is an important research tool and a clinically potential useful risk factor for VTE.

Familial Clustering of Venous Thromboembolism - A Danish Nationwide Cohort Study

BACKGROUND

Identification of risk factors for venous thromboembolism (VTE) is of utmost importance to improve current prophylactic regimes and treatment guidelines. The extent to which a family history contributes to the risk of VTE needs further exploration.

OBJECTIVES

To examine the relative rate of VTE in first-degree relatives compared with the general population.

METHODS

By crosslinking Danish nationwide registries we identified patients with VTE between 1978 and 2012, and their familial relations. The first member in a family to acquire VTE was defined as the proband. All first-degree relatives to probands were followed from the VTE date of the proband and until an event (VTE), death, emigration, 100 year birthday or end of study: 31st of December 2012, whichever came first. The relative rate of VTE was estimated by standardized incidence ratios (SIR) using time-dependent Poisson regression models, with the general population as a fixed reference.

RESULTS

We identified 70,767 children of maternal probands, 66,065 children of paternal probands, and 29,183 siblings to sibling probands. Having a maternal proband or a paternal proband were associated with a significantly increased VTE rate of 2.15 (CI: 2.00-2.30) and 2.06 (CI: 1.92-2.21), respectively. The highest estimate of VTE was observed among siblings (adjusted SIR of 2.60 [CI: 2.38-2.83]). Noteworthy, the rate of VTE increased for all first-degree relatives when the proband was diagnosed with VTE in a young age (≤ 50 years).

CONCLUSION

A family history of VTE was associated with a significantly increased rate of VTE among first-degree relatives compared with the general population.

Family history of venous thromboembolism is a risk factor for venous thromboembolism in combined oral contraceptive users: a nationwide case-control study

BACKGROUND

The aim was to assess the risk of venous thromboembolism (VTE) associated with use of combined oral contraceptives (COCs) in women with a family history of VTE.

METHODS

The study is a Swedish nationwide case-control study based on the Multigeneration register, the Swedish Hospital Discharge Register, the Outpatient Care Register, and the Swedish Prescribed Drug Register. Cases (n = 2,311) were non-pregnant Swedish women aged 15-49 with first VTE diagnoses between January 2006 and December 2010. Five controls without VTE were matched to each case on age and education level. Conditional logistic regression examined the associations with VTE with determination of odds ratio (OR) for first VTE diagnosis. Effect modification was assessed by interaction testing.

RESULTS

Both among controls (14.6 % vs. 4.5 %; p < 0.0001) and cases (27.2 % vs. 8.8 %; p < 0.0001) COC use was more common in women without a family history of VTE compared with women with a family history of VTE. In a multivariate conditional logistic regression model the OR for VTE was 2.53 (95 % CI 2.23-2.87) for COC users and 2.38 (2.09-2.71) for individuals with a family history of VTE. The OR for VTE for COC users with a family history of VTE was 6.02 (5.02-7.22). There was no significant interaction between family history of VTE and COC use (OR 0.92, 0.57-1.46).

CONCLUSIONS

Family history of VTE is a risk factor for VTE in women using COCs. The low prevalence of COC use among women with a family history of VTE suggests that family history of VTE is considered when COCs are prescribed in Sweden. The present study may therefore even underestimate the importance of family history of VTE. The lack of interaction indicates that the risk of COC use in women with family history of VTE is determined by the product of the ORs for family history and COC use.

Risk factors for venous thromboembolism in women under combined oral contraceptive. The PILl Genetic RIsk Monitoring (PILGRIM) Study

Identifying women at risk of venous thromboembolism (VTE) is a major public health issue. The objective of this study was to identify environmental and genetic determinants of VTE risk in a large sample of women under combined oral contraceptives (COC). A total of 968 women who had had one event of VTE during COC use were compared to 874 women under COC but with no personal history of VTE. Clinical data were collected and a systematic thrombophilia screening was performed together with ABO blood group assessment. After adjusting for age, family history, and type and duration of COC use, main environmental determinants of VTE were smoking (odds ratio [OR] =1.65, 95% confidence interval [1.30-2.10]) and a body mass index higher than 35 kg.m⁻² (OR=3.46 [1.81-7.03]). In addition, severe inherited thrombophilia (OR=2.13 [1.32-3.51]) and non-O blood groups (OR=1.98 [1.57-2.49]) were strong genetic risk factors for VTE. Family history poorly predicted thrombophilia as its prevalence was similar in patients with or without first degree family history of VTE (29.3% vs 23.9%, p=0.09). In conclusion, this study confirms the influence of smoking and obesity and shows for the first time the impact of ABO blood group on the risk of VTE in women under COC. It also confirms the inaccuracy of the family history of VTE to detect inherited thrombophilia.