Hormonal factors and risk of recurrent venous thrombosis: the prevention of recurrent venous thromboembolism trial

Inconsistency in UK Biobank Event Definitions From Different Data Sources and Its Impact on Bias and Generalizability: A Case Study of Venous Thromboembolism

The UK Biobank study contains several sources of diagnostic data, including hospital inpatient data and data on self-reported conditions for approximately 500,000 participants and primary-care data for approximately 177,000 participants (35%). Epidemiologic investigations require a primary disease definition, but whether to combine data sources to maximize statistical power or focus on only 1 source to ensure a consistent outcome is not clear. The consistency of disease definitions was investigated for venous thromboembolism (VTE) by evaluating overlap when defining cases from 3 sources: hospital inpatient data, primary-care reports, and self-reported questionnaires. VTE cases showed little overlap between data sources, with only 6% of reported events for persons with primary-care data being identified by all 3 sources (hospital, primary-care, and self-reports), while 71% appeared in only 1 source. Deep vein thrombosis-only events represented 68% of self-reported VTE cases and 36% of hospital-reported VTE cases, while pulmonary embolism-only events represented 20% of self-reported VTE cases and 50% of hospital-reported VTE cases. Additionally, different distributions of sociodemographic characteristics were observed; for example, patients in 46% of hospital-reported VTE cases were female, compared with 58% of self-reported VTE cases. These results illustrate how seemingly neutral decisions taken to improve data quality can affect the representativeness of a data set.

Recurrence after stopping anticoagulants in women with combined oral contraceptive-associated venous thromboembolism: A systematic review and meta-analysis

The risk of recurrence after discontinuation of anticoagulation for a combined oral contraceptive (COC)-associated venous thromboembolism (VTE) is unclear. Therefore, we conducted a systematic review and meta-analysis to estimate the incidence of recurrent VTE among women with COC-associated VTE, unprovoked VTE and to compare the incidence of recurrent VTE between the two groups. The Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Embase Classic +Embase and Medline ALL to July 2020 and citations from included studies were searched. Randomized controlled trials, prospective cohort studies and meta-analyses of these study types were selected. The analysis was conducted by random-effects model. Nineteen studies were identified including 1537 women [5828 person-years (PY)] with COC-associated VTE and 1974 women (7798 PY) with unprovoked VTE. Studies were at low risk of bias. The incidence rate of VTE recurrence was 1.22/100 PY [95% confidence interval (CI) 0.92-1.62, I²  = 6%] in women with COC-associated VTE, 3.89/100 PY (95% CI 2.93-5.17, I²  = 74%) in women with unprovoked VTE and the unadjusted incidence rate ratio was 0.34 (95% CI 0.26-0.46, I²  = 3%). The recurrence risk in women after COC-associated VTE is low and lower than after an unprovoked VTE.

Factors affecting the recurrence in patients with venous thromboembolism: A retrospective cohort study

Background

The aim of the study was to evaluate the frequency of recurrence and the risk factors for recurrence in patients who were diagnosed with venous thromboembolism.

Methods

Between January 2005 and January 2015, a total of 412 venous thromboembolism patients (164 males, 248 females; mean age: 53.5±16.6 years; range: 19 to 95 years) were retrospectively analyzed. The demographics, underlying risk factors, comorbidities, imaging findings, and treatment data of the patients were recorded.

Results

At least one transient/permanent risk factor was found in 341 (82.7%) of the index events, and the other 71 (17.2%) were idiopathic. Recurrence developed in 76 (18.4%) of the patients. The duration of the treatment in the first event was significantly longer in recurrent cases (p=0.007). The recurrence rate in patients diagnosed with only deep vein thrombosis or patients diagnosed with pulmonary thromboembolism + deep vein thrombosis was significantly higher than the patients diagnosed with only pulmonary thromboembolism (24% vs. 14.2%, respectively; p=0.007). The rate of idiopathic venous thromboembolism was higher in recurrent cases than in non-recurrent cases (26.3% vs. 15.2%, respectively; p=0.028). At the end of the first year, the mean D-dimer levels were higher in recurrent cases (p=0.034). Hereditary risk factors were also higher in recurrent cases (39.5% vs. 19.3%, respectively; p=0.031). There was no significant correlation between recurrence and mortality.

Conclusion

The presence of deep vein thrombosis, idiopathic events, high D-dimer levels at the end of the first year and hereditary risk factors seem to be associated with recurrence.

Sex-specific differences in the presentation, clinical course, and quality of life of patients with acute venous thromboembolism according to baseline risk factors. Insights from the PREFER in VTE

INTRODUCTION

Sex and the presence of specific provoking risk factors, along with age, influence the presentation and prognosis of venous thromboembolism (VTE). We investigated the presentation, course and quality of life in women and men with acute VTE classified according to their VTE provoking factors.

METHODS

PREFER in VTE is an international, non-interventional registry of patients with a first episode of acute symptomatic VTE. Baseline provoking factors were classified as follows: major transient, minor transient, active cancer, and none identifiable. The primary outcome was recurrent VTE. Quality of life and treatment satisfaction were secondary outcomes.

RESULTS

Of 3,455 patients with acute VTE, 1,623 (47%) were women. The mean age at the time of VTE was 61 (SD 18) in women, 60 (SD 15) in men. The distribution of provoking risk factors was similar between sexes, despite a tendency for higher frequency of minor and major transient risk factors in women, and cancer or unprovoked VTE in men. At 12-month follow-up, VTE recurrence was reported in 74 (6.5%) women and 80 (6.4%) men (absolute risk difference -0.1%, 95% CI -1.9%; +2.1%). In patients with unprovoked VTE, the VTE recurrence rate was 38/612 (6.2%) in women and 53/798 (6.6%) in men (absolute risk difference -0.4, 95% CI -3.0; +2.1%). Multivariable Cox regressions confirmed the absence of sex differences. Quality of life and treatment satisfaction scores one year after VTE were lower in women than in men irrespective of the provoking risk factors (p<0.001 for both scores).

CONCLUSIONS

Despite differences in the provoking risk factors for VTE, women and men had a similar rate VTE recurrence at one year. After acute VTE, women had lower quality of life and treatment satisfaction scores.

Which patients are at high risk of recurrent venous thromboembolism (deep vein thrombosis and pulmonary embolism)?

Recurrent venous thromboembolism (VTE, or deep vein thrombosis and pulmonary embolism) is associated with mortality and long-term morbidity. The circumstances in which an index VTE event occurred are crucial when personalized VTE recurrence risk is assessed. Patients who experience a VTE event in the setting of a transient major risk factor (such as surgery associated with general anesthesia for >30 minutes) are predicted to have a low VTE recurrence risk following discontinuation of anticoagulation, and limited-duration anticoagulation is generally recommended. In contrast, those patients whose VTE event occurred in the absence of risk factors or who have persistent risk factors have a higher VTE recurrence risk. Here, we review the literature surrounding VTE recurrence risk in a range of clinical conditions. We describe gender-specific risks, including VTE recurrence risk following hormone- and pregnancy-associated VTE events. Finally, we discuss how the competing impacts of VTE recurrence and bleeding have shaped international guideline recommendations.

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.

Which orally administered antithrombotic agent is most effective for preventing venous thromboembolism after total knee arthroplasty? A propensity score-matching analysis

Purpose

Even today, total knee arthroplasty (TKA) is associated with venous thromboembolism (VTE). The purpose of our study is to report the incidence of postoperative VTE and to compare the efficacy of commonly used orally administered antithrombotic agents.

Materials and methods

Seven hundred ad ninety-nine patients who underwent primary TKA were retrospectively reviewed. The patients were prescribed one of three antithrombotic agents: aspirin (n = 168), rivaroxaban (n = 117), or apixaban (n = 514). Before surgery, patient demographics and risk factors were matched via propensity scoring. After surgery, all three groups took the agent for 7 days and underwent ultrasonography to check for VTE.

Results

The overall incidence of postoperative VTE was 15.4% (123/799). Only one patient developed symptomatic VTE. Female sex and staged bilateral TKA were risk factors for postoperative VTE. The postoperative VTE rates in the aspirin, rivaroxaban, and apixaban groups were 16.2%, 6.0%, and 17.1%, respectively, significantly lower in the rivaroxaban group (p <  0.02). The majority of VTEs in all three groups were calf-vein thromboses.

Conclusions

All agents showed enough efficacy as antithrombotic agents. Considering that aspirin is inexpensive, aspirin is a cost-effective option for preventing postoperative VTE.

Long-term recurrence risk after a first venous thromboembolism in men and women under 50 years old: A French prospective cohort

BACKGROUND

Data on long-term venous thromboembolism (VTE) recurrence risk according to gender are conflicting.

OBJECTIVE

To evaluate long-term VTE recurrence risk after a first VTE in men and women under 50 years old.

METHODS

Since May 2000, 875 consecutive patients (315 men, 560 women) with a first symptomatic VTE under 50 years old were enrolled in a French prospective multicentre cohort study and were followed up as long as possible. The primary outcome was symptomatic recurrent VTE during follow-up.

RESULTS

At baseline, men were older and had more comorbidities than women. First VTE was mainly unprovoked in men (80.6%) and hormone-related in women (84.3%). During a median follow-up of 7.0 years (inter-quartile range, 5.0-11.0), recurrent VTE occurred in 97 men (30.8%) and in 72 women (12.9%) (annual incidence rates of recurrent VTE of 4.8% versus 1.8%-person-years, P<0.001). However, there was no difference according to gender in subgroups of patients with a first unprovoked VTE (5.8% versus 3.8%-person-years, P = 0.09). In women, duration of hormonal treatment before first VTE did not influence recurrence risk. In multivariable analysis, unprovoked VTE and family history of VTE were independently associated with recurrence (hazard ratio of 2.50 (95% confidence interval, 1.61 to 3.85) and 1.52 (1.11 to 2.09) respectively).

LIMITATIONS

Number of women with unprovoked VTE was low.

CONCLUSIONS

In patients with a first VTE under 50 years old, a first unprovoked episode and a family history of VTE, but not gender, were associated with a high risk of long-term recurrence.

Risk of Recurrent Venous Thromboembolism After an Initial Episode: Risk Stratification and Implications for Long-term Treatment

PURPOSE OF REVIEW

Venous thromboembolism (VTE) is a common condition with significant associated morbidity and mortality. Recurrent VTE after an initial episode is a preventable medical condition. The following review discusses data supporting recurrence risk estimates after an initial VTE episode as well as treatment strategies to mitigate risk of recurrent VTE.

RECENT FINDINGS

This review particularly highlights methods for stratifying the risk of recurrent VTE and recent studies that have evaluated direct oral anticoagulants for the prevention of recurrent VTE. Risk assessment for VTE recurrence should guide anticoagulation duration. In patients who present with unprovoked VTE events, there remains a high risk of recurrence that is significantly mitigated with extended duration anticoagulation with either a vitamin K antagonist or direct oral anticoagulant.

Sex, gender and venous thromboembolism: do we care enough?

: The role of sex and gender in determining clinical presentation, diagnostic approach and outcomes of venous thromboembolism is not fully and systematically addressed, except for hormone-related events in women. A lack of knowledge is also apparent regarding drug prescription patterns, physician bias, enrolment in clinical studies and analysis of sex-related confounders in preclinical and clinical studies. As was shown for cardiovascular disease, ignoring sex and gender in medicine can have important impact on outcomes, including mortality. In this review, we seek to address some aspects of venous thromboembolism such as epidemiology and clinical presentation, recurrence, risk factors, animal studies, safety and efficacy of antithrombotic drugs, highlighting what is known and what is not regarding the role of sex and gender, and hoping to focus some interest and to promote the inclusion of these variables in all future studies on venous thromboembolism.

Comparative efficacy and safety of low-intensity warfarin therapy in preventing unprovoked recurrent venous thromboembolism: A systematic review and meta-analysis

BACKGROUND

Although there exists potential risk of bleeding, extended 'lifelong' conventional-intensity [international normalized ratio (INR): 2.0-3.0] warfarin anticoagulation is recommended for unprovoked venous thromboembolism (VTE) patients because of risk of recurrent VTE. Whether long-term low-intensity (INR: 1.5-2.0) warfarin therapy reduced the risk of major bleeding without substantially lowered antithrombotic efficacy is not well understood. The aim of this study was to perform a systematic review and meta-analysis to evaluate the risk-benefits of low-intensity warfarin therapy.

METHODS

We conducted a comprehensive search of electronic databases and included randomized control trials (RCTs) that reported efficacy (recurrent VTE) and safety (bleeding episodes) of low-intensity warfarin therapy compared with conventional-intensity warfarin or placebo from inception through Jun 2016.

RESULTS

Four RCTs reporting high GRADE quality evidence were included. Although the relative risk of recurrent VTE with low-intensity therapy was significantly increased [2.96 (95% CI: 1.40 to 6.24), P < .004] compared to conventional-intensity warfarin, there was significant decrease of relative risk when compared with placebo [0.37 (95% CI: 0.24 to 0.56), P < .00001]. As per included publications, no significant major bleeding episodes were observed in low-intensity warfarin group.

CONCLUSIONS

Although less effective than conventional-intensity warfarin therapy this meta-analysis indicates that long-term low-intensity warfarin therapy is highly effective for preventing recurrent VTE than placebo, along with reduced risks of major bleeding and minimizing potential complications.

Antipsychotic drugs and the risk of recurrent venous thromboembolism: A prospective cohort study

BACKGROUND

Numerous studies have suggested that antipsychotic drugs are associated with an increased risk for a first episode of venous thromboembolism (VTE). However, after anticoagulation discontinuation, the impact of antipsychotic drugs on the risk of recurrent VTE (rVTE) remains unknown.

OBJECTIVE

To estimate the risk of rVTE in association with antipsychotic drugs.

METHODS

Between May 2000 and December 2012, we included all consecutive patients with a first unprovoked symptomatic VTE and who discontinued anticoagulation. During follow-up, exposure to antipsychotic drugs was systematically assessed.

RESULTS

A total of 736 patients with a first unprovoked symptomatic VTE were followed-up during a median period of 27.0 months (interquartile range (IQR) 6.2-60.0). Patients' median age was 66.0 years (IQR 49.0-76.0), 404 (54.9%) were men, and 61 (8.3%) were exposed to antipsychotics during follow-up. The incidence rate of r VTE was 12.1% person-year (95% CI 7.2-20.5) in antipsychotics users compared with 8.3% person-year (95% CI 7.1-9.8) in non-users (p = 0.20). Multivariate analysis showed a significant increased risk of recurrence associated with antipsychotic exposure (adjusted hazard ratio 1.9, 95% CI 1.1-3.3).

CONCLUSIONS

In this cohort study, exposure to antipsychotic drugs was found to be associated with an increased risk of rVTE among patients with a previous first unprovoked symptomatic VTE and who discontinued anticoagulation. Larger studies are needed to confirm and further explore this association.

Predicting the risk of recurrent venous thromboembolism

Venous thromboembolism (VTE) is a disease, which often recurs. The recurrence risk is highest in patients with unprovoked proximal deep-vein thrombosis (VT) or pulmonary embolism. Men have a higher risk than women. The risk is low in patients with VTE related to a temporary risk factor such as surgery or estrogen use. Other risk factors include overweight, post-thrombotic syndrome, history of VTE, residual VT or a vena cava filter.

Both factor V Leiden and the prothrombin mutation confer a negligible increase in recurrence risk. High clotting factor levels, deficiency of a natural coagulation inhibitor, or hyperhomocysteinaemia are also associated with an increased risk. Reasons why routine laboratory thrombophilia screening however is no longer warranted are addressed in this article. Prediction rules combining clinical characteristics and coagulation assays have recently been developed. One such model, the Vienna Prediction Model, allows predicting recurrent VTE on the basis of VTE location, sex and D-dimer. This article describes strategies to distinguish between patients with high risk of recurrent VTE from those with a lower risk, who might not benefit from long-term antithrombotic therapy.

First venous thromboembolism and hormonal contraceptives in young French women

Information on the clinical and biological characteristics of combined hormonal contraceptives (CHC) users experiencing a venous thromboembolism (VTE) event is scarce. Better knowledge of factors determining the VTE risk in CHC users could help identify women at high risk.Data were obtained from a large cohort of consecutive women with the first documented VTE event. Cross-sectional analysis of clinical and biological characteristics of the women was performed.Of the 3009 women with the first VTE included, 31% were nonusers and 69% CHC users at time of VTE. CHC users were significantly younger (29.0 ± 7.2) than nonusers (31.6 ± 7.1) (P < .001). No difference in VTE familial history was observed between the 2 groups. Compared with nonusers, the CHC users experienced more frequently pulmonary embolism: odds ratio (OR) = 1.28 (1.06-1.55; 95% confidence interval [CI]), factor V Leiden mutations were more frequent in this group (OR = 1.41 [1.11-1.80; 95% CI]). Venous sclerotherapy and travel were associated with VTE in CHC users, whereas surgery and bed rest were significantly associated with VTE in nonusers. Finally, 2/3 of CHC users with VTE had additional VTE risk factors.CHC users experiencing the first VTE differ from nonusers with respect to clinical and genetic background. Better understanding of the characteristics of VTE and associated risk factors could allow more appropriate management of these women and contribute to more accurate benefit-risk assessment before prescribing a CHC.

Guidance for the treatment of deep vein thrombosis and pulmonary embolism

This guidance document focuses on the diagnosis and treatment of venous thromboembolism (VTE). Efficient, cost effective diagnosis of VTE is facilitated by combining medical history and physical examination with pre-test probability models, D dimer testing and selective use of confirmatory imaging. Clinical prediction rules, biomarkers and imaging can be used to tailor therapy to disease severity. Anticoagulation options for acute VTE include unfractionated heparin, low molecular weight heparin, fondaparinux and the direct oral anticoagulants (DOACs). DOACs are as effective as conventional therapy with LMWH and vitamin K antagonists. Thrombolytic therapy is reserved for massive pulmonary embolism (PE) or extensive deep vein thrombosis (DVT). Inferior vena cava filters are reserved for patients with acute VTE and contraindications to anticoagulation. Retrievable filters are strongly preferred. The possibility of thoracic outlet syndrome and May-Thurner syndrome should be considered in patients with subclavian/axillary and left common iliac vein DVT, respectively in absence of identifiable triggers. The optimal duration of therapy is dictated by the presence of modifiable thrombotic risk factors. Long term anticoagulation should be considered in patients with unprovoked VTE as well as persistent prothrombotic risk factors such as cancer. Short-term therapy is sufficient for most patients with VTE associated with transient situational triggers such as major surgery. Biomarkers such as D dimer and risk assessment models such the Vienna risk prediction model offer the potential to customize VTE therapy for the individual patient. Insufficient data exist to support the integration of bleeding risk models into duration of therapy planning.

Rs5918ITGB3 Polymorphism, Smoking, and BMI as Risk Factors for Early Onset and Recurrence of DVT in Young Women

Objective:

To evaluate the contribution of rs5918ITGB3 on the incidence and recurrence of deep venous thrombosis (DVT) in women and the relationship with body mass index (BMI) and smoking and to compare with data in men.

Results:

Rs5918(C) polymorphism in ITGB3 gene was assessed in 224 patients diagnosed with DVT and 216 controls. Thrombophilic genetic variant rs5918(C) was significantly pronounced in women (χ2 =7.565, P = .008) and total patients (χ2 = 9.266, P = .002) but not in men. Women patients (<45 years) who were carriers of rs5918ITGB3 polymorphism had an early onset of DVT (34.5 vs 39.4 years, χ2 = 7.027, P = .008) as analyzed by Kaplan-Meier and a higher risk of the recurrent event (χ2 = 3.405, odds ratio = 2.581, P = .044). The period before recurrent venous thromboembolism event was related to smoking status and BMI in young female who were carriers of rs5918 polymorphism but not in the males.

Conclusions:

Carriage of genetic variant rs5918(C) polymorphism in ITGB3 gene in women contributes to higher risk of single and recurrent DVT events at younger age.

The epidemiology of venous thromboembolism

Venous thromboembolism (VTE) is categorized by the U.S. Surgeon General as a major public health problem. VTE is relatively common and associated with reduced survival and substantial health-care costs, and recurs frequently. VTE is a complex (multifactorial) disease, involving interactions between acquired or inherited predispositions to thrombosis and VTE risk factors, including increasing patient age and obesity, hospitalization for surgery or acute illness, nursing-home confinement, active cancer, trauma or fracture, immobility or leg paresis, superficial vein thrombosis, and, in women, pregnancy and puerperium, oral contraception, and hormone therapy. Although independent VTE risk factors and predictors of VTE recurrence have been identified, and effective primary and secondary prophylaxis is available, the occurrence of VTE seems to be relatively constant, or even increasing.

Sex difference in the risk of recurrent venous thrombosis: a detailed analysis in four European cohorts

BACKGROUND

Previous analyses reported a higher risk of recurrent venous thrombosis in men than women.

OBJECTIVES

We aimed to assess the risk of recurrence in men compared with women whilst taking female reproductive risk factors (oral contraception, postmenopausal hormone therapy and pregnancy) into account. In addition, we hypothesized that the sex difference in venous thrombosis was related to F9 Malmö, an X-linked prothrombotic factor.

METHODS

In four pooled European cohorts (CARROT study, Glasgow, UK; CVTE study, Cambridge, UK; AUREC study, Vienna, Austria; and LETS follow-up study, Leiden, the Netherlands), the risk of recurrent venous thrombosis was calculated in men, women with reproductive risk factors and women without reproductive risk factors at the time of their first venous thrombosis. F9 Malmö was genotyped and carriers and non-carriers contrasted.

RESULTS

In total, 2185 patients with a first venous thrombosis, 1043 men and 1142 women, were included. Overall, men had a 2.8-fold (95% confidence interval [CI], 2.2-3.4) higher risk of recurrent venous thrombosis than women. This risk was 5.2-fold (95% CI, 3.5-7.7) higher in men than in women with reproductive risk factors, and 2.3-fold (95% CI, 1.7-3.2) higher in men than in women without reproductive risk factors. No difference in risk of recurrence was found for carriers vs. non-carriers of F9 Malmö.

CONCLUSION

Men experienced a recurrent venous thrombosis twice as often as women without reproductive risk factors. These findings indicate that men have a higher intrinsic risk of venous thrombosis than women, which is partly masked by female reproductive risk factors. The sex difference cannot be explained by F9 Malmö.

Epidemiology of venous thromboembolism

Thrombosis can affect any venous circulation. Venous thromboembolism (VTE) includes deep-vein thrombosis of the leg or pelvis, and its complication, pulmonary embolism. VTE is a fairly common disease, particularly in older age, and is associated with reduced survival, substantial health-care costs, and a high rate of recurrence. VTE is a complex (multifactorial) disease, involving interactions between acquired or inherited predispositions to thrombosis and various risk factors. Major risk factors for incident VTE include hospitalization for surgery or acute illness, active cancer, neurological disease with leg paresis, nursing-home confinement, trauma or fracture, superficial vein thrombosis, and-in women-pregnancy and puerperium, oral contraception, and hormone therapy. Although independent risk factors for incident VTE and predictors of VTE recurrence have been identified, and effective primary and secondary prophylaxis is available, the occurrence of VTE seems to be fairly constant, or even increasing.

The risk of recurrence in women with venous thromboembolism while using estrogens: a prospective cohort study

BACKGROUND

The optimal duration of anticoagulation for women who had venous thromboembolism (VTE) associated with estrogen use is unknown.

OBJECTIVES

To test the hypothesis that women who had a first VTE while using estrogens have a low risk of recurrence.

METHODS

A Prospective cohort study of 630 women (333 estrogen users, 297 non-users) with a first VTE, who were followed for an average of 69 months after anticoagulation withdrawal. Women with a previous or secondary VTE, coagulation inhibitor deficiency, lupus anticoagulant, cancer, pregnancy, requirement of long-term antithrombotic therapy or homozygosity or double heterozygosity for factor V Leiden and/or the G20210A prothrombin mutation were excluded. The endpoint was objectively documented symptomatic recurrent VTE.

RESULTS

VTE recurred in 22 (7%) estrogen users and in 49 (17%) non-users. After 1, 2 and 5 years, the cumulative probability of recurrence was 1% (95% confidence interval [CI], 0-2), 1% (95% CI, 0-2) and 6% (95% CI, 3-9) among estrogen users and 5% (95% CI, 2-7), 9% (95% CI, 6-13) and 17% (95% CI, 12-22) among non-users. Compared with non-users, estrogen users had an adjusted relative risk (RR) of recurrent VTE of 0.4 (95% CI, 0.2-0.8). Compared with non-users in the respective age groups, the RR of recurrence was 0.4 (95% CI, 0.2-0.8) among estrogen-containing-contraceptive users and 0.7 (95% CI, 0.3-1.5) among women using estrogen-containing menopausal hormone therapy.

CONCLUSIONS

Women who had their first VTE while using estrogens have a low risk of recurrent VTE. These women might not benefit from extended anticoagulant therapy.

Prevalence of thrombophilia according to age at the first manifestation of venous thromboembolism: results from the MAISTHRO registry

Thrombophilia is a well-established risk factor for a venous thromboembolic event (VTE), and it has been proposed that hereditary thrombophilia may substantially contribute to the development of VTE in young patients. We aimed to analyse the prevalence of thrombophilia with special regard to the age of VTE manifestation. The study cohort consisted of 1490 patients (58% females) with a median age 43 years at the time of their first VTE. At least one thrombophilic disorder was identified in 50·1% of patients. The probability of detecting a hereditary thrombophilia declined significantly with advancing age (from 49·3% in patients aged 20 years and younger to 21·9% in patients over the age of 70 years; P < 0·001). This may be primarily attributed to the decreasing frequencies of the F5 R506Q (factor V Leiden) mutation and deficiencies of protein C or protein S with older age at the time of the initial VTE event. Moreover, thrombophilia was more prevalent in unprovoked compared with risk-associated VTE (57·7% vs. 47·7%; P = 0·001). The decline in the prevalence of hereditary thrombophilia with older ages supports the use of a selected thrombophilia screening strategy dependent on age and the presence or absence of additional VTE risk factors.

Risk of recurrent venous thromboembolism among young women after a first event while exposed to combined oral contraception versus not exposed to: a cohort study

The risk of recurrent venous thromboembolism (VTE) in young women after a first oestrogen contraception associated VTE episode is unknown. This uncertainty has an impact on the decision whether to stop anticoagulant treatment. Our objective was to assess the risk of recurrent VTE in women after a first VTE episode on oestrogen contraception. This was a prospective cohort study in which we consecutively enrolled between 1992 and 2011 all women under 50years with a first objectively confirmed VTE. The incidence of recurrent VTE during follow-up after stopping anticoagulation was compared between women users and non-users of combined oral contraception (COC) at the time of index VTE. Of the 241 women aged 50 or younger seen for a first VTE and followed-up after stopping anticoagulation, there were 180 COC-users and 61 non-users. Median duration of follow-up off-anticoagulants was 66 months (interquartile range: 33-103). There were 14 recurrences in COC-users and 5 cases in non-users. No significant association was found between exposure to COC and the incidence of recurrent VTE after adjustment for age or after restricting the analysis to major unprovoked VTE: incidence rate of recurrence 17.9/1,000/year (95% CI: 9.6-33.2) in women with COC as compared with 17.6/1,000/year (95% CI: 6.6-47) with an incidence ratio of 0.7 (95% CI: 0.2-2.4, p=0.59). The risk of recurrent VTE is low in young women after a first VTE. However, this risk is not significantly lower in women after a first VTE while exposed to combined oral contraception.

Management of patients with unprovoked venous thromboembolism: an evidence-based and practical approach

OPINION STATEMENT

The management of patients with unprovoked venous thromboembolism is a common and challenging clinical problem. Although the initial antithrombotic management is well-established, there is uncertainty about the optimal long-term anticoagulant management, specifically whether patients should receive a short (i.e., 3- to 6-month) duration of anticoagulant therapy or indefinite anticoagulation. Factors that may be considered to estimate patients' risk for recurrent thromboembolism include the mode of initial clinical presentation, as deep vein thrombosis or pulmonary embolism, patient sex, antecedent hormonal therapy use, thrombophilia, D-dimer levels, and residual vein occlusion in patients with deep vein thrombosis. Many of these factors have been integrated into clinical prediction guides which stratify patients with unprovoked venous thromboembolism according to their risk for disease recurrence and, thereby, can assist clinicians in decisions about the duration of anticoagulation. The objective of this review is to consider the evidence relating to the clinical significance of purported risk factors and provide a practical case-based approach to guide decisions on duration of anticoagulation for patients with unprovoked venous thromboembolism.

Predicting the risk of venous thromboembolism recurrence

Venous thromboembolism (VTE) is a chronic disease with a 30% ten-year recurrence rate. The highest incidence of recurrence is in the first 6 months. Active cancer significantly increases the hazard of early recurrence, and the proportions of time on standard heparin with an APTT ≥ 0.2 anti-X(a) U/mL, and on warfarin with an INR ≥ 2.0, significantly reduce the hazard. The acute treatment duration does not affect recurrence risk after treatment is stopped. Independent predictors of late recurrence include increasing patient age and body mass index, leg paresis, active cancer and other persistent VTE risk factors, idiopathic VTE, antiphospholipid antibody syndrome, antithrombin, protein C or protein S deficiency, hyperhomocysteinemia and a persistently increased plasma fibrin D-dimer. A recommendation for secondary prophylaxis should be individualized based on the risk for recurrent VTE (especially fatal pulmonary embolism) and bleeding. The appropriateness of secondary prophylaxis should be continuously reevaluated, and the prophylaxis stopped if the benefit no longer exceeds the risk.

Recurrent venous thromboembolism: what is the risk and how to prevent it

Venous thromboembolism (VTE) that includes deep vein thrombosis and/or pulmonary embolism is a frequent, severe, and potentially lethal disease. After a first episode, VTE has a strong tendency to recur. While VTE is an acute disease, it may have variable outcomes in early and late phases after initial presentation. Furthermore, the incidence of late, clinically important consequences (postthrombotic syndrome and/or chronic thromboembolic pulmonary hypertension) increases in case of recurrent events. The aims of the present review are (i) to analyze the incidence and risk factors for recurrence of VTE (either those related to the type of first thrombotic event or to the patients), the risks associated with occurrence of recurrent events, and the problems linked to the diagnosis, not always easy, of recurrent events; (ii) to discuss whether or not it is possible to predict the individual risk of recurrence after a first event, by stratifying patients at high or low risk of recurrence, and how this can influence their treatment; (iii) to comment what the current guidelines and guidance suggest/recommend about anticoagulant treatment after a first VTE event and, finally, to propose practical indications on how to manage individual patients affected by VTE.

Epidemiology of recurrent venous thrombosis

Venous thrombosis, including deep vein thrombosis and pulmonary embolism, is a common disease that frequently recurs. Recurrence can be prevented by anticoagulants, but this comes at the risk of bleeding. Therefore, assessment of the risk of recurrence is important to balance the risks and benefits of anticoagulant treatment. This review briefly outlines what is currently known about the epidemiology of recurrent venous thrombosis, and focuses in more detail on potential new risk factors for venous recurrence. The general implications of these findings in patient management are discussed.

[Risk factors for recurrent venous thromboembolism]

Recurrent venous thromboembolism (VTE) is frequent and can be fatal. Long-term antithrombotic treatment reduces the risk of recurrent VTE but increases the risk of bleeding and, therefore, cannot be proposed for all patients. Predicting the probability of recurrence in an individual patient is of utmost importance for assessing the risk-benefit ratio of long-term anticoagulation. Multiple clinical risk factors for recurrent VTE have been identified which include: unprovoked first episode, anatomical proximal location, male gender, residual venous thrombosis, cancer and antiphospholipid syndrome. d-dimer level after discontinuation of oral anticoagulation can help to predict the risk of recurrence with a good negative predictive value. Finally, genetic polymorphisms and rare inherited deficiencies of natural anticoagulant proteins do not seem to be strongly associated to recurrence. New antithrombotic drugs may, in the near future, improve the safety and of long-term anticoagulation treatment.

Risk of recurrence after venous thromboembolism in men and women: patient level meta-analysis

OBJECTIVE

To determine the effect of sex on the risk of recurrent venous thromboembolism in all patients and in patients with venous thromboembolism that was unprovoked or provoked (by non-hormonal factors). Data source Comprehensive search of electronic databases (Medline, Embase, CINAHL, Cochrane Central Register of Controlled Trials) until July 2010, supplemented by review of conference abstracts and contact with content experts.

STUDY SELECTION

Seven prospective studies investigating an association between D-dimer, measured after anticoagulation was stopped, and disease recurrence in patients with venous thromboembolism.

DATA EXTRACTION

Patient level databases were obtained, transferred to a central database, checked, and completed with further information provided by authors.

DATA SYNTHESIS

2554 patients with a first venous thromboembolism had follow-up for a mean of 27.1 (SD 19.6) months. The one year incidence of recurrent venous thromboembolism was 5.3% (95% confidence interval 4.1% to 6.7%) in women and 9.5% (7.9% to 11.4%) in men, and the three year incidence of recurrence was 9.1% (7.3% to 11.3%) in women and 19.7% (16.5% to 23.4%) in men. Among patients with unprovoked venous thromboembolism, men had a higher risk of recurrence than did women (hazard ratio 2.2, 95% confidence interval 1.7 to 2.8). After adjustment for women with hormone associated initial venous thromboembolism, the risk of recurrence remained higher in men (hazard ratio 1.8, 1.4 to 2.5). In patients with provoked venous thromboembolism, occurring after exposure to a major risk factor, recurrence of disease did not differ between men and women (hazard ratio 1.2, 0.6 to 2.4). In women with hormone associated venous thromboembolism and no other risk factors, recurrence was lower than that in women with unprovoked venous thromboembolism and no previous hormone use (hazard ratio 0.5, 0.3 to 0.8).

CONCLUSION

In patients with a first unprovoked venous thromboembolism, men have a 2.2-fold higher risk of recurrent venous thromboembolism than do women, which remained 1.8-fold higher in men after adjustment for previous hormone associated venous thromboembolism in women. In patients with a first provoked venous thromboembolism, risk of recurrence does not differ between men and women with or without hormone associated venous thromboembolism. Indefinite anticoagulation may be given greater consideration in men than in women after a first venous thromboembolism.

Sex, age and normal post-anticoagulation D-dimer as risk factors for recurrence after idiopathic venous thromboembolism in the Prolong study extension

BACKGROUND

The PROLONG randomized study showed that patients with an abnormal D-dimer after anticoagulation suspension for a first unprovoked episode of venous thromboembolism (VTE) benefited from anticoagulation resumption. Patients with normal D-dimer after anticoagulation suspension had a low recurrence rate (4.4% patient-years) but their anticoagulation optimal duration remained uncertain.

OBJECTIVES

To assess whether sex and age, in combination with normal D-dimer, are risk factors for VTE recurrence in patients enrolled in the PROLONG study extended follow-up.

METHODS

D-dimer was measured at 1 month after anticoagulation suspension. Patients with a normal D-dimer did not resume anticoagulants, whereas patients with an abnormal D-dimer were randomized either to resume or not anticoagulants. Primary outcome was recurrent VTE.

RESULTS

After excluding patients resuming anticoagulants for abnormal D-dimer, recurrences were higher in males than females [7.4% patient-years - 47/639 vs. 4.3% patient-years - 27/626; hazard ratio (HR) = 1.7; P = 0.027] and in patients aged 65 or older than in younger patients (8.4% patient-years - 50/598 vs. 3.6% patient-years - 24/667; HR = 2.1; P = 0.003). In patients with normal D-dimer and younger than 65, recurrences were higher in males than in females (5.1% vs. 0.4% patient-years; adjusted HR = 10.6; P = 0.023) and both females and males aged 65 years or older had more recurrences (6.6% and 8.1% patient-years, respectively, adjusted HR: 16.0; P = .008 and 16.0; P = 0.008, respectively) than females younger than 65.

CONCLUSIONS

In patients with idiopathic VTE and a normal D-dimer at 1 month after anticoagulation suspension, females younger than 65 had a very low risk of recurrence.

Risk factors for venous thromboembolism

Risk factors for venous thromboembolism (VTE) are often modifiable and overlap with risk factors for coronary artery disease. Encouraging our patients to adopt a heart-healthy lifestyle by abstaining from cigarettes, maintaining lean weight, limiting red meat intake, and controlling hypertension might lower the risk of pulmonary embolism and deep vein thrombosis (DVT), although a cause-effect relationship has not been firmly established. For hospitalized patients, guidelines have provided evidence-based strategies to identify patients at risk, such as elderly persons and those with cancer, congestive heart failure, or chronic obstructive pulmonary disease or undergoing major surgery. Most should receive pharmacological prophylaxis, which will minimize the risk of VTE. Because approximately 3 of every 4 pulmonary embolism and DVT events occur outside the hospital setting, patients should also be assessed for persistent high-risk of VTE at the time of hospital discharge.