Exploring Opportunities for Primary Prevention of Unprovoked Venous Thromboembolism: Ready for Prime Time?

Bariatric Surgery and the Long-Term Risk of Venous Thromboembolism: A Population-Based Cohort Study

PURPOSE

Bariatric surgery is associated with a greater venous thromboembolism (VTE) risk in the weeks following surgery, but the long-term risk of VTE is incompletely characterized. We evaluated bariatric surgery in relation to long-term VTE risk.

MATERIALS AND METHODS

This population-based retrospective matched cohort study within three United States-based integrated health care systems included adults with body mass index (BMI) ≥ 35 kg/m2 who underwent bariatric surgery between January 2005 and September 2015 (n = 30,171), matched to nonsurgical patients on site, age, sex, BMI, diabetes, insulin use, race/ethnicity, comorbidity score, and health care utilization (n = 218,961). Follow-up for incident VTE ended September 2015 (median 9.3, max 10.7 years).

RESULTS

Our population included 30,171 bariatric surgery patients and 218,961 controls; we identified 4068 VTE events. At 30 days post-index date, bariatric surgery was associated with a fivefold greater VTE risk (HRadj = 5.01; 95% CI = 4.14, 6.05) and a nearly fourfold greater PE risk (HRadj = 3.93; 95% CI = 2.87, 5.38) than no bariatric surgery. At 1 year post-index date, bariatric surgery was associated with a 48% lower VTE risk and a 70% lower PE risk (HRadj = 0.52; 95% CI = 0.41, 0.66 and HRadj = 0.30; 95% CI = 0.21, 0.44, respectively). At 5 years post-index date, lower VTE risks persisted, with bariatric surgery associated with a 41% lower VTE risk and a 55% lower PE risk (HRadj = 0.59; 95% CI = 0.48, 0.73 and HRadj = 0.45; 95% CI = 0.32, 0.64, respectively).

CONCLUSION

Although in the short-term bariatric surgery is associated with a greater VTE risk, in the long-term, it is associated with a substantially lower risk.

The Risk of Incident Venous Thromboembolism Attributed to Overweight and Obesity: The Tromsø Study

BACKGROUND

 Obesity is a well-established risk factor for venous thromboembolism (VTE). However, data on the proportion of incident VTEs attributed to overweight and obesity in the general population are limited.

OBJECTIVE

 To investigate the population attributable fraction (PAF) of VTE due to overweight and obesity in a population-based cohort with repeated measurements of body mass index (BMI).

METHODS

 Participants from the fourth to seventh surveys of the Tromsø Study (enrolment: 1994-2016) were followed through 2020, and all incident VTEs were recorded. In total, 36,341 unique participants were included, and BMI measurements were updated for those attending more than one survey. BMI was categorized as <25 kg/m2, 25-30 kg/m2 (overweight), and ≥30 kg/m2 (obesity). Time-varying Cox regression models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). The PAF was estimated based on age- and sex-adjusted HRs and the prevalence of BMI categories in VTE cases.

RESULTS

 At baseline, the prevalence of overweight and obesity was 37.9 and 13.8%, respectively. During a median follow-up of 13.9 years, 1,051 VTEs occurred. The age- and sex-adjusted HRs of VTE were 1.40 (95% CI: 1.21-1.61) for overweight and 1.86 (95% CI: 1.58-2.20) for obesity compared with subjects with BMI <25 kg/m2. The PAF of VTE due to overweight and obesity was 24.6% (95% CI: 16.6-32.9), with 12.9% (95% CI: 6.6-19.0) being attributed to overweight and 11.7% (95% CI: 8.5-14.9) to obesity. Similar PAFs were obtained in analyses stratified by sex and VTE subtypes (provoked/unprovoked events, deep vein thrombosis, pulmonary embolism).

CONCLUSION

 Our findings indicate that almost 25% of all VTE events can be attributed to overweight and obesity in a general population from Norway.

Leisure sedentary behaviour increases the risk of venous thromboembolism: a Mendelian randomisation study

BACKGROUND

Venous thromboembolism (VTE) is a substantial contributor to the global burden of disease. Observational studies have suggested that leisure sedentary behaviours (LSB) are related to the risk of VTE; however, the causal role of LSB in VTE remains unclear.

METHODS

Using data obtained from genome-wide association studies in the UK Biobank (N = 422,218), we identified 84, 21, and 4 single nucleotide polymorphisms (SNPs) related to sedentary television (TV) watching, computer use, and driving, respectively. These SNPs were employed as instrumental variables. Summary statistics for SNP-VTE associations was obtained from the FinnGen study (5,403 cases and 130,235 controls). Two-sample Mendelian randomisation (MR) analyses were performed using inverse-variance weighted (IVW), MR-Egger,weighted median, and weighted mode approaches. Sensitivity analyses were conducted to ensure robustness of the results.

RESULTS

The main IVW approach demonstrated a positive association between the genetically predicted sedentary TV watching and the risk of VTE [odds ratio (OR):1.35, 95% confidence interval (CI):1.02-1.80, P = 0.039]. However, no significant association was observed for genetically predicted sedentary computer use or driving and VTE risk. The results from our series of sensitivity analyses, including Cochran's Q test, MR-Egger intercept test, and MR-Pleiotropy RESidual Sum and Outlier method, further supported these findings.

CONCLUSION

This study provides evidence of an association between genetically predicted sedentary TV watching and the risk of VTE. Further studies are required to elucidate the underlying causal mechanisms.

Epidemiology and prevention of venous thromboembolism

Venous thromboembolism, that consists of the interrelated conditions deep-vein thrombosis and pulmonary embolism, is an under-appreciated vascular disease. In Western regions, approximately 1 in 12 individuals will be diagnosed with venous thromboembolism in their lifetime. Rates of venous thromboembolism are lower in Asia, but data from other regions are sparse. Numerous risk factors for venous thromboembolism have been identified, which can be classified as acute or subacute triggers (provoking factors that increase the risk of venous thromboembolism) and basal or acquired risk factors (which can be modifiable or static). Approximately 20% of individuals who have a venous thromboembolism event die within 1 year (although often from the provoking condition), and complications are common among survivors. Fortunately, opportunities exist for primordial prevention (prevention of the development of underlying risk factors), primary prevention (management of risk factors among individuals at high risk of the condition) and secondary prevention (prevention of recurrent events) of venous thromboembolism. In this Review, we describe the epidemiology of venous thromboembolism, including the incidence, risk factors, outcomes and opportunities for prevention. Meaningful health disparities exist in both the incidence and outcomes of venous thromboembolism. We also discuss these disparities as well as opportunities to reduce them.

Prediction of venous thromboembolism incidence in the general adult population using two published genetic risk scores

INTRODUCTION

Most strategies for prevention of venous thromboembolism focus on preventing recurrent events. Yet, primary prevention might be possible through approaches targeting the whole population or high-risk patients. To inform possible prevention strategies, population-based information on the ability of genetic risk scores to identify risk of incident venous thromboembolism is needed.

MATERIALS AND METHODS

We used proportional hazards regression to relate two published genetic risk scores (273-variants versus 5-variants) with venous thromboembolism incidence in the Atherosclerosis Risk in Communities Study (ARIC) cohort (n = 11,292), aged 45-64 at baseline, drawn from 4 US communities.

RESULTS

Over a median of 28 years, ARIC identified 788 incident venous thromboembolism events. Incidence rates rose more than two-fold across quartiles of the 273-variant genetic risk score: 1.7, 2.7, 3.4 and 4.0 per 1,000 person-years. For White participants, age, sex, and ancestry-adjusted hazard ratios (95% confidence intervals) across quartiles were strong [1 (reference), 1.30 (0.99,1.70), 1.85 (1.43,2.40), and 2.58 (2.04,3.28)] but weaker for Black participants [1, 1.05 (0.63,1.75), 1.37 (0.84,2.22), and 1.32 (0.80,2.20)]. The 5-variant genetic risk score showed a less steep gradient, with hazard ratios in Whites of 1, 1.17 (0.89,1.54), 1.48 (1.14,1.92), and 2.18 (1.71,2.79). Models including the 273-variant genetic risk score plus lifestyle and clinical factors had a c-statistic of 0.67.

CONCLUSIONS

In the general population, middle-aged adults in the highest quartile of either genetic risk score studied have approximately two-fold higher risk of an incident venous thromboembolism compared with the lowest quartile. The genetic risk scores show a weaker association with venous thromboembolism for Black people.

Haematological variables and risk of future venous thromboembolism in the British Regional Heart Study on men. Combined D-dimer and APTT as a predictive test for thromboembolism?

We examined the associations between haematological and inflammatory variables with future venous thromboembolism (VTE), in 3494 men aged 60-79 years, with no previous history of VTE or myocardial infarction, who were not receiving oral anticoagulants. After a mean follow-up period of 18 years, there were 149 confirmed cases of fatal or non-fatal VTE (deep vein thrombosis and/or pulmonary embolism). Among classical cardiovascular risk factors, only obesity and cigarette smoking were associated with VTE risk. After adjustment for age, obesity and smoking, VTE risk was associated with coagulation factor VIII, factor IX, von Willebrand factor (VWF), activated partial thromboplastin time (APTT), and fibrin D-dimer. Hazard ratios (95% CI) for top to bottom quarters (bottom to top for APTT), were respectively 2.17 (1.37, 3.44), 2.15 (1.30, 3.53), 2.02 (1.27, 3.22), 2.43 (1.47, 4.02) and 3.62 (2.18, 6.08). The 11% of men with both the shortest APTT and highest D-dimer combined had a 5.02 (2.37, 10.62) higher risk of VTE. VTE risk was not associated with fibrinogen, factor VII or activated protein C resistance; full blood count variables or with inflammatory markers, plasma viscosity, C-reactive protein or interleukin-6. The combination of D-dimer and APTT merits evaluation as an adjunct to VTE risk prediction scores.

Association between cardiovascular risk factors and venous thromboembolism in the elderly

BACKGROUND

The preponderance of the evidence supports no association between traditional cardiovascular risk factors and venous thromboembolism (VTE), other than obesity. There are limited data in older people.

OBJECTIVES

To investigate whether cardiovascular risk factors (body mass index, smoking, alcohol intake, hypertension, and diabetes) are associated with the risk of VTE in elderly and to assess the combined effect between cardiovascular risk factors and genetic risk factors for VTE (factor V Leiden/prothrombin 20210A, positive family history of VTE, and non-O blood group).

METHODS

The Age and Thrombosis, Acquired and Genetic risk factors in the Elderly study is a multicenter case-control study performed in Vermont, USA and Leiden, the Netherlands, comprising 401 cases with first VTE and 431 control subjects, all aged ≥70 years. To assess the risk of VTE, odds ratios (OR) with 95% confidence intervals (CIs) were calculated, adjusting for potential confounders.

RESULTS

Both height and weight were positively associated with VTE risk: the ORs were 2.2 (95% CI, 1.2-3.9) and 1.5 (95% CI, 1.0-2.4) in the top quartile for height and weight separately. This risk was more pronounced for unprovoked VTE. Smoking, alcohol intake, and diabetes were not associated with VTE. Higher systolic and diastolic blood pressure and hypertension were associated with a decreased risk of VTE. In the presence of a genetic predisposition, height and weight further increased the risk of VTE.

CONCLUSIONS

In the elderly, height and weight are positively associated with the risk of VTE. With genetic predisposition, higher levels of height and weight further increase the risk of VTE.

Awareness and Perception of Hospitalized Patients on Thromboembolism and Thromboprophylaxis: A Cross-Sectional Study in Sana'a-Yemen

PURPOSE

Patients' awareness toward VTE and thromboprophylaxis is critical for medication adherence. This study aimed to evaluate the patient's awareness and perception towards VTE and its prophylaxis and to assess patient's satisfaction towards the information given by the medical staff.

PARTICIPANTS AND METHODS

A cross-sectional survey was conducted among hospitalized patients who received VTE prophylaxis in public and private hospitals in Sana'a, Yemen. Besides sociodemographic variables, participants' awareness and perception of VTE and its prophylaxis were evaluated. Variables' association with VTE awareness were analyzed using univariable and multivariable logistic regression using SPSS.

RESULTS

A total of 396 of the hospitalized patients agreed to participate in the study, with 31% (n = 121) have ever heard about VTE. The multivariable logistic regression findings revealed that the participants who did not have a profession had OR = 17.182 (P < 0.001) of being unaware of VTE compared with those who had one. Participants who did not have a personal history of VTE had OR = 7.580 (P < 0.001) of being unaware of DVT/PE compared with the participants who had a personal history of VTE. Male participants had OR = 2.839 (P < 0.005) of being unaware of DVT/PE compared with female participants. Participants who were illiterate had OR = 2.832 (P < 0.022) of being unaware of DVT/PE compared with participants with a higher level of education.

CONCLUSION

The study revealed lack of awareness and perception of VTE and its prophylaxis among hospitalized patients in Yemen. The patients who are unaware of the disease have wrong perception about their role in DVT prophylaxis. Patient's education must be considered in healthcare setting to improve patient's health outcomes.

No prospective association of a polygenic risk score for coronary artery disease with venous thromboembolism incidence

BACKGROUND

Previous studies are inconsistent about whether chronic coronary artery disease or generalized atherosclerosis is a causal risk factor for venous thromboembolism. No study seems to have taken a genomic approach to this question.

OBJECTIVE

To test in a prospective study whether a polygenic risk score for coronary artery disease is associated with risk of venous thromboembolism.

PARTICIPANTS/METHODS

Within the Atherosclerosis Risk in Communities Study cohort, we computed a previously validated polygenic risk score for coronary artery disease among 9144 White participants at baseline in 1987-1989. We followed the participants through 2015 for incident hospitalized venous thromboembolism events, validated by physician review. We used Cox proportional hazards regression to associate quintiles of the polygenic risk score to venous thromboembolism incidence rates.

RESULTS

Over the median of 26 years of follow-up, 476 participants had a venous thromboembolism event. There was no apparent association between the coronary artery disease polygenic risk score and incident venous thromboembolism, with age, sex, body mass index adjusted hazard ratios across quintiles being 1 (reference), 0.87 (0.65, 1.15), 1.08 (0.82, 1.42), 0.96 (0.72, 1.27), and 1.03 (0.78, 1.37).

CONCLUSIONS

A genetic disposition to coronary artery disease did not confer an increased risk of venous thromboembolism in this prospective study.

Contrasting Associations of Prudent and Western Dietary Patterns with Risk of Developing Venous Thromboembolism

BACKGROUND

Published studies are inconsistent about whether differences in diet are associated with risk of venous thromboembolism. We studied the association between dietary patterns and incident venous thromboembolism in a large US cohort.

METHODS

The Atherosclerosis Risk in Communities study followed 14,818 middle-aged males and females for incident venous thromboembolism over an average of 22 years between 1987 and 2015. Trained interviewers assessed dietary intake at visits 1 and 3, using a food frequency questionnaire. We derived 2 dietary pattern scores using principal component analysis and ascertained and verified hospitalized venous thromboembolism. In separate proportional hazards regression analyses, we examined associations of quintiles of the prudent and the Western dietary pattern scores with risk of developing non-cancer-related and total venous thromboembolism, adjusting for demographic characteristics, lifestyle factors, body mass index, and diabetes.

RESULTS

With 860 total incident venous thromboembolism events, the hazard ratios (95% confidence intervals) of incident non-cancer-related venous thromboembolism (n = 631) across quintiles of the prudent dietary pattern score were 1 (reference), 1.04 (0.81-1.32), 0.84 (0.65-1.08), 0.70 (0.53-0.91), and 0.88 (0.67-1.15), Ptrend = .04. Across quintiles of the Western dietary pattern score, hazard ratios of non-cancer-related venous thromboembolism were 1 (reference), 1.13 (0.87-1.45), 1.20 (0.92-1.56), 1.03 (0.77-1.39), and 1.58 (1.13-2.21), Ptrend = .04. Associations were similar for total venous thromboembolism.

CONCLUSIONS

In this community-based cohort, a prudent dietary pattern was associated with a lower risk of future venous thromboembolism, whereas a Western dietary pattern was associated with a higher risk.

Exploring Opportunities for Primary Prevention of Unprovoked Venous Thromboembolism: Ready for Prime Time?

Venous thromboembolism (VTE) is an important vascular disease and public health problem. Prevention of VTE has focused mainly on using thromboprophylaxis to avoid provoked VTE or recurrent VTE, with little attention paid to the possibility of preventing the one third to one half of VTEs that are unprovoked. We review growing research suggesting that unhealthy lifestyle risk factors may cause a considerable proportion of unprovoked VTE. Using epidemiologic data to calculate population attributable risks, we estimate that in the United States obesity may contribute to 30% of VTEs, physical inactivity to 4%, current smoking to 3%, and Western dietary pattern to 11%. We also review possibilities for VTE primary prevention either through a high-risk individual approach or a population-wide approach. Interventions for outpatients at high VTE risk but without VTE provoking factors have not been fully tested; yet, improving patient awareness of risk and symptoms, lifestyle counseling, and possibly statins or direct oral anticoagulants may prove useful in primary prevention of unprovoked VTE. A population approach to prevention would bolster awareness of VTE and aim to shift lifestyle risk factors downward in the whole population using education, environmental changes, and policy. Assuming the epidemiological associations are accurate, causal, and independent of each other, a reduction of obesity, physical inactivity, current smoking, and Western diet by 25% in the general population might reduce the incidence of unprovoked VTE by 12%. We urge further research and consideration that primary prevention of unprovoked VTE may be a worthwhile public health aim.