Hyperhomocysteinemia and low B vitamin levels are independently associated with venous thromboembolism: results from the EDITH study: a hospital-based case-control study

Methylcobalamin Deficiency Presenting as Thalamic Syndrome in the Elderly: Association or Chance?

Vitamin deficiency is common in the geriatric population and is responsible for majorly imbalanced hematological, neurological, and neuropsychiatric functioning. Methylcobalamin deficiency or vitamin B12 deficiency can be underestimated in some cases and be misdiagnosed as other illnesses, such as thalamic syndrome. Timely diagnosis of this deficiency is essential, especially in the geriatric population, as it might cause irreversible structural brain damage. This is also presented as elevated levels of homocysteine and methylmalonic acid. Clinically, it presents with the following symptoms: lower sensitivity levels to touch and light, psychosis, paresthesia, anemia, imbalance, fatigue, cognitive disturbances, difficulty remembering, and confusion. Symptoms are usually progressive and worsen over a period of time. In this case report, we present the case of a 62-year-old male with clinical symptoms of numbness and tingling in the right side of the body. The neurological presentations resembled left thalamic infarct, but the underlying reason was methylcobalamin deficiency.

Predictors of Recurrent Venous Thromboembolism or Arterial Thrombotic Events during and after Anticoagulation for a First Venous Thromboembolism

After first episodes of venous thromboembolism (VTE), patients are at increased risk of recurrent VTE and arterial thrombotic events (ATE) compared with the general population, two disorders that are influenced by anticoagulation. However, risk factors of these conditions occurring during and after anticoagulation are little described. Using cause-specific hazard regression models, we aimed to determine risk factors of the composite outcome recurrent VTE/ATE, and separately recurrent VTE or ATE, during and after anticoagulation in patients with first episodes of VTE from a prospective cohort. Hazard ratios (HRs) are given with 95% confidence intervals (CIs). A total of 2,011 patients treated for at least 3 months were included. A total of 647 patients had recurrent VTE/ATE (incidence: 4.69% per patient-years) during overall follow-up (median: 92 months). Of these events, 173 occurred during anticoagulation (incidence: 3.67% per patient-years). Among patients free of events at the end of anticoagulation, 801 had a post-anticoagulation follow-up ≥3 months; and 95 had recurrent VTE/ATE (incidence: 1.27% per patient-years). After adjustment for confounders, cancer-associated VTE (HR: 2.64, 95% CI: 1.70-4.11) and unprovoked VTE (HR: 1.95, 95% CI: 1.35-2.81) were the identified risk factors of recurrent VTE/ATE during anticoagulation (vs. transient risk factor-related VTE). Risk factors of recurrent VTE/ATE after anticoagulation included 50 to 65 years of age (vs. < 50, HR: 1.99, 95% CI: 1.04-3.81), older than 65 years (vs. < 50, HR: 5.28, 95% CI: 3.03-9.21), and unprovoked VTE (vs. transient risk factor-related VTE, HR: 2.06, 95% CI: 1.27-3.34). Cancer-associated VTE and unprovoked VTE are the main risk factors of recurrent VTE/ATE during anticoagulation, while older age and unprovoked VTE mainly predict the risk of these events after anticoagulation.

Risk Factors of Cardiovascular Death after Venous Thromboembolism: Results from a Prospective Cohort Study

BACKGROUND

 Cardiovascular deaths (CVDTs) are more frequent in patients with venous thromboembolism (VTE) than in the general population; however, risk factors associated with this increased risk of CVDT in patients with VTE are not described.

METHODS

 To determine the risk factors of CVDT in patients with VTE from a multicenter prospective cohort study, Fine and Gray subdistribution hazard models were conducted.

RESULTS

 Of the 3,988 included patients, 426 (10.7%) died of CVDT during a median follow-up of 5 years. The risk factors of CVDT after multivariate analyses were: age of 50 to 65 years (vs. <50 years, hazard ratio [HR]: 3.22, 95% confidence interval [CI]: 1.67-6.62), age >65 years (vs. <50 years, HR: 7.60, 95% CI: 3.73-15.52), cancer-associated VTE (vs. transient risk factor-related VTE, HR: 1.73, 95% CI: 1.15-2.61), unprovoked VTE (vs. transient risk factor-related VTE, HR: 1.42, 95% CI: 1.02-2.00), past tobacco use (vs. never, HR: 1.43, 95% CI: 1.06-1.94), current tobacco use (vs. never, HR: 1.87, 95% CI: 1.15-3.01), hypertension (HR: 2.11, 95% CI: 1.51-2.96), chronic heart failure (HR: 2.28, 95% CI: 1.37-3.79), chronic respiratory failure (HR: 1.72, 95% CI: 1.02-2.89), and atrial fibrillation (HR: 1.67, 95% CI: 1.06-2.60). The risk of CVDT was significantly reduced with direct oral anticoagulants (vs. vitamin-K antagonists) and with longer duration of treatment (>3 months).

CONCLUSION

 Risk factors of CVDT after VTE include some traditional cardiovascular risk factors and other risk factors that are related to characteristics of VTE, and patients' comorbidities.

Vitamin B12 levels in patients with retinal vein occlusion and their relation with clinical outcome: a retrospective study

Retinal vein occlusion (RVO) is the second most common retinal vascular disorder, after diabetic retinopathy. Most patients suffering RVO develop some degree of visual loss consequent to retinal complications such as edema and microhemorrhages. Even if some risk factors for RVO have been identified, the clinical outcome of RVO remains highly unpredictable because studies investigating potential prognostic markers for visual improvement are lacking. Cyanocobalamin belongs to the group of B vitamins and plays a role in homocysteine metabolism; however, cyanocobalamin deficiency associates with an increase of some toxic bioproducts involved in endothelial injury and platelet activation independent of homocysteine levels. We retrospectively evaluated the levels of vitamin B12 at diagnosis in 203 patients with RVO, and in a parallel cohort of 120 age- and sex-matched patients without RVO from an internal medicine ward, and correlated them with visual outcome at follow-up (median time 150 days, IQR 30-210). In patients with RVO, vitamin B12 levels at diagnosis were significantly lower than in controls and independently predicted worse clinical outcome at multivariate analysis (OR 3.2; CIs 1.2-8.2; p = 0.015). Our data suggest the opportunity to prospectively evaluate the effect on visual outcome of cyanocobalamin supplementation in RVO patients.

Venous thromboembolism risk assessment of surgical patients in Southwest China using real-world data: establishment and evaluation of an improved venous thromboembolism risk model

Background

Venous thromboembolism (VTE) risk assessment in surgical patients is important for the appropriate diagnosis and treatment of patients. The commonly used Caprini model is limited by its inadequate ability to discriminate between risk stratums on the surgical population in southwest China and lengthy risk factors. The purpose of this study was to establish an improved VTE risk assessment model that is accurate and simple.

Methods

This study is based on the clinical data from 81,505 surgical patients hospitalized in the Southwest Hospital of China between January 1, 2019 and June 18, 2021. Among the population, 559 patients developed VTE. An improved VTE risk assessment model, SW-model, was established through Logistic Regression, with comparisons to both Caprini and Random Forest.

Results

The SW-model incorporated eight risk factors. The area under the curve (AUC) of SW-model (0.807 [0.758, 0.853], 0.804 [0.765, 0.840]), are significantly superior (p = 0.001 and p = 0.044) to those of the Caprini (0.705 [0.652, 0.757], 0.758 [0.719, 0795]) on two test sets, but inferior (p < 0.001 and p = 0.002) to Random Forest (0.854 [0.814, 0.890], 0.839 [0.806, 0.868]). In decision curve analysis, within threshold range from 0.015 to 0.04, the DCA curves of the SW-model are superior to Caprini and two default strategies.

Conclusions

The SW-model demonstrated a higher discriminative capability to distinguish VTE positive in surgical patients compared with the Caprini model. Compared to Random Forest, Logistic Regression based SW-model provided interpretability which is essential in guarantee the procedure of risk assessment transparent to clinicians.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12911-022-01795-9.

Cerebral venous sinus thrombosis: a complication of nitrous oxide abuse

Nitrous oxide (NO) is an inhalant that has become increasingly popular as a recreational drug. While it is presumed to be harmless, a number of adverse effects of NO have been described. We discuss the case of a 24-year-old man with no medical history, who initially presented to the emergency department with progressive polyneuropathy caused by vitamin B12 deficiency after NO abuse. Two days after being discharged with hydroxocobalamin supplementation, the patient returned with a severe headache, blurry vision and slurred speech. Imaging revealed cerebral venous sinus thrombosis. Hypercoagulability workup showed slightly elevated homocysteine and normalised vitamin B12 after supplementation. Genetic testing showed a heterozygous prothrombin G20210A mutation. He was treated with low-molecular-weight heparin followed by dabigatran. We hypothesise that NO use may increase the risk of developing cerebral venous thrombosis, especially in patients with multiple risk factors and elevated homocysteine levels.

Risk of venous thromboembolism in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune joint disease with persistent systemic inflammation. Patients with RA suffer from joint pain and physical disability, but have their prognosis mostly driven by cardiovascular events, including venous thromboembolism (VTE). The risk of VTE is more than double in patients with RA compared with the general population. The incidence rate in patients with RA is estimated around 4 cases per 1000 person-years. The etiology of thrombotic tendency in RA is linked to various mechanisms and causal factors (antiphsolpholid antibodies, hyperhomocyteinemia, inflammation…): vascular injury, hypercoagulation, and venous stasis, the three components of the Virchow's triad, are activated in patients with RA. In clinical practice, situations that put patients for VTE should be identified (e.g., surgery, first year after RA diagnosis, hospitalization for acute illness…). Patients with RA are exposed to reversible risk factors, such as major surgery (knee or hip surgery) or hospitalization with immobilization. Similarly, uncontrolled RA, which is defined by the necessity to switch a biological disease-modifying anti-rheumatic drugs (DMARD), increases the incidence of VTE in observational studies. Moreover, DMARDs may impact the risk of VTE, especially in the time window after first prescription. Several biological DMARDs like tofacitinib have been associated with an increased risk of VTE. Therefore, patients with RA may require specific measures in terms of VTE diagnosis and management. In this review, we provide current insights into the pathophysiology, epidemiology, clinical considerations, and treatment strategies of VTE highlighting gaps in evidence and perspectives in patients with RA.

Lymphocyte Disturbances in Primary Antiphospholipid Syndrome and Application to Venous Thromboembolism Follow-Up

Among patients with venous thromboembolism (VTE), the persistent detection of antiphospholipid (aPL) antibodies (Ab) represents an independent high risk factor for recurrence. However, oral anticoagulation vitamin K antagonist therapy, frequently used in these patients, is problematic in assessing and/or confirming a diagnosis of primary aPL syndrome (pAPS), suggesting use of alternative strategies. For this reason, and by analogy with other autoimmune diseases, a flow cytometer approach testing peripheral T cell subsets (CD3, CD4, and CD8), B cell subsets (B1, transitional, naive, and memory), and NK cells can be proposed. As an example and to validate the concept, pAPS patients selected from the monocentric VTE case-control EDITH's cohort were selected during their follow-up. As suspected and in contrast to non-APS VTE patients, other autoimmune diseases, and controls, pAPS VTE patients displayed specific lymphocyte disturbances. Quantitative and qualitative modifications were related to total CD4⁺ T cell reduction, a lower CD4/CD8 ratio, and disturbance in B cell homeostasis with increased proportions of B1 cells, transitional B cells (CD24⁺⁺CD38⁺⁺), and naive B cells (IgD⁺CD27^-), while memory B cells (IgD⁺CD27⁺ and IgD^-CD27⁺) were reduced. Interestingly, the absolute number of CD4⁺ T cells positively correlated with IgG anti-cardiolipin Ab levels. Altogether, disturbances of T and B cell homeostasis characterized pAPS VTE patients during their follow-up. This suggests a means of profiling that could be used in addition to existing criteria to characterize them.

Association between hospitalization for acute medical illness and VTE risk: A lower efficacy of thromboprophylaxis in elderly patients? Results from the EDITH case-control study

INTRODUCTION

Whether the association between hospitalization and venous thromboembolism (VTE) is modified by the use of thromboprophylaxis in older patients remains insufficiently evaluated. Our objective was to estimate VTE risk associated with hospitalization for acute medical illness depending on prescription of pharmacological thromboprophylaxis, in two different age categories using a 75years cutoff.

METHODS

Using a case-control design, we estimated the risk for symptomatic VTE associated with hospitalization for acute medical illness depending on prescription of pharmacological thromboprophylaxis in two different age categories using a 75 years cut-off.

RESULTS

750 symptomatic VTE cases and their 750 age and sex-matched controls were analyzed. A total of 145 cases (19.3%) and 91 controls (12.1%) were hospitalized for acute medical illness in the preceding 3months prior to inclusion in the study (p<0.001). Hospitalization for acute medical illness was associated with a 75% increase in VTE risk: OR 1.75 (95% CI: 1.32-2.33). In patients <75years, there was a 2-fold increase in VTE risk associated with hospitalization when thromboprophylaxis was not prescribed: OR 2.01 (95% CI: 1.11-3.62), whereas no association was found when thromboprophylaxis was prescribed: OR 0.93 (95% CI: 0.44-1.95). In patients ≥75years, VTE risk associated with hospitalization remained significant whether or not thromboprophylaxis was prescribed: OR 2.69 (95% CI 1.28-5.66) and OR 2.02 (95% CI: 1.01-4.03) respectively.

CONCLUSION

Our results suggest that VTE prevention in acutely ill medical patients may be less effective in patients ≥75years. This finding needs to be addressed in further studies.

Is there still room for additional common susceptibility alleles for venous thromboembolism?

Essentials Genetic architecture of venous thromboembolism (VTE) remains to be fully disentangled. 11 newly discovered candidate polymorphisms were genotyped in 3019 VTE cases and 2605 controls. None of the 11 polymorphisms were significantly associated with VTE risk. Additional major efforts are needed to identify VTE-associated genetic variants.

SUMMARY

Background Through a meta-analysis of 12 genome-wide association studies, the International Network against VENous Thrombosis (INVENT) consortium identified two novel susceptibility loci for venous thromboembolism (VTE). This project has also generated other candidates that need to be confirmed. Objectives To assess the association with VTE of common single-nucleotide polymorphisms (SNPs) that demonstrated strong statistical, but not genome-wide, significance in the INVENT cohorts. Patients/methods Eleven SNPs were genotyped and tested for association with VTE in three case-control studies totaling 3019 patients and 2605 healthy individuals. Results and conclusions None of the tested SNPs showed evidence for association with VTE. Different strategies are needed to decipher the whole spectrum of common and rare genetic variations associated with VTE risk.

Serum levels of 25(OH)D are not associated with venous thromboembolism in the elderly population. A case-control study

The prevalence of both vitamin D deficiency and venous thromboembolism (VTE) is important in the elderly. Previous studies have provided evidence for a possible association between vitamin D status and the risk of VTE. Thus, we aimed to investigate the association between vitamin D levels and VTE in the population aged 75 and over included in the EDITH case-control study. The association between vitamin D status and VTE was analysed. We also analysed the monthly and seasonal variations of VTE and vitamin D. Between May 2000 and December 2009, 340 elderly patients (mean age 81.5 years, 32% men) with unprovoked VTE and their controls were included. The univariate and multivariate analysis found no significant association between serum levels of vitamin D and the risk of unprovoked VTE. In the unadjusted analysis, a higher BMI was statistically associated with an increased risk of VTE (OR 1.09; 95% CI 1.05-1.13) whereas a better walking capacity and living at home were associated with a decreased rate of VTE: OR 0.57; 95% CI 0.36-0.90 and 0.40; 95% CI 0.25-0.66, respectively. Although not significant, more VTE events occurred during winter (p=0.09). No seasonal variations of vitamin D levels were found (p=0.11). In conclusion, in contrast with previous reports our findings suggest that vitamin D is not associated with VTE in the elderly population.

Study on relationships among deep vein thrombosis, homocysteine & related B group vitamins

Objectives:

Hyperhomocysteinemia has been considered as a potential risk factor for deep venous thrombosis (DVT) but it is still controversy. We aimed to evaluate the prevalence of hyperhomocysteinemia in patients with DVT. Our second objective was to document the prevalence of folate, Vitamin B6, and Vitamin B12 level in this patient population.

Methods:

Sixty patients with DVT aged from 23 to 84 years, were assessed regarding demographic characteristics, serum levels of homocysteine, folate, vitamin B12, and vitamin B6. The diagnosis of DVT was based upon Wells scoring system and serum D-dimer level and confirmed by deep venous Doppler ultrasonography of the lower limbs.

Results:

Mean serum homocysteine levels were found significantly higher in patients over the age of 40 years (10.81±4.26 µmol/L vs 9.13±3.23 µmol/L). Of all the patients, 9 patients had homocysteine level above the 15µmol/L, 26 had folic acid level below 3 ng/ml, one had vitamin B12 level below 150 pmol/L, and two had vitamin B6 level below 30 nmol/L. In the hyperhomocysteinemic group, five patients had low folic acid level, one had low vitamin B12 level, and two had low vitamin B6 level.

Conclusions:

Hyperhomocysteinemia, in women older than 40 years, may be a risk factor for DVT. Folic acid deficiency may also influence serum homocysteine concentrations. Folate therapy may be offered to the patients with DVT. However further studies are required to clarify the underlying molecular mechanisms.

Meta-analysis of 65,734 individuals identifies TSPAN15 and SLC44A2 as two susceptibility loci for venous thromboembolism

Venous thromboembolism (VTE), the third leading cause of cardiovascular mortality, is a complex thrombotic disorder with environmental and genetic determinants. Although several genetic variants have been found associated with VTE, they explain a minor proportion of VTE risk in cases. We undertook a meta-analysis of genome-wide association studies (GWASs) to identify additional VTE susceptibility genes. Twelve GWASs totaling 7,507 VTE case subjects and 52,632 control subjects formed our discovery stage where 6,751,884 SNPs were tested for association with VTE. Nine loci reached the genome-wide significance level of 5 × 10(-8) including six already known to associate with VTE (ABO, F2, F5, F11, FGG, and PROCR) and three unsuspected loci. SNPs mapping to these latter were selected for replication in three independent case-control studies totaling 3,009 VTE-affected individuals and 2,586 control subjects. This strategy led to the identification and replication of two VTE-associated loci, TSPAN15 and SLC44A2, with lead risk alleles associated with odds ratio for disease of 1.31 (p = 1.67 × 10(-16)) and 1.21 (p = 2.75 × 10(-15)), respectively. The lead SNP at the TSPAN15 locus is the intronic rs78707713 and the lead SLC44A2 SNP is the non-synonymous rs2288904 previously shown to associate with transfusion-related acute lung injury. We further showed that these two variants did not associate with known hemostatic plasma markers. TSPAN15 and SLC44A2 do not belong to conventional pathways for thrombosis and have not been associated to other cardiovascular diseases nor related quantitative biomarkers. Our findings uncovered unexpected actors of VTE etiology and pave the way for novel mechanistic concepts of VTE pathophysiology.

Inherited Thrombophilia

Thrombophilia alters normal hemostasis, shifting the balance in favor of thrombus formation. Inherited conditions include factor V Leiden (FVL), prothrombin G20210A mutation, deficiencies in natural anticoagulants (antithrombin [AT], protein C, and protein S), hyperhomocysteinemia, and elevations in clotting factors (factors VIII and XI). Although FVL and prothrombin mutation are common disorders, deficiencies in the natural anticoagulants are rare. The risk of initial thrombosis conferred by inherited thrombophilia varies with the highest risk in those homozygous for either FVL or prothrombin mutation, or with AT deficiency. In the nonpregnant patient, the presence of a thrombophilia does not affect treatment of an acute event. Although vitamin B supplementation has been shown to decrease the levels of homocysteine, the treatment has failed to show a benefit in thrombus prevention and is therefore not recommended.

Body mass index, a major confounder to insulin resistance association with unprovoked venous thromboembolism. Results from the EDITH case-control study

Shared risk factors help explain the association between venous thromboembolism (VTE) and atherothrombosis. The potential association between insulin resistance and VTE has been poorly evaluated. Thus, we aimed to assess the association between insulin resistance and VTE in the EDITH hospital-based case-control study. Between May 2000 and December 2004, 677 patients with unprovoked VTE and their age- and sex-matched controls were included. Fasting glycaemia and insulinaemia were measured and insulin resistance was estimated with the homeostasis model assessment of insulin resistance (HOMA-IR) equation. The association between HOMA-IR and VTE was determined in non-diabetic patients in a quintile-based analysis. A total of 590 non-diabetic cases (median age 73.0 years, 255 men) and 581 non-diabetic controls (median age 72.0 years, 247 men) were analysed. There was a trend for a higher median level of HOMA-IR index in cases than in controls (1.21 [interquartile range 0.84-2.10] vs1.19 [interquartile range 0.72-2.02], p=0.08). The unadjusted analysis showed an increased risk of unprovoked VTE associated with increasing HOMA-IR (odds ratio [OR] 1.53; 95% confidence interval [CI] 1.00-2.34 for the highest quintile of HOMA-IR compared with the first quintile). Adjustment for lipid lowering drugs and antiplatelet agents use slightly modified the association (OR 1.51; 95% CI 0.97-2.34). When body mass index was added in the adjusted model, HOMA-IR was no longer associated with VTE (OR 1.08; 95% CI 0.67-1.73). Our results highlight the role of body mass index in the association between cardiovascular risk factors and VTE.

Association between B-group vitamins and venous thrombosis: systematic review and meta-analysis of epidemiological studies

A homocysteine-independent role for B-group vitamins on venous thrombosis (VT) development has been reported. However, related research findings remain inconsistent. PUBMED, EMBASE, and COCHRANE databases were searched to collect information on all eligible studies to make a meta-analysis about the relationship between B-group vitamins and VT. Literature search results did not suggest a correlation between thiamin, pantothenic acid, niacin, or riboflavin with VT. Based on their correlations in the literature, folic acid, vitamin B12, B6 were considered in the meta-analysis and systematic review. Significant standardized mean differences were obtained for plasma folic acid (-0.55; 95% CI, -0.75 to -0.36) and vitamin B12 (-0.34; 95% CI, -0.55 to -0.13). Reduced levels of folic acid and vitamin B12 may be independent risk factors of VT. Moreover, a qualitative systematic review indicated that low level of vitamin B6 was an independent risk factor of VT. Randomized clinical studies of B-group vitamins supplementation showed varying results on VT prevention. Multivitamin supplementation for VT prevention, regardless of homocysteine level, would be of interest. Further prospective clinical studies are needed to provide additional evidence on the clinical benefits of B-group vitamin supplementation for VT.

C677T methylenetetrahydrofolate reductase gene polymorphism as a risk factor involved in venous thromboembolism: a population-based case-control study

The aim of the current study was to investigate the possible correlation between the C677T methylenetetrahydrofolate reductase (MTHFR) polymorphism and venous thromboembolism (VTE) in a population-based case-control study. Homocysteine (Hcy) was quantified by Abbott IMx immunoassay; screening for C677T MTHFR substitution was performed by polymerase chain reaction (PCR) and restriction analysis. The results from the two groups (440 patients and 440 controls) revealed that the frequency of T alleles and TT carriers was significantly higher in patients compared with that of the healthy controls. The plasma levels of Hcy in the VTE group (13.05±2.37 µmol/l) were significantly higher compared with those in the control group (11.94±2.03 µmol/l, P<0.001). The C677T MTHFR polymorphism is suggested to be associated with the risk for VTE. Plasma levels of Hcy were raised in individuals with the homozygous MTHFR 677TT genotype. In conclusion, the results of the current study suggest that hyperhomocysteinemia and the homozygous 677TT MTHFR genotype are risk factors for VTE.

Impact of genetic factors (VKORC1, CYP2C9, CYP4F2 and EPHX1) on the anticoagulation response to fluindione

AIM

Genetic variants of the enzyme that metabolizes warfarin, cytochrome P-450 2C9 (CYP2C9) and of a key pharmacologic target of vitamin K antagonists, vitamin K epoxide reductase (VKORC1), contribute to differences in patients' responses to coumarin derivatives. The role of these variants in fluindione response is unknown. Our aim was to assess whether genetic factors contribute to the variability in the response to fluindione.

METHODS

Four hundred sixty-five patients with a venous thromboembolic event treated by fluindione for at least 3 months with a target international normalized ratio (INR) of 2.0 to 3.0 were studied. VKORC1, CYP2C9, CYP4F2 and EPHX1 genotypes were assessed. INR checks, fluindione doses and bleeding events were collected.

RESULTS

VKORC1 genotype had a significant impact on early anticoagulation (INR value ≥2 after the first two intakes) (P < 0.0001), on the time required to reach a first INR within the therapeutic range (P < 0.0001) and on the time to obtain a first INR value > 4 (P= 0.0002). The average daily dose of fluindione during the first period of stability was significantly associated with the VKORC1 genotype: 19.8 mg (±5.5) for VKORC1 CC, 14.7mg (±6.2) for VKORC1 CT and 8.2mg (±2.5) for VKORC1 TT (P < 0.0001). CYP2C9, CYP4F2 and EPHX1 genotypes did not significantly influence the response to fluindione.

CONCLUSIONS

VKORC1 genotype strongly affected anticoagulation induced by fluindione whereas CYP2C9, CYP4F2 and EPHX1 genotypes seemed less determining.

Lipid parameters, lipid lowering drugs and the risk of venous thromboembolism

BACKGROUND

Besides their effects on atherogenesis, lipids and lipoproteins could contribute to the development of venous thromboembolism (VTE). This association has been investigated in a few studies with conflicting results.

METHODS

Plasma levels of total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, apolipoprotein A-I and apolipoprotein B were measured in 467 patients with a first unprovoked VTE event diagnosed between May 2000 and December 2004 and in 467 age and sex matched controls. The association between these parameters and VTE was determined in non-users of lipid lowering drugs (LLD), in statin users and in fibrate users in a quartile-based analysis. We repeated this stratified analysis within each stratum of men and women.

RESULTS

The median age of patients was 73 years [interquartile range 58-80], 41.5% were men. Among the 934 patients of the study, 100 were treated with statin, 91 with fibrate and 743 were not receiving LLD. Among non users of LLD, high levels of apolipoprotein B were associated with VTE (OR 1.82, 95% CI 1.19-2.79) after adjustment for age and body mass index. Elevated LDL-cholesterol levels were associated with VTE only in men (OR 2.32, 95% CI 1.07-5.01). High levels of LDL/HDL-cholesterol and apolipoprotein B/apolipoprotein A-I ratios were associated with VTE (OR 2.76, 95% CI 1.69-4.50 and OR 1.86, 95% CI 1.16-2.97 respectively) but this effect was mainly observed in men. There was no association between lipid parameters and VTE in statin users and in fibrate users.

CONCLUSION

Our results are in line with the new concept of a global cardiovascular disease combining atherosclerosis and VTE.

Venous thromboembolism in patients with pancreatic cancer: implications of circulating tissue factor

Among cancers, pancreatic cancer is known to be associated with a higher incidence of venous thromboembolism (VTE). The aim of the study was to determine the implication of circulating tissue factor (TF) in VTE related to active pancreatic cancer. One hundred and sixty-four consecutive patients who participated to the Etude des Determinants et Interactions de la Thrombose veineuse (EDITH) study between January 2005 and August 2007 for symptomatic VTE related to active pancreatic cancer (n = 8), active cancer of other location (n = 42) or classified as unprovoked (n = 114) were included. TF activity (TFa) was measured in a one-stage kinetic chromogenic method. There were no differences of median TFa levels between patients with VTE related to cancer of other type than pancreas [2.01 pmol/l range (0.05-43.92)] and patients with unprovoked VTE [1.78 pmol/l (range 0.05-63.72), P = 0.21]. Median TFa levels were higher in patients with VTE related to pancreatic cancer [12.67 pmol/l (range 0.05-112.04)] than in patients with VTE related to cancer of other type [2.01 pmol/l (range 0.05-43.92), P = 0.02]. Higher levels of circulating TFa during the course of pancreatic cancer may explain the higher incidence of VTE associated with this type of cancer.

Vitamin B12 deficiency, hyperhomocysteinemia and thrombosis: a case and control study

This study aimed at assessing the relationship between thrombosis, hyperhomocysteinemia and vitamin B12 deficiency using a case-control study carried out in 326 patients with thrombosis (case group) and 351 patients from the same hospital (control group). Apart from the classic risk factors, a number of hematological variables were evaluated, including serum vitamin B12 (B12), red cell folate (RCF), and serum homocysteine (Hcy). An evaluation of serum methylmalonic acid (MMA) and a clinical study were carried out to investigate B12 pathology. Results of univariate analysis demonstrated decreased B12 levels in thrombosis (Student's t test, p < 0.0001). Vitamin B12 below 200 pmol/l (LB200) or below 150 pmol/l (LB150), and red cell folate below 600 nmol/l were found in 17.2, 8.6, and 2.2% of cases with thromboembolism, respectively. An increase in Hcy was detected in 86 cases with thrombosis (26.3%). An abnormality in vitamin B12 and/or renal function was found in 80% of cases with hyperHcy and thrombosis. The MMA increase demonstrated that vitamin B12 deficiency was present in these patients with low levels of vitamin B12 in serum, and the MMA levels were in concordance with Hcy levels. The clinical study revealed B12 malabsorption in most cases with LB200. Multivariate analysis showed that serum vitamin B12 (RR 0.998, CI 0.997-0.999) was moderately related to thromboembolism. The results indicated that vitamin B12 deficiency was common among patients with hyperhomocysteinemia and thrombosis. Moreover, HyperHcy was caused by vitamin B12 deficiency and/or chronic renal failure in most patients with thrombosis. As the main cause of vitamin B12 deficiency was vitamin malabsorption, parenteral vitamin B12 with or without folic acid should be administered for the treatment of this condition. However, it remains to be demonstrated whether this treatment approach prevents recurrent thromboses in patients with vitamin B12 deficiency and thrombosis, as suggested by some case reports.

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.

Antihypertensive drugs and risk of venous thromboembolism: results from the EDITH case-control study

Previous studies evaluating the association between arterial blood pressure and venous thromboembolism (VTE) reported conflicting results. The relationship between antihypertensive therapy and VTE has never been specifically evaluated. This report from a hospital-based case-control study included 785 cases with confirmed unprovoked VTE and their 785 age- and sex-matched controls. Cases and controls were asked for drug exposure in a one-to-one standardized interview using the same questionnaire. Drug exposure was defined as current use of drugs at admission with onset at least 1 week ago. Three hundred and eighty-four out of 785 cases (48.9%) and 379 out 785 controls (48.3%) reported that they were currently using at least one antihypertensive drug. Among all antihypertensive therapies, only angiotensin II receptor blockers were significantly associated with a reduced risk for VTE: adjusted conditional odds ratio (OR) 0.45 (95% CI, 0.29-0.70). In this hospital-based case-control study, a preventive role for angiotensin II receptor blockers as regards VTE risk was suggested. More studies are needed in order to further elucidate the biological mechanisms involved.

Should plasma homocysteine be used as a biomarker of venous thromboembolism? A case-control study

Mild or moderate hyperhomocysteinemia as a risk factor for venous thrombosis is still a matter of debate. The strength of this study is to bring a body of elements to evaluate whether hyperhomocysteinemia should be used as a biomarker for venous thromboembolism (VTE). These elements consist of a biological evaluation of several hematological risk factors, and an original control group made of patients with a negative Doppler ultrasonography. A total of 151 cases and 155 controls were included. Total plasma homocysteine level, MTHFR C677T polymorphism, inherited abnormalities of the natural anticoagulant system as well as plasma folate and cobalamin levels were determined. A total of 41 (27.2 %) of cases and only 9 (5.8%) of controls had at least one of the coagulation defects studied. No significant difference was observed for total homocysteine levels between the 2 groups: median (interquartile range) = 8.3 (7.2-10.8) micromol/L for cases and 8.4 (7-10.9) micromol/L for controls. We found significantly more plasma folates and/or cobalamin deficiencies in controls (18.3%) than in cases (8.6%). After adjustment for several variables significantly related to risk factors of VTE, hyperhomocysteinemia (>13.2 micromol/L) was not found statistically associated with VTE: odds ratio 1.36 (95% confidence interval, 0.52-3.54). The prevalence of the homozygous 677TT polymorphism in the MTHFR gene was not increased in cases compared with controls. Mild or moderate hyperhomocysteinemia does not seem to be a strong determinant in VTE not only when the control group does not exclusively include healthy persons but also in investigated disease-free (thromboembolic disease) controls.

Relationship between methionine synthase, methionine synthase reductase genetic polymorphisms and deep vein thrombosis among South Indians

BACKGROUND

The rationale behind this study was to examine the relationship between polymorphisms in genes that regulate remethylation of homocysteine to methionine, i.e., methionine synthase (MTR A2756G) and methionine synthase reductase (MTRR A66G), and risk of deep vein thrombosis (DVT) in a South Indian cohort (163 DVT cases and 163 controls), as elevated homocysteine has been documented as an independent risk factor for DVT in the same cohort.

METHODS

Plasma homocysteine analysis was carried out by reverse phase HPLC. The MTR A2756G and MTRR A66G genetic polymorphisms were detected using PCR-restriction fragment length polymorphism method. For statistical analyses, Fisher's exact test was used for categorical variables and Student's t-test and analysis of variance were used for continuous variables.

RESULTS

The MTRR 66GG genotype was associated with a 2.74-fold [95% confidence interval (CI): 1.73, 4.34] risk of DVT. The MTR A2756G polymorphism was not a risk factor. MTRR GG/MTR AG and MTRR GG/MTR GG genotypes cumulatively were found to increase the risk of DVT by 2.38-fold (95% CI: 1.43, 3.96). A positive association was observed between plasma homocysteine and the MTRR G allele, and the MTR G allele was shown to have an additive effect. The risk associated with the MTRR 66GG genotype was further increased in subjects compound heterozygous for methylene tetrahydrofolate reductase (MTHFR) [odds ratio (OR): 3.46, 95% CI: 1.38, 8.63].

CONCLUSIONS

The MTRR 66GG genotype is a risk factor for DVT among South Indians. This risk is increased further in the presence of the MTHFR 677CT/1298AC genotype.

Association between antipsychotic drugs, antidepressant drugs and venous thromboembolism: results from the EDITH case-control study

Cohort studies suggest that exposure to antipsychotic agents may be associated with an increased risk of venous thromboembolism (VTE). Few data concerning antidepressant drugs are available. Using a different methodological approach, the aim of this study was to estimate the association between neuroleptic and antidepressant drug use and the risk of VTE. We report the results of a case-control study designed to evaluate interactions between acquired and inherited risk factors of VTE. We included 677 cases hospitalized with deep vein thrombosis and or pulmonary embolism with no major acquired risk factor for VTE, and 677 controls matched for gender and age. Drug exposure was defined as current use of drugs at admission. Neuroleptic exposure was associated with an increased risk of VTE (OR = 2.1, 95% CI 1.4-3.2). Among neuroleptics, antipsychotic agent use was associated with a 3.5-fold increased risk of VTE (OR = 3.5, 95% CI 2.0-6.2). No association was found between antidepressant drug exposure and the risk of VTE (OR = 1.1, 95% CI 0.9-1.5). In this hospital-based case-control study, exposure to antipsychotic drugs was associated with an increased risk of VTE. These results, added to previous results, suggest that clinicians should consider antipsychotic drug exposure as a potential risk factor of VTE. More studies are needed in order to further elucidate this adverse effect, and to determine the possible predisposing factors and the biological mechanisms involved.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Links between arterial and venous disease

An increasing body of evidence suggests the likelihood of a link between arterial and venous disease. According to the results of recent studies, atherosclerosis and venous thromboembolism (VTE) share common risk factors, including age, obesity, diabetes mellitus and metabolic syndrome. Atherosclerosis has the potential to promote the development of thrombotic disorders in the venous system. Another scenario assumes that the two clinical conditions are simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system. Several recent studies have consistently shown that patients with VTE of unknown origin are at a higher risk of cardiovascular diseases, including atherosclerotic complications, than patients with secondary VTE and matched control individuals. Future studies are needed to clarify the nature of this association, to assess its extent and to evaluate its implications for clinical practice.

Venous thromboembolism and atherosclerosis: is there a link?

After the initial demonstration provided 4 years ago by a case-control study in the New England Journal of Medicine, numerous investigations have addressed the association between venous and arterial thrombotic disorders. According to the results of recent studies, the two conditions are likely to share common risk factors, including age, obesity, cigarette smoking, diabetes mellitus, arterial hypertension, hyperlipemia and metabolic syndrome. The nature of this association is unclear. On the one hand, atherosclerosis has the potential to promote the development of thrombotic disorders in the venous system. On the other hand, the two clinical conditions can be simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system. Based on the results of two population-based studies carried out in the USA, atherosclerosis is unlikely to constitute a risk factor for venous thromboembolic (VTE) disorders. Several recent studies have consistently shown that subjects with VTE of unknown origin are at a higher risk of subsequent arterial cardiovascular events than subjects with secondary VTE and matched control individuals. In conclusion, the separate nature of arterial and venous disorders has been challenged. Future studies are needed to clarify the nature of this association, to assess its extent, and to evaluate its implications for clinical practice.

Plasma homocysteine cutoff values for venous thrombosis

BACKGROUND

Hyperhomocysteinemia is considered an independent risk factor for vascular occlusive diseases. To date, there is no general agreement on hyperhomocysteinemia cutoff values.

METHODS

To establish a homocysteine cutoff value, we performed a case-control study in 118 patients suffering from venous thrombosis and in 115 healthy subjects. We calculated odds ratios at different cutoff points and considered hyperhomocysteinemia as homocysteine levels above which the risk of venous thrombosis was increased.

RESULTS

Initially we used the 97.5th percentiles for fasting homocysteine levels in the control group to calculate odds ratios (95% CI) of 9.5 (2.6-35.3), 3.7 (0.8-17.9) and 4.5 (1.7-123.8) for the total population, women and men, respectively. When individuals with well-known thrombotic risk factors were excluded (selected population), odds ratios were 10.5 (2.7- 41.1), 6.5 (1.3-32.1) and 11.2 (1.2-103.1), respectively, confirming hyperhomocysteinemia as an independent risk factor for venous thrombosis. We did not find any association of venous thrombosis with the homozygous methylenetetrahydrofolate reductase C677T mutation. When the hyperhomocysteinemia cutoff was set at other arbitrary points, odds ratios for the selected population were statistically significant only at >12 micromol/L.

CONCLUSIONS

Based on our results, we propose 12 micromol/L as the hyperhomocysteinemia cutoff value.

Hyperhomocysteinemia and the compound heterozygous state for methylene tetrahydrofolate reductase are independent risk factors for deep vein thrombosis among South Indians

To investigate the role of methylene tetrahydrofolate reductase (MTHFR) (677 C-->T and 1298 A-->C), factor V (1691 G-->A), factor II (20210 G-->A) genetic polymorphisms and hyperhomocysteinemia in the aetiology of deep vein thrombosis (DVT) in 163 cases and 163 controls. Polymerase chain reaction-restriction fragment length polymorphism was used for genotyping, reverse-phase high-performance liquid chromatography for plasma homocysteine, and Student's t-test and Fisher exact tests were used for statistical analysis. Elevated mean plasma homocysteine levels were observed in DVT cases irrespective of gender differences. Homocysteine elevation above the 95th percentile of the control group associated with 9.4-fold and 7.6-fold increased risk for DVT in men and women, respectively. Genotyping showed the MTHFR 677CT/1298AC genotype (i.e. compound heterozygosity) is associated with 3.5-fold risk for thrombosis. The factor V Leiden mutation frequency was higher in DVT cases, but not statistically significant; however, genetic predisposition to this mutation was associated with early age of DVT onset. Factor II mutation was absent in cases and controls. Co-segregation of two or more risk factors was associated with 11.7-fold increased risk for thrombosis. This study projects that hyperhomocysteinemia and compound heterozygous state for MTHFR are independent risk factors for DVT among South Indians.

Who should be tested for thrombophilia?

PURPOSE OF REVIEW

The purpose of this review is to identify on the basis of available data and expert opinions who would benefit most from screening for thrombophilia.

RECENT FINDINGS

Recent studies have clearly defined the risk of venous thromboembolism in members of families with inherited thrombophilia. Meta-analyses have shown the role of the most common thrombophilic conditions in increasing the risk of recurrent venous thromboembolism in carriers. Screening for thrombophilia in venous thromboembolism patients might help identify those at higher risk of recurrences even though it is unclear how this information can be of use in modifying their management. Thrombophilia seems to play a role in early fetal losses as also shown in women at their first intended pregnancy, which makes it interesting to screen women after only one bad pregnancy outcome.

SUMMARY

Screening for thrombophilia can be performed particularly in young patients with venous thromboembolism. Carriers of inherited thrombophilia are at increased risk of venous thromboembolism recurrences. Screening families of venous thromboembolism patients with thrombophilia allows the identification of still asymptomatic carriers who may benefit from thromboprophylaxis. This may be true of women in fertile age belonging to thrombophilic families. In thrombophilic women with pregnancy complications prophylaxis may be offered to prevent recurrences.