Mechanisms and mitigating factors for venous thromboembolism in chronic kidney disease: the REGARDS study.

Essentials Chronic kidney disease (CKD) is associated with procoagulant and inflammatory biomarkers. We studied the association of CKD and venous thromboembolism (VTE) in a case-cohort study. Factor VIII, D-dimer and C-reactive protein appeared to explain the association of CKD and VTE. Statin use was protective against VTE in those with and without CKD. SUMMARY: Background Chronic kidney disease (CKD) is associated with venous thromboembolism (VTE) risk via unknown mechanisms. Whether factors associated with reduced VTE risk in the general population might also be associated with reduced VTE risk in CKD patients is unknown. Objectives To determine whether thrombosis biomarkers attenuate VTE risk, and whether factors associated with reduced VTE risk are similarly effective in CKD patients. Methods Baseline biomarkers were measured in a cohort (294 VTE cases; 939 non-cases) from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a nationwide prospective cohort study of 30 239 persons aged ≥45 years with 4.3 years of follow-up. The hazard ratio (HR) of VTE per 10 mL min-1 1.73 m-2 decrease in estimated glomerular filtration rate (eGFR), and the percentage attenuation of this HR by each biomarker, were calculated. Associations of protective factors (physical activity, lower body mass index [BMI], and aspirin, warfarin and statin use) with VTE were estimated in those with and without CKD. Results The HR for VTE with lower eGFR was 1.13 (95% confidence interval [CI] 1.02-1.25), and VTE risk was attenuated by 23% (95% CI 5-100) by D-dimer, by 100% (95% CI 50-100) by factor VIII, and by 15% (95% CI 2-84) by C-reactive protein. Normal BMI was associated with lower VTE risk in those without CKD (HR 0.47, 95% CI 0.32-0.70), but not in those with CKD (HR 1.07, 95% CI 0.51-2.22). Statin use, physical activity and warfarin use were associated with lower VTE risk in both groups. Conclusions Procoagulant and inflammatory biomarkers mediated the association of eGFR with VTE. Higher physical activity, statin use and warfarin use mitigated VTE risk in those with CKD and those without CKD, but normal BMI did not mitigate VTE risk in CKD patients.

Longitudinal increases in blood biomarkers of inflammation or cardiovascular disease and the incidence of venous thromboembolism.

Essentials Inflammatory and cardiac diseases are associated with increased venous thromboembolism (VTE) risk. Our prospective study assessed rise in inflammatory or cardiac biomarkers and VTE risk. A greater 6-year rise in N-terminal natriuretic peptide is associated with increased VTE incidence. Volume overload or impending cardiac disease may contribute to VTE occurrence. SUMMARY: Background We previously showed that participants in the population-based Atherosclerosis Risk in Communities (ARIC) cohort with elevated levels of blood biomarkers of inflammation or cardiac disease were at increased risk of venous thromboembolism (VTE). Objective We hypothesized that ARIC participants with larger 6-year increases in the levels of three biomarkers - C-reactive protein (CRP), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and troponin T - would also have an increased subsequent risk of VTE. Methods We measured changes in the levels of these biomarkers in 9844 participants from 1990-1992 to 1996-1998, and then identified VTEs through 2015. Results A greater 6-year rise in the level of NT-proBNP, but not in that of CRP or troponin T, was significantly associated with increased VTE incidence over a median of 17.6 years of follow-up. After adjustment for other VTE risk factors, those whose NT-proBNP level rose from < 100 pg mL-1 to ≥ 100 pg mL-1 had a hazard ratio for VTE of 1.44 (95% confidence interval [CI] 1.15-1.80), as compared with the reference group with an NT-proBNP level of < 100 pg mL-1 at both times. This hazard ratio was slightly higher (1.66, 95% CI 1.19-2.31) during the first 10 years of follow-up, but was attenuated (1.24, 95% CI 0.99-1.56) after adjustment for prevalent and incident coronary heart disease, heart failure, and atrial fibrillation. Conclusions The two most likely explanations for our results are that: (i) an increasing NT-proBNP level reflects increasing subclinical volume overload and potentially increased venous stasis or subclinical PE that had gone unrecognized over time; or (ii) an increasing NT-proBNP level is a risk marker for impending cardiac disease that places patients at risk of VTE.

Hemostasis biomarkers and incident cognitive impairment: the REGARDS study.

Essentials Cognitive disorders are increasing and vascular risk factors play a role in this. We performed a nested case control study of hemostasis biomarkers and cognitive impairment (CI). Higher baseline fibrinogen, factor VIII and D-dimer were related to incident CI over 3.5 years. Adjusted for other risk factors, 2+ abnormal markers (but not single ones) led to higher risk. SUMMARY: Background Vascular risk factors are associated with cognitive impairment, a condition that imposes a substantial public health burden. We hypothesized that hemostasis biomarkers related to vascular disease would be associated with the risk of incident cognitive impairment. Methods We performed a nested case-control study including 1082 participants with 3.5 years of follow-up in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a longitudinal cohort study of 30 239 black and white Americans aged ≥ 45 years. Participants were free of stroke or cognitive impairment at baseline. Baseline D-dimer, fibrinogen, factor VIII and protein C levels were measured in 495 cases who developed cognitive impairment during follow-up (based on abnormal scores on two or more of three cognitive tests) and 587 controls. Results Unadjusted odds ratios (ORs) for incident cognitive impairment were 1.32 (95% confidence interval [CI] 1.02-1.70) for D-dimer > 0.50 µg mL-1 , 1.83 (95% CI 1.24-2.71) for fibrinogen > 90th percentile, 1.63 (95% CI 1.11-2.38) for FVIII > 90th percentile, and 1.10 (95% CI 0.73-1.65) for protein C < 10th percentile. There were no differences in associations by race or region. Adjustment for demographic, vascular and health behavior risk factors attenuated these associations. However, having at least two elevated biomarkers was associated with incident cognitive impairment, with an adjusted OR of 1.73 (95% CI 1.10-2.69). Conclusion Elevated D-dimer, fibrinogen and FVIII levels were not associated with the occurrence of cognitive impairment after multivariable adjustment; however, having at least two abnormal biomarkers was associated with the occurrence of cognitive impairment, suggesting that the burden of these biomarkers is relevant.

Vasomotor symptoms and the risk of incident venous thrombosis in postmenopausal women.

Essentials Vasomotor symptoms have been proposed as markers of changing cardiovascular risk. In this cohort study, we evaluated these symptoms as markers of venous thrombosis (VT) risk. We found no evidence that vasomotor symptom presence or severity were associated with VT risk. Among these postmenopausal women, vasomotor symptoms are not a useful marker of VT risk. SUMMARY: Background Vasomotor symptoms may be markers of changes in cardiovascular risk, but it is unknown whether these symptoms are associated with the risk of venous thrombosis (VT). Objective To evaluate the association of vasomotor symptom presence and severity with incident VT risk among postmenopausal women, independent of potential explanatory variables. Methods This cohort study included participants of the Women's Health Initiative (WHI) Hormone Therapy Trials (n = 24 508) and Observational Study (n = 87 783), analyzed separately. At baseline, women reported whether hot flashes or night sweats were present and, if so, their severity. Using Cox proportional hazards models, we estimated the VT risk associated with vasomotor symptom presence and severity, adjusted for potential explanatory variables: age, body mass index, smoking status, race/ethnicity, and time-varying current hormone therapy use. Results At baseline, WHI Hormone Therapy Trial participants were aged 64 years and WHI Observational Study participants were aged 63 years, on average. In the WHI Hormone Therapy Trials over a median of 8.2 years of follow-up, 522 women experienced a VT event. In the WHI Observational Study, over 7.9 years of follow-up, 1103 women experienced a VT event. In adjusted analyses, we found no evidence of an association between vasomotor symptom presence (hazard ratio [HR]adj  0.91, 95% confidence interval [CI] 0.75-1.1 in the WHI Hormone Therapy Trials; HRadj  1.1, 95% CI 0.99-1.3 in the WHI Observational Study) or severity (HRadj for severe versus mild 0.99, 95% CI 0.53-1.9 in the WHI Hormone Therapy Trials; HRadj  1.3, 95% CI 0.89-2.0) in the WHI Observational Study) and the risk of incident VT. Conclusions Although vasomotor symptoms have been associated with the risk of other cardiovascular events in published studies, our findings do not suggest that vasomotor symptoms constitute a marker of VT risk.

Effect of rosuvastatin on risk markers for venous thromboembolism in cancer.

Essentials Statins lower venous thromboembolism risk in general but have not been studied in cancer patients. We completed a randomized trial of rosuvastatin vs. placebo among cancer patients on chemotherapy. Rosuvastatin did not significantly lower prothrombotic biomarkers including D-dimer. The role of statins in venous thrombosis prevention in cancer patients remains unknown. SUMMARY: Background Statin therapy is associated with lower risk of venous thromboembolism (VTE) but has not been prospectively evaluated in patients with advanced cancer. Objectives We determined if statin administration in this high-risk population reduces the risk of VTE, based on established and emerging biomarkers. Patients/Methods This double-blind, crossover, randomized controlled trial among patients with advanced cancer receiving systemic therapy allocated participants to rosuvastatin 20 mg daily or placebo for 3-4 weeks prior to crossover to the alternative therapy, with a 3-5-week washout. D-dimer, C-reactive protein (CRP), soluble (s)P-selectin, factor VIII (FVIII), thrombin generation and exploratory biomarkers focusing on endogenous thrombin potential, including tissue factor (TF), activated factor IX (FIXa) and activated factor XI (FXIa), were measured at the start and end of both treatment periods. The primary outcome was change in D-dimer with rosuvastatin compared with placebo. Results Of 38 enrolled participants, 24 (63%) completed the study. Rosuvastatin did not cause statistically significant changes in D-dimer levels or any other biomarker. CRP levels decreased by 40%; 4.3 mg L-1 (95% confidence interval, -11.0 to +2.5 mg L-1 ) compared with placebo. In post-hoc analysis, participants who received rosuvastatin initially during their first line of treatment had a 13% decrease in D-dimer. Circulating TF, FIXa and FXIa were detected in 26%, 68% and 71% of cancer patients despite not being found in healthy individuals. Conclusions Rosuvastatin did not cause favorable changes in biomarkers of VTE risk in advanced cancer patients receiving chemotherapy. The role of statin therapy as thromboprophylaxis in the cancer population remains uncertain.

Atrial fibrillation and venous thromboembolism: evidence of bidirectionality in the Atherosclerosis Risk in Communities Study.

Essentials Atrial fibrillation (AF) may increase risk of venous thromboembolism (VTE), and vice versa. Bidirectionality was assessed prospectively via data from 15 129 black and white individuals. AF was associated with greater risk of developing VTE, and VTE with greater risk of AF. Associations were strongest among blacks and in the first 6 months after initial diagnosis. SUMMARY: Background Atrial fibrillation (AF) and venous thromboembolism (VTE) frequently co-occur. These conditions have shared risk factors and are accompanied by coagulation abnormalities. Furthermore, mechanistic pathways may directly link the disorders. Objectives To test the hypothesis that individuals with incident AF are at greater risk of developing VTE, and those with VTE are at elevated risk of AF. We also tested whether associations were stronger in the first 6 months after the initial diagnosis, and explored race differences. Patients/Methods A total of 15 129 ARIC study participants (45-64 years, 55% female, 26% Black) were followed from 1987 to 2011 for incident AF and VTE (median follow-up 19.8 years). Multivariable-adjusted Cox regression was used, with AF and VTE modeled as time-dependent exposures. Results Incident AF was associated with greater risk of subsequent incident VTE (hazard ratio [95% CI], 1.71 [1.32-2.22]); the association was stronger in Black people (2.30 [1.48-3.58]) and during the first 6 months after AF diagnosis (5.08 [3.08-8.38]). Similarly, incident VTE was associated with increased risk of incident AF (1.73 [1.34-2.24]), especially in Black people (2.40 [1.55-3.74]) and in the first 6 months after VTE diagnosis (4.50 [2.61-7.77]). Conclusions The occurrence of AF was associated with increased risk of incident VTE, and occurrence of VTE was associated with greater risk of incident AF. Associations were particularly strong among Black people and during the first 6 months after the initial diagnosis, although they remained elevated even after 6 months. These findings highlight patient populations that may be at increased risk of AF and VTE, and perhaps should be targeted with preventive strategies.

Galectin-3 and risk of ischaemic stroke: Reasons for Geographic and Racial Differences in Stroke cohort.

BACKGROUND AND PURPOSE: Galectin-3 is a biomarker of atherosclerotic and cardiovascular disease, and may be a useful marker for ischaemic stroke risk. METHODS: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort enrolled and examined 30 239 US participants between 2003 and 2007 (41% black, 59% white and 55% in the southeastern stroke belt). Baseline galectin-3 was measured in 526 subjects with incident ischaemic stroke over 5.4 years and in a cohort random sample (CRS) of 947 participants. Cox proportional hazards models were used to calculate hazard ratios (HRs) of ischaemic stroke by quartiles of galectin-3. RESULTS: In the CRS, galectin-3 was significantly higher with older age, black race, female sex, body mass index, hypertension, diabetes mellitus and kidney disease, and also in those who developed incident stroke. Participants with galectin-3 levels in the fourth versus first quartile had a 2.3-fold increased stroke risk [95% confidence interval (CI) 1.6, 3.4] in an unadjusted model. An interaction with age was found (P = 0.06), and therefore age-stratified analyses were performed. Amongst those younger than age 64, baseline galectin-3 in the second-fourth quartiles was associated with increased stroke risk (HR 3.0, 95% CI 1.6, 5.5) compared to the first quartile in an age-, race- and sex-adjusted model. The HR was 2.0 (95% CI 1.0, 4.0) with multivariable adjustment. There was no association amongst older participants. CONCLUSIONS: Galectin-3 was associated with incident ischaemic stroke in younger but not older individuals. Confirmation of this finding, and elucidation of its implications for stroke pathophysiology and prevention, is needed.

Associations of coagulation factors IX and XI levels with incident coronary heart disease and ischemic stroke: the REGARDS study.

Essentials Coagulation factors (F) IX and XI have been implicated in cardiovascular disease (CVD) risk. We studied associations of FIX and FXI with incident coronary heart disease (CHD) and stroke. Higher FIX antigen was associated with incident CHD risk in blacks but not whites. Higher levels of FIX antigen may be a CHD risk factor among blacks. SUMMARY: Background Recent studies have suggested the importance of coagulation factor IX and FXI in cardiovascular disease (CVD) risk. Objectives To determine whether basal levels of FIX or FXI antigen were associated with the risk of incident coronary heart disease (CHD) or ischemic stroke. Patients/Methods The REasons for Geographic And Racial Differences in Stroke (REGARDS) study recruited 30 239 participants across the contiguous USA between 2003 and 2007. In a case-cohort study within REGARDS, FIX and FXI antigen were measured in participants with incident CHD (n = 609), in participants with incident ischemic stroke (n = 538), and in a cohort random sample (n = 1038). Hazard ratios (HRs) for CHD and ischemic stroke risk were estimated with Cox models per standard deviation higher FIX or FXI level, adjusted for CVD risk factors. Results In models adjusting for CHD risk factors, higher FIX levels were associated with incident CHD risk (HR 1.19; 95% confidence interval [CI] 1.01-1.40) and the relationship of higher FXI levels was slightly weaker (HR 1.15; 95% CI 0.97-1.36). When stratified by race, the HR of FIX was higher in blacks (HR 1.39; 95% CI 1.10-1.75) than in whites (HR 1.06; 95% CI 0.86-1.31). After adjustment for stroke risk factors, there was no longer an association of FIX levels with ischemic stroke, whereas the association of FXI levels with ischemic stroke was slightly attenuated. Conclusions Higher FIX antigen levels were associated with incident CHD in blacks but not in whites. FIX levels may increase CHD risk among blacks.

Taller height as a risk factor for venous thromboembolism: a Mendelian randomization meta-analysis.

Essentials Observational data suggest taller people have a higher risk of venous thromboembolism (VTE). We used Mendelian randomization techniques to further explore this association in three studies. Risk of VTE increased by 30-40% for each 10 cm increment in height. Height was more strongly associated with deep vein thrombosis than with pulmonary embolism. SUMMARY: Background Taller height is associated with a greater risk of venous thromboembolism (VTE). Objectives To use instrumental variable (IV) techniques (Mendelian randomization) to further explore this relationship. Methods Participants of European ancestry were included from two cohort studies (Atherosclerosis Risk in Communities [ARIC] study and Cardiovascular Health Study [CHS]) and one case-control study (Mayo Clinic VTE Study [Mayo]). We created two weighted genetic risk scores (GRSs) for height; the full GRS included 668 single-nucleotide polymorphisms (SNPs) from a previously published meta-analysis, and the restricted GRS included a subset of 362 SNPs not associated with weight independently of height. Standard logistic regression and IV models were used to estimate odds ratios (ORs) for VTE per 10-cm increment in height. ORs were pooled across the three studies by the use of inverse variance-weighted random effects meta-analysis. Results Among 9143 ARIC and 3180 CHS participants free of VTE at baseline, there were 367 and 109 incident VTE events. There were 1143 VTE cases and 1292 controls included from Mayo. The pooled ORs from non-IV models and models using the full and restricted GRSs as IVs were 1.27 (95% confidence interval [CI] 1.11-1.46), 1.34 (95% CI 1.04-1.73) and 1.45 (95% CI 1.04-2.01) per 10-cm greater height, respectively. Conclusions Taller height is associated with an increased risk of VTE in adults of European ancestry. Possible explanations for this association, including taller people having a greater venous surface area, a higher number of venous valves, or greater hydrostatic pressure, need to be explored further.

Association of stroke risk biomarkers with stroke symptoms: the Reasons for Geographic and Racial Differences in Stroke cohort.

Essentials Stroke symptom history predicts future stroke and may indicate prior unrecognized stroke. We studied associations of stroke symptoms with stroke risk biomarkers. Several stroke risk biomarkers were independently associated with stroke symptom history. Findings support a hypothesis that stroke symptoms may represent unrecognized stroke. SUMMARY: Background History of stroke symptoms in the absence of prior diagnosed stroke or transient ischemic attack (TIA) is associated with future stroke risk, as are biomarkers of inflammation, cardiac function and hemostasis. Objective To better elucidate the pathobiology of stroke symptoms, we studied associations of these biomarkers with history of stroke symptoms. Methods The Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort enrolled 30 239 black and white Americans age 45 years and older in 2003-7. In cross-sectional analyses in a random sample of 960 participants without prior stroke or TIA, levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP), fibrinogen, factor VIII (FVIII), factor XI (FXI), C-reactive protein (CRP) and D-dimer were studied in relation to self-reported history of six sudden onset stroke symptoms. Results There were 190 participants with at least one stroke symptom and 770 without. Adjusting for age, race, sex and stroke risk factors, NT-proBNP, FXI, CRP and D-dimer in the top vs. bottom quartile were associated with prevalent stroke symptoms with odds ratios 2.69 (95% confidence interval [CI], 1.45-4.98), 1.65 (95% CI, 1.00-2.73), 2.21 (95% CI, 1.32-3.71) and 2.14 (95% CI, 1.22-3.75), respectively. Conclusions Strong associations of stroke risk biomarkers with stroke symptoms in persons without a clinical history of cerebrovascular disease support a hypothesis that some of these stroke symptoms represent unrecognized cerebrovascular disease. Future work is needed to determine whether these biomarkers identify persons with stroke symptoms who have a particularly high stroke risk.

Lung function, respiratory symptoms and venous thromboembolism risk: the Atherosclerosis Risk in Communities Study.

Essentials The association of lung function with venous thromboembolism (VTE) is unclear. Chronic obstructive pulmonary disease (COPD) patterns were associated with a higher risk of VTE. Symptoms were also associated with a higher risk of VTE, but a restrictive pattern was not. COPD may increase the risk of VTE and respiratory symptoms may be a novel risk marker for VTE. SUMMARY: Background The evidence for the association between chronic obstructive pulmonary disease (COPD) and venous thromboembolism (VTE) is limited. There is no study investigating the association between restrictive lung disease (RLD) and respiratory symptoms with VTE. Objectives To investigate prospectively the association of lung function and respiratory symptoms with VTE. Patients/Methods In 1987-1989, we assessed lung function by using spirometry, and obtained information on respiratory symptoms (cough, phlegm, and dyspnea) in 14 654 participants aged 45-64 years, without a history of VTE or anticoagulant use, and followed them through 2011. Participants were classified into four mutually exclusive groups: 'COPD' (forced expiratory volume in 1 s [FEV1 ]/forced vital capacity [FVC] below the lower limit of normal [LLN]), 'RLD' (FEV1 /FVC ≥ LLN and FVC < LLN), 'respiratory symptoms with normal spirometic results' (without RLD or COPD), and 'normal' (without respiratory symptoms, RLD, or COPD). Results We documented 639 VTEs (238 unprovoked and 401 provoked VTEs). After adjustment for VTE risk factors, VTE risk was increased for individuals with either respiratory symptoms with normal spirometric results (hazard ratio [HR] 1.40, 95% confidence interval [CI] 1.12-1.73) or COPD (HR 1.33, 95% CI 1.07-1.67) but not for those with RLD (HR 1.15, 95% CI 0.82-1.60). These elevated risks of VTE were derived from both unprovoked and provoked VTE. Moreover, FEV1 and FEV1 /FVC showed dose-response relationships with VTE. COPD was more strongly associated with pulmonary embolism than with deep vein thrombosis. Conclusions Obstructive spirometric patterns were associated with an increased risk of VTE, suggesting that COPD may increase the risk of VTE. Respiratory symptoms may represent a novel risk marker for VTE.

Genetic risk factors for venous thrombosis in the elderly in a case-control study.

UNLABELLED: Essentials Risk of venous thrombosis (VT) related to common genetic variants in those aged 70+ is unknown. We studied Factor V Leiden, prothrombin mutation, non-O blood group and family history (FH) of VT. Risk of VT was increased 2.2-, 1.4-, 1.3- and 2.1-fold respectively. FH is easy to obtain and can be implemented in clinical decision rules of VT risk in the elderly. Click to hear Prof. Reitsma discuss genetic risk factors of arterial and venous thrombosis SUMMARY: Background As the incidence of venous thrombosis (VT) increases steeply with age and the number of elderly people is on the rise, studies of VT in this age group are important. Objectives We aimed to study the associations of common genetic risk factors (i.e. the factor V Leiden and prothrombin G20210A mutations, non-O blood group and family history of VT) with risk of a first VT in older age (> 70 years). Methods Four hundred and one consecutive cases with a first-time thrombosis and 431 controls (all ≥ 70 years) were included in the AT-AGE case-control study. Information on risk factors for VT, including family history of VT in first-degree relatives, was obtained by interview. Unprovoked VT was defined as thrombosis not related to surgery, fracture, plaster cast or immobility within 3 months prior to VT. Results The risk of VT was 2.2-fold increased in factor V Leiden carriers (95% confidence interval [CI], 1.2-3.9), 1.4-fold increased in prothrombin mutation carriers (95% CI, 0.5-3.9), and 1.3-fold increased in those with non-O blood group (95% CI, 1.0-1.8). Positive family history of VT was associated with a 2.1-fold increased risk of VT (95% CI, 1.5-3.1). The highest risk of VT was found in individuals who had both a positive family history and were carriers of one of the two prothrombotic mutations. Conclusions Genetic factors clearly related to VT in younger populations were also risk factors in older age and a positive family history was also important in this age group.

Replication of a genetic risk score for venous thromboembolism in whites but not in African Americans.

UNLABELLED: ESSENTIALS: There is little prospective information on genetic risk scores to predict venous thromboembolism (VT). Community based cohort followed a median of 22.6 years for VT occurrence. A 5-SNP risk score identified whites at risk of VT, but not African Americans. The utility of genetic risk scores for VT is yet to be established. BACKGROUND: Case-control studies have created genetic risk scores of single nucleotide polymorphisms (SNPs) associated with venous thromboembolism (VTE) and documented their ability to predict VTE, but prospective data are lacking. OBJECTIVE: To test the ability of a genetic risk score to predict VTE incidence in a prospective study, particularly in African Americans. METHODS: We computed a previously proposed genetic risk score, based on five established VTE SNPs in the F5, F2, ABO, FGG, and F11 genes, in 9520 whites and 3049 African Americans initially free of VTE. We followed them a median of 22.6 years for VTE occurrence (n = 380 events in whites and n = 187 in African Americans). RESULTS: In whites, the five-SNP weighted genetic risk score ranged from 0 to 5.8, and VTE risk increased 1.41-fold (95% confidence interval [CI] 1.27-fold to 1.56-fold) per allele increment. In African Americans, the weighted genetic risk score ranged from 0 to 4.6 and the hazard ratio per risk allele was 1.14 (95% CI 0.94-1.38), with adjustment for 10 principal components of ancestry. The area under the receiver operating characteristic curve for 20-year prediction of VTE from the weighted genetic risk score was 0.59 (95% CI 0.56-0.63) in whites and 0.56 (95% CI 0.51-0.61) in African Americans. Adding non-genetic factors increased the area under the curve to 0.67 in whites and to 0.66 in African Americans. CONCLUSIONS: Higher values for a five-SNP genetic risk score helped identify white adults at risk of VTE. The genetic risk score did not identify future VTE occurrence in African Americans.

Central venous catheters and upper extremity deep vein thrombosis in medical inpatients: the Medical Inpatients and Thrombosis (MITH) Study.

BACKGROUND: Upper extremity deep vein thrombosis (UEDVT) is an increasingly recognized complication in medical inpatients, with few data available regarding the incidence, risk factors and association with central venous catheter (CVC) use. METHODS: Between 2002 and 2009 all cases of hospital-acquired venous thromboembolism (VTE) at a university hospital were frequency matched 1 : 2 to non-cases without VTE by admission year and medical service. Records were abstracted to identify, characterize and assess risk factors for UEDVT. Weighted logistic regression was used to calculate odds ratios (ORs) for UEDVT associated with use of a CVC, adjusting for known VTE risk factors. RESULTS: Two hundred and ninety-nine cases of VTE complicated 64 034 admissions to medical services (4.6 per 1000 admissions). UEDVT constituted 51% (91/180) of all deep vein thrombosis (DVT), for an incidence of 1.4 per 1000 admissions (95% confidence interval [CI], 0.8-1.7). There were 247 CVCs placed per 1000 admissions (95% CI, 203-292). The use of a CVC was associated with a 14.0-fold increased risk of UEDVT (95% CI, 5.9-33.2), but was not associated with a significantly increased risk of PE (OR, 1.3; 95% CI, 0.8-2.1). Peripherally inserted central catheters had a higher OR for UEDVT (OR, 13.0; 95% CI, 6.1-27.6) than centrally inserted central venous catheters (CICC) (OR, 3.4; 95% CI, 1.7-6.8). CONCLUSION: UEDVT is a relevant complication affecting medical inpatients, accounting for half of hospital-acquired DVTs. Use of CVCs was strongly associated with risk of UEDVT.

Coagulation factor XII genetic variation, ex vivo thrombin generation, and stroke risk in the elderly: results from the Cardiovascular Health Study.

BACKGROUND: The relationships of thrombin generation (TG) with cardiovascular disease risk are underevaluated in population-based cohorts. OBJECTIVES: To evaluate the relationships of TG influenced by the contact and tissue factor coagulation pathways ex vivo with common single-nucleotide polymorphisms (SNPs) and incident cardiovascular disease and stroke. PATIENTS/METHODS: We measured peak TG (pTG) in baseline plasma samples of Cardiovascular Health Study participants (n = 5411), both with and without inhibitory anti-factor XIa antibody (pTG/FXIa(-) ). We evaluated their associations with ~ 50 000 SNPs by using the IBCv2 genotyping array, and with incident cardiovascular disease and stroke events over a median follow-up of 13.2 years. RESULTS: The minor allele for an SNP in the FXII gene (F12), rs1801020, was associated with lower pTG in European-Americans (ß = - 34.2 ± 3.5 nm; P = 3.3 × 10(-22) ; minor allele frequency [MAF] = 0.23) and African-Americans (ß = - 31.1 ± 7.9 nm; P = 9.0 × 10(-5) ; MAF = 0.42). Lower FXIa-independent pTG (pTG/FXIa(-) ) was associated with the F12 rs1801020 minor allele, and higher pTG/FXIa(-) was associated with the ABO SNP rs657152 minor allele (ß = 16.3 nm; P = 4.3 × 10(-9) ; MAF = 0.37). The risk factor-adjusted ischemic stroke hazard ratios were 1.09 (95% confidence interval CI 1.01-1.17; P = 0.03) for pTG, 1.06 (95% CI 0.98-1.15; P = 0.17) for pTG/FXIa(-) , and 1.11 (95% CI 1.02-1.21; P = 0.02) for FXIa-dependent pTG (pTG/FXIa(+) ), per one standard deviation increment (n = 834 ischemic strokes). In a multicohort candidate gene analysis, rs1801020 was not associated with incident ischemic stroke (ß = - 0.02; standard error = 0.08; P = 0.81). CONCLUSIONS: These results support the importance of contact activation pathway-dependent TG as a risk factor for ischemic stroke, and indicate the importance of F12 SNPs for TG ex vivo and in vivo.

Adiponectin is independently associated with NT-proBNP: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIMS: To investigate the associations between selected adipokines and the N-terminal prohormone of B-type natriuretic peptide (NT-proBNP). METHODS AND RESULTS: As many as 1489 individuals enrolled in the Multi-Ethnic Study of Atherosclerosis were evaluated at 4 clinic visits about every 2 years. The evaluation included fasting venous blood, which was analyzed for NT-proBNP (at visits 1 and 3) and the adipokines adiponectin and leptin (at visits 2 and 3). The mean age was 64.8 ± 9.6 years and 48% were female. After multivariable adjustment, a 1-SD increment in adiponectin was associated with a 14 pg/ml higher NT-proBNP level (p < 0.01), while, compared to the 1st quartile of adiponectin, the 2nd, 3rd and 4th quartiles had 28, 45 and 67% higher NT-proBNP levels (p < 0.01 for all). For changes in NT-proBNP over the follow-up period, and after multivariable adjustment including baseline NT-proBNP, a 1-SD increment in adiponectin was associated with a 25 pg/ml absolute increase in NT-proBNP (p < 0.01), while those in the 2nd, 3rd and 4th quartiles of adiponectin were associated with increases of 5, 28 and 65 pg/ml (p = 0.74, 0.09 and <0.01, respectively). There was a significant interaction between adiponectin and sex for visit 3 NT-proBNP (p-interaction < 0.01), with significantly stronger associations in men. Leptin was not associated with NT-proBNP. CONCLUSION: Higher adiponectin, but not leptin, is significantly associated with higher levels of NT-proBNP, as well as with greater longitudinal increases in NT-proBNP. The associations were stronger in men.

The safety and efficacy of early-initiation exercise training after acute venous thromboembolism: a randomized clinical trial.

BACKGROUND: Exercise training after myocardial infarction is the standard of care within a cardiac rehabilitation setting. However, there is scant evidence regarding the safety and efficacy of early exercise training following a venous thromboembolism (VTE). METHODS: Eligible consenting participants were randomly allocated, on an individual basis, to either a 3-month exercise and behavioral weight loss intervention group or a control group. The primary clinical outcomes were change in health behavior (body weight and physical activity) and objectively measured fitness (Vo2peak ). RESULTS: From 2013 to 2014, 239 patients presented to a community-based specialty clinic after an acute VTE; 43 (18%) of these met the eligibility criteria for inclusion in the study. Of these, 19 (44%) consented to participate (nine in the intervention group; 10 in the control group). There were no adverse events in either group over a 3-month period. The mean difference in body weight between the intervention and control groups was - 4.6 kg (95% confidence interval [CI] - 11.4 to 2.2) in favor of the intervention. The mean difference in duration of physical activity from baseline to 3 months between the intervention and control groups was 133 min (95% CI 7-248) in favor of the intervention. There was a significant change in fitness over a 3-month period for the intervention group (baseline Vo2peak , 26.1 ± 5.4 mL O2 kg(-1)  min(-1) ; postintervention Vo2peak , 29.8 ± 5.4 mL O2 kg(-1)  min(-1) ). CONCLUSION: Early initiation of exercise training resulted in improvements in physical activity and fitness, and did not result in adverse events while individuals were receiving therapeutic anticoagulation. These are the first data on initiation of an exercise training and behavioral weight loss program in the early post-VTE setting.

Risk of recurrence after a first unprovoked venous thromboembolism: external validation of the Vienna Prediction Model with pooled individual patient data.

BACKGROUND: In order to stratify patients with a first unprovoked venous thromboembolism (VTE) according to their recurrence risk and to identify those who would actually benefit from indefinite anticoagulation, three prediction models have been developed so far; none of them has been yet externally validated. OBJECTIVE: To externally validate the Vienna Prediction Model (VPM), a prediction guide for estimating the recurrence risk after a first unprovoked VTE developed through Cox modeling and including sex, D-dimer and index VTE site as predictors. PATIENTS/METHODS: Nine hundred and four patients pooled from five prospective studies evaluating the prognostic value of D-dimer for VTE recurrence served as the validation cohort. The validity of the VPM in stratifying patients according to their relative recurrence risk (discrimination) and in predicting the absolute recurrence risk (calibration) was tested with survival analysis methods. RESULTS: The ability of the VPM to distinguish patients' risk for recurrent VTE in the validation cohort was at least as good as in the original cohort, with a calibration slope of 1.17 (95% confidence interval 0.71-1.64; P = 0.456 for the hypothesis of a significant difference from 1), and a c-statistic of 0.626 (vs. 0.651 in the original derivation cohort). The VPM absolute predictions in terms of cumulative rates tended to underestimate the observed recurrence rates at 12 months. CONCLUSIONS: By using a pooled individual patient database as a validation cohort, we confirmed the ability of the VPM to stratify patients with a first unprovoked VTE according to their risk of recurrence.

Prospective study of sickle cell trait and venous thromboembolism incidence.

BACKGROUND: Sickle cell trait may increase risk of venous thromboembolism, but this is not fully established. OBJECTIVES: We sought to determine the association of sickle cell trait with deep vein thrombosis and pulmonary embolism. METHODS: Middle-aged African Americans participating in a prospective, population-based cohort investigation, the Atherosclerosis Risk in Communities Study, were followed from 1987 through 2011 for incident hospitalized pulmonary embolism (n = 111) or isolated deep vein thrombosis (n = 138), verified by physician review of medical records. Sickle cell trait (heterozygosity for hemoglobin S, n = 268) was compared with no sickle cell trait (n = 3748). RESULTS: Over a median of 22 years of follow-up, 249 participants had an incident venous thromboembolism. The hazard ratio of venous thromboembolism was 1.50 (95% confidence interval [CI] 0.96-2.36) for participants with vs. without sickle cell trait, after adjustment for age, sex, ancestry, hormone replacement therapy (women), body mass index, diabetes, and estimated glomerular filtration rate. This hazard ratio was 2.05 (95% CI 1.12-3.76) for pulmonary embolism and 1.15 (95% CI 0.58-2.27) for deep vein thrombosis without pulmonary embolism. CONCLUSIONS: Sickle cell trait in African Americans carries a 2-fold increased risk of pulmonary embolism but does not elevate deep vein thrombosis risk. Because neonatal screening for sickle hemoglobin is being conducted in the United States, consideration should be paid to the increased pulmonary embolism risk of individuals with sickle cell trait.