Venous thrombosis risk assessment in medical inpatients: the medical inpatients and thrombosis (MITH) study

Development and validation of a risk model for hospital-acquired venous thrombosis: the Medical Inpatients Thrombosis and Hemostasis study

BACKGROUND

Regulatory organizations recommend assessing hospital-acquired (HA) venous thromboembolism (VTE) risk for medical inpatients.

OBJECTIVES

To develop and validate a risk assessment model (RAM) for HA-VTE in medical inpatients using objective and assessable risk factors knowable at admission.

METHODS

The development cohort included people admitted to medical services at the University of Vermont Medical Center (Burlington, Vermont) between 2010 and 2019, and the validation cohorts included people admitted to Hennepin County Medical Center (Minneapolis, Minnesota), University of Michigan Medical Center (Ann Arbor, Michigan), and Harris Health Systems (Houston, Texas). Individuals with VTE at admission, aged <18 years, and admitted for <1 midnight were excluded. We used a Bayesian penalized regression technique to select candidate HA-VTE risk factors for final inclusion in the RAM.

RESULTS

The development cohort included 60 633 admissions and 227 HA-VTE, and the validation cohorts included 111 269 admissions and 651 HA-VTE. Seven HA-VTE risk factors with t statistics ≥1.5 were included in the RAM: history of VTE, low hemoglobin level, elevated creatinine level, active cancer, hyponatremia, increased red cell distribution width, and malnutrition. The areas under the receiver operating characteristic curve and calibration slope were 0.72 and 1.10, respectively. The areas under the receiver operating characteristic curve and calibration slope were 0.70 and 0.93 at Hennepin County Medical Center, 0.70 and 0.87 at the University of Michigan Medical Center, and 0.71 and 1.00 at Harris Health Systems, respectively. The RAM performed well stratified by age, sex, and race.

CONCLUSION

We developed and validated a RAM for HA-VTE in medical inpatients. By quantifying risk, clinicians can determine the potential benefits of measures to reduce HA-VTE.

The Use of Risk Scores for Thromboprophylaxis in Medically Ill Patients-Rationale and Design of the RICO trial

Background  Venous thromboembolism (VTE) in hospitalized medically ill patients is a significant cause of morbidity and mortality. Guidelines suggest that VTE and bleeding risk assessment models (RAMs) should be integrated into the clinical decision-making process on thromboprophylaxis. However, poor evidence is available comparing the use of a RAM versus clinical judgement in evaluating VTE and bleeding occurrence. Methods  Reducing Important Clinical Outcomes in hospitalized medical ill patients (RICO) is a multicenter, cluster-randomized, controlled clinical trial (ClinicalTrials.gov Identifier: NCT04267718). Acutely ill patients hospitalized in Internal Medicine wards are randomized to the use of RAMs-namely the Padua Prediction Score and the International Medical Prevention Registry on Venous Thromboembolism Bleeding Score-or to clinical judgement. The primary study outcome is a composite of symptomatic objectively confirmed VTE and major bleeding at 90-day follow-up. Secondary endpoints include the evaluation of clinical outcomes at hospital discharge and the assessment of VTE prophylaxis prescription during the study period. In order to demonstrate a 50% reduction in the primary outcome in the experimental group and assuming an incidence of the primary outcome of 3.5% in the control group at 90-day; 2,844 patients across 32 centers will be included in the study. Discussion  The RICO trial is a randomized study of clinical management assessing the role of RAMs in hospitalized medical ill patients with the aim of reducing VTE and bleeding occurrence. The study has the potential to improve clinical practice since VTE still represents an important cause of morbidity and mortality in this setting.

Simple yet (more?) effective. Venous thromboembolism risk assessment model for germ cell tumour patients receiving first-line chemotherapy

BACKGROUND

Germ cell tumours (GCT) are highly curable malignancies. Venous thromboembolism (VTE) is a serious complication, needing better risk assessment models (RAM).

AIM

Identification of VTE incidence and risk factors in metastatic GCT patients starting first-line chemotherapy. Developing a RAM and comparing it to Khorana risk score (KRS) and Padua Prediction Score (PPS).

MATERIAL AND METHODS

We retrospectively analysed GCT patients staged IS-IIIC. VTE risk factors were identified with logistic regression. Area under curve of receiver operating characteristic (AUC-ROC), Akaike and Bayesian Information Criteria (AIC, BIC) were calculated for the developed RAM, KRS and PPS.

RESULTS

Among 495 eligible patients, VTE occurred in 69 (13.9%), including 40 prior to chemotherapy. Vein compression (OR: 8.96; 95% CI: 2.85-28.13; p < 0.001), clinical stage IIIB-IIIC (OR: 5.68; 95% CI: 1.82-17.70; p = 0.003) and haemoglobin concentration (OR for 1 g/dL decrease: 1.32; 95% CI: 1.03-1.67; p = 0.026) were significant in our RAM. KRS ≥ 3 (OR: 3.31; 95% CI: 1.77-6.20; p < 0.001), PPS 4-5 (OR: 3.06; 95% CI: 1.49-6.29; p = 0.002) and PPS > 5 (OR 8.05; 95% CI 3.79-17.13; p < 0.001) correlated with VTE risk. Diagnostic criteria (AUC-ROC, AIC, BIC) for the developed RAM, KRS and PPS were (0.885; 0.567; -1641), (0.588; 0.839; -1576) and (0.700; 0.799; -1585), respectively. In the numerical score, the optimal cut-off point for high-risk was ≥9, with sensitivity, specificity, positive and negative predictive value of 0.78, 0.77, 0.35 and 0.96, respectively.

CONCLUSIONS

Our RAM, based on vein compression, clinical stage and haemoglobin concentration proved superior to both KRS and PPS. VTE is frequent in GCT patients.

Association between inflammatory biomarkers and venous thromboembolism: a systematic review and meta-analysis

BACKGROUND

Venous thromboembolism (VTE) is a common thrombotic vascular disease that has a significant impact on people's well-being and quality of life. A plethora of clinical studies explore the relationship between inflammatory biomarkers and VTE but yield conflicting results. This article proposed to pool these studies to draw a more convincing conclusion.

METHODS

We searched several databases for studies before April 2023. Available data was processed using Stata software (version 15.0 SE) and R (version 4.1.2). This meta-analysis has been registered in PROSPERO (CRD42022321815). The VTE in this review encompassed pulmonary embolism, deep vein thrombosis, and cerebral venous thrombosis.

RESULTS

A total of 25 articles were finally involved in this study. Our results revealed that higher levels of high-sensitivity C-reactive protein (hs-CRP, MD, 0.63, 95%CI, 0.21-1.05) and C-reactive protein (CRP)> 3ug/ml (OR, 1.52, 95%CI, 1.18-1.96) might be regarded as risk factors for future VTE occurrence. The elevated levels of monocyte (MD, 0.03, 95%CI, 0.00-0.05), hs-CRP (0.85, 0.61-1.08), CRP (0.66, 0.20-1.13) and IL-6 (0.47, 0.25-0.70) might represent the previous VTE; a series of markers such as white blood cell (1.43, 0.88-1.98), neutrophil (1.79, 1.02-2.56), monocyte (0.17, 0.14-0.21), hs-CRP (3.72, 1.45-5.99), IL-6 (5.99, 4.52-7.46), platelet-lymphocyte ratio (33.1, 24.45-41.78) and neutrophil-lymphocyte ratio (1.34, 0.95-1.73) increased during the acute phase of VTE.

CONCLUSIONS

In general, activated inflammatory biomarkers might not only be correlated with an increased risk of VTE, but may also give a hint of the occurrence of VTE in clinical settings.

Development of a computable phenotype using electronic health records for venous thromboembolism in medical inpatients: the Medical Inpatient Thrombosis and Hemostasis study

Background

Accurate and efficient methods to identify venous thromboembolism (VTE) events in hospitalized people are needed to support large-scale studies. Validated computable phenotypes using a specific combination of discrete, searchable elements in electronic health records to identify VTE and distinguish between hospital-acquired (HA)-VTE and present-on-admission (POA)-VTE would greatly facilitate the study of VTE, obviating the need for chart review.

Objectives

To develop and validate computable phenotypes for POA- and HA-VTE in adults hospitalized for medical reasons.

Methods

The population included admissions to medical services from 2010 to 2019 at an academic medical center. POA-VTE was defined as VTE diagnosed within 24 hours of admission, and HA-VTE as VTE identified more than 24 hours after admission. Using discharge diagnosis codes, present-on-admission flags, imaging procedures, and medication administration records, we iteratively developed computable phenotypes for POA-VTE and HA-VTE. We assessed the performance of the phenotypes using manual chart review and survey methodology.

Results

Among 62,468 admissions, 2693 had any VTE diagnosis code. Using survey methodology, 230 records were reviewed to validate the computable phenotypes. Based on the computable phenotypes, the incidence of POA-VTE was 29.4 per 1000 admissions and that of HA-VTE was 3.6 per 1000 admissions. The POA-VTE computable phenotype had positive predictive value and sensitivity of 88.8% (95% CI, 79.8%-94.0%) and 99.1% (95% CI, 94.0%- 99.8%), respectively. Corresponding values for the HA-VTE computable phenotype were 84.2% (95% CI, 60.8%-94.8%) and 72.3% (95% CI, 40.9%-90.8%).

Conclusion

We developed computable phenotypes for HA-VTE and POA-VTE with adequate positive predictive value and sensitivity. This phenotype can be used in electronic health record data-based research.

Current use of D-dimer for the exclusion of venous thrombosis in hospitalized patients

D-dimer assay’s utility for excluding venous thromboembolism (VTE) in hospitalized patients is debatable. We aimed to assess the current use of D-dimer as a diagnostic tool for excluding VTE in hospitalized patients and examine a mandatory age-adjusted D-dimer (AADD) threshold for diagnostic imaging. Retrospective cohort study between 2014 to 2019 that included patients from medical and surgical wards with a positive AADD result drawn during their hospitalization. The outcomes were determining a D-dimer threshold requiring further evaluation and assessing the prognostic value of D-dimer in predicting clinically relevant VTE in hospitalized patients. The cohort included 354 patients, 56% of them underwent definitive diagnostic imaging, and 7.6% were diagnosed with VTE after a positive AADD within 90 days of follow-up. Mortality rates were higher in patients diagnosed with VTE (33.3% vs. 15.9%, p = 0.03). Patients with pneumonia and other infectious etiologies were less likely to be further evaluated by definitive imaging (p = 0.001). Patients with a respiratory complaint (p = 0.02), chest pain (p < 0.001), or leg swelling (p = 0.01) were more likely to undergo diagnostic imaging. Patients with D-dimer levels > X2 the AADD were at increased risk of VTE [OR 3.87 (1.45–10.27)]. At 90 days of follow-up, no excess mortality was observed for patients without diagnostic evaluation following elevated AADD. D-dimer may be used in hospitalized patients to exclude VTE using the traditional AADD thresholds, with a high negative predictive value. D-dimer levels > X2 the AADD usually mandates further diagnostic imaging, while lower levels, probably do not require additional workup, with a sensitivity of almost 80% and no excess mortality.

Venous thrombosis risk during and after medical and surgical hospitalizations: The medical inpatient thrombosis and hemostasis (MITH) study

BACKGROUND

Thirty to seventy percent of all venous thromboembolism (VTE) events are associated with hospitalization. The absolute and relative risks during and after hospitalization are poorly characterized.

OBJECTIVES

Quantify the absolute rate and relative risk of VTE during and up to 3 months after medical and surgical hospitalizations.

PATIENTS/METHODS

We conducted an observational cohort study between 2010 and 2016 of patients cared for by the University of Vermont (UVM) Health Network's primary care population. Cox proportional hazard models with hospitalization modeled as a time-varying covariate were used to estimate VTE risk.

RESULTS

Over 4.3 years of follow-up, 55 220 hospitalizations (156 per 1000 person-years) and 713 first venous thromboembolism events (2.0 per 1000 person-years) occurred. Among individuals not recently hospitalized, the rate of venous thromboembolism was 1.4 per 1000 person-years and 71.8 per 1000 person-years during hospitalization. During the first, second, and third months after discharge, the rates of venous thromboembolism were 35.1, 11.3, and 5.2 per 1000 person-years, respectively. Relative to those not recently hospitalized, the age- and sex-adjusted HRs of venous thromboembolism were 38.0 (95% CI 28.0, 51.5) during hospitalization, and 18.4 (95% CI 15.0, 22.6), 6.3 (95% CI 4.3, 9.0), and 3.0 (95% CI 1.7, 5.4) during the first, second, and third months after discharge, respectively. Stratified by medical versus surgical services the rates were similar.

CONCLUSION

Hospitalization and up to 3 months after discharge were strongly associated with increased venous thromboembolism risk. These data quantify this risk for use in future studies.

Assessment of Postoperative Outcomes of Spine Fusion Patients With History of Cardiac Disease

INTRODUCTION

There is paucity on the effect of different cardiac diagnoses on outcomes in elective spine fusion patients.

METHODS

Patients undergoing elective spine fusion surgery were isolated in the PearlDiver database. Patients were stratified by having a previous history of coronary artery disease (CAD), congestive heart failure (CHF), valve disorder (valve), dysrhythmia, and no heart disease (control). Means comparison tests (chi-squared and independent samples t-tests, as appropriate) compared differences in demographics, diagnoses, comorbidities, procedural characteristics, length of stay, complication outcomes, and total hospital charges among the cohort.

RESULTS

In total, 537,252 elective spine fusion patients were stratified into five groups: CAD, CHF, valve, dysrhythmia, and control. Among the cohort, patients with CHF had significantly higher rates of morbid obesity, peripheral vascular disease, and chronic kidney disease (P < 0.001 for all). Patients with CAD had significantly higher rates of chronic obstructive pulmonary disease, diabetes, hypertension, and hyperlipidemia (all P < 0.001). Comparing postoperative outcomes for CAD and control subjects, CAD was associated with higher odds of myocardial infarction (odds ratio [OR]: 1.64 [1.27 to 2.11]) (P < 0.05). Assessing postoperative outcomes for CHF versus control subjects, patients with CHF had higher rates of pneumonia, cerebrovascular accident (CVA), myocardial infarction, sepsis, and death (P < 0.001). Compared with control subjects, CHF was a significant predictor of death in spine fusion patients (OR: 2.0 [1.1 to 3.5], P = 0.022). Patients with valve disorder compared with control displayed significantly higher rates of 30-day readmission (P < 0.05) and 1.38× greater odds of CVA by 90 days postoperatively (OR: 1.4 [1.1 to 1.7], P = 0.007). Patients with dysrhythmia were associated with significantly higher odds of CVA (OR: 1.8 [1.4 to 2.3], P < 0.001) by 30 days postoperatively.

CONCLUSION

Heart disease presents an additional challenge to spine fusion patients who are undergoing a challenging and risky procedure. Before surgical intervention, a proper understanding of cardiac diagnoses could give insight into the potential risks for each patient based on their heart condition and preventive measures showing benefit in minimizing perioperative complications after elective spine fusion.

A retrospective cohort study of disease-related risk factors for central venous catheter-related symptomatic thrombosis in intensive care unit inpatients

Central venous catheters (CVC) are widely used in critically ill patients given their benefits in monitoring vital signs, treatment administration, and renal replacement therapy in intensive care unit (ICU) patients, but these catheters have the potential to induce symptomatic catheter-related venous thrombosis (CRVT). This study reported the rate of symptomatic CRVT in ICU patients receiving CVC and analyzed the disease-related risk factors for symptomatic CRVT in ICU patients.A retrospective analysis was performed on the consecutive ICU 1643 critically ill patients with CVCs inserted from January 2015 to December 2019. Symptomatic CRVT was confirmed by ultrasound. CVCs were divided into 2 groups based on the presence of symptomatic CRVT, and the variables were extracted from the electronic medical record system. Logistic univariate and multivariate regression analyses were used to determine the disease-related risk factors of symptomatic CRVT.A total of 209 symptomatic CRVT events occurred among 2114 catheters. The rate of CRVT was 9.5 per 1000 catheter days. Univariate analysis revealed that trauma, major surgery, heart failure, respiratory failure, and severe acute pancreatitis were risk factors for symptomatic CRVT in the ICU. Multivariate analysis showed that trauma (odds ratio [OR], 2.046; 95% confidence interval [CI] [1.325-3.160], P = .001), major surgery (OR, 2.457; 95% CI [1.641-3.679], P = .000), and heart failure (OR, 2.087; 95% CI [1.401-3.111], P = .000) were independent disease-related risk factors for symptomatic CRVT in ICU. The C-statistic for this model was 0.61 (95% CI [0.57-0.65], P = .000).The incidence rate of symptomatic CRVT in the ICU population was 9.5 per 1000 catheter days. Trauma, major surgery, and heart failure are independent disease-related risk factors of symptomatic CRVT.

Post-discharge thrombosis and bleeding in medical patients: A novel risk score derived from ubiquitous biomarkers

BACKGROUND

Some hospitalized medical patients experience venous thromboembolism (VTE) following discharge. Prophylaxis extended beyond hospital discharge (extended duration thromboprophylaxis [EDT]) may reduce this risk. However, EDT is costly and can cause bleeding, so selecting appropriate patients is essential. We formerly reported the performance of a mortality risk prediction score (Intermountain Risk Score [IMRS]) that was minimally predictive of 90-day hospital-associated venous thromboembolism (HA-VTE) and major bleeding (HA-MB). We used the components of the IMRS to calculate de novo risk scores to predict 90-day HA-VTE (HA-VTE IMRS) and major bleeding (HA-MB IMRS).

METHODS

From 45 669 medical patients we randomly assigned 30 445 to derive the HA-VTE IMRS and the HA-MB IMRS. Backward stepwise regression and bootstrapping identified predictor covariates from the blood count and basic chemistry. These candidate variables were split into quintiles, and the referent quintile was that with the lowest event rate for HA-VTE and HA-MB; respectively. A clinically relevant rate of HA-VTE and HA-MB was used to inform outcome rates. Performance was assessed in the derivation set of 15 224 patients.

RESULTS

The HA-VTE IMRS and HA-MB IMRS area under the receiver operating curve (AUC) in the derivation set were 0.646, and 0.691, respectively. In the validation set, the HA-VTE IMRS and HA-MB IMRS AUCs were 0.60 and 0.643.

CONCLUSIONS

Risk scores derived from components of routine labs ubiquitous in clinical care identify patients that are at risk for 90-day postdischarge HA-VTE and major bleeding. This may identify a subset of patients with high HA-VTE risk and low HA-MB risk who may benefit from EDT.

Risk-assessment models for VTE and bleeding in hospitalized medical patients: an overview of systematic reviews

Multiple risk-assessment models (RAMs) for venous thromboembolism (VTE) in hospitalized medical patients have been developed. To inform the 2018 American Society of Hematology (ASH) guidelines on VTE, we conducted an overview of systematic reviews to identify and summarize evidence related to RAMs for VTE and bleeding in medical inpatients. We searched Epistemonikos, the Cochrane Database, Medline, and Embase from 2005 through June 2017 and then updated the search in January 2020 to identify systematic reviews that included RAMs for VTE and bleeding in medical inpatients. We conducted study selection, data abstraction and quality assessment (using the Risk of Bias in Systematic Reviews [ROBIS] tool) independently and in duplicate. We described the characteristics of the reviews and their included studies, and compared the identified RAMs using narrative synthesis. Of 15 348 citations, we included 2 systematic reviews, of which 1 had low risk of bias. The reviews included 19 unique studies reporting on 15 RAMs. Seven of the RAMs were derived using individual patient data in which risk factors were included based on their predictive ability in a regression analysis. The other 8 RAMs were empirically developed using consensus approaches, risk factors identified from a literature review, and clinical expertise. The RAMs that have been externally validated include the Caprini, Geneva, IMPROVE, Kucher, and Padua RAMs. The Padua, Geneva, and Kucher RAMs have been evaluated in impact studies that reported an increase in appropriate VTE prophylaxis rates. Our findings informed the ASH guidelines. They also aim to guide health care practitioners in their decision-making processes regarding appropriate individual prophylactic management.

Risk models for VTE and bleeding in medical inpatients: systematic identification and expert assessment

Risk assessment models (RAMs) for venous thromboembolism (VTE) and bleeding in hospitalized medical patients inform appropriate use of thromboprophylaxis. Our aim was to use a novel approach for selecting risk factors for VTE and bleeding to be included in RAMs. First, we used the results of a systematic review of all candidate factors. Second, we used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of the evidence for the identified factors. Third, we using a structured approach to select factors to develop the RAMs, by building on clinical and methodological expertise. The expert panel made judgments on whether to include, potentially include, or exclude risk factors, according to domains of the GRADE approach and the Delphi method. The VTE RAM included age >60 years, previous VTE, acute infections, immobility, acute paresis, active malignancy, critical illness, and known thrombophilia. The bleeding RAM included age ≥65 years, renal failure, thrombocytopenia, active gastroduodenal ulcers, hepatic disease, recent bleeding, and critical illness. We identified acute infection as a factor that was not considered in widely used RAMs. Also, we identified factors that require further research to confirm or refute their importance in a VTE RAM (eg, D-dimer). We excluded autoimmune disease which is included in the IMPROVE (International Medical Prevention Registry on Venous Thromboembolism) bleeding RAM. Our results also suggest that sex, malignancy, and use of central venous catheters (factors in the IMPROVE bleeding RAM) require further research. In conclusion, our study presents a novel approach to systematically identifying and assessing risk factors to be included or further explored during RAM development.

Development of a Risk Model for Pediatric Hospital-Acquired Thrombosis: A Report from the Children's Hospital-Acquired Thrombosis Consortium

OBJECTIVE

To identify pertinent clinical variables discernible on the day of hospital admission that can be used to assess risk for hospital-acquired venous thromboembolism (HA-VTE) in children.

STUDY DESIGN

The Children's Hospital-Acquired Thrombosis Registry is a multi-institutional registry for all hospitalized participants aged 0-21 years diagnosed with a HA-VTE and non-VTE controls. A risk assessment model (RAM) for the development of HA-VTE using demographic and clinical VTE risk factors present at hospital admission was derived using weighted logistic regression and the least absolute shrinkage and selection (Lasso) procedure. The models were internally validated using 5-fold cross-validation. Discrimination and calibration were assessed using area under the receiver operating characteristic curve and Hosmer-Lemeshow goodness of fit, respectively.

RESULTS

Clinical data from 728 cases with HA-VTE and 839 non-VTE controls, admitted between January 2012 and December 2016, were abstracted. Statistically significant RAM elements included age <1 year and 10-22 years, cancer, congenital heart disease, other high-risk conditions (inflammatory/autoimmune disease, blood-related disorder, protein-losing state, total parental nutrition dependence, thrombophilia/personal history of VTE), recent hospitalization, immobility, platelet count >350 K/μL, central venous catheter, recent surgery, steroids, and mechanical ventilation. The area under the receiver operating characteristic curve was 0.78 (95% CI 0.76-0.80).

CONCLUSIONS

Once externally validated, this RAM will identify those who are at low-risk as well as the greatest-risk groups of hospitalized children for investigation of prophylactic strategies in future clinical trials.

Prognostic factors for VTE and bleeding in hospitalized medical patients: a systematic review and meta-analysis

There may be many predictors of venous thromboembolism (VTE) and bleeding in hospitalized medical patients, but until now, systematic reviews and assessments of the certainty of the evidence have not been published. We conducted a systematic review to identify prognostic factors for VTE and bleeding in hospitalized medical patients and searched Medline and EMBASE from inception through May 2018. We considered studies that identified potential prognostic factors for VTE and bleeding in hospitalized adult medical patients. Reviewers extracted data in duplicate and independently and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. Of 69 410 citations, we included 17 studies in our analysis: 14 that reported on VTE, and 3 that reported on bleeding. For VTE, moderate-certainty evidence showed a probable association with older age; elevated C-reactive protein (CRP), D-dimer, and fibrinogen levels; tachycardia; thrombocytosis; leukocytosis; fever; leg edema; lower Barthel Index (BI) score; immobility; paresis; previous history of VTE; thrombophilia; malignancy; critical illness; and infections. For bleeding, moderate-certainty evidence showed a probable association with older age, sex, anemia, obesity, low hemoglobin, gastroduodenal ulcers, rehospitalization, critical illness, thrombocytopenia, blood dyscrasias, hepatic disease, renal failure, antithrombotic medication, and presence of a central venous catheter. Elevated CRP, a lower BI, a history of malignancy, and elevated heart rate are not included in most VTE risk assessment models. This study informs risk prediction in the management of hospitalized medical patients for VTE and bleeding; it also informs guidelines for VTE prevention and future research.

Prescribing patterns and outcomes of venous thromboembolism prophylaxis in hospitalized medical and cancer patients: Observations from the Ottawa Hospital

Guidelines suggest broad use of pharmacologic prophylaxis to prevent venous thromboembolism (VTE) in hospitalized medical patients, however little 'real-world' data exists to support this. Our goal was to describe the use of thromboprophylaxis among general medical and cancer patients admitted to hospital, compare VTE and bleeding outcomes according to use of thromboprophylaxis, and to determine what variables influence prescribing patterns and outcomes. Patients admitted to the general medical and oncology services at The Ottawa Hospital between 2010 and 2015 were retrospectively reviewed and classified according to whether they received initial, delayed, or no pharmacologic thromboprophylaxis during their first hospitalization. Patients with an alternate indication for anticoagulation or those admitted with a bleeding event were excluded from analysis. The primary efficacy outcome was any symptomatic VTE during index hospitalization or within 90 days of discharge, and the primary safety outcome was clinically relevant bleeding during the index hospitalization. 17,262 patients were included in our final analysis. General medical patients selected to receive no, initial, or delayed thromboprophylaxis had 0.4%, 0.7%, and 2.4% rates of VTE; and 0.2%, 0.7%, and 1.5% rates of clinically relevant bleeding complications, respectively. Cancer patients had significantly higher rates of VTE: 3.3%, 3.9%, and 5.0%; and 0.9%, 0.7%, and 3.0% rates of clinically relevant bleeding among those selected to receive no, initial, or delayed thromboprophylaxis, respectively. Overall, our study suggests that broad use of pharmacologic thromboprophylaxis may be unnecessary in select low-risk general medical patients and may be less effective in cancer patients in whom new studies are indicated.

Predicting postdischarge hospital-associated venous thromboembolism among medical patients using a validated mortality risk score derived from common biomarkers

BACKGROUND

Discharged medical patients are at risk for venous thromboembolism (VTE). It is difficult to identify which discharged patients would benefit from extended duration thromboprophylaxis. The Intermountain Risk Score is a prediction score derived from discrete components of the complete blood cell count and basic metabolic panel and is highly predictive of 1-year mortality. We sought to ascertain if the Intermountain Risk Score might also be predictive of 90-day postdischarge hospital-associated VTE (HA-VTE).

METHODS

We applied the Intermountain Risk Score to 60 064 medical patients who survived 90 days after discharge and report predictiveness for HA-VTE. Area under the receiver operating curve analyses were performed. We then assessed whether the Intermountain Risk Score improved prediction of 2 existing VTE risk assessment models.

RESULTS

The Intermountain Risk Score poorly predicted HA-VTE (area under the curve = 0.58; 95% confidence interval [CI], 0.56-0.60). Each clinical risk assessment model was superior to the Intermountain Risk Score (UTAH area under the curve, 0.63; Kucher area under the curve, 0.62; Intermountain Risk Score area under the curve, 0.58; P < .001 for each comparison). Adding the Intermountain Risk Score to these scores did not substantially improve the performance of either risk assessment model (UTAH + Intermountain Risk Score, 0.65; Kucher + Intermountain Risk Score, 0.64).

CONCLUSION

The Intermountain Risk Score demonstrated poor predictiveness for HA-VTE when compared to existing risk assessment models. Adding the Intermountain Risk Score to existing risk assessment models did not improve upon either risk assessment model alone to justify the added complexity.

Black Patients Experience Highest Rates of Cancer-associated Venous Thromboembolism

PURPOSE

Cancer patients are at a higher risk of venous thromboembolism (VTE) than the general population. In the general population, blacks are at a higher risk of VTE compared with whites. The influence of race on cancer-associated VTE remains unexplored. We examined whether black cancer patients are at a higher risk of VTE and whether these differences are present in specific cancer types.

DESIGN

A retrospective study was performed in the largest safety net hospital of New England using a cohort of cancer patients characterized by a substantial number of nonwhites.

RESULTS

We identified 16,498 subjects with solid organ and hematologic malignancies from 2004 to 2018. Among them, we found 186 unique incident VTE events, of which the majority of the events accrued within the first 2 years of cancer diagnosis. Overall, blacks showed a 3-fold higher incidence of VTE (1.8%) compared with whites (0.6%; P<0.001). This difference was observed in certain cancer types such as lung, gastric and colorectal. In lung cancer, the odds of developing VTE in blacks was 2.77-times greater than those in white patients (confidence interval, 1.33-5.91; P=0.007). Despite the greater incidence of cancer-associated VTE in blacks, their Khorana risk score of VTE was not higher.

CONCLUSIONS

In a diverse cancer cohort, we observed a higher incidence of cancer-associated VTE in blacks compared with patients from other races. This study indicates the consideration of race in the risk assessment of cancer-associated VTE. It could also lead to future mechanistic studies aiming at identifying reasons for differential VTE risk depending on cancer type.

Risk factors for cancer-associated venous thromboembolism: The venous thromboembolism prevention in the ambulatory cancer clinic (VTE-PACC) study

BACKGROUND

The Khorana Score is a validated risk score for predicting 6-month incidence of cancer-associated venous thromboembolism (CAT) among patients starting chemotherapy. Venous thromboembolism (VTE) risk factors important in the general population, including age, sex, prior VTE, and hospitalization, are not included in this score, their association with VTE in cancer patients is unknown.

OBJECTIVE

To examine risk factors for CAT and the impact of incorporating longitudinal hospitalization into risk assessment.

METHODS

Risk factors were recorded among patients starting chemotherapy at a single institution from 2012-14. Hospitalization and time-periods after hospitalization were assessed as time-varying covariates. Logistic regression was used to determine factors related to 6-month CAT risk (the Khorana Score endpoint). Proportional hazard models were used for risk factor identification throughout the 3-year observation period.

RESULTS

Among 1,583 patients starting chemotherapy (mean age 60, 48% male), 187 developed CAT (11.8%) with 129 (69%) cases occurring within 6 months of starting chemotherapy. In the 6-month analysis, no additional risk factors were associated with CAT. In the 3-year analysis, male sex (HR 1.57, 95%CI 1.21, 2.07), prior VTE (HR 2.12, 95%CI 1.41, 3.18), and hospitalization (HR 2.69, 95%CI 1.92, 3.75) were associated with increased hazard of CAT, adjusting for risk factors in the Khorana score.

CONCLUSIONS

When time-to-event data were incorporated into CAT risk assessment, male sex, prior VTE, and hospitalization were important risk factors. These data highlight the need to consider dynamic methods for assessing VTE risk in cancer patients, with particular attention to the period around hospitalizations.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: prophylaxis for hospitalized and nonhospitalized medical patients

BACKGROUND

Venous thromboembolism (VTE) is the third most common vascular disease. Medical inpatients, long-term care residents, persons with minor injuries, and long-distance travelers are at increased risk.

OBJECTIVE

These evidence-based guidelines from the American Society of Hematology (ASH) intend to support patients, clinicians, and others in decisions about preventing VTE in these groups.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline-development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and adult patients. The Grading of Recommendations Assessment, Development and Evaluation approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 19 recommendations for acutely ill and critically ill medical inpatients, people in long-term care facilities, outpatients with minor injuries, and long-distance travelers.

CONCLUSIONS

Strong recommendations included provision of pharmacological VTE prophylaxis in acutely or critically ill inpatients at acceptable bleeding risk, use of mechanical prophylaxis when bleeding risk is unacceptable, against the use of direct oral anticoagulants during hospitalization, and against extending pharmacological prophylaxis after hospital discharge. Conditional recommendations included not to use VTE prophylaxis routinely in long-term care patients or outpatients with minor VTE risk factors. The panel conditionally recommended use of graduated compression stockings or low-molecular-weight heparin in long-distance travelers only if they are at high risk for VTE.

Atrial fibrillation is related to lower incidence of deep venous thrombosis in patients with pulmonary embolism

Background

Atrial fibrillation (AF) is an established risk factor of left atrial thrombosis and systemic embolism. Traditionally pulmonary embolism (PE) is a recognized complication of deep vein thrombosis (DVT). However, whether AF is responsible for right atrial thrombosis and leads to PE has not been examined.

Methods

We retrospectively analyzed medical records of patients with confirmed diagnosis of PE with AF (study group) from 2002-2015. Patients with PE without AF, matched by age and sex, served as controls (control group). The CHA₂DS₂-VASc and CHADS₂ scores were classified into two categories, low-intermediate (<2 points) and high-risk (≥2 points).

Results

A total of 330 patients (110 in study group and 220 in control group). The study group had significantly lower incidence of newly diagnosed DVT (21% vs. 44%, P<0.001), previous history of DVT (6% vs. 17%, P=0.006) and recent surgery or trauma (10% vs. 23%, P=0.004) compared to the control group. When stratified by the CHADS₂ score, 49 patients (44.5%) were considered low-intermediate risk. This proportion significantly differed when stratified using CHA₂DS₂-VASc, in which 13 patients (13.6%) were considered low-intermediate risk, P<0.001.

Conclusions

The incidence of DVT was much lower in the study group, suggesting the possibility of clots originated from the right heart that may increase the risk of PE. The CHA₂DS₂-VASc scoring system might be more sensitive for prediction and stratification of the PE in AF patients than the CHADS₂ score.

The epidemiology of venous thromboembolism

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

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.

Inflammation in venous thromboembolism: Cause or consequence?

Venous thromboembolism (VTE) which includes deep vein thrombosis (DVT) and pulmonary thromboembolism (PTE) is a moderately common disease especially in elderly population with high rate of recurrence and complications. Evidence is accumulating that VTE is not restricted to coagulation system and immune system appears to be involved in formation and resolution of thrombus. The present study was aimed at reviewing current evidences on immune system abnormalities such as alterations in cytokines, chemokines and immune cells. Also, current evidences suggest that; a, inflammation in general functions as a double-edged sword, b, inflammation can be both a cause and a consequence of VTE, and c, current anti-coagulation therapies are not well-equipped with the capacity to selectively inhibit inflammatory cells and pathways. Applying such inferences for selective pharmacological targeting of immune mediators in VTE and thereby for adoption of higher effective anti-thromboinflammatory strategies, either therapeutic or prophylactic, is henceforth to be considered as the line of research for future.

Venous thrombosis and cancer: from mouse models to clinical trials

Cancer patients have a ~4 fold increased risk of venous thromboembolism (VTE) compared with the general population and this is associated with significant morbidity and mortality. This review summarizes our current knowledge of VTE and cancer, from mouse models to clinical studies. Notably, the risk of VTE varies depending on the type and stage of cancer. For instance, pancreatic and brain cancer patients have a higher risk of VTE than breast and prostate cancer patients. Moreover, patients with metastatic disease have a higher risk than those with localized tumors. Tumor-derived procoagulant factors and growth factors may directly and indirectly enhance VTE. For example, increased levels of circulating tumor-derived, tissue factor-positive microvesicles may trigger VTE. In a mouse model of ovarian cancer, tumor-derived IL-6 and hepatic thrombopoietin have been linked to increased platelet production and thrombosis. In addition, mouse models of mammary and lung cancer showed that tumor-derived granulocyte colony-stimulating factor causes neutrophilia and activation of neutrophils. Activated neutrophils can release neutrophil extracellular traps (NETs) that enhance thrombosis. Cell-free DNA in the blood derived from cancer cells, NETs and treatment with cytotoxic drugs can activate the clotting cascade. These studies suggest that there are multiple mechanisms for VTE in patients with different types of cancer. Preventing and treating VTE in cancer patients is challenging; the current recommendations are to use low-molecular-weight heparin. Understanding the underlying mechanisms may allow the development of new therapies to safely prevent VTE in cancer patients.

Epidemiology of venous thromboembolism

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

Inflammation markers and incident venous thromboembolism: the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort

BACKGROUND

Inflammation biomarkers are associated with the venous thromboembolism (VTE) risk factors obesity and age; however, the relationships of inflammation with VTE risk remain controversial.

OBJECTIVES

To examine associations of four inflammation biomarkers, i.e. C-reactive protein (CRP), serum albumin, white blood cell (WBC) count, and platelet count (PLTC), with incident VTE, and to determine whether they mediate the association of age or obesity with VTE.

PATIENTS/METHODS

Hazards models adjusted for VTE risk factors were used to calculate the prospective association of each biomarker with incident VTE in 30,239 participants of the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Mediation of the associations of obesity and age with VTE were examined by bootstrapping. Over a period of 4.6 years, there were 268 incident VTE events. After adjustment for VTE risk factors, the hazard ratios (HRs) were 1.25 (95% confidence interval [CI] 1.09-1.43) per standard deviation (SD) higher log-CRP and 1.25 (95% CI 1.06-1.48) per SD lower albumin; there were no associations for WBC count or PLTC. The association of body mass index (BMI), but not age, with VTE was partially mediated by CRP and albumin. In risk factor-adjusted models, the percentage attenuations of the BMI HR for VTE after introduction of CRP or albumin into the models were 15.4% (95% CI 7.7-33.3%) and 41.0% (95% CI 12.8-79.5%), respectively.

CONCLUSION

Higher CRP levels and lower serum albumin levels were associated with increased VTE risk, and statistically mediated part of the association of BMI with VTE. These data suggest that inflammation may be a potential mechanism underlying the relationship between obesity and VTE risk.

Identification of APOH polymorphisms as common genetic risk factors for venous thrombosis in the Chinese population

BACKGROUND

Venous thrombosis (VT) is a worldwide medical problem. In order to identify individuals at high risk early, it is necessary to find more genetic risk factors. Nowadays, the studies on genetic factors of thrombosis are mainly focused on coagulation and anticoagulation factors. The exploration of other proteins involved in thrombosis and hemostasis may lead to a breakthrough.

OBJECTIVES

We used APOH as a candidate gene to investigate the existence of genetic variation that could increase the risk of thrombosis.

METHODS/RESULTS

In the current study, with a resequencing method followed by a case-control study, four polymorphisms (c.-32C>A, c.422T>C, c.461G>A, and c.1004G>C) in APOH (encoding β2 -glycoprotein I) were found to be in high linkage disequilibrium, which could result in three haplotypes. The H2 heterozygotes and H3 homozygotes had approximately 1.5-fold and seven-fold increased risks for VT, respectively. The minor allele frequency in the general population was ~ 10%. In addition, H3 individuals showed a significantly decreased level of β2 -glycoprotein I, but an increased level of thrombin generation. Functional tests indicated that the mutant β2 -glycoprotein I had a significantly lower capacity to extend thrombin clotting time and increase thrombin generation potential.

CONCLUSIONS

This study revealed APOH as a new candidate gene associated with thrombosis, and further genetic research on this gene in patients in whom the cause of thrombophilia is unknown is therefore warranted.

Defining quality indicators for best-practice management of inflammatory bowel disease in Canada

BACKGROUND

There is a paucity of published data regarding the quality of care of inflammatory bowel disease (IBD) in Canada. Clinical quality indicators are quantitative end points used to guide, monitor and improve the quality of patient care. In Canada, where universal health care can vary significantly among provinces, quality indicators can be used to identify potential gaps in the delivery of IBD care and standardize the approach to interprovincial management.

METHODS

The Emerging Practice in IBD Collaborative (EPIC) group generated a shortlist of IBD quality indicators based on a comprehensive literature review. An iterative voting process was used to select quality indicators to take forward. In a face-to-face meeting with the EPIC group, available evidence to support each quality indicator was presented by the EPIC member aligned to it, followed by group discussion to agree on the wording of the statements. The selected quality indicators were then ratified in a final vote by all EPIC members.

RESULTS

Eleven quality indicators for the management of IBD within the single-payer health care system of Canada were developed. These focus on accurate diagnosis, appropriate and timely management, disease monitoring, and prevention or treatment of complications of IBD or its therapy.

CONCLUSIONS

These quality indicators are measurable, reflective of the evidence base and expert opinion, and define a standard of care that is at least a minimum that should be expected for IBD management in Canada. The next steps for the EPIC group involve conducting research to assess current practice across Canada as it pertains to these quality indicators and to measure the impact of each of these indicators on patient outcomes.

Racial and regional differences in venous thromboembolism in the United States in 3 cohorts

BACKGROUND

Blacks are thought to have a higher risk of venous thromboembolism (VTE) than whites. However, prior studies are limited to administrative databases that lack specific information on VTE risk factors or have limited geographic scope.

METHODS AND RESULTS

We ascertained VTE from 3 prospective studies: the Atherosclerosis Risk in Communities Study (ARIC), the Cardiovascular Health Study (CHS), and the Reasons for Geographic and Racial Differences in Stroke study (REGARDS). We tested the association of race with VTE using Cox proportional hazard models adjusted for VTE risk factors. Over 438 090 person-years, 916 incident VTE events (302 in blacks) occurred in 51 149 individuals (17 318 blacks) who were followed up. In risk factor-adjusted models, blacks had a higher rate of VTE than whites in the CHS (hazard ratio, 1.81; 95% confidence interval, 1.20-2.73) but not ARIC (hazard ratio, 1.21; 95% confidence interval, 0.96-1.54). In REGARDS, there was a significant region-by-race interaction (P=0.01): Blacks in the Southeast had a significantly higher rate of VTE than blacks in the rest of the United States (hazard ratio, 1.63; 95% confidence interval, 1.08-2.48) that was not seen in whites (hazard ratio, 0.83; 95% confidence interval, 0.61-1.14).

CONCLUSIONS

The association of race with VTE differed in each cohort, which may reflect the different time periods of the studies or different regional rates of VTE. Further studies of environmental and genetic risk factors for VTE are needed to determine which underlie racial and perhaps regional differences in VTE.

Imaging characteristics of ischemic strokes related to patent foramen ovale

BACKGROUND AND PURPOSE

Subclinical atrial fibrillation (AF) and patent foramen ovale (PFO) are the major causes of cryptogenic stroke, and neuroimaging may help distinguish the cause. We compared the imaging characteristics of ischemic stroke caused by PFO (PFO-stroke) and AF (AF-stroke).

METHODS

We recruited 117 patients with PFO-stroke and 358 patients with AF-stroke after excluding other causes. The lesion patterns were classified according to number, location, size, and pertinent vascular territory and were compared between the 2 groups. Occlusion of the corresponding artery and its recanalization rate were also investigated.

RESULTS

The lesion pattern of a PFO-stroke was more frequently observed as a single cortical infarction (34.2% versus 3.1%; P<0.001) or multiple small (<15 mm) scattered lesions (23.1% versus 5.9%; P<0.001) and in the vertebrobasilar artery territory (44.4% versus 22.9%; P<0.001). By contrast, AF-stroke was more frequently observed as a large cortico-subcortical infarction or confluent lesion (>15 mm) with additional lesions in multicirculatory territories. For a PFO-stroke, occlusion of the corresponding vessel on angiography was less frequent (34.2% versus 71.5%; P<0.001), and the neurological deficit evaluated by the National Institutes of Health Stroke Scale was mild (3.48±4.16 versus 9.15±7.35; P<0.001). The recanalization rate was also lower (57.1% versus 78.3%; P=0.007).

CONCLUSIONS

A PFO-stroke usually appears as a single cortical or multiple small ischemic lesions in the vertebrobasilar circulation without any visible vessel occlusion on angiography. The recanalization rate is significantly lower than in AF-stroke. These imaging characteristics of PFO-stroke may help to diagnose the mechanism and determine the treatment strategy.