External validation of a risk assessment model for venous thromboembolism in the hospitalised acutely-ill medical patient (VTE-VALOURR)

Converting IMPROVE bleeding and VTE risk assessment models into a fast-and-frugal decision tree for optimal hospital VTE prophylaxis

ABSTRACT

Current hospital venous thromboembolism (VTE) prophylaxis for medical patients is characterized by both underuse and overuse. The American Society of Hematology (ASH) has endorsed the use of risk assessment models (RAMs) as an approach to individualize VTE prophylaxis by balancing overuse (excessive risk of bleeding) and underuse (risk of avoidable VTE). ASH has endorsed IMPROVE (International Medical Prevention Registry on Venous Thromboembolism) risk assessment models, the only RAMs to assess short-term bleeding and VTE risk in acutely ill medical inpatients. ASH, however, notes that no RAMs have been thoroughly analyzed for their effect on patient outcomes. We aimed to validate the IMPROVE models and adapt them into a simple, fast-and-frugal (FFT) decision tree to evaluate the impact of VTE prevention on health outcomes and costs. We used 3 methods: the "best evidence" from ASH guidelines, a "learning health system paradigm" combining guideline and real-world data from the Medical University of South Carolina (MUSC), and a "real-world data" approach based solely on MUSC data retrospectively extracted from electronic records. We found that the most effective VTE prevention strategy used the FFT decision tree based on an IMPROVE VTE score of ≥2 or ≥4 and a bleeding score of <7. This method could prevent 45% of unnecessary treatments, saving ∼$5 million annually for patients such as the MUSC cohort. We recommend integrating IMPROVE models into hospital electronic medical records as a point-of-care tool, thereby enhancing VTE prevention in hospitalized medical patients.

Gynecological Cancer and Venous Thromboembolism: A Narrative Review to Increase Awareness and Improve Risk Assessment and Prevention

The prevention and appropriate management of venous thromboembolism in cancer patients is of paramount importance. However, the literature data report an underestimation of this major problem in patients with gynecological cancers, with an inconsistent venous thromboembolism risk assessment and prophylaxis in this patient setting. This narrative review provides a comprehensive overview of the available evidence regarding the management of venous thromboembolism in cancer patients, focusing on the specific context of gynecological tumors, exploring the literature discussing risk factors, risk assessment, and pharmacological prophylaxis. We found that the current understanding and management of venous thromboembolism in gynecological malignancy is largely based on studies on solid cancers in general. Hence, further, larger, and well-designed research in this area is needed.

Comparison of the PADUA and IMPROVE scores in assessing venous thromboembolism risk in 42,257 medical inpatients in China

Venous thromboembolism (VTE) is a major contributor to hospital mortality and disability-adjusted life-year (DALY) loss. Multiple guidelines recommend using the Padua or IMPROVE scores to stratify VTE risk in hospitalized medical patients. However, the IMPROVE score is not recommended in Chinese guidelines, and there is very little evaluation of its clinical application and effectiveness in the Chinese population. The objective of this study is to compare the efficacy of the Padua and IMPROVE scoring models for assessing VTE risk in Chinese medical inpatients. We conducted a retrospective analysis of the clinical characteristics and thrombotic risk of 42,257 medical inpatients at a tertiary hospital in Guangdong, China, between 2021 and 2022. Logistic regression was used to assess thrombotic risk factors. The Receiver Operating Characteristic (ROC) curves, Area Under the Curve (AUC), sensitivity, and specificity were employed to evaluate the performance of the two models. Of the 42,257 patients included, 948 (2.24%) experienced VTE during hospitalization. According to the Padua score, 3,7513 (88.78%) of patients were considered low risk, while 4,744 (18.22%) were classified as high risk. The IMPROVE score identified 20,744 (49.09%) of patients as low risk, 20799(49.22%) as intermediate risk, and 714(1.69%) as high risk. The AUC for the Padua score was 0.735 (95% CI: 0.717-0.753), with a sensitivity of 49.4% and specificity of 89.6%. For the IMPROVE score, the AUC was 0.711 (95% CI: 0.693-0.729), with a sensitivity of 32.5% and specificity of 99.0%. The DeLong test, used to compare the AUCs, yielded a z-value of 1.886 with a P-value of 0.059, indicating no statistical difference. When assessing VTE risk in patients with stroke, cancer, nephrotic syndrome, and critical illness (ICU/CCU stay), both scoring models showed comparable predictive performance with AUCs ranging between 0.7 and 0.8. Both the Padua score and IMPROVE score have good predictive ability for VTE events during hospitalization in medical patients. Among them, the IMPROVE score has objective assessment items, simpler operation, and more detailed risk stratification, which is beneficial for clinicians to take physical and pharmacological preventive measures at different levels.ChiCTR2200056903, February 22, retrospectively registered.

System-Wide Thromboprophylaxis Interventions for Hospitalized Patients at Risk of Venous Thromboembolism: Focus on Cross-Platform Clinical Decision Support

Thromboprophylaxis of hospitalized patients at risk of venous thromboembolism (VTE) presents challenges owing to patient heterogeneity and lack of adoption of evidence-based methods. Intuitive practices for thromboprophylaxis have resulted in many patients being inappropriately prophylaxed. We conducted a narrative review summarizing system-wide thromboprophylaxis interventions in hospitalized patients. Multiple interventions for thromboprophylaxis have been tested, including multifaceted approaches such as national VTE prevention programs with audits, pre-printed order entry, passive alerts (either human or electronic), and more recently, the use of active clinical decision support (CDS) tools incorporated into electronic health records (EHRs). Multifaceted health-system and order entry interventions have shown mixed results in their ability to increase appropriate thromboprophylaxis and reduce VTE unless mandated through a national VTE prevention program, though the latter approach is potentially costly and effort- and time-dependent. Studies utilizing passive human or electronic alerts have also shown mixed results in increasing appropriate thromboprophylaxis and reducing VTE. Recently, a universal cloud-based and EHR-agnostic CDS VTE tool incorporating a validated VTE risk score revealed high adoption and effectiveness in increasing appropriate thromboprophylaxis and reducing major thromboembolism. Active CDS tools hold promise in improving appropriate thromboprophylaxis, especially with further refinement and widespread implementation within various EHRs and clinical workflows.

Evaluation of venous thromboembolism risk assessment models for hospital inpatients: the VTEAM evidence synthesis

Background

Pharmacological prophylaxis during hospital admission can reduce the risk of acquired blood clots (venous thromboembolism) but may cause complications, such as bleeding. Using a risk assessment model to predict the risk of blood clots could facilitate selection of patients for prophylaxis and optimise the balance of benefits, risks and costs.

Objectives

We aimed to identify validated risk assessment models and estimate their prognostic accuracy, evaluate the cost-effectiveness of different strategies for selecting hospitalised patients for prophylaxis, assess the feasibility of using efficient research methods and estimate key parameters for future research.

Design

We undertook a systematic review, decision-analytic modelling and observational cohort study conducted in accordance with Enhancing the QUAlity and Transparency Of health Research (EQUATOR) guidelines.

Setting

NHS hospitals, with primary data collection at four sites.

Participants

Medical and surgical hospital inpatients, excluding paediatric, critical care and pregnancy-related admissions.

Interventions

Prophylaxis for all patients, none and according to selected risk assessment models.

Main outcome measures

Model accuracy for predicting blood clots, lifetime costs and quality-adjusted life-years associated with alternative strategies, accuracy of efficient methods for identifying key outcomes and proportion of inpatients recommended prophylaxis using different models.

Results

We identified 24 validated risk assessment models, but low-quality heterogeneous data suggested weak accuracy for prediction of blood clots and generally high risk of bias in all studies. Decision-analytic modelling showed that pharmacological prophylaxis for all eligible is generally more cost-effective than model-based strategies for both medical and surgical inpatients, when valuing a quality-adjusted life-year at £20,000. The findings were more sensitive to uncertainties in the surgical population; strategies using risk assessment models were more cost-effective if the model was assumed to have a very high sensitivity, or the long-term risks of post-thrombotic complications were lower. Efficient methods using routine data did not accurately identify blood clots or bleeding events and several pre-specified feasibility criteria were not met. Theoretical prophylaxis rates across an inpatient cohort based on existing risk assessment models ranged from 13% to 91%.

Limitations

Existing studies may underestimate the accuracy of risk assessment models, leading to underestimation of their cost-effectiveness. The cost-effectiveness findings do not apply to patients with an increased risk of bleeding. Mechanical thromboprophylaxis options were excluded from the modelling. Primary data collection was predominately retrospective, risking case ascertainment bias.

Conclusions

Thromboprophylaxis for all patients appears to be generally more cost-effective than using a risk assessment model, in hospitalised patients at low risk of bleeding. To be cost-effective, any risk assessment model would need to be highly sensitive. Current evidence on risk assessment models is at high risk of bias and our findings should be interpreted in this context. We were unable to demonstrate the feasibility of using efficient methods to accurately detect relevant outcomes for future research.

Future work

Further research should evaluate routine prophylaxis strategies for all eligible hospitalised patients. Models that could accurately identify individuals at very low risk of blood clots (who could discontinue prophylaxis) warrant further evaluation.

Study registration

This study is registered as PROSPERO CRD42020165778 and Researchregistry5216.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR127454) and will be published in full in Health Technology Assessment; Vol. 28, No. 20. See the NIHR Funding and Awards website for further award information.

The effect of obligatory Padua prediction scoring in hospitalized medically ill patients: A retrospective cohort study

BACKGROUND

Venous thromboembolism (VTE) is considered a preventable cause of mortality. The evidence for the benefit of VTE prophylaxis in acute medical patients is non-conclusive. Meta-analysis of RCTs failed to demonstrate reduction of all-cause mortality, while showing higher risk of bleeding. The Israeli Ministry of Health has instructed to assess all acute medical patients for the risk for VTE using the Padua Prediction Score, without mandating prophylaxis.

AIM

To evaluate the effect of filling the Padua score on clinical outcomes and VTE prophylaxis rates.

METHODS

Retrospective Study was performed in Israel during the years 2014-2017. The participants were divided to Padua compliance vs non-compliance group. Primary outcome: 30-day mortality. Secondary outcomes: 90-day incidence of VTE and suspected major bleeding. A propensity-weighted logistic multiple regression was performed.

RESULTS

18,890 patients were included in the study. The fulfillment of the Padua score was associated with an increased use of VTE prophylaxis, OR 1.66 (95% CI 1.49-1.84). However, there was no reduction of mortality or VTE events, OR 1.13 (95% CI 0.97-1.31) and OR 1.22 (95% CI 0.79-1.8) respectively. Hospitalizations related to hemoglobin decrease were not statistically different between the two groups.

CONCLUSIONS

Padua score for the assessment of VTE risk in medical wards was associated with higher administration of pharmacological prophylaxis without reduction in VTE or mortality rate. Its usage should be reassessed as a performance measure.

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.

Anticoagulant therapy in orthopedic surgery - a review on anticoagulant agents, risk factors, monitoring, and current challenges

Orthopedic surgeries are associated with high-risk of thromboembolism which occurs in 40% to 60% of orthopedic patients in the absence of thromboprophylaxis. Conventionally heparin anticoagulants were used for thromboprophylaxis and currently direct oral anticoagulants (DOACs) are widely used due to their minimal complexity. Anticoagulant use carries bleeding risk and requires optimal laboratory monitoring through conventional thrombin-based assays, anti-Xa assay, anti-IIa assay and contemporary ecarin chromogenic assay (ECA) and rotational thromboelastometry. Monitoring requires multiple hospital visits and hence, the development of point-of-care assays is gaining momentum. Also, a thorough risk assessment model (RAM) is necessary for successful anticoagulant therapy since it enables personalized approach for better thromboprophylaxis outcomes. Despite welcoming changes, lack of guideline consensus, population-based thromboprophylaxis, deficiencies in risk stratification and non-adherence are still a concern. Stronger clinical and process support system with uniform guidelines approaches and patient-specific RAM can aid in the successful implementation of anticoagulant therapy.

A review of venous thromboembolism risk assessment models for different patient populations: What we know and don't!

Venous thromboembolism (VTE) is a common cause of morbidity and mortality in hospitalized patients. Globally, it is also the third leading vascular disease, after myocardial infarction and stroke. The incidence of VTE is reportedly higher in Western countries than in Asian countries. However, recent reports suggest an increasing incidence of VTE in Asian countries, including India. Since VTE is largely a preventable disease, early identification of risk factors can lead to disease prevention or the adoption of appropriate prophylactic measures. To this end, several VTE risk assessment models (RAMs) have been developed and validated for different populations who are at risk of developing VTE, such as hospitalized patients with medical illness/surgical indication, patients with cancer, and pregnant women. Evidence indicates that the systematic use of RAMs improves prophylaxis rates and lowers the burden of VTE. Given the increasing burden of VTE in the Indian population and poor prophylaxis rates, the implementation of systematic RAMs in routine clinical practice might ameliorate the disease burden in the country. We have assessed the evidence-based utilities of available RAMs and have delineated the most common and suitable RAMs for different populations including coronavirus disease 2019 affected patients. This review depicts the current status of implementation and validation of RAMs in the Indian scenario. It also highlights the need for additional validation studies, improved awareness, and implementation of RAMs in clinical practice for lowering the burden of VTE.

Ability of IMPROVE and IMPROVE-DD scores to predict outcomes in patients with severe COVID-19: a prospective observational study

In this study we aimed to evaluate the ability of IMPROVE and IMPROVE-DD scores in predicting in-hospital mortality in patients with severe COVID-19. This prospective observational study included adult patients with severe COVID-19 within 12 h from admission. We recorded patients' demographic and laboratory data, Charlson comorbidity index (CCI), SpO₂ at room air, acute physiology and chronic health evaluation II (APACHE II), IMPROVE score and IMPROVE-DD score. In-hospital mortality and incidence of clinical worsening (the need for invasive mechanical ventilation, vasopressors, renal replacement therapy) were recorded. Our outcomes included the ability of the IMPROVE and IMPROVE-DD to predict in-hospital mortality and clinical worsening using the area under receiver operating characteristic curve (AUC) analysis. Multivariate analysis was used to detect independent risk factors for the study outcomes. Eighty-nine patients were available for the final analysis. The IMPROVE and IMPROVE-DD score showed the highest ability for predicting in-hospital mortality (AUC [95% confidence intervals {CI}] 0.96 [0.90–0.99] and 0.96 [0.90–0.99], respectively) in comparison to other risk stratification tools (APACHE II, CCI, SpO₂). The AUC (95% CI) for IMPROVE and IMPROVE-DD to predict clinical worsening were 0.80 (0.70–0.88) and 0.79 (0.69–0.87), respectively. Using multivariate analysis, IMPROVE-DD and SpO₂ were the only predictors for in-hospital mortality and clinical worsening. In patients with severe COVID-19, high IMPROVE and IMOROVE-DD scores showed excellent ability to predict in-hospital mortality and clinical worsening. Independent risk factors for in-hospital mortality and clinical worsening were IMPROVE-DD and SpO₂.

A Useful Blood Flow Restriction Training Risk Stratification for Exercise and Rehabilitation

Blood flow restriction training (BFRT) is a modality with growing interest in the last decade and has been recognized as a critical tool in rehabilitation medicine, athletic and clinical populations. Besides its potential for positive benefits, BFRT has the capability to induce adverse responses. BFRT may evoke increased blood pressure, abnormal cardiovascular responses and impact vascular health. Furthermore, some important concerns with the use of BFRT exists for individuals with established cardiovascular disease (e.g., hypertension, diabetes mellitus, and chronic kidney disease patients). In addition, considering the potential risks of thrombosis promoted by BFRT in medically compromised populations, BFRT use warrants caution for patients that already display impaired blood coagulability, loss of antithrombotic mechanisms in the vessel wall, and stasis caused by immobility (e.g., COVID-19 patients, diabetes mellitus, hypertension, chronic kidney disease, cardiovascular disease, orthopedic post-surgery, anabolic steroid and ergogenic substance users, rheumatoid arthritis, and pregnant/postpartum women). To avoid untoward outcomes and ensure that BFRT is properly used, efficacy endpoints such as a questionnaire for risk stratification involving a review of the patient’s medical history, signs, and symptoms indicative of underlying pathology is strongly advised. Here we present a model for BFRT pre-participation screening to theoretically reduce risk by excluding people with comorbidities or medically complex histories that could unnecessarily heighten intra- and/or post-exercise occurrence of adverse events. We propose this risk stratification tool as a framework to allow clinicians to use their knowledge, skills and expertise to assess and manage any risks related to the delivery of an appropriate BFRT exercise program. The questionnaires for risk stratification are adapted to guide clinicians for the referral, assessment, and suggestion of other modalities/approaches if/when necessary. Finally, the risk stratification might serve as a guideline for clinical protocols and future randomized controlled trial studies.

An update on the global use of risk assessment models and thromboprophylaxis in hospitalized patients with medical illnesses from the World Thrombosis Day steering committee: Systematic review and meta-analysis

INTRODUCTION

Venous thromboembolism (VTE) is a leading cause of cardiovascular morbidity and mortality. The majority of VTE events are hospital-associated. In 2008, the Epidemiologic International Day for the Evaluation of Patients at Risk for Venous Thromboembolism in the Acute Hospital Care Setting (ENDORSE) multinational cross-sectional study reported that only approximately 40% of medical patients at risk of VTE received adequate thromboprophylaxis.

METHODS

In our systematic review and meta-analysis, we aimed at providing updated figures concerning the use of thromboprophylaxis globally. We focused on: (a) the frequency of patients with an indication to thromboprophylaxis according with individual models; (b) the use of adequate thromboprophylaxis; and (c) reported contraindications to thromboprophylaxis. Observational nonrandomized studies or surveys focusing on medically ill patients were considered eligible.

RESULTS

After screening, we included 27 studies from 20 countries for a total of 137 288 patients. Overall, 50.5% (95% confidence interval [CI]: 41.9-59.1, I2 99%) of patients had an indication to thromboprophylaxis: of these, 54.5% (95% CI: 46.2-62.6, I2 99%) received adequate thromboprophylaxis. The use of adequate thromboprophylaxis was 66.8% in Europe (95% CI: 50.7-81.1, I2 98%), 44.9% in Africa (95% CI: 31.8-58.4, I2 96%), 37.6% in Asia (95% CI: 25.7-50.3, I2 97%), 58.3% in South America (95% CI: 31.1-83.1, I2 99%), and 68.6% in North America (95% CI: 64.9-72.6, I2 96%). No major differences in adequate thromboprophylaxis use were found across risk assessment models. Bleeding, thrombocytopenia, and renal/hepatic failure were the most frequently reported contraindications to thromboprophylaxis.

CONCLUSIONS

The use of anticoagulants for VTE prevention has been proven effective and safe, but thromboprophylaxis prescriptions are still unsatisfactory among hospitalized medically ill patients around the globe with marked geographical differences.

Validation of risk assessment models predicting venous thromboembolism in inpatients with AECOPD: a multicenter cohort study

BACKGROUND

As inpatients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are at increased risk for venous thromboembolism (VTE), identifying high-risk patients requiring thromboprophylaxis is critical to reduce the mortality and morbidity associated with VTE. This study aimed to evaluate and compare the validities of the Padua Prediction Score and Caprini risk assessment model (RAM) in predicting the risk of VTE in inpatients with AECOPD.

METHODS

The inpatients with AECOPD were prospectively enrolled from seven medical centers of China between September 2017 and January 2020. Caprini and Padua scores were calculated on admission, and the incidence of 3-month VTE was investigated.

RESULTS

Among the 3277 eligible patients with AECOPD, 128 patients (3.9%) developed VTE within 3 months after admission. The distribution of the study population by the Caprini risk level was as follows: high, 53.6%; moderate, 43.0%; and low, 3.5%. The incidence of VTE increased by risk level as high, 6.1%; moderate, 1.5%; and low, 0%. According to the Padua RAM, only 10.9% of the study population was classified as high risk and 89.1% as low risk, with the corresponding incidence of VTE 7.9% and 3.4%, respectively. The Caprini RAM had higher area under curve (AUC) compared with the Padua RAM (0.713  0.021 vs 0.644 ± 0.023, P = 0.029).

CONCLUSION

The Caprini RAM was superior to the Padua RAM in predicting the risk of VTE in inpatients with AECOPD and might better guide thromboprophylaxis in these patients.

Derivation and validation of a clinical prediction model for risks of venous thromboembolism in diabetic and general populations

Most studies on the prediction of venous thromboembolism (VTE) focused on hospitalized, surgery, and cancer patients or women receiving hormonal contraceptives or menopausal hormone therapy. No study considered diabetic and general populations to establish a VTE prediction model, especially in Asia. We developed a predictive model for VTE among type 2 diabetic patients and the general population.This study considered 2 nationwide retrospective cohort studies consisting of 52,427 diabetic participants and 508,664 participants from the general population aged 30 to 85 years during 2001 to 2004 in Taiwan. All participants were followed up until VTE event, death, or December 2011. The outcome event was VTE, including deep venous thrombosis and pulmonary embolism. Candidate predictors consisted of socio-demographic factors, diabetes-related factors and biomarkers, comorbidities, and medicine use. Our study followed the procedures proposed by the Framingham Heart Study to develop prediction models by using a Cox regression model. The predictive accuracy and performance characteristics were assessed using the area under curve of receiver operating characteristics curve and calibration of a risk score were performed by Hosmer-Lemeshow goodness-of-fit test.The common factors for persons with type 2 diabetes and general population included age, hospitalization status 1 year before the baseline, hypertension, chronic kidney disease, chronic obstructive pulmonary disease, and anti-diabetes medications; the specific factors for persons with type 2 diabetes consisted of body mass index, glycosylated hemoglobin A1C, and creatinine; and the factors for general population included gender, peripheral vascular disease, cancer, hypertension medication, cardiovascular medication, and non-steroidal anti-inflammatory drug. The area under curve of 3-, 5-, and 8-year VTE prediction models were 0.74, 0.71, and 0.69 in the diabetic population and 0.77, 0.76, and 0.75 in the general population, respectively.The new clinical prediction models can help identify a high risk of VTE and provide medical intervention in diabetic and general populations.

Risk assessment models for venous thromboembolism in hospitalised adult patients: a systematic review

INTRODUCTION

Hospital-acquired thrombosis accounts for a large proportion of all venous thromboembolism (VTE), with significant morbidity and mortality. This subset of VTE can be reduced through accurate risk assessment and tailored pharmacological thromboprophylaxis. This systematic review aimed to determine the comparative accuracy of risk assessment models (RAMs) for predicting VTE in patients admitted to hospital.

METHODS

A systematic search was performed across five electronic databases (including MEDLINE, EMBASE and the Cochrane Library) from inception to February 2021. All primary validation studies were eligible if they examined the accuracy of a multivariable RAM (or scoring system) for predicting the risk of developing VTE in hospitalised inpatients. Two or more reviewers independently undertook study selection, data extraction and risk of bias assessments using the PROBAST (Prediction model Risk Of Bias ASsessment Tool) tool. We used narrative synthesis to summarise the findings.

RESULTS

Among 6355 records, we included 51 studies, comprising 24 unique validated RAMs. The majority of studies included hospital inpatients who required medical care (21 studies), were undergoing surgery (15 studies) or receiving care for trauma (4 studies). The most widely evaluated RAMs were the Caprini RAM (22 studies), Padua prediction score (16 studies), IMPROVE models (8 studies), the Geneva risk score (4 studies) and the Kucher score (4 studies). C-statistics varied markedly between studies and between models, with no one RAM performing obviously better than other models. Across all models, C-statistics were often weak (<0.7), sometimes good (0.7-0.8) and a few were excellent (>0.8). Similarly, estimates for sensitivity and specificity were highly variable. Sensitivity estimates ranged from 12.0% to 100% and specificity estimates ranged from 7.2% to 100%.

CONCLUSION

Available data suggest that RAMs have generally weak predictive accuracy for VTE. There is insufficient evidence and too much heterogeneity to recommend the use of any particular RAM.

PROSPERO REGISTRATION NUMBER

Steve Goodacre, Abdullah Pandor, Katie Sworn, Daniel Horner, Mark Clowes. A systematic review of venous thromboembolism RAMs for hospital inpatients. PROSPERO 2020 CRD42020165778. Available from https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=165778https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=165778.

Inter-observer reliability of a risk assessment model for venous thromboembolism in acutely-ill medical hospitalized patients: Results from a prospective cohort study

OBJECTIVES

To analyze the inter-observer reliability of risk for venous thromboembolism (VTE) in a population of adult acutely-ill medical patients.

METHODS

In this prospective cohort study, we collected risk factors and risk classification for VTE using RAM IMPROVE7. Kappa statistics was used to evaluate inter-observer reliability between lead clinicians and trained researchers. We evaluated occurrence of VTE in patients with mismatched classification.

RESULTS

We included 2,380 patients, median age 70 years (interquartile range [IQR], 58-79), 56.2% female. Adjusted Kappa for VTE risk factors ranged from substantial (0.64, 95% confidence interval [CI], 0.61-0.67) for "immobilization", to almost perfect (0.98; 95% CI 0.97-0.99) for "thrombophilia"; risk classification was 0.64 (95% CI 0.60-0.67). Divergent risk classification occurred in 434 patients (18.2%) of whom seven (1.6%) developed VTE.

CONCLUSION

Despite substantial to almost perfect reliability between observers for risk factors and risk classification, lead clinicians tended to underestimate the risk for VTE.

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.

Comparison between the Khorana prediction score and Caprini risk assessment models for assessing the risk of venous thromboembolism in hospitalized patients with cancer: a retrospective case control study

OBJECTIVES

This study aimed to evaluate the optimal risk assessment model (RAM) to stratify the risk of venous thromboembolism (VTE) in hospitalized patients with cancer. We examined and compared the VTE predictive ability of the Khorana score (KS) and the Caprini RAM in hospitalized cancer patients.

METHODS

We performed a retrospective case-control study among hospitalized cancer patients admitted to a comprehensive hospital in China from January 2015 to December 2016. A total of 221 cases were confirmed to have VTE during hospitalization and 221 controls were selected randomly. The Caprini RAM and KS were implemented and the individual scores of each risk factor were summed to generate a cumulative risk score. Meanwhile, the sensitivity, specificity, areas under curve of the receiver operating characteristic curve and calibration of these 2 models were analysed.

RESULTS

Significant differences were observed in risk factors between VTE and non-VTE hospitalized cancer patients and the VTE risk increased significantly with an increase in the cumulative KS or Caprini RAM score. A classification of 'high risk' according to KS and Caprini RAM was associated with 2.272-fold and 3.825-fold increases in VTE risk, respectively. However, the Caprini RAM could identify 82.4% of the VTE cases that required preventive anticoagulant therapy according to American College of Chest Physicians guidelines, whereas the KS could only identify 35.3% of the VTE cases. In addition, the areas under curve of Caprini RAM were significantly higher than those of the KS (0.705 ± 0.024 vs 0.581 ± 0.025, P < 0.001), with a best cut-off value of 5 score, which happened to be the cut-off value for high risk of VTE in Caprini RAM. Both Caprini RAM and KS showed an excellent calibration curve (0.612 vs 0.141, P > 0.05), but the risk of VTE events predicted by Caprini seemed closer to the observed risk of VTE events.

CONCLUSIONS

The Caprini RAM was found to be more effective than the KS in identifying hospitalized patients with cancer at risk of VTE.

Post-hospital discharge venous thromboembolism prophylaxis in medically ill patients

There is a widely expressed concern about an unmet need for post hospitalization venous thromboembolism (VTE) prophylaxis in medically ill patients, however, physicians and hospitals have been slow to implement this measure. Recommendations against extended VTE prophylaxis in medical patients from the American Society of Hematology (ASH) in 2018 and the withholding of approval of betrixiban by the European Medicines Agency also in 2018 may have been influential in this regard. Furthermore, rivaroxaban the other drug approved for this indication in the U.S has not yet been approved in Europe. In addition, hospital administrators, those monitoring expenses in the U.S, have been reluctant to support a treatment which will mostly involve outpatients. Internal medicine physicians, hospitalists and nursing home physicians have not shared the fervor for post hospital VTE prophylaxis, whether with anticoagulants or aspirin, that their orthopedic surgery colleagues have, particularly in hip and knee arthroplasty. This is despite an increased risk of post hospital discharge thrombosis in both groups of patients. Enter hospitalized patients with COVID-19, a potentially severe medical illness with high hospitalization related thrombosis risk, and questions arise as to whether these medical patients, who are clearly more hypercoagulable during hospitalization than those in previous studies, should warrant post hospital discharge prophylaxis.

Validation of the IMPROVE-DD risk assessment model for venous thromboembolism among hospitalized patients with COVID-19

BACKGROUND

Antithrombotic guidance statements for hospitalized patients with coronavirus disease 2019 (COVID-19) suggest a universal thromboprophylactic strategy with potential to escalate doses in high-risk patients. To date, no clear approach exists to discriminate patients at high risk for venous thromboembolism (VTE).

OBJECTIVES

The objective of this study is to externally validate the IMPROVE-DD risk assessment model (RAM) for VTE in a large cohort of hospitalized patients with COVID-19 within a multihospital health system.

METHODS

This retrospective cohort study evaluated the IMPROVE-DD RAM on adult inpatients with COVID-19 hospitalized between March 1, 2020, and April 27, 2020. Diagnosis of VTE was defined by new acute deep venous thrombosis or pulmonary embolism by Radiology Department imaging or point-of-care ultrasound. The receiver operating characteristic (ROC) curve was plotted and area under the curve (AUC) calculated. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated using standard methods.

RESULTS

A total of 9407 patients were included, with a VTE prevalence of 2.9%. The VTE rate was 0.4% for IMPROVE-DD score 0-1 (low risk), 1.3% for score 2-3 (moderate risk), and 5.3% for score ≥ 4 (high risk). Approximately 45% of the total population scored high VTE risk, while 21% scored low VTE risk. IMPROVE-DD discrimination of low versus medium/high risk showed sensitivity of 0.971, specificity of 0.218, PPV of 0.036, and NPV of 0.996. ROC AUC was 0.702.

CONCLUSIONS

The IMPROVE-DD VTE RAM demonstrated very good discrimination to identify hospitalized patients with COVID-19 as low, moderate, and high VTE risk in this large external validation study with potential to individualize thromboprophylactic strategies.

Do Inpatients Receive Risk-Based Prophylactic Treatment for Thrombotic Events?

BACKGROUND

Current guidelines recommend risk-based use of prophylaxis for preventing medical inpatients from venous thromboembolism (VTE). Little is known about the current prescription practice, and even less whether differences between subspecialists like cardiologists, usually treating patients with thrombotic or thromboembolic diseases, and gastroenterologists, treating more patients with gastrointestinal bleeding complications, exist.

METHODS

We performed a retrospective chart review of patients on cardiology and gastroenterology wards of our university hospital. Patients with a clear indication for anticoagulation and contraindication against antithrombotic treatment were excluded. A total of 450 patients per specialty were included. Quantitative risk assessment models were used to determine the risk of a VTE (Padua Prediction Score (PPS), IMPROVE Score) and bleeding (IMPROVE-Bleeding and HAS-BLED Score).

RESULTS

The overall rate of VTE prophylaxis was high in both patient populations. Significant more low-risk cardiology compared to gastroenterology patients received drug-based prophylaxis. Furthermore, crucial discrepancies were found in the way individual patients would be classified based on PPS and IMPROVE Score. Finally, not the risk category but the length of hospital stay was best at predicting which patient received prophylaxis.

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.

Prevention, Diagnosis, and Treatment of VTE in Patients With Coronavirus Disease 2019: CHEST Guideline and Expert Panel Report

BACKGROUND

Emerging evidence shows that severe coronavirus disease 2019 (COVID-19) can be complicated by a significant coagulopathy, that likely manifests in the form of both microthrombosis and VTE. This recognition has led to the urgent need for practical guidance regarding prevention, diagnosis, and treatment of VTE.

METHODS

A group of approved panelists developed key clinical questions by using the PICO (Population, Intervention, Comparator, Outcome) format that addressed urgent clinical questions regarding the prevention, diagnosis, and treatment of VTE in patients with COVID-19. MEDLINE (via PubMed or Ovid), Embase, and Cochrane Controlled Register of Trials were systematically searched for relevant literature, and references were screened for inclusion. Validated evaluation tools were used to grade the level of evidence to support each recommendation. When evidence did not exist, guidance was developed based on consensus using the modified Delphi process.

RESULTS

The systematic review and critical analysis of the literature based on 13 Population, Intervention, Comparator, Outcome questions resulted in 22 statements. Very little evidence exists in the COVID-19 population. The panel thus used expert consensus and existing evidence-based guidelines to craft the guidance statements.

CONCLUSIONS

The evidence on the optimal strategies to prevent, diagnose, and treat VTE in patients with COVID-19 is sparse but rapidly evolving.

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.

Validation of risk assessment models predicting venous thromboembolism in acutely ill medical inpatients: A cohort study

BACKGROUND

Because hospital-acquired venous thromboembolism (VTE) represents a frequent cause of preventable deaths in medical inpatients, identifying at-risk patients requiring thromboprophylaxis is critical. We aimed to externally assess the Caprini, IMPROVE, and Padua VTE risk scores and to compare their performance to advanced age as a stand-alone predictor.

METHODS

We performed a retrospective analysis of patients prospectively enrolled in the PREVENU trial. Patients aged 40 years and older, hospitalized for at least 2 days on a medical ward were consecutively enrolled and followed for 3 months. Critical ill patients were not recruited. Patients diagnosed with VTE within 48 hours from admission, or receiving full dose anticoagulant treatment or who underwent surgery were excluded. All suspected VTE and deaths occurring during the 3-month follow-up were adjudicated by an independent committee. The three scores were retrospectively assessed. Body mass index, needed for the Padua and Caprini scores, was missing in 44% of patients.

RESULTS

Among 14 910 eligible patients, 14 660 were evaluable, of which 1.8% experienced symptomatic VTE or sudden unexplained death during the 3-month follow-up. The area under the receiver operating characteristic curves (AUC) were 0.60 (95% confidence interval [CI] 0.57-0.63), 0.63 (95% CI 0.60-0.66) and 0.64 (95% CI 0.61-0.67) for Caprini, IMPROVE, and Padua scores, respectively. None of these scores performed significantly better than advanced age as a single predictor (AUC 0.61, 95% CI 0.58-0.64).

CONCLUSION

In our study, Caprini, IMPROVE, and Padua VTE risk scores have poor discriminative ability to identify not critically ill medical inpatients at risk of VTE, and do not perform better than a risk evaluation based on patient's age alone.

Should You Treat This Acutely Ill Medical Inpatient With Venous Thromboembolism Chemoprophylaxis?: Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Venous thromboembolism (VTE), which includes both deep venous thrombosis and pulmonary embolism, is a common and potentially fatal condition. Medical inpatients are at high risk for VTE because of immobility as well as acute and chronic illness. Several randomized trials demonstrated that chemoprophylaxis, or low-dose anticoagulation, prevents VTE in selected medical inpatients. The 2018 American Society of Hematology clinical practice guideline on prophylaxis for hospitalized and nonhospitalized medical patients conditionally recommends chemoprophylaxis for non-critically ill medical inpatients, leaving much to the discretion of the treating physician. Here, 2 experts, a hematologist and a hospitalist, reflect on the care of a woman hospitalized with a rheumatologic disorder. They consider the risks and benefits of chemoprophylaxis, discuss VTE risk stratification, and recommend which patients should receive chemoprophylaxis and with which agents.

Recommendations for VTE Prophylaxis in Medically Ill Patients

Venous thromboembolism (VTE) remains highly prevalent in medically ill patients, and often leads to increased mortality and cost burden during hospitalization and post-discharge. Nearly half of all VTEs occur during or after hospitalization, with pulmonary embolism accounting for 10% of inpatient mortality. Appropriate prophylaxis in high-risk medically ill patients has been shown to reduce risk of VTE and related mortality. Despite current evidence-based guidelines, VTE prophylaxis has been under-used. This owes greatly to ambiguity and concerns related to appropriate patient and prophylactic agent selection, and duration of prophylaxis. Because many acutely ill medical patients have multiple comorbidities, the risk of major bleeding must be considered when choosing to implement pharmacological VTE prophylaxis. Multiple risk assessment models have been developed and validated to help estimate VTE and bleeding risks in this population. While studies have shown that the risk for VTE often extends far beyond hospital discharge, there is no evidence to support extending prophylaxis after hospital discharge. The appropriate selection of VTE prophylaxis requires consideration for cost, availability, patient preference, compliance, and underlying comorbidities. Our paper reviews the current evidence and reasoning for appropriate selection of VTE prophylaxis in acutely medical ill patients, and highlights our own approach and recommendations.

Reassessment of venous thromboembolism and bleeding risk in medical patients receiving VTE prophylaxis

RATIONALE, AIMS, AND OBJECTIVES

The majority of hospitalized nonsurgical medical patients receive pharmacological prophylaxis for venous thromboembolism (VTE), and reassessment of changes in thrombosis and bleeding risk factors during hospital admission may represent an opportunity to discontinue unnecessary or unsafe therapy. The use of validated, clinically derived risk assessment models (RAMs) represents a shift towards an individualized, patient-centred approach to VTE prophylaxis. We are interested in using these tools to assess whether risk categories for VTE and bleeding change during admission and to assess whether such changes result in discontinuation of prophylaxis. Our primary objective was to determine whether VTE and bleed risk categories changed during the course of admission to warrant discontinuation of VTE prophylaxis, using the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) VTE and Bleed RAMs, respectively. Secondary objectives were to determine the number of patients whose risk categorizations for VTE and bleeding warranted discontinuation of VTE prophylaxis and to survey whether prophylaxis was continued or discontinued.

METHODS

A retrospective review was undertaken for a cross-sectional, randomly selected sample of patients who received VTE prophylaxis while admitted to medical wards in a collection of regional hospitals.

RESULTS

Of the 351 medical records reviewed, only eight patients (2.3%) changed their VTE risk category and six (1.7%) changed their bleed risk category to warrant discontinuation of VTE prophylaxis. Ninety patients (26%) were at high risk of VTE and low risk of bleed throughout admission, warranting continued VTE prophylaxis. The majority of patients remained at low risk of VTE throughout admission but remained on VTE prophylaxis until discharge.

CONCLUSIONS

Risk categories for VTE and bleeding for medical patients did not appreciably change throughout hospital admission. Use of VTE RAMs at admission and prior to initiation of therapy should reduce unnecessary prophylaxis in the majority of medical patients who are at low risk of VTE.

Modified IMPROVE VTE Risk Score and Elevated D-Dimer Identify a High Venous Thromboembolism Risk in Acutely Ill Medical Population for Extended Thromboprophylaxis

An individualized approach to identify acutely ill medical patients at increased risk of venous thromboembolism (VTE) and a low risk of bleeding to optimize the benefit and risk of extended thromboprophylaxis (ET) is needed. The International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) VTE risk score has undergone extensive external validation in medically ill patients for in-hospital use and a modified model was used in the MARINER trial of ET also incorporating an elevated D-dimer. The MAGELLAN study demonstrated efficacy with rivaroxaban but had excess bleeding. This retrospective analysis investigated whether the modified IMPROVE VTE model with an elevated D-dimer could identify a high VTE risk subgroup of patients for ET from a subpopulation of the MAGELLAN study, which was previously identified as having a lower risk of bleeding. We incorporated the modified IMPROVE VTE score using a cutoff score of 4 or more or 2 and 3 with an elevated D-dimer (>2 times the upper limit of normal) to the MAGELLAN subpopulation. In total, 56% of the patients met the high-risk criteria. In the placebo group, the total VTE event rate at Day 35 was 7.94% in the high-risk group and 2.83% for patients in the lower-risk group. A reduction in VTE was observed with rivaroxaban in the high-risk group (relative risk [RR]: 0.68, 95% confidence interval [CI]: 0.51-0.91, p  = 0.008) and in the lower-risk group (RR: 0.69, 95% CI: 0.40 -1.20, p  = 0.187). The modified IMPROVE VTE score with an elevated D-dimer identified a nearly threefold higher VTE risk subpopulation of patients where a significant benefit exists for ET using rivaroxaban.

Overuse of venous thromboembolism prophylaxis among hospitalized patients with liver disease

INTRODUCTION

Patients with liver disease are at risk of venous thromboembolism (VTE); however, little is understood regarding the safety and efficacy of VTE prophylaxis in patients with cirrhosis. We examined the application of a VTE risk assessment model in VTE prophylaxis decision-making in a closed cohort of hospitalized patients with liver disease.

METHODS

Sequential patients admitted to an inpatient hepatology service at a tertiary care center were evaluated for need for VTE prophylaxis. Risk assessment by IMPROVE was compared with current practice patterns of VTE prophylaxis. Rates of bleeding and clotting events were noted.

RESULTS

98 patient encounters were included in our analysis. 76% of patients received VTE prophylaxis in practice. IMPROVE recommended use of VTE prophylaxis in 19% of patients. Patients who received VTE prophylaxis that was not warranted had significantly lower risk of clotting compared with patients in whom VTE prophylaxis was warranted per IMPROVE.

CONCLUSIONS

Application of IMPROVE risk assessment would significantly reduce VTE prophylaxis use among hospitalized patients with liver disease. Our findings challenge the "one-size-fits-all" current practice pattern of VTE prophylaxis. Future studies are needed in large cohorts of hospitalized patients with liver disease that include clinical outcomes of bleeding and clotting risk.

Net-clinical benefit of extended prophylaxis of venous thromboembolism with betrixaban in medically ill patients aged 80 or more

BACKGROUND

Extended-duration thromboprophylaxis with betrixaban reduces the risk of venous thromboembolism (VTE) without increasing major bleeding rates in acutely ill medical patients as compared to standard duration enoxaparin. We aimed to assess the risk-benefit of betrixaban in patients aged ≥ 80 years enrolled in the APEX trial.

METHODS

APEX was a randomized, double-blind trial in which patients hospitalized for acute medical illnesses received enoxaparin 40 mg qd for 10 ± 4 days or oral betrixaban 80 mg qd for 35 to 42 days. The primary efficacy outcome was VTE, the principal safety outcome was major bleeding. Net clinical benefit (NCB) was defined by the occurrence of VTE or major bleeding.

RESULTS

Of 7513 patients enrolled in the APEX trial, 2781 (37%) were aged ≥ 80 years. In this subgroup, VTE or major bleeding occurred in 7.0% of betrixaban patients and in 8.4% of enoxaparin patients, for a relative risk in the NCB of 0.82 (95% confidence interval 0.62-1.10). The relative risk reduction obtained with betrixaban was similar between those aged ≥ 80 years and patients younger than 80 years (5.0% and 6.7%, respectively, NCB 0.75, 0.58-0.96, P = .024), with no significant interaction across age groups (P = .33).

CONCLUSIONS

Event rates were higher in medically ill patients aged ≥ 80 years enrolled in the APEX study than in patients younger than 80 years. The predefined NCB was reduced with extended betrixaban therapy in both groups with no signs of age-related interactions. However, the primary efficacy endpoint was not achieved with betrixaban for patients 80 years of age or older.

The case for extended thromboprophylaxis in medically hospitalised patients – not yet made

Background

The role of extended thromboprophylaxis is established for surgical patients, but not yet for hospitalised medical patients.

Design

This systematic review and meta-analysis sought to explore the role of extended thromboprophylaxis for medically ill hospitalised patients.

Methods

Medline, EMBASE and Cochrane Libraries were searched and five randomised controlled trials were identified, comprising 20,046 extended and 20,078 standard duration thromboprophylaxis patients.

Results

Allocation to extended treatment, compared with standard duration therapy, significantly reduced the risk of symptomatic deep vein thrombosis (relative risk (RR) 0.47, 95% confidence interval (CI) 0.29–0.78, P = 0.003) and non-fatal pulmonary embolism (RR 0.59, 95% CI 0.39–0.91, P = 0.02). The risk of venous thromboembolism-related death was comparable between the extended and standard duration treatment groups (RR 0.81, 95% CI 0.6–1.09, P = 0.16). Extended treatment also doubled the risk of major bleeding (RR 2.04, 95% CI 1.42–2.91, P &lt; 0.001), without significantly affecting the risk of intracranial bleeding or bleeding-associated death. The cost of preventing one symptomatic deep vein thrombosis and non-fatal pulmonary embolism was found to be £24,972 (€27,969) and £45,148 (€50,566), respectively, which outweigh the direct cost of managing established venous thromboembolism as previously reported.

Conclusions

Extended duration thromboprophylaxis caused a reduction in the risk of venous thromboembolic events, but also a numerically comparable increase in major bleeding. Further trials are required in high-risk subpopulations who may derive mortality benefits from treatment. Only then could a change in current policy and practice be supported.

Person-centred prophylaxis for venous thromboembolism

All medical admissions should receive risk assessment for the value of prophylaxis against venous thromboembolism. Unfortunately, for such patients the risk of thromboembolism is closely balanced with the risk of haemorrhage exaggerated by chemical prophylaxis. The recent NICE guideline continues to recommend comprehensive risk assessment, and to use prophylaxis where the risk of thromboembolism exceeds the risk of bleeding. The widely used Department of Health Risk Assessment Tool does not rank the risks of thromboembolism and bleeding, but NICE was unable to mandate another assessment tool fit for the purpose in the UK. Validated risk scores are used elsewhere, and could enable safer and better targeted prophylaxis, pending further research in the UK.

Betrixaban for Extended Venous Thromboembolism Prophylaxis in High-Risk Hospitalized Patients: Putting the APEX Results into Practice

Acutely ill hospitalized medical patients remain at high thromboembolic risk for several weeks after discharge. Previous trials with extended-duration thromboprophylaxis using enoxaparin, apixaban, and rivaroxaban failed to achieve acceptable net clinical benefit, largely due to excess of major bleeding. Betrixaban is a novel factor Xa inhibitor with unique pharmacokinetic properties, including low renal clearance, long half-life, and low peak-to-trough ratio. The phase III APEX trial (N = 7513) compared a betrixaban 160 mg loading dose followed by 80 mg once daily for 35-42 days, with enoxaparin 40 mg once daily for 6-14 days; the betrixaban dose was reduced for renal impairment or a concomitant strong P-glycoprotein (P-gp) inhibitor. The primary efficacy endpoint of composite thrombotic events was not different between treatment arms in cohort 1 (D-dimer ≥ 2 × upper limit of normal). Subsequent exploratory analyses showed a statistically significant difference favoring betrixaban for symptomatic venous thromboembolism and net clinical benefit in the overall population. For the primary safety outcome, betrixaban did not significantly increase major bleeding compared with enoxaparin. Based on available data from the APEX trial and subanalyses, the use of betrixaban in patients similar to those enrolled in the APEX trial can reduce the risk of thromboembolic events without increasing the risk of major bleeding. Patients who may benefit more from betrixaban therapy include those with elevated D-dimer, history of venous thromboembolism, hospitalized for ischemic stroke, hospitalized for heart failure with N-terminal pro-B-type natriuretic peptide ≥ 1975 ng/L, or two or more VTE risk factors. Reduced-dose betrixaban does not appear to provide the same clinical utility as full-dose betrixaban.

Compliance with Guidelines on Thromboprophylaxis for Acutely Admitted Medical Patients

INTRODUCTION

The risk of venous thromboembolism (VTE) is increased by more than 100-fold among hospitalised medical patients compared to subjects in the community. The Danish Council for the Use of Expensive Hospital Medicines has published national guidelines on thromboprophylaxis (TP) in which the risks of VTE and bleeding are balanced. We wanted to investigate the proportion of acutely admitted medical patients for whom thromboprophylaxis was indicated and to what extent the guidelines were followed.

METHODS

Data from patients hospitalised at two medical wards were screened. We registered the proportion of patients for whom mechanical or pharmacologic TP (MTP and PTP, respectively) was indicated and whether national guidelines were followed. All data extraction and analyses were performed retrospectively.

RESULTS

After exclusion criteria were applied, 340 cases remained. PTP was indicated in 26 patients (7.6%) but only 4 patients were treated besides 12 patients who were already in anticoagulant treatment at submission. Conversely, 8/306 patients, in whom TP was not indicated, were started on PTP. MTP was indicated in 8/340 patients (2.4%) but therapy was not initiated in any of them. The majority (320/340, 94.1%) of cases was managed in accordance with existing guidelines. However, this high proportion was mainly explained by the large number of untreated patients, where TP was not indicated.

CONCLUSION

A large proportion of hospitalised medical patients was managed in conflict with national guidelines. A systematic approach to TP in patients with acute medical illness should be implemented. Plain language summary available for this article.

Updated clinical models for VTE prediction in hospitalized medical patients

Venous thromboembolism (VTE) occurring in hospitalized medical patients is associated with increased length of hospitalization, high rate of acute care hospital transfer, longer inpatient rehabilitation and multiplication of health-care costs. Identification of acutely ill hospitalized medical patients eligible for thromboprophylaxis is a sophisticated process. Global VTE risk stems from the combination of predictors related with the acute medical illness, comorbidities, associated treatments and patients' intrinsic risk factors. Emerging clinical risk factors related to underlying pathologies should be considered when VTE risk is assessed. The Padua Prediction Score (PPS), the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE-RAM) and the Geneva Risk Score are three robust risk assessment models (RAM) which underwent extensive external validation in cohorts of acutely ill hospitalized medical patients. The development of the IMPROVE bleeding risk assessment model and the identification of D-Dimer increase as a biomarker-predictor of VTE are some steps forward for personalized thromboprophylaxis. The beneficial impact of the RAMs in VTE prevention is already seen by the decrease of in-hospital VTE rates when RAMs are incorporated in electronic alert systems.

Rivaroxaban for Thromboprophylaxis after Hospitalization for Medical Illness

BACKGROUND

Patients who are hospitalized for medical illness remain at risk for venous thromboembolism after discharge, but the role of extended thromboprophylaxis in the treatment of such patients is a subject of controversy.

METHODS

In this randomized, double-blind trial, medically ill patients who were at increased risk for venous thromboembolism on the basis of a modified International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) score of 4 or higher (scores range from 0 to 10, with higher scores indicating a higher risk of venous thromboembolism) or a score of 2 or 3 plus a plasma d-dimer level of more than twice the upper limit of the normal range (defined according to local laboratory criteria) were assigned at hospital discharge to either once-daily rivaroxaban at a dose of 10 mg (with the dose adjusted for renal insufficiency) or placebo for 45 days. The primary efficacy outcome was a composite of symptomatic venous thromboembolism or death due to venous thromboembolism. The principal safety outcome was major bleeding.

RESULTS

Of the 12,024 patients who underwent randomization, 12,019 were included in the intention-to-treat analysis. The primary efficacy outcome occurred in 50 of 6007 patients (0.83%) who were given rivaroxaban and in 66 of 6012 patients (1.10%) who were given placebo (hazard ratio, 0.76; 95% confidence interval [CI], 0.52 to 1.09; P=0.14). The prespecified secondary outcome of symptomatic nonfatal venous thromboembolism occurred in 0.18% of patients in the rivaroxaban group and 0.42% of patients in the placebo group (hazard ratio, 0.44; 95% CI, 0.22 to 0.89). Major bleeding occurred in 17 of 5982 patients (0.28%) in the rivaroxaban group and in 9 of 5980 patients (0.15%) in the placebo group (hazard ratio, 1.88; 95% CI, 0.84 to 4.23).

CONCLUSIONS

Rivaroxaban, given to medical patients for 45 days after hospital discharge, was not associated with a significantly lower risk of symptomatic venous thromboembolism and death due to venous thromboembolism than placebo. The incidence of major bleeding was low. (Funded by Janssen Research and Development; MARINER ClinicalTrials.gov number, NCT02111564 .).

Electronic alerts, comparative practitioner metrics, and education improve thromboprophylaxis and reduce venous thrombosis in community hospitals

BACKGROUND

Venous thromboembolism prophylaxis remains underutilized in hospitalized medical patients at high risk for venous thromboembolism. We previously reported that a multifaceted intervention was associated with a sustained increase in appropriate thromboprophylaxis and reduced symptomatic venous thromboembolism among medical patients hospitalized in two urban teaching hospitals. The effectiveness of this intervention in community hospitals is unknown.

METHODS

We performed a prospective multicenter cohort study in three community hospitals. All medical patients admitted from February 1, 2011 to January 31, 2014 were eligible. Consecutive eligible patients were enrolled into the 12-month "control," 12-month "intervention," or 12-month "maintenance" group. We provided electronic alerts, physician performance feedback, and targeted medical education for the intervention group. Only the alert component of the intervention continued in the maintenance group. The primary outcome was the rate of appropriate thromboprophylaxis among patients at high risk for venous thromboembolism defined as the prescription of guideline recommended chemoprophylaxis, or identification of a chemoprophylaxis contraindication. Secondary outcomes included rates of symptomatic venous thromboembolism, major bleeding, all-cause mortality, heparin-induced thrombocytopenia, physician satisfaction, and alert fatigue.

RESULTS

Appropriate thromboprophylaxis when compared to the control group rate of 67% was higher for the intervention group (85%) and for the maintenance group (77%; P < .001 for each comparison). A reduction of 90-day symptomatic venous thromboembolism accompanied the intervention (control 4.5%, intervention 3.4%, maintenance 3.0%, P = .04).

CONCLUSIONS

This multifaceted intervention was associated with an overall increase in appropriate thromboprophylaxis of medical patients compared with the control period. Hospital-associated venous thrombosis rates decreased.

Assessment of the Risk of Venous Thromboembolism in Medical Inpatients using the Padua Prediction Score and Caprini Risk Assessment Model

Aim: The optimal risk assessment model (RAM) to stratify the risk of venous thromboembolism (VTE) in medical inpatients is not known. We examined and compared how well the Padua Prediction Score (PPS) and the Caprini RAM stratify VTE risk in medical inpatients.

Methods: We undertook a retrospective case-control study among medical inpatients admitted to a large general hospital in China during a 4-year period. In total, 902 cases were confirmed to have VTE during hospitalization and 902 controls were selected randomly to match cases by medical service.

Results: The VTE risk increased significantly with an increase of the cumulative PPS or Caprini RAM score. A PPS and Caprini RAM “high risk” classification was, respectively, associated with a 5.01-fold and 4.10-fold increased VTE risk. However, the Caprini RAM could identify 84.3% of the VTE cases to receive prophylaxis according to American College of Chest Physicians guidelines, whereas the PPS could only identify 49.1% of the VTE cases. In the medical inpatients studied, five risk factors seen more frequently in VTE cases than in controls in the Caprini RAM were not included in the PPS. The Caprini RAM risk levels were linked almost perfectly to in-hospital and 6-month mortality.

Conclusions: Both the PPS and Caprini RAM can be used to stratify the VTE risk in medical inpatients effectively, but the Caprini RAM may be considered as the first choice in a general hospital because of its incorporation of comprehensive risk factors, higher sensitivity to identify patients who may benefit from prophylaxis, and potential for prediction of mortality.

A systematic review of mobility/immobility in thromboembolism risk assessment models for hospitalized patients

Hospitalized patients are at risk of venous thromboembolism (VTE) and prophylaxis is often suboptimal due to difficulty in identifying at-risk patients. Simple and validated risk-assessment models (RAMs) are available to assist clinicians in identifying patients who have a high risk for developing VTE. Despite the well-documented association of immobility with increased risk of thrombosis, immobility is not consistently defined in clinical studies. We conducted a systematic review of published VTE RAMs and used objective criteria to determine how the term immobility is defined in RAMs. We identified 17 RAMs with six being externally validated. The concept of immobility is vaguely described in different RAMs, impacting the validity of these models in clinical practice. The wide variability in defining mobility in RAMs precluded its accurate clinical application, further limiting generalization of published RAMs. Externally validated RAMs with clearly defined qualitative or quantitative terms of immobility are needed to assess VTE risk in real-time at the point-of-care.

Extended thromboprophylaxis in the acutely ill medical patient after hospitalization - a paradigm shift in post-discharge thromboprophylaxis

Venous thromboembolism (VTE) is a significant healthcare burden with approximately 900,000 events annually in the United States, over half of which are healthcare-associated. This number is anticipated to double by 2050. Group prophylaxis strategies confined to the inpatient setting appear to have minimal impact on the reduction of post-discharge VTE in medically ill patients due to shortened lengths of stay and a heterogenous population that includes patients at low risk for VTE. In accordance with current guideline recommendations, very few (<5%) medically ill patients are discharged with extended prophylaxis, which potentially creates a clinical gap for at-risk patients as VTE risk has been shown to persist for up to 90 days. Initial studies of extended thromboprophylaxis in acutely ill medical patients with enoxaparin, rivaroxaban and apixaban showed little to no benefit towards VTE reduction that was consistently outweighed by increased bleeding. The more recent APEX study that compared betrixaban to enoxaparin in an enriched patient population at high-risk for VTE was the first study of extended thromboprophylaxis that showed similar efficacy in VTE prevention without an increase in major bleeding. Based on the APEX results, betrixaban recently gained FDA approval for extended thromboprophylaxis in acutely ill medical patients. Recognition that up to half of medically ill patients are not at sufficient risk to warrant thromboprophylaxis has driven extensive research towards development of scientifically derived and validated VTE risk assessment models intended to identify patients who do not warrant prophylaxis, as well as those at high risk who may derive benefit from extended thromboprophylaxis. This article will review prior and ongoing extended thromboprophylaxis studies, VTE and bleed risk assessment models, incorporation of biomarkers in VTE risk assessment and key issues in the paradigm shift towards individualized VTE prophylaxis in acutely ill medical patients.

Risk assessment models for venous thromboembolism in acutely ill medical patients

Although the use of thromboprophylaxis is recommended for acutely ill medical patients at increased risk of venous thromboembolism (VTE), it remains unclear which risk assessment model (RAM) should be routinely used to identify at-risk patients requiring thromboprophylaxis. We therefore aimed to describe existing RAMs, and to compare these tools in terms of validity and applicability for clinical decisionmaking. We performed a comprehensive systematic search in MEDLINE from the date of initiation until May 2016 for studies in acutely ill medical patients investigating validity of RAMs for VTE. Two reviewers independently screened the title, abstract, and full text, and evaluated the characteristics of studies, and the composition, evidence of validation, and results on validity of the RAMs. We included 11 studies assessing eight RAMs: 4-Element RAM, Caprini RAM, a full logistic model, Geneva risk score, IMPROVE-RAM, Kucher Model, a “Multivariable Model”, and Padua Prediction Score. The 4-Element RAM, IMPROVE-RAM, Multivariable Model, and full logistic model had derivation by identifying factors with predictive power. The other four RAMs were empirically generated based on consensus guidelines, published data, and clinical expertise. The Kucher Model, the Padua Prediction Score, the Geneva Risk Score and the IMPROVE-RAM underwent multicenter external validation. The Kucher Model, the Padua Prediction Score, and the Geneva Risk Score improved rates of thromboprophylaxis or clinical outcomes. In conclusion, existing RAMs to evaluate the need of thromboprophylaxis in acutely ill medical patients are difficult to compare and none fulfills the criteria of an ideal RAM. Nevertheless, the adequacy of thromboprophylaxis may be improved by implementing one of the validated RAMs.

The IMPROVEDD VTE Risk Score: Incorporation of D-Dimer into the IMPROVE Score to Improve Venous Thromboembolism Risk Stratification

Background  The IMPROVE score is a validated venous thromboembolism (VTE) assessment tool to risk stratify hospitalized, medically ill patients based on clinical variables. It was hypothesized that addition of D-dimer measurement to derive a new IMPROVEDD score would improve identification of at risk of VTE.

Methods  The association of the IMPROVE score and D-dimer ≥ 2 × the upper limit of normal (ULN) with the risk of symptomatic deep vein thrombosis, nonfatal pulmonary embolism, or VTE-related death was evaluated in 7,441 hospitalized, medically ill patients randomized in the APEX trial. Based on the Cox regression analysis, the IMPROVEDD score was derived by adding two points to the IMPROVE score if the D-dimer was ≥ 2 × ULN.

Results  Baseline D-dimer was independently associated with symptomatic VTE through 77 days (adjusted HR: 2.22 [95% CI: 1.38–1.58], p  = 0.001). Incorporation of D-dimer into the IMPROVE score improved VTE risk discrimination (ΔAUC: 0.06 [95% CI: 0.02–0.09], p  = 0.0006) and reclassification (continuous NRI: 0.34 [95% CI: 0.17–0.51], p  = 0.001; categorical NRI: 0.13 [95% CI: 0.03–0.23], p  = 0.0159). Patients with an IMPROVEDD score of ≥2 had a greater VTE risk compared with those with an IMPROVEDD score of 0 to 1 (HR: 2.73 [95% CI: 1.52–4.90], p  = 0.0007).

Conclusion  Incorporation of D-dimer into the IMPROVE VTE risk assessment model further improves risk stratification in hospitalized, medically ill patients who received thromboprophylaxis. An IMPROVEDD score of ≥2 identifies hospitalized, medically ill patients with a heightened risk for VTE through 77 days.