Cost-of-illness analysis of long-term healthcare resource utilization and disease burden in patients with pulmonary embolism: insights from the PREFER in VTE registry

Background

Pulmonary embolism (PE) is responsible for considerable personal and societal costs. Detailing this burden would support an efficient public health resource allocation. However, cost estimates so far have failed to account for both resource utilization and excess costs in its long-term management beyond the acute phase.

Purpose

To provide estimates for the economic and disease burden of PE in the European Union (EU) also accounting for long-term healthcare utilization and costs beyond the acute phase.

Methods

This is a cost-of-illness analysis, from a societal perspective, with a bottom-top approach and a time horizon of 12 months based on data from the PREFER in VTE registry. We calculated direct and indirect costs of an acute PE event and its 12-month follow-up. We used cost inputs derived from the literature and as directly reported in the PREFER in VTE registry and we adjusted them for inflation and purchasing power parity to 2020 Euros (€). Total average costs per PE patient comprised six general categories: costs for the index PE hospitalization; costs for clinical events during follow-up; costs for anticoagulation after the index event; costs for ambulatory visits during follow-up; the patient's own contribution; and costs related to productivity loss (using the friction cost method). A stratified analysis was performed according to the presence of active cancer, non-cancer provoked PE, and unprovoked PE. In addition, we used the EQ-5D health questionnaire to derive a disability weight for the post-PE state 12 months after the index event and the corresponding disability adjusted life years (DALYs) presumably due to PE.

Results

Annual disease-specific costs for each incident PE case ranged between 9,135 € and 10,620 €. Costs for patients with cancer (8,274 to 9,752 €) and patients with unprovoked PE (8,695 to 9,612 €) were lower than costs for non-cancer patients with provoked PE (10,423 to 11,307 €), mainly due to differences in productivity loss. The indirect costs were mainly driven by productivity losses and their proportion to total costs was 42–49% for the overall population (28–33% for cancer, 52–56% for non-cancer provoked PE and 43–47% for unprovoked PE) (Figure 1). Anticoagulation accounted for 18–21% of total costs for cancer patients (while only 5–6% for non-cancer patients) and was primarily driven by the use of low-molecular-weight heparins and fondaparinux (Figure 2). The calculated disability weight for cancer-free survivors of PE 12 months after the index event was 0.017 (bootstrapped 95% CI 0.0002–0.0344) and the estimated annual DALYs per incident case were 1.17 (bootstrapped 95% CI 0.75–1.59).

Conclusion

PE imposes a significant annual economic burden, for which productivity loss is the main driver. Total costs in the EU could range between 0.5 and 3.8 billion €. The disease burden from PE is notable and translates to the loss of roughly 1.2 years of healthy life per incident PE case per year.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This study was supported by an unrestricted grant from Daiichi Sankyo (Title: “Filling the gaps of knowledge on healthcare outcomes during long-term anticoagulant treatment of pulmonary embolism”, grant number DSE-DE-CV-20001).

AngioJet Pharmacomechanical Thrombectomy and Catheter Directed Thrombolysis vs. Catheter Directed Thrombolysis Alone for the Treatment of Iliofemoral Deep Vein Thrombosis: A Single Centre Retrospective Cohort Study

OBJECTIVE

Percutaneous thrombus removal is used for the treatment of iliofemoral deep vein thrombosis (DVT), but the efficacy of different treatment modalities has not yet been determined. The aim of this study was to compare the outcomes of patients treated with additional AngioJet pharmacomechanical thrombectomy (PCDT) vs. catheter directed lysis (CDT) alone.

METHODS

A retrospective review of all patients who received thrombolysis for the treatment of symptomatic acute iliofemoral DVT between 2011 and 2017 was carried out. Outcome measures included the incidence of post-thrombotic syndrome (PTS), procedural outcomes (lytic exposure), the incidence of complications, and vessel patency. All patients were followed up for a minimum of one year.

RESULTS

A total of 151 limbs were treated, 70 limbs with PCDT and 81 limbs with CDT alone. Demographic data and prevalence of risk factors were comparable. Incidence of PTS (Villalta score at one year) showed no significant difference (22.2% PCDT vs. 24.7% CDT alone, p = .74). Use of PCDT resulted in a non-statistically significant trend for fewer bleeds (n = 4/63 [6.3%] vs. 13/76 [17.1%]; relative risk 0.37, 95% confidence interval [CI] 0.13-1.08; p = .07), a statistically significant reduction in lysis duration (40 h [95% CI 34-46] vs. 53 h [95% CI 49-58]; p < .001) and a reduction in lytic dose (49 mg [95% CI 42-55] vs. 57 mg [95% CI 52-61]; p = .011) compared with CDT. This reduction was accentuated in 24 cases primarily treated with AngioJet PowerPulse mode (27 h, 95% CI 20-34 [p < .001] and 42 mg, 95% CI 34-50 [p = .009]). Incidences of complications were comparable between groups, with one death due to an intracranial haemorrhage following CDT. Although the incidence of haemoglobinuria was increased following PCDT (12/63 [19.0%] vs. 3/76 [3.9%]; p = .006), no significant difference in acute kidney injury was observed (3/63 [4.8%] vs. 1/76 [1.3%]; p = .33). No significant difference in vessel patency over two years was observed (p = .73).

CONCLUSION

The use of PCDT for the treatment of iliofemoral DVT was observed to provide comparable patient outcomes, comparable vessel patency, an acceptable safety profile, and reduced overall lytic dose.

Deep Vein Thrombosis in Europe-Health-Related Quality of Life and Mortality

Objectives:

Deep vein thrombosis (DVT) is a major health-care burden in Europe, but exact estimates are lacking. This study reports results from the PREFER venous thromboembolism (VTE) study concerning health-related quality of life (HrQoL) and mortality of patients with DVT.

Methods:

PREFER VTE was a prospective, observational study, conducted in 7 European countries, designed to provide data concerning treatment patterns, resource utilization, mortality, and QoL. First-time or recurrent patients with DVT were followed at 1, 3, 6, and 12 months. Health-related QoL—as measured by the EuroQoL 5-Dimension 5-Level instrument ( EQ-5D-5L)—was analyzed using Tobit regression with repeated measures, assessing the impact of baseline characteristics stratified by cancer activity. Mortality was analyzed using logistic regression.

Results:

At baseline, patients with DVT had a 0.14 lower EQ-5D-5L index score (0.72 for total sample) compared to the reference UK population (0.85). The EQ-5D-5L index score improved from baseline to 12 months in patients with active cancer (from 0.70 to 0.79) and those without (0.72-0.87); 7.3% died within a year, a 5.2% excess mortality compared to the age- and gender-adfjusted general population. The 12-month mortality rate of DVT varied between 2.9% in the pooled data from Germany, Switzerland, or Austria and 15.4% in Italy. Furthermore, the mortality rate differed between patients with active cancer and those without (42.9% vs 4.7%).

Conclusions:

Deep vein thrombosis is associated with a substantial burden of illness in terms of HrQoL at baseline, which following treatment normalizes after 12 months and has a significant mortality rate. In addition, active cancer has a significant impact on mortality and the HrQoL of patients with DVT.

Machine learning to predict venous thrombosis in acutely ill medical patients

BACKGROUND

The identification of acutely ill patients at high risk for venous thromboembolism (VTE) may be determined clinically or by use of integer-based scoring systems. These scores demonstrated modest performance in external data sets.

OBJECTIVES

To evaluate the performance of machine learning models compared to the IMPROVE score.

METHODS

The APEX trial randomized 7513 acutely medically ill patients to extended duration betrixaban vs. enoxaparin. Including 68 variables, a super learner model (ML) was built to predict VTE by combining estimates from 5 families of candidate models. A "reduced" model (rML) was also developed using 16 variables that were thought, a priori, to be associated with VTE. The IMPROVE score was calculated for each patient. Model performance was assessed by discrimination and calibration to predict a composite VTE end point. The frequency of predicted risks of VTE were plotted and divided into tertiles. VTE risks were compared across tertiles.

RESULTS

The ML and rML algorithms outperformed the IMPROVE score in predicting VTE (c-statistic: 0.69, 0.68 and 0.59, respectively). The Hosmer-Lemeshow goodness-of-fit P-value was 0.06 for ML, 0.44 for rML, and <0.001 for the IMPROVE score. The observed event rate in the lowest tertile was 2.5%, 4.8% in tertile 2, and 11.4% in the highest tertile. Patients in the highest tertile of VTE risk had a 5-fold increase in odds of VTE compared to the lowest tertile.

CONCLUSION

The super learner algorithms improved discrimination and calibration compared to the IMPROVE score for predicting VTE in acute medically ill patients.

288Thrombotic events in bleeding patients treated with andexanet alpha: an ANNEXA-4 sub-study

Background/Introduction

Andexanet alfa (“andexanet”) was developed as a specific reversal agent for patients with major bleeding while using factor Xa (FXa) inhibitors. While thrombotic events (TEs) have been reported in patients receiving andexanet, the scope, nature, and timing of these events have not been fully characterized.

Purpose

The ANNEXA-4 study was a prospective, single-arm, open-label clinical trial that evaluated the safety and efficacy of andexanet in patients with acute major bleeding. In this secondary analysis, the occurrence of TEs was investigated.

Methods

Patients presenting with acute major bleeding within 18 hours after their last dose of FXa inhibitor were treated with andexanet. Safety outcomes, including TEs (reviewed by an adjudication committee), were evaluated at 30 days.

Results

Among 352 patients treated with andexanet, 34 (9.7%) experienced one or more TEs (Table). Strokes and deep vein thromboses were the most frequent TE types. Compared to patients with arterial TEs, patients with venous TEs were more likely to have been originally anticoagulated for venous thromboembolism. Median time to first TE was 10.5 days (Figure); time to event was shorter for arterial TEs than for venous TEs. TEs were nonfatal for most patients. Subgroups by age, bleed type, baseline anti-fXa activity, FXa inhibitor dose, and andexanet dose were not associated with the occurrence of TEs. Of the 34 TE patients, 26 (76.4%) had TEs before restart of any (full or prophylactic) anticoagulation; all first TEs occurred in patients not receiving oral anticoagulation. No TEs occurred after resumption of oral anticoagulation (N=100).

Table 1. Thrombotic event characteristics Characteristic Result (n/N [%]) TE type   Strokes 14/352 (4.0%)   Deep vein thromboses 13/352 (3.7%)   Myocardial infarctions 7/352 (2.0%)   Pulmonary embolisms 5/352 (1.4%)   Transient ischemic attacks 1/352 (0.3%) Bleed type   Intracranial 23/227 (10.1%)   Gastrointestinal 7/90 (7.8%)   Other 4/35 (11.4%) Arterial TEs   Anticoagulated for AF 17/22 (77.3%)   Anticoagulated for VTE 6/22 (27.3%) Venous TEs   Anticoagulated for AF 11/18 (61.1%)   Anticoagulated for VTE 8/18 (44.4%)   Median time to first TE 10.5 days   Arterial 6 days   Venous 15 days Outcome   Fatal 7/34 (20.6%)   Nonfatal 27/34 (79.4%) AF = atrial fibrillation; n = number of patients with TEs; N = total number of patients for each characteristic; TE = thrombotic event; VTE = venous thromboembolism.

Figure 1. Thrombotic Events Over Time

Conclusions

In patients with FXa inhibitor-associated acute major bleeding treated with andexanet, TEs occurred a rate not unexpected given the high thrombotic risk of the population. No factors predictive of TEs were identified. Resumption of anticoagulation was associated with fewer TEs.

Acknowledgement/Funding

Study funded by Portola Pharmaceuticals, Inc.

Incidence and risk factors of chronic thromboembolic pulmonary hypertension following venous thromboembolism, a population-based cohort study in England

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of unresolved organised pulmonary emboli/thrombi obstructing the major pulmonary arteries. The aim of this study was to estimate the incidence and risk factors of CTEPH in a cohort with first venous thromboembolism (VTE). This was a population-based cohort study of patients with first VTE and no active cancer in England between 2001 and 2012. CTEPH was assessed using a rigorous case-ascertainment algorithm. Risk factors for CTEPH were studied using a nested case-control approach by matching CTEPH cases to VTE patients without CTEPH. Adjusted odds ratios (OR) of comorbidities were estimated from conditional logistic regression. During 81,413 person-years of follow-up among 23,329 patients with first VTE (mean follow-up 3.5 years; maximum 11.0 years) 283 patients were diagnosed with CTEPH (incidence rate 3.5 per 1000 person-years); cumulative incidence was 1.3% and 3.3% at 2 and 10 years after pulmonary embolism, and 0.3% and 1.3% following deep vein thrombosis (DVT), respectively. Risk factors for CTEPH included age over 70, OR 2.04 (95% CI 1.23 to 3.38), female gender, 1.44 (1.06 to 1.94), pulmonary embolism at first VTE, 3.11 (2.23 to 4.35), subsequent pulmonary embolism and DVT, 3.17 (2.02 to 4.96) and 2.46 (1.34 to 4.51) respectively, chronic obstructive pulmonary disease 3.17 (2.13 to 4.73), heart failure 2.52 (1.76 to 3.63) and atrial fibrillation, 2.42 (1.71 to 3.42). CTEPH develops most commonly after pulmonary embolism and less frequently after DVT. Awareness of risk factors may increase referrals to specialised centres for confirmation of CTEPH and initiation of specific treatment.

A Dose Ranging Study to Evaluate Dermatan Sulphate in Preventing Deep Vein Thrombosis following Total Hip Arthroplasty

Dermatan sulphate catalyses thrombin inhibition by heparin cofactor II; it has a lower haemorrhagic to antithrombotic ratio than that of heparin in animal models. Consecutive patients aged forty years or more, electively undergoing total hip replacement under general anaesthesia, were randomly allocated to one of three dosage regimens of dermatan sulphate (MF701, Mediolanum Farmaceutici) given intramuscularly. These were 200 mg once daily (n = 50), 200 mg twice daily (n = 52) and 300 mg twice daily (n = 51), administered from twenty-four hours pre-operatively until the tenth postoperative day. The overall incidence of DVT assessed by bilateral venography was 53%, 51% and 34% respectively (Chi-square test for trend p = 0.06). The incidence of major proximal DVT was 10.6%, 8.5% and 2.1% respectively. Pulmonary embolism (PE) and bleeding were assessed in all 153 patients. There was one case of PE in each dose group. The incidence of bleeding episodes, volume of blood lost and blood transfusion requirements were low and showed no increase with increasing dose. The patients were followed up 4-8 weeks after discharge.

We conclude that the two lower doses were subtherapeutic in this population, however dermatan sulphate given 300 mg twice daily, proved to be efficacious with an incidence of proximal major DVT of 2.1% and a low incidence of bleeding complications. A trial of dermatan sulphate 300 mg twice daily compared to standard prophylactic agents is needed.

Effect of extended-duration thromboprophylaxis on venous thromboembolism and major bleeding among acutely ill hospitalized medical patients: a bivariate analysis

Essentials Anticoagulants prevent venous thromboembolism but may be associated with greater bleeding risks. Bivariate analysis assumes a non-linear relationship between efficacy and safety outcomes. Extended full-dose betrixaban is favorable over standard enoxaparin in bivariate endpoint. Clinicians must weigh efficacy and safety outcomes in decision-making on thromboprophylaxis.

SUMMARY

Background Among acutely ill hospitalized medical patients, extended-duration thromboprophylaxis reduces the risk of venous thromboembolism (VTE), but some pharmacologic strategies have been associated with greater risks of major bleeding, thereby offsetting the net clinical benefit (NCB). Methods To assess the risk-benefit profile of anticoagulation regimens, a previously described bivariate method that does not assume a linear risk-benefit tradeoff and can accommodate different margins for efficacy and safety was performed to simultaneously assess efficacy (symptomatic VTE) and safety (major bleeding) on the basis of data from four randomized controlled trials of extended-duration (30-46 days) versus standard-duration (6-14 days) thromboprophylaxis among 28 227 patients (EXCLAIM, ADOPT, MAGELLAN and APEX trials). Results Extended thromboprophylaxis with full-dose betrixaban (80 mg once daily) was superior in efficacy and non-inferior in safety to standard-duration enoxaparin, and showed a significantly favorable NCB, with a risk difference of - 0.51% (- 0.89% to - 0.10%) in the bivariate outcome. Extended enoxaparin was superior in efficacy and inferior in safety (bivariate outcome: 0.03% [- 0.37% to 0.43%]), whereas apixaban and rivaroxaban were non-inferior in efficacy and inferior in safety (- 0.20% [- 0.49% to 0.17%] and 0.23% [- 0.16% to 0.69%], respectively). Reduced-dose betrixaban did not show a significant difference in either efficacy or safety (0.41% [- 0.85% to 1.94%]). Conclusions In a bivariate analysis that assumes non-linear risk-benefit tradeoffs, extended prophylaxis with full-dose betrixaban was superior to standard-duration enoxaparin, whereas other regimens failed to simultaneously achieve both superiority and non-inferiority with respect to symptomatic VTE and major bleeding in the management of acutely ill hospitalized medical patients.

Risk of recurrent venous thromboembolism after discontinuation of vitamin K antagonist treatment: a nested case-control study

Essentials Vitamin K antagonists (VKA) in venous thromboembolism (VTE) lower the risk of recurrences. 41 841 VKA-treated VTE patients had 1242 recurrent VTEs on therapy or early after cessation. An increased risk of recurrence was found in the first 120 days after VKA cessation. Patient education for the early detection of recurrent VTE after VKA cessation is recommended.

SUMMARY

Background The standard treatment for venous thromboembolism (VTE) and the prevention of recurrent VTE (rVTE) consists of anticoagulant therapy. The optimal duration of anticoagulation depends on the presence of risk factors for rVTE. Objectives To estimate the risk of rVTE in association with time since discontinuation of vitamin K antagonist (VKA) treatment. Methods From the UK Clinical Practice Research Datalink with linked information on hospitalization and cause of death, a cohort of patients with a first VTE receiving initial VKA treatment between 2001 and 2013 was formed. With a nested case-control approach, patients with incident rVTE (cases) were matched to patients with VTE but without rVTE (controls). Adjusted rate ratios (RRs) of rVTE associated with time since VKA discontinuation relative to current VKA use were estimated from conditional logistic regression. Results The VTE cohort comprised 41 841 patients with 1242 rVTEs and 6205 matched controls. The RR of rVTE was increased within 60 days following VKA discontinuation (RR 2.23, 95% confidence interval [CI] 1.71-2.91) and within 61-120 days following VKA discontinuation (RR 1.49, 95% CI 1.08-2.05) relative to current VKA use. The increased RR corresponded to excess incidence rates of 6.72 (95% CI 3.90-10.06) rVTE cases per 100 person-years within 60 days, and of 2.68 (95% CI 0.42-5.58) rVTE cases per 100 person-years within 61-120 days after VKA discontinuation. Conclusions VKA discontinuation results in a transient increased risk of rVTE, which peaks within 60 days and lasts for up to 120 days after VKA discontinuation. Specific patient education for increased vigilance for signs and symptoms of recurrences is recommended in this period.

Prolonged prophylaxis against venous thromboembolism with enoxaparin in patients undergoing cancer surgery: long-term survival analysis

Objective: ENOXACAN II was a randomized, double-blind trial that showed prolonged (four-week) thromboprophylaxis with enoxaparin to be more effective than and as safe as standard (one-week) thromboprophylaxis in patients undergoing surgery with a curative intent for abdominopelvic cancer. This follow-up study compared long-term, all-cause mortality in both groups.

Methods: Survival rates were calculated on the randomized, treated population ( n = 501). The primary efficacy endpoint was survival at one year. An exploratory analysis including survival data up to 44 months was performed. Because some patients were deemed to have undergone palliative as opposed to curative surgery, and there was a significant difference between the treatment groups in the percentage of patients undergoing palliative surgery, the survival analyses were adjusted for the type of surgery performed.

Results: When adjusted for type of surgery, there was a trend towards reduced mortality among patients undergoing palliative surgery in the prolonged prophylaxis group (hazard ratio [HR] = 0.598, P = 0.3565) that became more pronounced beyond the pre-specified one year follow-up period (HR = 0.469, P = 0.078). This trend may reflect a beneficial effect of prolonged prophylaxis on survival in the palliative surgery group (one-year survival 65.4 versus 50% for standard prophylaxis). In patients undergoing curative surgery, one-year survival rates were equal in the standard and prolonged prophylaxis groups (93.8 and 93.2%, respectively).

Conclusion: Prolonged thromboprophylaxis with enoxaparin may affect long-term survival in palliative surgery for cancer, but further investigation is warranted.

Vitamin K antagonists' use and fracture risk: results from a systematic review and meta-analysis

BACKGROUND

Although vitamin K antagonists (VKAs) lower serum values of bone deposition markers, the link with osteoporosis and fractures remains controversial.

OBJECTIVES

To assess whether the use of VKAs is associated with an increased prevalence and/or incidence of osteoporosis, fractures, or lower bone mineral density (BMD) values.

METHODS

We conducted a systematic PubMed and EMBASE literature search until August 31, 2014, and a meta-analysis of cross-sectional and longitudinal studies investigating fractures and BMD, comparing patients treated with VKAs and healthy controls (HCs) or with patients with medical illness (medical controls, MCs). Standardized mean differences ± 95% and confidence intervals (CIs) were calculated for BMD, and risk ratios (RRs) were calculated for prevalent and incident fractures.

RESULTS

Of 4597 initial hits, 21 studies were eligible, including 79 663 individuals treated with VKAs vs. 597,348 controls. Compared with HCs, VKA-treated individuals showed significantly higher fracture risk in cross-sectional (three studies; RR = 1.24; 95% CI: 1.12-1.39, P < 0.0001) and longitudinal studies (seven studies; RR = 1.09; 95% CI: 1.01-1.18, P = 0.03) and more incident hip fractures (four studies; RR = 1.17; 95% CI: 1.05-1.31, P = 0.003). Analyzing studies that matched VKA participants with HCs (four studies), both these findings in longitudinal studies became non-significant. Notably, the VKA and MC group had similar BMD values at all investigated sites. Compared with HCs, a single study showed significantly lower spine T-scores in the VKA-treated group (standardized mean difference = - 0.45; 95% CI: - 0.75, - 0.14, P = 0.004).

CONCLUSION

VKAs neither increased prospectively-assessed fracture risk compared with MCs when matching eliminated confounding factors nor reduced BMD beyond effects of medical illness. Future studies, using careful matching and/or adequate MC groups, are needed to further clarify the short- and long-term effects of VKAs on bone health.

Declining Long-term Risk of Adverse Events after First-time Community-presenting Venous Thromboembolism: The Population-based Worcester VTE Study (1999 to 2009)

INTRODUCTION

Contemporary trends in health-care delivery are shifting the management of venous thromboembolism (VTE) events (deep vein thrombosis [DVT] and/or pulmonary embolism [PE]) from the hospital to the community, which may have implications for its prevention, treatment, and outcomes.

MATERIALS AND METHODS

Population-based surveillance study monitoring trends in clinical epidemiology among residents of the Worcester, Massachusetts, metropolitan statistical area (WMSA) diagnosed with an acute VTE in all 12 WMSA hospitals. Patients were followed for up to 3 years after their index event. Total of 2334 WMSA residents diagnosed with first-time community-presenting VTE (occurring in an ambulatory setting or diagnosed within 24 hours of hospitalization) from 1999 through 2009.

RESULTS

While PE patients were consistently admitted to the hospital for treatment over time, the proportion diagnosed with DVT-alone admitted to the hospital decreased from 67% in 1999 to 37% in 2009 (p value for trend <0.001). Among hospitalized patients, the mean length of stay decreased from 5.6 to 4.8 days (p value for trend <0.001). Between 1999 and 2009, treatment of VTE shifted from warfarin and unfractionated heparin towards use of low-molecular-weight heparins and newer anticoagulants; also, 3-year cumulative event rates decreased for all-cause mortality (41-26%), major bleeding (12-6%), and recurrent VTE (17-9%).

CONCLUSIONS

A decade of change in VTE management was accompanied by improved long-term outcomes. However, rates of adverse events remained fairly high in our population-based surveillance study, implying that new risk-assessment tools to identify individuals at increased risk for developing major adverse outcomes over the long term are needed.

Epidemiology of first and recurrent venous thromboembolism: a population-based cohort study in patients without active cancer

Contemporary data from population studies on the incidence and complications of venous thromboembolism (VTE) are limited. An observational cohort study was undertaken to estimate the incidence of first and recurrent VTE. The cohort was identified from all patients in the UK Clinical Practice Research Datalink (CPRD) with additional linked information on hospitalisation and cause of death. Between 2001 and 2011, patients with first VTE were identified and the subset without active cancer-related VTE observed for up to 10 years for recurrent VTE. The 10-year cumulative incidence rates (CIR) were derived with adjustment for mortality as a competing risk event. A total of 35,373 first VTE events (12,073 provoked, 16,708 unprovoked and 6592 active cancer-associated VTE) among 26.9 million person-years of observation were identified. The overall incidence rate (IR) of VTE was 131.5 (95% CI, 130.2-132.9) per 100,000 person-years and 107.0 (95% CI, 105.8-108.2) after excluding cancer-associated VTE. DVT was more common in the young and PE was more common in the elderly. VTE recurrence occurred in 3671 (CIR 25.2%). The IR for recurrence peaked in the first six months at around 11 per 100 person years. It levelled out after three years and then remained at around 2 per 100 person years from year 4-10 of follow-up. The IRs for recurrences were particularly high in young men. In conclusion, VTE is common and associated with high recurrence rates. Effort is required to prevent VTE and to reduce recurrences.

D-dimer as a predictor of venous thromboembolism in acutely ill, hospitalized patients: a subanalysis of the randomized controlled MAGELLAN trial

BACKGROUND

D-dimer concentrations have not been evaluated extensively as a predictor of increased venous thromboembolism (VTE) risk in acutely ill, hospitalized medical patients.

OBJECTIVES

To analyze the relationships between D-dimer concentration, VTE and bleeding in the MAGELLAN trial (NCT00571649).

PATIENTS/METHODS

This was a multicenter, randomized, controlled trial. Patients aged ≥ 40 years, hospitalized for acute medical illnesses with risk factors for VTE received subcutaneous enoxaparin 40 mg once daily for 10 ± 4 days then placebo up to day 35, or oral rivaroxaban 10 mg once daily for 35 ± 4 days. Patients (n = 7581) were grouped by baseline D-dimer ≤ 2 × or > 2 × the upper limit of normal. VTE and major plus non-major clinically relevant bleeding were recorded at day 10, day 35, and between days 11 and 35.

RESULTS

The frequency of VTE was 3.5-fold greater in patients with high D-dimer concentrations. Multivariate analysis showed that D-dimer was an independent predictor of the risk of VTE (odds ratio 2.29 [95% confidence interval 1.75-2.98]), and had a similar association to established risk factors for VTE, for example cancer and advanced age. In the high D-dimer group, rivaroxaban was non-inferior to enoxaparin at day 10 and, unlike the low D-dimer group, superior to placebo at day 35 (P < 0.001) and days 11-35 (P < 0.001). In both groups, bleeding outcomes favored enoxaparin/placebo.

CONCLUSIONS

Elevated baseline D-dimer concentrations may identify acutely ill, hospitalized medical patients at high risk of VTE for whom extended anticoagulant prophylaxis may provide greater benefit than for those with low D-dimer concentrations.

An adaptive-design dose-ranging study of PD 0348292, an oral factor Xa inhibitor, for thromboprophylaxis after total knee replacement surgery

BACKGROUND

PD 0348292 is an oral, selective, direct and reversible factor Xa inhibitor. This was an adaptive dose-ranging study evaluating a 100-fold PD 0348292 dose range in subjects undergoing total knee replacement (TKR).

OBJECTIVE

To assess the efficacy and safety of a dose range of PD 0348292 relative to enoxaparin for the prevention of venous thromboembolism (VTE).

METHODS

Extensive dose-response modeling and trial simulations were used to select the PD 0348292 dose range for the Phase 2 study. Subjects were randomized to a blinded PD 0348292 dose (0.1 mg qd to 10 mg qd) or open-label enoxaparin (30 mg bid) for 6-14 days after TKR surgery. Efficacy was assessed by mandatory bilateral venography. Results were analyzed using a dose-response modeling approach.

RESULTS

Observed VTE frequency ranged from 1.4-37.1% across PD 0348292 doses and was 18.1% for enoxaparin. The PD 0348292 dose-response relationship for VTE was statistically significant (P < 0.0001). The dose of PD 0348292 equivalent to enoxaparin 30 mg bid for VTE prevention was estimated to be 1.16 mg (95% CI = 0.56 mg, 2.41 mg) qd. Total bleeding ranged from 4.9% to 13.8% across PD 0348292 doses and was 6.3% with enoxaparin. The dose-response relationship for total bleeding was not statistically significant (P = 0.2464). Overall, PD 0348292 and enoxaparin were well tolerated.

CONCLUSION

Characterization of the dose-response relationship for VTE and bleeding using an adaptive Phase 2 study design provided a strong quantitative basis for Phase 3 dose selection.

Comparison of idraparinux with vitamin K antagonists for prevention of thromboembolism in patients with atrial fibrillation: a randomised, open-label, non-inferiority trial

BACKGROUND

Vitamin K antagonists, the current standard treatment for prophylaxis against stroke and systemic embolism in patients with atrial fibrillation, require regular monitoring and dose adjustment; an unmonitored, fixed-dose anticoagulant regimen would be preferable. The aim of this randomised, open-label non-inferiority trial was to compare the efficacy and safety of idraparinux with vitamin K antagonists.

METHODS

Patients with atrial fibrillation at risk for thromboembolism were randomly assigned to receive either subcutaneous idraparinux (2.5 mg weekly) or adjusted-dose vitamin K antagonists (target of an international normalised ratio of 2-3). Assessment of outcome was done blinded to treatment. The primary efficacy outcome was the cumulative incidence of all stroke and systemic embolism. The principal safety outcome was clinically relevant bleeding. Analyses were done by intention to treat; the non-inferiority hazard ratio was set at 1.5. This trial is registered with ClinicalTrials.gov, number NCT00070655.

FINDINGS

The trial was stopped after randomisation of 4576 patients (2283 to receive idraparinux, 2293 to receive vitamin K antagonists) and a mean follow-up period of 10.7 (SD 5.4) months because of excess clinically relevant bleeding with idraparinux (346 cases vs 226 cases; 19.7 vs 11.3 per 100 patient-years; p<0.0001). There were 21 instances of intracranial bleeding with idraparinux and nine with vitamin K antagonists (1.1 vs 0.4 per 100 patient-years; p=0.014); elderly patients and those with renal impairment were at greater risk of such complications. There were 18 cases of thromboembolism with idraparinux and 27 cases with vitamin K antagonists (0.9 vs 1.3 per 100 patient-years; hazard ratio 0.71, 95% CI 0.39-1.30; p=0.007), satisfying the non-inferiority criterion. There were 62 deaths with idraparinux and 61 with vitamin K anatagonists (3.2 vs 2.9 per 100 patient-years; p=0.49).

INTERPRETATION

In patients with atrial fibrillation at risk for thromboembolism, long-term treatment with idraparinux was no worse than vitamin K antagonists in terms of efficacy, but caused significantly more bleeding.

Extended prophylaxis of venous thromboembolism with idraparinux

BACKGROUND

The extended use of vitamin K antagonists for prophylaxis against venous thromboembolism is often constrained by risk-benefit limitations and inconvenience. We evaluated the efficacy and safety of a 6-month extension of prophylaxis against recurrent venous thromboembolism with idraparinux in patients who had initially received 6 months of prophylaxis with an anticoagulant.

METHODS

We randomly assigned patients who had completed 6 months of prophylaxis with idraparinux or a vitamin K antagonist and in whom extended anticoagulation was warranted to receive once-weekly injections of 2.5 mg of idraparinux or placebo for 6 months without monitoring. The primary efficacy and safety outcomes were recurrent venous thromboembolism and major bleeding.

RESULTS

Of 1215 patients, 6 of 594 (1.0%) in the idraparinux group and 23 of 621 (3.7%) in the placebo group had recurrent venous thromboembolism (P=0.002). Major bleeding occurred in 11 patients (1.9%) in the idraparinux group and in none in the placebo group (P<0.001). Of these 11 episodes, 3 were fatal intracranial hemorrhages. As compared with patients whose initial treatment was a vitamin K antagonist, patients whose initial treatment was idraparinux who were assigned to 6 months in the placebo group had a lower incidence of recurrent thromboembolism (0.7% vs. 5.9%); patients who received 6 additional months of idraparinux therapy had a higher incidence of major bleeding (3.1% vs. 0.9%).

CONCLUSIONS

During a 6-month extension of thromboprophylaxis, idraparinux was effective in preventing recurrent thromboembolism but was associated with an increased risk of a major hemorrhage. (ClinicalTrials.gov number, NCT00071279 [ClinicalTrials.gov].).

Idraparinux versus standard therapy for venous thromboembolic disease

BACKGROUND

Venous thromboembolism is treated with unfractionated heparin or low-molecular-weight heparin, followed by a vitamin K antagonist. We investigated the potential use of idraparinux, a long-acting inhibitor of activated factor X, as a substitute for standard therapy.

METHODS

We conducted two randomized, open-label noninferiority trials involving 2904 patients with deep-vein thrombosis and 2215 patients with pulmonary embolism to compare the efficacy and safety of idraparinux versus standard therapy. Patients received either subcutaneous idraparinux (2.5 mg once weekly) or a heparin followed by an adjusted-dose vitamin K antagonist for either 3 or 6 months. The primary efficacy outcome was the 3-month incidence of symptomatic recurrent venous thromboembolism (nonfatal or fatal).

RESULTS

In the study of patients with deep venous thrombosis, the incidence of recurrence at day 92 was 2.9% in the idraparinux group as compared with 3.0% in the standard-therapy group (odds ratio, 0.98; 95% confidence interval [CI], 0.63 to 1.50), a result that satisfied the prespecified noninferiority requirement. At 6 months, the hazard ratio for idraparinux was 1.01. The rates of clinically relevant bleeding at day 92 were 4.5% in the idraparinux group and 7.0% in the standard-therapy group (P=0.004). At 6 months, bleeding rates were similar. In the study of patients with pulmonary embolism, the incidence of recurrence at day 92 was 3.4% in the idraparinux group and 1.6% in the standard-therapy group (odds ratio, 2.14; 95% CI, 1.21 to 3.78), a finding that did not meet the noninferiority requirement.

CONCLUSIONS

In patients with deep venous thrombosis, once-weekly subcutaneous idraparinux for 3 or 6 months had an efficacy similar to that of heparin plus a vitamin K antagonist. However, in patients with pulmonary embolism, idraparinux was less efficacious than standard therapy. (ClinicalTrials.gov numbers, NCT00067093 [ClinicalTrials.gov] and NCT00062803 [ClinicalTrials.gov].).

The use of graduated compression stockings in association with fondaparinux in surgery of the hip

Little is known about the efficacy of graduated compression stockings in preventing venous thromboembolism after hip surgery. We conducted a prospective, randomised single-blind study to determine whether the addition of compression stockings to fondaparinux conferred any additional benefit.

The study included 874 patients, of whom 795 could be evaluated (400 in the fondaparinux group and 395 in the fondaparinux plus compression stocking group). Fondaparinux was given post-operatively for five to nine days, either alone or combined with wearing stockings, which were worn for a mean 42 days (35 to 49).

The study outcomes were venous thromboembolism, or sudden death before day 42. Duplex ultrasonography was scheduled within a week of day 42. Safety outcomes were bleeding and death from venous thromboembolism.

The prevalence of deep-vein thrombosis was similar in the two groups 5.5% (22 of 400) in the fondaparinux group and 4.8 (19 of 395) in the fondaparinux plus stocking group (odds ratio 0.88, 95% confidence interval 0.46 to 1.65, p = 0.69). Major bleeding occurred in only one patient.

The addition of graduated compression stockings to fondaparinux appears to offer no additional benefit over the use of fondaparinux alone.

Thromboprophylaxis in major abdominal surgery for cancer

AIMS

To review the epidemiology and pathogenesis of venous thromboembolism (VTE) in surgical cancer patients, in addition to the use of thromboprophylaxis in major abdominal surgery, such as low-molecular-weight heparin (LMWH) and fondaparinux.

METHODS

Systematic review of the literature, focussing on risk factors for VTE, parenteral methods of thromboprophylaxis, approaches to prolonged prophylaxis, and effects on patient survival.

FINDINGS

Patients with cancer undergoing abdominal surgery are at substantially higher risk for VTE than patients without cancer. Furthermore, prolonged thromboprophylaxis for up to 4 weeks is more effective than short-term administration in these high-risk patients. The concurrent use of graduated compression stockings has a synergistic effect on the reduction in VTE risk.

CONCLUSIONS

Thromboprophylaxis with LMWH has been shown to minimise the incidence of thromboembolic events, and is a well-established therapy worldwide. The American College of Chest Physicians recommends the routine use of thromboprophylaxis, with LMWH or unfractionated heparin, in patients with cancer who are undergoing surgical procedures, and the appropriate use of these thromboprophylactic agents has significant implications for the clinical care and quality of life of surgical patients with cancer.

Randomized clinical trial of postoperative fondaparinux versus perioperative dalteparin for prevention of venous thromboembolism in high-risk abdominal surgery

BACKGROUND

The aim of this study was to assess whether the synthetic factor Xa inhibitor fondaparinux reduced the risk of venous thromboembolism more efficiently than the low molecular weight heparin dalteparin in patients undergoing major abdominal surgery.

METHODS

In a double-blind double-dummy randomized study, patients scheduled for major abdominal surgery under general anaesthesia received once-daily subcutaneous injections of fondaparinux 2.5 mg or dalteparin 5000 units for 5-9 days. Fondaparinux was started 6 h after surgery. The first two doses of dalteparin, 2500 units each, were given 2 h before surgery and 12 h after the preoperative administration. The primary outcome measure was a composite of deep vein thrombosis detected by bilateral venography and symptomatic, confirmed deep vein thrombosis or pulmonary embolism up until day 10. The main safety outcome measure was major bleeding during treatment.

RESULTS

Among 2048 patients evaluable for efficacy, the rate of venous thromboembolism was 4.6 per cent (47 of 1027) with fondaparinux compared with 6.1 per cent (62 of 1021) with dalteparin, a relative risk reduction of 24.6 (95 per cent confidence interval -9.0 to 47.9) per cent (P = 0.144), which met the predetermined criterion for non-inferiority of fondaparinux. Major bleeding was observed in 49 (3.4 per cent) of 1433 patients given fondaparinux and 34 (2.4 per cent) of 1425 given dalteparin (P = 0.122).

CONCLUSION

Postoperative fondaparinux was at least as effective as perioperative dalteparin in patients undergoing high-risk abdominal surgery.

Meta-analysis of trials comparing ximelagatran with low molecular weight heparin for prevention of venous thromboembolism after major orthopaedic surgery

Background

Use of low molecular weight heparin (LMWH) is standard practice for preventing postoperative venous thromboembolism (VTE). Ximelagatran is a new direct thrombin inhibitor for this indication.

Methods

A systematic review was conducted to compare the efficacy and safety of LMWH with ximelagatran in orthopaedic surgery.

Results

Six eligible, well conducted clinical trials (10 051 patients) were identified. Overall, the risk of VTE (OR (odds ratio) 1·22 (95 per cent confidence interval (c.i.) 0·89 to 1·67)) and serious bleeding (OR 0·70 (95 per cent c.i. 0·42 to 1·18)) was not significantly different for LMWH compared with ximelagatran. Exploratory analyses to investigate statistical heterogeneity found that results varied by surgical subtype and treatment regimen. Compared with postoperative ximelagatran, LMWH had a significantly lower rate of VTE (OR 0·68 (95 per cent c.i. 0·56 to 0·82); P &lt; 0·001), with no significant difference in bleeding rate (OR 1·09 (95 per cent c.i. 0·62 to 1·94); P = 0·76), in hip surgery, and no significant differences in knee surgery. When ximelagatran was started immediately before surgery, LMWH had a significantly higher rate of VTE in both hip (OR 1·87 (95 per cent c.i. 1·20 to 2·92); P = 0·006) and knee (OR 1·49 (95 per cent c.i. 1·14 to 1·93); P = 0·003) surgery, but less bleeding: hip OR 0·30 (95 per cent c.i. 0·17 to 0·53; P &lt; 0·001); knee OR 0·71 (95 per cent c.i. 0·30 to 1·67; P = 0·43).

Conclusion

This review demonstrated no overall advantage for either LMWH or ximelagatran in thromboprophylaxis following orthopaedic surgery. Benefits in VTE prevention with ximelagatran were gained at the expense of an increased risk of serious bleeding.

Epidemiology of venous thromboembolism in Asian patients undergoing major orthopedic surgery without thromboprophylaxis. The SMART study

BACKGROUND

In Asian patients undergoing surgery, the incidence of venous thromboembolism (VTE) is thought to be low relative to Western patients, and the routine use of thromboprophylaxis is controversial.

OBJECTIVES

The aim of this work was to study the epidemiology of VTE in Asian patients undergoing orthopedic surgery without thromboprophylaxis.

PATIENTS AND METHODS

We performed a prospective observational study of a cohort of consecutive Asian patients hospitalized for total hip or knee replacement or hip fracture surgery without thromboprophylaxis. The primary study outcome was the incidence of the composite of symptomatic VTE or sudden death at hospital discharge. This outcome was also assessed at 1 month's follow-up.

RESULTS

Between April 2001 and July 2002, 2420 patients were enrolled. Median age was 68 years and the median duration of hospital stay was 13 days. The rate of symptomatic VTE or sudden death as notified by investigators was 2.3%[55 patients, 99% confidence interval (CI) 1.6, 3.2] and 1.2% (28 patients, 99% CI 0.7, 1.8) after adjudication by an independent committee. Chronic heart failure, varicose veins and a history of VTE were independent risk factors (P < 0.05) for the occurrence of the primary endpoint. At 1 month's follow-up, the incidence of adjudicated symptomatic VTE or sudden death was 1.5% (35/2264 patients).

CONCLUSION

In Asian patients, the incidence of symptomatic VTE after major orthopedic surgery is not low, consistent with the rates observed in Western countries. The use of thromboprophylaxis should be considered in Asian patients undergoing such high-risk surgical procedures.

Fatal pulmonary embolism in hospitalised patients: a necropsy review

AIMS

To carry out a retrospective review of all postmortem reports during the period 1991 to 2000 at King's College Hospital, London, as an extension of a previous analysis performed for the period 1965 to 1990.

METHODS

The number of deaths resulting from necropsy confirmed fatal pulmonary embolism in hospitalised patients was determined, and a limited analysis of the clinical characteristics of those patients who died was performed.

RESULTS

During the 10 year period, 16 104 deaths occurred and 6833 (42.4%) necropsies were performed. The outcome measure, fatal pulmonary embolism, was recorded as cause of death in 265 cases (3.9% of all necropsies; 5.2% of adult cases). No deaths from pulmonary embolism occurred in patients under 18 years of age; 80.0% occurred in patients older than 60 years. Of the fatal emboli, 214 of 265 (80.8%) occurred in patients who had not undergone recent surgery. Of these patients, 110 (51.4%) had suffered an acute medical illness in the six weeks before death, most often an acute infectious episode (26 cases).

CONCLUSIONS

Thromboembolic events remain a relatively common cause of death in hospitalised patients and appear to occur more frequently in non-surgical than in surgical patients.

The direct thrombin inhibitor melagatran followed by oral ximelagatran compared with enoxaparin for the prevention of venous thromboembolism after total hip or knee replacement: the EXPRESS study

BACKGROUND

Ximelagatran and its subcutaneous (s.c.) form melagatran are novel direct thrombin inhibitors for the prevention and treatment of thromboembolic disease.

METHODS

In a double-blind study, 2835 consecutive patients undergoing total hip or knee replacement were randomized to either melagatran/ximelagatran or enoxaparin. Melagatran 2 mg was started immediately before surgery; 3 mg was then administered postoperatively, followed by 24 mg of oral ximelagatran b.i.d. beginning the next day. Enoxaparin 40 mg, administered subcutaneously o.d., was started 12 h before surgery. Both treatments were continued for 8-11 days. The main efficacy outcome measures were major venous thromboembolism (VTE); [proximal deep vein thrombosis (DVT), non-fatal and/or fatal pulmonary embolism (PE), death where PE could not be ruled out], and total VTE (proximal and distal DVT; PE; death from all causes). DVT was detected by mandatory bilateral ascending venography at the end of the treatment period or earlier if clinically suspected. The main safety outcome was bleeding.

RESULTS

The rates of major and total VTE were significantly lower in the melagatran/ximelagatran group compared with the enoxaparin group (2.3% vs. 6.3%, P = 0.0000018; and 20.3% vs. 26.6%, P < 0.0004, respectively). Fatal bleeding, critical site bleeding and bleeding requiring reoperation did not differ between the two groups. 'Excessive bleeding as judged by the investigator' was more frequent with melagatran/ximelagatran than with enoxaparin.

CONCLUSIONS

In patients undergoing total hip or knee replacement, preoperatively initiated s.c. melagatran followed by oral ximelagatran was significantly more effective in preventing VTE than preoperatively initiated s.c. enoxaparin.

Prophylaxis of venous thromboembolism in medical patients

Prophylaxis of venous thromboembolism in medical patients is an area where the potential benefits to patients are great. Venous thromboembolism is at least as common among medical as it is among surgical patients. Despite the widespread use of thromboprophylaxis in surgical patients, fatal pulmonary embolism is one of the most common causes of preventable death in the hospital. This may result from underuse of thromboprophylaxis in medical patients. The incidence of venous thromboembolism varies, but a history of previous venous thromboembolism, age 40 years and older, immobility, and specific illnesses such as stroke, myocardial infarction, heart failure, and cancer put patients at particular risk. Most early studies assessed the use of anticoagulants such as unfractionated heparin, low-molecular-weight heparin, and warfarin at reducing the incidence of venous thromboembolism in surgical patients. More recent studies and those currently being carried out are assessing the role of thromboprophylaxis in general medical patients and those with specific medical illnesses. As the evidence accumulates and guidelines are strengthened physicians will be able to tailor the use of thromboprophylaxis to the individual patient's needs.

Extended thromboprophylaxis following lower limb arthroplasty: what do the clinical trials mean?

Patients undergoing major orthopaedic surgery are at high risk of thromboembolic complications. Of the available options for pharmacologic prophylaxis, the low-molecular-weight heparins (LMWHs) have been shown to be most effective in reducing the incidence of venous thromboembolic complications and are well tolerated. However, as the risk of venous thromboembolism persists for several weeks post-discharge, there is controversy regarding the ideal duration of prophylaxis. Six recent studies have examined the efficacy and safety of prolonged prophylaxis in this setting. Five of these studies have demonstrated that prolonged LMWH prophylaxis (either enoxaparin or dalteparin) for 4--5 weeks is beneficial and significantly superior to conventional prophylaxis for 7--15 days. The other study, using ardeparin, examined clinical endpoints and showed a minor trend but no significant reduction in these events. Furthermore, two of the studies -- one with enoxaparin and one with dalteparin -- also demonstrated a significant reduction in the incidence of proximal deep vein thrombosis. Analysis of all clinical events from the five studies that have published that information shows a halving or 51% reduction in favour of prolonged prophylaxis. On the basis of current evidence, prolonged thromboprophylaxis with LMWH for up to 35 days after major orthopaedic surgery is recommended.

Complications in breast augmentation: prevention and correction

The decision-making process for breast augmentation begins at the initial consultation. Most complications can be avoided with careful planning and decision making. Primary augmentation demands a careful evaluation of the breast morphology and chest wall anatomy. Perioperative techniques such as precise dissection of the pectoralis muscle under direct vision can ensure an adequate pocket, which minimizes the risk for capsular contracture and implant malposition. Secondary breast augmentation for problems such as thinning of the breast skin envelope, long-term pressure atrophy of existing parenchyma, and visibility of the implant can be minimized with appropriate selection of implant type, size, and placement. Patients should understand clearly the immediate and long-term risks associated with breast augmentation and the requirement for future reoperation.