Cost-effectiveness of ruling out deep venous thrombosis in primary care versus care as usual

Potential impact of a new sepsis prediction model for the primary care setting: early health economic evaluation using an observational cohort

OBJECTIVES

To estimate the potential referral rate and cost impact at different cut-off points of a recently developed sepsis prediction model for general practitioners (GPs).

DESIGN

Prospective observational study with decision tree modelling.

SETTING

Four out-of-hours GP services in the Netherlands.

PARTICIPANTS

357 acutely ill adult patients assessed during home visits.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome is the cost per patient from a healthcare perspective in four scenarios based on different cut-off points for referral of the sepsis prediction model. Second, the number of hospital referrals for the different scenarios is estimated. The potential impact of referral of patients with sepsis on mortality and hospital admission was estimated by an expert panel. Using these study data, a decision tree with a time horizon of 1 month was built to estimate the referral rate and cost impact in case the model would be implemented.

RESULTS

Referral rates at a low cut-off (score 2 or 3 on a scale from 0 to 6) of the prediction model were higher than observed for patients with sepsis (99% and 91%, respectively, compared with 88% observed). However, referral was also substantially higher for patients who did not need hospital assessment. As a consequence, cost-savings due to referral of patients with sepsis were offset by increased costs due to unnecessary referral for all cut-offs of the prediction model.

CONCLUSIONS

Guidance for referral of adult patients with suspected sepsis in the primary care setting using any cut-off point of the sepsis prediction model is not likely to save costs. The model should only be incorporated in sepsis guidelines for GPs if improvement of care can be demonstrated in an implementation study.

TRIAL REGISTRATION NUMBER

Dutch Trial Register (NTR 7026).

Are the latest point-of-care D-dimer devices ready for use in general practice? A prospective clinical evaluation of five test systems with a capillary blood feature for suspected venous thromboembolism

INTRODUCTION

We evaluated clinical performance of five novel point-of-care (POC) D-dimer devices with a capillary finger stick feature for predicting venous thromboembolism (VTE) in general practice: Exdia TRF Plus (E), AFIAS-1® (A), Standard F200® (S), LumiraDx™ (L) and Hipro AFS/1® (H).

MATERIALS AND METHODS

Primary care patients with a low suspicion of a VTE were asked to consent to (i) draw additional venous blood samples, (ii) perform a capillary POC D-dimer test, (iii) approach their general practitioner afterwards for clinical outcomes. Venous plasma samples were processed on all POC devices and a laboratory-based assay (STA-Liatest®D-Di PLUS assay). Results were compared with clinical outcomes to generate performance characteristics. Capillary and venous blood results were used for a matrix comparison.

RESULTS

Venous plasma samples from 511 participants, of whom 57 had VTE, were used for clinical performance analyses. Areas under Receiving Operating Characteristic Curves ranged from 0.90 (95 % CI: 0.86-0.94) (H) to 0.93 (0.90-0.96) (E). All false-negative rates were below 1.4 % (95 % CI: 0.5 %-3.4 %). Matrix comparison demonstrated correlation coefficients ranging from r = 0.11 (95 % CI: -0.15-0.36) (H) to r = 0.94 (0.90-0.97) (A) with concordance percentages ranging from 71.4 % (applying a D-dimer cutoff of 500 ng/mL) (H) to 100 % (applying an age-dependent D-dimer cutoff) (A).

CONCLUSIONS

Clinical performance of the POC D-dimer devices for predicting a VTE in low-risk patients was comparable to that of a laboratory-based assay. However, our results indicate that the finger stick feature of certain devices should be further improved. (NL71809.028.19.).

Clinical decision rules in primary care: necessary investments for sustainable healthcare

Clinical judgement in primary care is more often decisive than in the hospital. Clinical decision rules (CDRs) can help general practitioners facilitating the work-through of differentials that follows an initial suspicion, resulting in a concrete 'course of action': a 'rule-out' without further testing, a need for further testing, or a specific treatment. However, in daily primary care, the use of CDRs is limited to only a few isolated rules. In this paper, we aimed to provide insight into the laborious path required to implement a viable CDR. At the same time, we noted that the limited use of CDRs in primary care cannot be explained by implementation barriers alone. Through the case study of the Oudega rule for the exclusion of deep vein thrombosis, we concluded that primary care CDRs come out best if they are tailor-made, taking into consideration the specific context of primary health care. Current CDRs should be evaluated frequently, and future decision rules should anticipate the latest developments such as the use of point-of-care (POC) tests. Hence, such new powerful diagnostic CDRs could improve and expand the possibilities for patient-oriented primary care.

Two point-of-care test-based approaches for the exclusion of deep vein thrombosis in general practice: a cost-effectiveness analysis

BACKGROUND

In the diagnostic work-up of deep vein thrombosis (DVT), the use of point-of-care-test (POCT) D-dimer assays is emerging as a promising patient-friendly alternative to regular D-dimer assays, but their cost-effectiveness is unknown. We compared the cost-effectiveness of two POCT-based approaches to the most common, laboratory-based, situation.

METHODS

A patient-level simulation model was developed to simulate the diagnostic trajectory of patients presenting with symptoms of DVT at the general practitioner (GP). Three strategies were defined for further diagnostic work-up: one based on current guidelines ('regular strategy') and two alternative approaches where a POCT for D-dimer is implemented at the 1) phlebotomy service ('DVT care pathway') and 2) GP practice ('fast-POCT strategy'). Probabilities, costs and health outcomes were obtained from the literature. Costs and effects were determined from a societal perspective over a time horizon of 6 months. Uncertainty in model outcomes was assessed with a one-way sensitivity analysis.

RESULTS

The Quality-Adjusted Life Years (QALYs) scores for the three DVT diagnostic work-up strategies were all around 0.43 across a 6 month-time horizon. Cost-savings of the two POCT-based strategies compared to the regular strategy were €103/patient for the DVT care pathway (95% CI: -€117-89), and €87/patient for the fast-POCT strategy (95% CI: -€113-67).

CONCLUSIONS

Point-of-care-based approaches result in similar health outcomes compared with regular strategy. Given their expected cost-savings and patient-friendly nature, we recommend implementing a D-dimer POCT device in the diagnostic DVT work-up.

Cost-effectiveness of clopidogrel vs. ticagrelor in patients of 70 years or older with non-ST-elevation acute coronary syndrome

OBJECTIVE

The POPular AGE trial showed that clopidogrel significantly reduced bleeding risk compared with ticagrelor without any signs of an increase in thrombotic events. The aim of this analysis was to estimate the long-term cost-effectiveness of clopidogrel compared with ticagrelor in these patients aged 70 years or older with non-ST-elevation acute coronary syndrome (NSTE-ACS).

METHODS AND RESULTS

A 1-year decision tree based on the POPular AGE trial in combination with a lifelong Markov model was developed to compare clopidogrel with ticagrelor in terms of clinical outcomes, costs, and quality-adjusted life years (QALYs) in elderly patients (above 70 year) with NSTE-ACS. Cost-effectiveness was assessed from a Dutch healthcare system perspective. Events rates and utility data observed in the POPular AGE trial were combined with lifetime projections to evaluate costs and effects for a fictional cohort of 1000 patients. Treatment with clopidogrel instead of ticagrelor led to a cost saving of €1484 575 (€1485 per patient) and a decrease of 10.96 QALYs (0.011 QALY per patient) in the fictional cohort. In an alternative base case with equal distribution over health states in the first year, treatment with clopidogrel led to an increase in QALYs. In all scenario analyses, treatment with clopidogrel was cost-saving.

CONCLUSION

Clopidogrel is a cost-saving alternative to ticagrelor in elderly patients after NSTE-ACS, though regarding overall cost-effectiveness clopidogrel was not superior to ticagrelor, as it resulted in a small negative effect on QALYs. However, based on the results of the alternative base case and clinical outcomes of the POPular AGE trial, clopidogrel could be a reasonable alternative to ticagrelor for elderly NSTE-ACS patients with a higher bleeding risk.

Cost Effectiveness of a CYP2C19 Genotype-Guided Strategy in Patients with Acute Myocardial Infarction: Results from the POPular Genetics Trial

INTRODUCTION

The POPular Genetics trial demonstrated that a CYP2C19 genotype-guided P2Y₁₂ inhibitor strategy reduced bleeding rates compared with standard treatment with ticagrelor or prasugrel without increasing thrombotic event rates after primary percutaneous coronary intervention (PCI).

OBJECTIVE

In this analysis, we aimed to evaluate the cost effectiveness of a genotype-guided strategy compared with standard treatment with ticagrelor or prasugrel.

METHODS

A 1-year decision tree based on the POPular Genetics trial in combination with a lifelong Markov model was developed to compare costs and quality-adjusted life-years (QALYs) between a genotype-guided and a standard P2Y₁₂ inhibitor strategy in patients with myocardial infarction undergoing primary PCI. The cost-effectiveness analysis was conducted from a Dutch healthcare system perspective. Within-trial survival and utility data were combined with lifetime projections to evaluate lifetime cost effectiveness for a cohort of 1000 patients. Costs and utilities were discounted at 4 and 1.5%, respectively, according to Dutch guidelines for health economic studies. Besides deterministic and probabilistic sensitivity analyses, several scenario analyses were also conducted (different time horizons, different discount rates, equal prices for P2Y₁₂ inhibitors, and equal distribution of thrombotic events between the two strategies).

RESULTS

Base-case analysis with a hypothetical cohort of 1000 subjects demonstrated 8.98 QALYs gained and €725,550.69 in cost savings for the genotype-guided strategy (dominant). The deterministic and probabilistic sensitivity analysis confirmed the robustness of the model and the cost-effectiveness results. In scenario analyses, the genotype-guided strategy remained dominant.

CONCLUSION

In patients undergoing primary PCI, a CYP2C19 genotype-guided strategy compared with standard treatment with ticagrelor or prasugrel resulted in QALYs gained and cost savings.

TRIAL REGISTRATION

Clinicaltrials.gov number: NCT01761786, Netherlands trial register number: NL2872.

Building a CAT clinic - real-world systems approaches to prevention and treatment

Cancer patients have an increased risk of developing venous thrombosis. The implementation of a cancer associated thrombosis clinic can be instrumental for the prevention, early recognition, and management of venous thromboembolism in this vulnerable population. Cancer thrombosis clinics rely on a multidisciplinary approach to care and require standardization along with a dedicated team of healthcare professionals. Cancer thrombosis clinics have the potential to improve patient outcomes and lower healthcare expenditure. Herein, we describe a successful model of a cancer thrombosis clinic and highlight the potential impact on clinical outcomes.

Performance Evaluation of the Quantitative Point-of-Care LumiraDx D-Dimer Test

INTRODUCTION

Fibrin degradation product D-dimer can be a valuable indicator for venous thromboembolism (VTE). The use of D-dimer testing in primary care settings can be limited by restricted access to laboratory services. This performance evaluation compares a quantitative, point-of-care (POC) D-dimer assay (LumiraDx D-Dimer Test) with a reference laboratory-based D-dimer assay.

METHODS

Plasma samples from patients presenting to secondary care in the UK, USA, and Germany were analyzed centrally using the LumiraDx D-Dimer Test and the reference test (bioMérieux VIDAS D-Dimer Exclusion II immunoassay). Method comparison used Passing-Bablok regression analysis with pre-specified equivalence criteria of r ≥ 0.9 and slope of 0.9-1.1. The NOVEL-3 study (NCT04375982) compared equivalency of fingerstick, venous blood (VB), and plasma samples from the same patient, tested at US primary care clinics next to the patient using the POC LumiraDx D-Dimer device. Measurements obtained from fingerstick and VB samples were compared with results from plasma samples, using Deming regression. The healthy reference range was determined using plasma samples of healthy volunteers, collected by commercial suppliers in Germany and the USA, which were analyzed centrally using the LumiraDx D-Dimer Test and the reference test.

RESULTS

The LumiraDx D-Dimer Test demonstrated agreement with the bioMérieux VIDAS D-Dimer Exclusion II immunoassay for plasma samples (r = 0.923, slope of 1.016, n = 1767). There was good agreement between fingerstick/VB samples and plasma samples (r = 0.980-0.986, n = 93) measured using the LumiraDx D-Dimer Test. Overall error rates were 1.8%. The healthy reference range 90% percentile for D-dimer was calculated as 533 µg/l fibrinogen equivalent units (FEU).

CONCLUSIONS

The quantitative LumiraDx D-Dimer Test is easy to use and can accurately measure D-dimer levels in a range of blood sample types, including fingerstick samples, which could improve assessment of VTE cases in community and hospital near-patient settings.

Cost-minimization modeling of venous thromboembolism diagnostics: performing limited compression ultrasound in primary health care reduces costs compared to referring patients to a hospital

Background

The aim of this retrospective study was to determine whether diagnosing a deep venous thrombosis (DVT) in primary health care using limited compression ultrasound (LCUS) can save resources compared to referring these patients to hospital. According to the current literature, LCUS is as safe as a standard protocol based on a whole-leg ultrasound (US).

Methods

We created a standardized patient for this cost-analysis model based on 76 patients that were referred to hospital for a suspected DVT. Travel distance to the health care centre and hospital was calculated based on the home address. Hospital costs were acquired from the hospital price list and Finnish legislation. Time spent in the hospital was retrieved from hospital statistics. Time spent in the health care centre and travelling were estimated and monetized based on average salary. The cost of participating physicians attending a US training course was estimated based on the national average salary of a general practitioner as well as the course participation fee. A cost-minimization modeling was performed for this standardized patient comparing the total costs, including private and public costs, of standard and LCUS strategies.

Results

The total costs per patient of standard and LCUS pathways were 1151.52€ and 301.94€ [difference 849.59€ (95% CI 800.21€–898.97€, p < 0.001)], respectively. The real-life costs of these strategies, considering that some patients are probably referred to hospital every year and including training costs, are 1151.53€ and 508.69€ [difference 642.84€ (95% CI 541.85€–743.82€)], respectively.

Conclusion

Using LCUS in diagnosing DVT in primary health care instead of referring these patients to the hospital is shown to save a significant amount of public and private resources.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13089-021-00227-5.

CAVA (Ultrasound-Accelerated Catheter-Directed Thrombolysis on Preventing Post-Thrombotic Syndrome) Trial: Long-Term Follow-Up Results

Background

The CAVA (Ultrasound‐Accelerated Catheter‐Directed Thrombolysis Versus Anticoagulation for the Prevention of Post‐Thrombotic Syndrome) trial did not show a reduction of post‐thrombotic syndrome (PTS) after additional ultrasound‐accelerated catheter‐directed thrombolysis in patients with acute iliofemoral deep vein thrombosis at 1‐year follow‐up. This prespecified analysis of the CAVA trial aimed to determine the impact of additional thrombolysis on outcomes of PTS at long‐term follow‐up.

Methods and Results

Patients aged 18 to 85 years with a first‐time acute iliofemoral deep vein thrombosis were included and randomly assigned (1:1) to either standard treatment plus ultrasound‐accelerated catheter‐directed thrombolysis or standard treatment alone. The primary outcome was the proportion of PTS (Villalta score ≥5 on 2 occasions ≥3 months apart or venous ulceration) at the final follow‐up visit. Additionally, PTS according to the International Society on Thrombosis and Haemostasis (ISTH) consensus definition was assessed to allow external comparability. Major bleedings were the main safety outcome. At a median follow‐up of 39.0 months (interquartile range, 23.3–63.8), 120 patients (79.8%) participated in the final follow‐up visit: 62 from the intervention group and 58 from the standard treatment group. PTS developed in 19 (30.6%) versus 26 (44.8%) patients, respectively (odds ratio [OR], 0.54; 95% CI, 0.26 to 1.15 [P=0.11]), with an absolute difference between groups of −14.2% (95% CI, −32.0% to 4.8%). Using the ISTH consensus definition, a significant reduction in PTS was observed (29 [46.8%] versus 40 [69.0%]) (OR, 0.40; 95% CI, 0.19–0.84 [P=0.01]) with an absolute difference between groups of −22.2% (95% CI, −39.8% to −2.8%). No new major bleedings occurred following the 12‐month follow‐up.

Conclusions

The impact of additional ultrasound‐accelerated catheter‐directed thrombolysis on the prevention of PTS was found to increase with time. Although this study was limited by its sample size, the overall findings indicate a reduction of mild PTS without impact on quality of life.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT00970619.

Point-of-Care Testing for D-Dimer in the Diagnosis of Venous Thromboembolism in Primary Care: A Narrative Review

Venous thromboembolism (VTE) is regarded as a significant cause of mortality and disability, affecting 1-2 per 1000 people annually, presenting with a relatively wide range of symptoms, which can pose a diagnostic challenge. Historically, people in whom VTE is suspected will have been taken to hospital for diagnosis and treatment; however, a high proportion of patients are found not to have VTE. Concerns have been expressed about potential delays in treatment, with the risk of additional morbidity and disability, and death. Diagnostic strategies are typically based on the use of a clinical prediction rule to determine the pre-test probability, complemented with a measurement of D-dimer, with confirmation by imaging assessment. This narrative review explores the literature on the use of point-of-care testing (POCT) for the measurement of D-dimer, as part of a clinical decision rule, for the diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) in the primary care setting. In the two main prospective management (validation) studies that included D-dimer POCT or similar technologies, with a total cohort of 1600 participants, DVT was ruled out in 49% of patients, with a false negative rate of 1.4%, whereas PE was ruled out in 45% of patients, with a false negative rate of 1.5%. This suggests that uptake of POCT D-dimer in primary care has the potential to reduce the number of referrals to hospitals for imaging confirmatory investigation, with consequent cost savings. Thus, adopting POCT for D-dimer in primary care can offer clinical and cost benefits, particularly when quantitative POCT assays are being used. Furthermore, POCT should be undertaken in collaboration with the local laboratories to ensure the harmonisation of D-dimer methods and quality assurance to improve the diagnosis of VTE.

Prevalence of venous obstructions in (recurrent) venous thromboembolism: a case-control study

Background

The role of venous obstructions as a risk factor for recurrent venous thromboembolism has never been evaluated. This study aimed to determine whether there is a difference in prevalence of venous obstructions between patients with and without recurrent venous thromboembolism. Furthermore, its influence on the development of post-thrombotic syndrome and patient-reported quality of life was assessed.

Methods

This matched nested case-control study included 32 patients with recurrent venous thromboembolism (26 recurrent deep-vein thrombosis and 6 pulmonary embolism) from an existing prospective cohort of deep-vein thrombosis patients and compared them to 24 age and sex matched deep-vein thrombosis patients without recurrent venous thromboembolism. All participants received standard post-thrombotic management and underwent an additional extensive duplex ultrasonography. Post-thrombotic syndrome was assessed by the Villalta-scale and quality of life was measured using the SF36v2 and VEINES-QOL/Sym-questionnaires.

Results

Venous obstruction was found in 6 patients (18.8%) with recurrent venous thromboembolism compared to 5 patients (20.8%) without recurrent venous thromboembolism (Odds ratio 0.88, 95%CI 0.23–3.30, p = 1.000). After a median follow-up of 60.0 months (IQR 41.3–103.5) the mean Villalta-score was 5.55 ± 3.02 versus 5.26 ± 2.63 (p = 0.909) and post-thrombotic syndrome developed in 20 (62.5%) versus 14 (58.3%) patients, respectively (Odds ratio 1.19, 95%CI 0.40–3.51, p = 0.752). If venous obstruction was present, it was mainly located in the common iliac vein (n = 7, 63.6%). In patients with an objectified venous obstruction the mean Villalta-score was 5.11 ± 2.80 versus 5.49 ± 2.87 in patients without venous obstruction (p = 0.639). Post-thrombotic syndrome developed in 6 (54.5%) versus 28 (62.2%) patients, respectively (Odds ratio 1.37, 95%CI 0.36–5.20, p = 0.736). No significant differences were seen regarding patient-reported quality of life between either groups.

Conclusions

In this exploratory case-control study patients with recurrent venous thromboembolism did not have a higher prevalence of venous obstruction compared to patients without recurrent venous thromboembolism. The presence of recurrent venous thromboembolism or venous obstruction had no impact on the development of post-thrombotic syndrome or the patient-reported quality of life.

Ultrasound-accelerated catheter-directed thrombolysis versus anticoagulation for the prevention of post-thrombotic syndrome (CAVA): a single-blind, multicentre, randomised trial

BACKGROUND

Early thrombus removal might prevent post-thrombotic syndrome by preserving venous function and restoring flow. Previous trials comparing additional catheter-directed thrombolysis to standard treatment showed conflicting outcomes. We aimed to assess the benefit of additional ultrasound-accelerated catheter-directed thrombolysis for the prevention of post-thrombotic syndrome compared with standard therapy in patients with iliofemoral deep-vein thrombosis.

METHODS

We did a multicentre, randomised, single-blind, allocation-concealed, parallel group, superiority trial in 15 hospitals in the Netherlands. Patients aged 18-85 years with a first-time acute iliofemoral deep-vein thrombosis and symptoms for no more than 14 days were randomly assigned (1:1) to either standard treatment with additional ultrasound-accelerated catheter-directed thrombolysis or standard treatment alone. Randomisation was done with a web-based automatic programme and a random varying block size (2-12), stratified by age and centre. Standard treatment included anticoagulant therapy, compression therapy (knee-high elastic compression stockings; 30-40 mmHg), and early ambulation. Additional ultrasound-accelerated catheter-directed thrombolysis was done with urokinase with a starting bolus of 250 000 international units (IU) in 10 mL NaCl followed by a continuous dose of 100 000 IU/h for a maximum of 96 h through the Ekos Endowave-system. Adjunctive percutaneous transluminal angioplasty, thrombosuction, or stenting was performed at the discretion of the physician who performed the intervention. The primary outcome was the proportion of patients with post-thrombotic syndrome at 12 months diagnosed according to the original Villalta criteria-a Villalta-score of at least 5 on two consecutive occasions at least 3 months apart or the occurrence of venous ulceration-and was assessed in a modified intention-to-treat population of all randomly assigned patients who passed screening and started treatment. The safety analysis was assessed in the same modified intention-to-treat population. This study is complete and is registered at ClinicalTrials.gov, NCT00970619.

FINDINGS

Between May 28, 2010, and Sept 18, 2017, 184 patients were randomly assigned to either additional ultrasound-accelerated catheter-directed thrombolysis (n=91) or standard treatment alone (n=93). Exclusion because of screening failure or early withdrawal of informed consent resulted in 77 patients in the intervention group and 75 in the standard treatment group starting allocated treatment. Median follow-up was 12·0 months (IQR 6·0-12·0). 12-month post-thrombotic syndrome occurred in 22 (29%) patients allocated to additional treatment versus 26 (35%) patients receiving standard treatment alone (odds ratio 0·75 [95% CI 0·38 to 1·50]; p=0·42). Major bleeding occurred in four (5%) patients in the intervention group, with associated neuropraxia or the peroneal nerve in one patient, and no events in the standard treatment group. No serious adverse events occurred. None of the four deaths (one [1%] in the intervention group vs three [4%] in the standard treatment group) were treatment related.

INTERPRETATION

This study showed that additional ultrasound-accelerated catheter-directed thrombolysis does not change the risk of post-thrombotic syndrome 1 year after acute iliofemoral deep-vein thrombosis compared with standard therapy alone. Although this trial is inconclusive, the outcome suggests the possibility of a moderate beneficial effect with additional ultrasound-accelerated catheter-directed thrombolysis. Further research is therefore warranted to better understand this outcome in the context of previous trials, preferably by combining the available evidence in an individual patient data meta-analysis.

FUNDING

The Netherlands Organisation for Health Research and Development (ZonMw), Maastricht University Medical Centre, BTG-Interventional Medicine.

Extended Treatment with Apixaban for Venous Thromboembolism Prevention in the Netherlands: Clinical and Economic Effects

Background  Dutch guidelines advise extended anticoagulant treatment with direct oral anticoagulants or vitamin K antagonists for patients with idiopathic venous thromboembolism (VTE) who do not have high bleeding risk.

Objectives  The aim of this study was to analyze the economic effects of extended treatment of apixaban in the Netherlands, based on an updated and adapted previously published model.

Methods  We performed a cost-effectiveness analysis simulating a population of 1,000 VTE patients. The base-case analysis compared extended apixaban treatment to no treatment after the first 6 months. Five additional scenarios were conducted to evaluate the effect of different bleeding risks and health care payers' perspective. The primary outcome of the model is the incremental cost-effectiveness ratio (ICER) in costs (€) per quality-adjusted life-year (QALY), with one QALY defined as 1 year in perfect health. To account for any influence of the uncertainties in the model, probabilistic and univariate sensitivity analyses were conducted. The treatment was considered cost-effective with an ICER less than €20,000/QALY, which is the most commonly used willingness-to-pay (WTP) threshold for preventive drugs in the Netherlands.

Results  The model showed a reduction in recurrent VTE and no increase in major bleeding events for extended treatment in all scenarios. The base-case analysis showed an ICER of €9,653/QALY. The probability of being cost-effective for apixaban in the base-case was 70.0% and 91.4% at a WTP threshold of €20,000/QALY and €50,000/QALY, respectively.

Conclusion  Extended treatment with apixaban is cost-effective for the prevention of recurrent VTE in Dutch patients.

Point-of-care testing in primary care: needs and attitudes of Irish GPs

Background

Studies outside of Ireland have demonstrated that GPs believe point-of-care tests (POCTs) are useful and would like to have more of these tests available in daily practice. This study establishes the views of Irish GPs on this topic for the first time and also explores GPs’ perceptions of barriers to having POCT devices in primary care.

Aim

To establish Irish GPs' perception of the benefits and barriers to POCT use.

Design & setting

A quantitative cross-sectional observational survey of Irish GPs attending continuing medical educational meetings (CME) in November 2015.

Method

Data was collected using an anonymous and confidential questionnaire.

Results

Out of a total of 250, 70% of GPs (n = 143) completed the questionnaire. Of these, 92% (n = 132) indicated they would like to have access to POCTs. Guidance in decision making 43% (n = 61), reduced referral rates 29% (n = 42), and diagnosis assistance 13% (n = 18) were the main benefits expressed. Cost 45% (n = 64) and time 34% (n = 48) were the main barriers identified.

Conclusion

This study proved that Irish GPs would also like increased access to POCTs. They feel that these tests would benefit patient care. Unsurprisingly, cost and time were two barriers identified to using POCT devices, which supports outcomes from studies. Radical changes would be required in primary care to facilitate implementation of POCTs and attention must be paid to how the costs of POCTs will be funded. This study may act as a prompt for future international research to further explore this area.

Model-based economic evaluations of diagnostic point of care tests were rarely fit for purpose

OBJECTIVES

Linked evidence models are recommended to predict health benefits and cost-effectiveness of diagnostic tests. We considered how published models accounted for changes in patient pathways that occur with point of care tests (POCTs) and their impact on patient health and costs.

STUDY DESIGN AND SETTING

Model-based evaluations of diagnostic POCTs published from 2004 to 2017 were identified from searching six databases. For each model, we assessed the outcomes considered, and whether reduced time to diagnosis and increased access to testing affected patient health and costs.

RESULTS

Seventy-four model-based evaluations were included: 95% incorporated evidence on test accuracy, but 34% only assessed intermediate outcomes such as rates of correct diagnosis. Of 54 models where POCTs reduced testing time, 39% addressed the economic and 37% addressed the health benefits of faster diagnosis. No model considered differences in access to tests.

CONCLUSION

Many models fail to capture the effects of POCTs in increasing access, advancing speed of diagnosis and treatment, and reducing anxiety and the associated costs. Many only consider the impact of testing from changes in accuracy. Ensuring models incorporate changes in patient pathways from faster and more accessible testing will lead to economic evaluations that better reflect the impact of POCTs.

European Union-28: An annualised cost-of-illness model for venous thromboembolism

Annual costs for venous thromboembolism (VTE) have been defined within the United States (US) demonstrating a large opportunity for cost savings. Costs for the European Union-28 (EU-28) have never been defined. A literature search was conducted to evaluate EU-28 cost sources. Median costs were defined for each cost input and costs were inflated to 2014 Euros (€) in the study country and adjusted for Purchasing Power Parity between EU countries. Adjusted costs were used to populate previously published cost-models based on adult incidence-based events. In the base model, annual expenditures for total, hospital-associated, preventable, and indirect costs were €1.5–2.2 billion, €1.0–1.5 billion, €0.5–1.1 billion and €0.2–0.3 billion, respectively (indirect costs: 12 % of expenditures). In the long-term attack rate model, total, hospital-associated, preventable, and indirect costs were €1.8–3.3 billion, €1.2–2.4 billion, €0.6–1.8 billion and €0.2–0.7 billion (indirect costs: 13 % of expenditures). In the multiway sensitivity analysis, annual expenditures for total, hospital-associated, preventable, and indirect costs were €3.0–8.5 billion, €2.2–6.2 billion, €1.1–4.6 billion and €0.5–1.4 billion (indirect costs: 22 % of expenditures). When the value of a premature life-lost increased slightly, aggregate costs rose considerably since these costs are higher than the direct medical costs. When evaluating the models aggregately for costs, the results suggests total, hospital-associated, preventable, and indirect costs ranging from €1.5–13.2 billion, €1.0–9.7 billion, €0.5–7.3 billion and €0.2–6.1 billion, respectively. Our study demonstrates that VTE costs have a large financial impact upon the EU-28’s healthcare systems and that significant savings could be realised if better preventive measures are applied.

Cost-effectiveness analysis of rivaroxaban for treatment and secondary prevention of venous thromboembolism in the Netherlands

BACKGROUND

Until recently, standard treatment of venous thromboembolism (VTE) concerned a combination of short-term low-molecular-weight heparin (LMWH) and long-term vitamin-K antagonist (VKA). Risk of bleeding and the requirement for regular anticoagulation monitoring are, however, limiting their use. Rivaroxaban is a novel oral anticoagulant associated with a significantly lower risk of major bleeds (hazard ratio = 0.54, 95% confidence interval = 0.37-0.79) compared to LMWH/VKA therapy, and does not require regular anticoagulation monitoring.

AIMS

To evaluate the health economic consequences of treating acute VTE patients with rivaroxaban compared to treatment with LMWH/VKA, viewed from the Dutch societal perspective.

METHODS

A life-time Markov model was populated with the findings of the EINSTEIN phase III clinical trial to analyze cost-effectiveness of rivaroxaban therapy in treatment and prevention of VTE from a Dutch societal perspective. Primary model outcomes were total and incremental quality-adjusted life years (QALYs), as well as life expectancy and costs.

RESULTS

Over a patient's lifetime, rivaroxaban was shown to be dominant, with health gains of 0.047 QALYs and cost savings of €304 compared to LMWH/VKA therapy. Dominance was robustly present in all sensitivity analyses. Major drivers of the differences between the two treatment arms were related to anticoagulation monitoring (medical costs, travel costs, and loss of productivity) and the occurrence of major bleeds.

CONCLUSION

Rivaroxaban treatment of patients with venous thromboembolism results in health gains and cost savings compared to LMWH/VKA therapy. This conclusion holds for the Dutch setting, both for the societal perspective, as well as the healthcare perspective.

Dabigatran for the Treatment and Secondary Prevention of Venous Thromboembolism; A Cost-Effectiveness Analysis for the Netherlands

Background

Dabigatran was proven to have similar effect on the prevention of recurrence of venous thromboembolism (VTE) and a lower risk of bleeding compared to vitamin K antagonists (VKA). The aim of this study is to assess the cost-effectiveness (CE) of dabigatran for the treatment and secondary prevention in patients with VTE compared to VKAs in the Dutch setting.

Methods

Previously published Markov model was modified and updated to assess the CE of dabigatran and VKAs for the treatment and secondary prevention in patients with VTE from a societal perspective in the base-case analysis. The model was populated with efficacy and safety data from major dabigatran trials (i.e. RE-COVER, RECOVER II, RE-MEDY and RE-SONATE), Dutch specific costs, and utilities derived from dabigatran trials or other published literature. Univariate, probabilistic sensitivity and a number of scenario analyses evaluating various decision-analytic settings (e.g. the perspective of analysis, use of anticoagulants only for treatment or only for secondary prevention, or comparison to no treatment) were tested on the incremental cost-effectiveness ratio (ICER).

Results

In the base-case scenario, patients on dabigatran gained an additional 0.034 quality adjusted life year (QALY) while saving €1,598. Results of univariate sensitivity analysis were quite robust. The probability that dabigatran is cost-effective at a willingness-to-pay threshold of €20,000/QALY was 98.1%. From the perspective of healthcare provider, extended anticoagulation with dabigatran compared to VKAs was estimated at €2,158 per QALY gained. The ICER for anticoagulation versus no treatment in patients with equipoise risk of recurrent VTE was estimated at €33,379 per QALY gained. Other scenarios showed dabigatran was cost-saving.

Conclusion

From a societal perspective, dabigatran is likely to be a cost-effective or even cost-saving strategy for treatment and secondary prevention of VTE compared to VKAs in the Netherlands.

Budget Impact of Increasing Market Share of Patient Self-Testing and Patient Self-Management in Anticoagulation

BACKGROUND

Patient self-testing (PST) and/or patient self-management (PSM) might provide better coagulation care than monitoring at specialized anticoagulation centers. Yet, it remains an underused strategy in the Netherlands.

METHODS

Budget-impact analyses of current and new market-share scenarios of PST and/or PSM compared with monitoring at specialized centers were performed for a national cohort of 260,338 patients requiring long-term anticoagulation testing. A health care payer perspective and 1- to 5-year time horizons were applied. The occurrence of thromboembolic and hemorrhagic complications in the aforementioned patient population was assessed in a Markov model. Dutch-specific costs were applied, next to effectiveness data derived from a meta-analysis on PST and/or PSM. Sensitivity and scenario analyses were performed to assess uncertainty on budget-impact analysis results.

RESULTS

Increasing PST and/or PSM usage in the national cohort from the current 15.4% to 50% resulted in savings ranging from €8 million after the first year to €184 million after 5 years. Further increases in the use of PST and/or PSM produced greater savings. Sensitivity analyses revealed budget-impact model sensitivity to the baseline and relative risks of thromboembolic complications. Unfavorable budget impact was found in scenarios exploring an increase in the use of PST alone as well as an increase in the market share of PST and PSM in patients with atrial fibrillation.

CONCLUSIONS

Overall study findings indicated that PST and PSM are more favorable alternatives to monitoring at specialized centers in patients without atrial fibrillation.

Outpatient services and primary care: scoping review, substudies and international comparisons

Aim

This study updates a previous scoping review published by the National Institute for Health Research (NIHR) in 2006 (Roland M, McDonald R, Sibbald B.Outpatient Services and Primary Care: A Scoping Review of Research Into Strategies For Improving Outpatient Effectiveness and Efficiency. Southampton: NIHR Trials and Studies Coordinating Centre; 2006) and focuses on strategies to improve the effectiveness and efficiency of outpatient services.

Findings from the scoping review

Evidence from the scoping review suggests that, with appropriate safeguards, training and support, substantial parts of care given in outpatient clinics can be transferred to primary care. This includes additional evidence since our 2006 review which supports general practitioner (GP) follow-up as an alternative to outpatient follow-up appointments, primary medical care of chronic conditions and minor surgery in primary care. Relocating specialists to primary care settings is popular with patients, and increased joint working between specialists and GPs, as suggested in the NHS Five Year Forward View, can be of substantial educational value. However, for these approaches there is very limited information on cost-effectiveness; we do not know whether they increase or reduce overall demand and whether the new models cost more or less than traditional approaches. One promising development is the increasing use of e-mail between GPs and specialists, with some studies suggesting that better communication (including the transmission of results and images) could substantially reduce the need for some referrals.

Findings from the substudies

Because of the limited literature on some areas, we conducted a number of substudies in England. The first was of referral management centres, which have been established to triage and, potentially, divert referrals away from hospitals. These centres encounter practical and administrative challenges and have difficulty getting buy-in from local clinicians. Their effectiveness is uncertain, as is the effect of schemes which provide systematic review of referrals within GP practices. However, the latter appear to have more positive educational value, as shown in our second substudy. We also studied consultants who held contracts with community-based organisations rather than with hospital trusts. Although these posts offer opportunities in terms of breaking down artificial and unhelpful primary–secondary care barriers, they may be constrained by their idiosyncratic nature, a lack of clarity around roles, challenges to professional identity and a lack of opportunities for professional development. Finally, we examined the work done by other countries to reform activity at the primary–secondary care interface. Common approaches included the use of financial mechanisms and incentives, the transfer of work to primary care, the relocation of specialists and the use of guidelines and protocols. With the possible exception of financial incentives, the lack of robust evidence on the effect of these approaches and the contexts in which they were introduced limits the lessons that can be drawn for the English NHS.

Conclusions

For many conditions, high-quality care in the community can be provided and is popular with patients. There is little conclusive evidence on the cost-effectiveness of the provision of more care in the community. In developing new models of care for the NHS, it should not be assumed that community-based care will be cheaper than conventional hospital-based care. Possible reasons care in the community may be more expensive include supply-induced demand and addressing unmet need through new forms of care and through loss of efficiency gained from concentrating services in hospitals. Evidence from this study suggests that further shifts of care into the community can be justified only if (a) high value is given to patient convenience in relation to NHS costs or (b) community care can be provided in a way that reduces overall health-care costs. However, reconfigurations of services are often introduced without adequate evaluation and it is important that new NHS initiatives should collect data to show whether or not they have added value, and improved quality and patient and staff experience.

Funding

The NIHR Health Services and Delivery Research programme.

[Cost-effectiveness of the deep vein thrombosis diagnosis process in primary care]

OBJECTIVE

To analyse the cost effectiveness of the application of diagnostic algorithms in patients with a first episode of suspected deep vein thrombosis (DVT) in Primary Care compared with systematic referral to specialised centres.

DESIGN

Observational, cross-sectional, analytical study.

LOCATION

Patients from hospital emergency rooms referred from Primary Care to complete clinical evaluation and diagnosis.

PARTICIPANTS

A total of 138 patients with symptoms of a first episode of DVT were recruited; 22 were excluded (no Primary Care report, symptoms for more than 30 days, anticoagulant treatment, and previous DVT). Of the 116 patients finally included, 61% women and the mean age was 71 years.

MAIN MEASUREMENTS

Variables from the Wells and Oudega clinical probability scales, D-dimer (portable and hospital), Doppler ultrasound, and direct costs generated by the three algorithms analysed: all patients were referred systematically, referral according to Wells and Oudega scale.

RESULTS

DVT was confirmed in 18.9%. The two clinical probability scales showed a sensitivity of 100% (95% CI: 85.1 to 100) and a specificity of about 40%. With the application of the scales, one third of all referrals to hospital emergency rooms could have been avoided (P<.001). The diagnostic cost could have been reduced by € 8,620 according to Oudega and € 9,741 according to Wells, per 100 patients visited.

CONCLUSION

The application of diagnostic algorithms when a DVT is suspected could lead to better diagnostic management by physicians, and a more cost effective process.

Cost-Effectiveness of Dabigatran Compared to Vitamin-K Antagonists for the Treatment of Deep Venous Thrombosis in the Netherlands Using Real-World Data

Background

Vitamin-K antagonists (VKAs) present an effective anticoagulant treatment in deep venous thrombosis (DVT). However, the use of VKAs is limited because of the risk of bleeding and the necessity of frequent and long-term laboratory monitoring. Therefore, new oral anticoagulant drugs (NOACs) such as dabigatran, with lower rates of (major) intracranial bleeding compared to VKAs and not requiring monitoring, may be considered.

Objectives

To estimate resource utilization and costs of patients treated with the VKAs acenocoumarol and phenprocoumon, for the indication DVT. Furthermore, a formal cost-effectiveness analysis of dabigatran compared to VKAs for DVT treatment was performed, using these estimates.

Methods

A retrospective observational study design in the thrombotic service of a teaching hospital (Deventer, The Netherlands) was applied to estimate real-world resource utilization and costs of VKA monitoring. A pooled analysis of data from RE-COVER and RE-COVER II on DVT was used to reflect the probabilities for events in the cost-effectiveness model. Dutch costs, utilities and specific data on coagulation monitoring levels were incorporated in the model. Next to the base case analysis, univariate probabilistic sensitivity and scenario analyses were performed.

Results

Real-world resource utilization in the thrombotic service of patients treated with VKA for the indication of DVT consisted of 12.3 measurements of the international normalized ratio (INR), with corresponding INR monitoring costs of €138 for a standardized treatment period of 180 days. In the base case, dabigatran treatment compared to VKAs in a cohort of 1,000 DVT patients resulted in savings of €18,900 (95% uncertainty interval (UI) -95,832, 151,162) and 41 (95% UI -18, 97) quality-adjusted life-years (QALYs) gained calculated from societal perspective. The probability that dabigatran is cost-effective at a conservative willingness-to pay threshold of €20,000 per QALY was 99%. Sensitivity and scenario analyses also indicated cost savings or cost-effectiveness below this same threshold.

Conclusions

Total INR monitoring costs per patient were estimated at minimally €138. Inserting these real-world data into a cost-effectiveness analysis for patients diagnosed with DVT, dabigatran appeared to be a cost-saving alternative to VKAs in the Netherlands in the base case. Cost savings or favorable cost-effectiveness were robust in sensitivity and scenario analyses. Our results warrant confirmation in other settings and locations.

Sample Size Estimation for Non-Inferiority Trials: Frequentist Approach versus Decision Theory Approach

BACKGROUND

Non-inferiority trials are performed when the main therapeutic effect of the new therapy is expected to be not unacceptably worse than that of the standard therapy, and the new therapy is expected to have advantages over the standard therapy in costs or other (health) consequences. These advantages however are not included in the classic frequentist approach of sample size calculation for non-inferiority trials. In contrast, the decision theory approach of sample size calculation does include these factors. The objective of this study is to compare the conceptual and practical aspects of the frequentist approach and decision theory approach of sample size calculation for non-inferiority trials, thereby demonstrating that the decision theory approach is more appropriate for sample size calculation of non-inferiority trials.

METHODS

The frequentist approach and decision theory approach of sample size calculation for non-inferiority trials are compared and applied to a case of a non-inferiority trial on individually tailored duration of elastic compression stocking therapy compared to two years elastic compression stocking therapy for the prevention of post thrombotic syndrome after deep vein thrombosis.

RESULTS

The two approaches differ substantially in conceptual background, analytical approach, and input requirements. The sample size calculated according to the frequentist approach yielded 788 patients, using a power of 80% and a one-sided significance level of 5%. The decision theory approach indicated that the optimal sample size was 500 patients, with a net value of €92 million.

CONCLUSIONS

This study demonstrates and explains the differences between the classic frequentist approach and the decision theory approach of sample size calculation for non-inferiority trials. We argue that the decision theory approach of sample size estimation is most suitable for sample size calculation of non-inferiority trials.

The IDEAL DVT study, individualised duration elastic compression therapy against long-term duration of therapy for the prevention of post-thrombotic syndrome: protocol of a randomised controlled trial

INTRODUCTION

Post-thrombotic syndrome (PTS) is a serious complication of deep vein thrombosis (DVT) of the leg that affects 20-50% of patients. Once a patient experiences PTS there is no treatment that effectively reduces the debilitating complaints. Two randomised controlled trials showed that elastic compression stocking (ECS) therapy after DVT for 24 months can reduce the incidence of PTS by 50%. However, it is unclear whether all patients benefit to the same extent from ECS therapy or what the optimal duration of therapy for individual patients should be. ECS therapy is costly, inconvenient, demanding and sometimes even debilitating. Tailoring therapy to individual needs could save substantial costs. The objective of the IDEAL DVT study, therefore, is to evaluate whether tailoring the duration of ECS therapy on signs and symptoms of the individual patient is a safe and effective method to prevent PTS, compared with standard ECS therapy.

METHODS AND ANALYSIS

A multicentre, single-blinded, allocation concealed, randomised, non-inferiority trial. A total of 864 consecutive patients with acute objectively documented proximal DVT of the leg are randomised to either standard duration of 24 months or tailored duration of ECS therapy following an initial therapeutic period of 6 months. Signs and symptoms of PTS are recorded at regular clinic visits. Furthermore, quality of life, costs, patient preferences and compliance are measured. The primary outcome is the proportion of patients with PTS at 24 months.

ETHICS AND DISSEMINATION

Based on current knowledge the standard application of ECS therapy is questioned. The IDEAL DVT study will address the central questions that remain unanswered: Which individual patients benefit from ECS therapy and what is the optimal individual treatment duration? Primary ethics approval was received from the Maastricht University Medical Centre.

RESULTS

Results of the study will be disseminated via peer-reviewed publications and presentations at scientific conferences.

TRIAL REGISTRATION NUMBER

NCT01429714 and NTR 2597.

Economic evaluation of apixaban for the prevention of stroke in non-valvular atrial fibrillation in the Netherlands

BACKGROUND

Stroke prevention is the main goal of treating patients with atrial fibrillation (AF). Vitamin-K antagonists (VKAs) present an effective treatment in stroke prevention, however, the risk of bleeding and the requirement for regular coagulation monitoring are limiting their use. Apixaban is a novel oral anticoagulant associated with significantly lower hazard rates for stroke, major bleedings and treatment discontinuations, compared to VKAs.

OBJECTIVE

To estimate the cost-effectiveness of apixaban compared to VKAs in non-valvular AF patients in the Netherlands.

METHODS

Previously published lifetime Markov model using efficacy data from the ARISTOTLE and the AVERROES trial was modified to reflect the use of oral anticoagulants in the Netherlands. Dutch specific costs, baseline population stroke risk and coagulation monitoring levels were incorporated. Univariate, probabilistic sensitivity and scenario analyses on the impact of different coagulation monitoring levels were performed on the incremental cost-effectiveness ratio (ICER).

RESULTS

Treatment with apixaban compared to VKAs resulted in an ICER of €10,576 per quality adjusted life year (QALY). Those findings correspond with lower number of strokes and bleedings associated with the use of apixaban compared to VKAs. Univariate sensitivity analyses revealed model sensitivity to the absolute stroke risk with apixaban and treatment discontinuations risks with apixaban and VKAs. The probability that apixaban is cost-effective at a willingness-to-pay threshold of €20,000/QALY was 68%. Results of the scenario analyses on the impact of different coagulation monitoring levels were quite robust.

CONCLUSIONS

In patients with non-valvular AF, apixaban is likely to be a cost-effective alternative to VKAs in the Netherlands.

Point-of-care tests in general practice: hope or hype?

Point-of-care tests are biomedical tests on patients' specimens like blood, saliva, urine or faeces, which can be used near the patient, without interference of a laboratory. The use of these tests, many of which have been recently developed, is increasing in general practice, where they add to the GP's set of diagnostic instruments. The question is, however, whether they always contribute to an effective and high-quality diagnostic process by GPs. We present a set of criteria that can be used by guideline developers, regional primary care organizations and individual GPs to evaluate a new point-of-care test in a practice setting. These criteria do not relate only to their use and quality. A point-of-care test needs to be evaluated in the right population and for the right indications, and GPs then need to use them for the indications for which they were evaluated. Expanding the range of indications can lead to an increase in false-positive and false-negative test results.

Diagnostic and prognostic prediction models

Risk prediction models can be used to estimate the probability of either having (diagnostic model) or developing a particular disease or outcome (prognostic model). In clinical practice, these models are used to inform patients and guide therapeutic management. Examples from the field of venous thrombo-embolism (VTE) include the Wells rule for patients suspected of deep venous thrombosis and pulmonary embolism, and more recently prediction rules to estimate the risk of recurrence after a first episode of unprovoked VTE. In this paper, the three phases that are recommended before a prediction model may be used in daily practice are described: development, validation, and impact assessment. In the development phase, the focus is on model development commonly using a multivariable logistic (diagnostic) or survival (prognostic) regression analysis. The performance of the developed model is expressed by discrimination, calibration and (re-) classification. In the validation phase, the developed model is tested in a new set of patients using these same performance measures. This is important, as model performance is commonly poorer in a new set of patients, e.g. due to case-mix or domain differences. Finally, in the impact phase the ability of a prediction model to actually guide patient management is evaluated. Whereas in the development and validation phase single cohort designs are preferred, this last phase asks for comparative designs, ideally randomized designs; therapeutic management and outcomes after using the prediction model is compared to a control group not using the model (e.g. usual care).

Cost-effectiveness of pharmacogenetics in anticoagulation: international differences in healthcare systems and costs

Genotyping patients for CYP2C9 and VKORC1 polymorphisms can improve the accuracy of dosing during the initiation of anticoagulation with vitamin K antagonists (coumarin derivatives). The anticipated degree of improvement in the safety of anticoagulation with coumarins through genotyping may vary depending on the quality of patient care, which varies both with and among countries. The management and the cost of anticoagulant care can therefore influence the cost-effectiveness of genotyping within any given country. In this article, we provide an overview of the cost-effectiveness of pharmacogenetics-guided dosing of coumarin derivatives. We describe the organization of anticoagulant care in the UK, Sweden, The Netherlands, Greece, Germany and Austria, where a genotype-guided dosing algorithm is currently being investigated as part of the EU-PACT trial. We also explore the costs of anticoagulant care for the treatment of atrial fibrillation in these countries.

Economic evaluation of different screening alternatives for patients with clinically suspected acute deep vein thrombosis

INTRODUCTION

We examined the cost-effectiveness of the three different D-dimer measurements in the screening of DVT in models with and without calculation of pre-test probability (PTP) score. Moreover, we calculated the minimal cost in DVT detection.

MATERIAL AND METHODS

In the group of 192 patients with clinically suspected acute DVT, we examined the three different D-dimer measurements (Innovance D-dimer, Hemosil D-dimer HS and Vidas D-dimer Exclusion II) in combination with and without PTP assessment.

RESULTS

The diagnostic alternative employing Vidas D-dimer Exclusion II assay without and with PTP calculation gave lower incremental cost-effectiveness ratio (ICER) than the alternative employing Hemosil D-dimer HS assay (0.187 Euros vs. 0.998 Euros per one additional DVT positive patient selected for CUS in model without PTP assessment and 0.450 vs. 0.753 Euros per one DVT positive patient selected for CUS in model with PTP assessment). According to sensitivity analysis, the Hemosil D-dimer HS assay was the most cost effective alternative when one patient was admitted to the vascular ambulance per day. Vidas D-dimer Exclusion II assay was the most cost effective alternative when more than one patient were admitted to the vascular ambulance per day. Cost minimisation analysis indicated that selection of patients according to PTP score followed by D-dimer analysis decreases the cost of DVT diagnosis.

CONCLUSIONS

ICER analysis enables laboratories to choose optimal laboratory tests according to number of patients admitted to laboratory. Results support the feasibility of using PTP scoring and D-dimer measurement before CUS examination in DVT screening.

The cost-effectiveness of a novel SIAscopic diagnostic aid for the management of pigmented skin lesions in primary care: a decision-analytic model

OBJECTIVES

Pigmented skin lesions are commonly presented in primary care. Appropriate diagnosis and management is challenging because the vast majority are benign. The MoleMate system is a handheld SIAscopy scanner integrated with a primary care diagnostic algorithm aimed at improving the management of pigmented skin lesions in primary care.

METHODS

This decision-model-based economic evaluation draws on the results of a randomized controlled trial of the MoleMate system versus best practice (ISRCTN79932379) to estimate the expected long-term cost and health gain of diagnosis with the MoleMate system versus best practice in an English primary care setting. The model combines trial results with data from the wider literature to inform long-term prognosis, health state utilities, and cost.

RESULTS

Results are reported as mean and incremental cost and quality-adjusted life-years (QALYs) gained, incremental cost-effectiveness ratio with probabilistic sensitivity analysis, and value of information analysis. Over a lifetime horizon, the MoleMate system is expected to cost an extra £18 over best practice alone, and yield an extra 0.01 QALYs per patient examined. The incremental cost-effectiveness ratio is £1,896 per QALY gained, with a 66.1% probability of being below £30,000 per QALY gained. The expected value of perfect information is £43.1 million.

CONCLUSIONS

Given typical thresholds in the United Kingdom (£20,000-£30,000 per QALY), the MoleMate system may be cost-effective compared with best practice diagnosis alone in a primary care setting. However, there is considerable decision uncertainty, driven particularly by the sensitivity and specificity of MoleMate versus best practice, and the risk of disease progression in undiagnosed melanoma; future research should focus on reducing uncertainty in these parameters.

Effect of a public awareness campaign on the incidence of symptomatic objectively confirmed deep vein thrombosis: a controlled study

BACKGROUND

Although there have been attempts to raise public awareness about deep vein thrombosis (DVT), their influence on identifying confirmed cases is unknown.

OBJECTIVE

To determine the effect and its duration of a public awareness campaign about venous thromboembolism.

PATIENTS/METHODS

A campaign to raise public awareness of DVT was conducted during one year in an urban population of approximately 100,000 (pop A). A comparison urban population of approximately 1,574,000 (pop B) was not exposed to this campaign. Patients symptomatic for DVT in both populations were referred by general practitioners for a standardized compression ultrasound (CUS) of the whole leg at no charge. Positive CUS examinations documented by photographs were analyzed by an independent adjudication committee blinded to the population. Pop A was followed for 8 months after the information campaign ended.

RESULTS AND CONCLUSIONS

  Symptomatic objectively confirmed DVT was found in 48 of 800 subjects tested in pop A and 226 of 2384 tested in pop B. The 1-year incidence of confirmed DVT (proximal and distal) was 46/100,000 (95% CI, 33-59) in A and 14/100,000 (95% CI, 12-16) in B (P < 0.001). The increase in pop A was due to distal DVT (36/100,000 vs. 5/100,000 in pop B, P < 0.001). The DVT rate for pop A in an 8-month follow-up period was 12/100,000, significantly lower than in the first 8 months of the study period (34/100,000/8 months) (P = 0.001). The public awareness campaign significantly increased the diagnosis of distal DVT. When the campaign ended, DVT rates returned to community baseline.

Randomized clinical trial of ultrasound-guided foam sclerotherapy versus surgery for the incompetent great saphenous vein

BACKGROUND

New minimally invasive treatment modalities, such as ultrasound-guided foam sclerotherapy (UGFS), are becoming more popular. In a multicentre randomized controlled non-inferiority trial, the effectiveness and costs of UGFS and surgery for treatment of the incompetent great saphenous vein (GSV) were compared.

METHODS

Patients with primary great saphenous varicose veins were assigned randomly to either UGFS or surgical stripping with high ligation. Recurrence, defined as reflux combined with venous symptoms, was determined on colour duplex scans at baseline, 3 months, 1 year and 2 years after initial treatment. Secondary outcomes were presence of recurrent reflux (irrespective of symptoms), reduction of symptoms, health-related quality of life (EQ-5D(™)), adverse events and direct hospital costs.

RESULTS

Two hundred and thirty patients were treated by UGFS and 200 underwent GSV stripping. The 2-year probability of recurrence was similar in the UGFS and surgery groups: 11·3 per cent (24 of 213) and 9·0 per cent (16 of 177) respectively (P = 0·407). At 2 years, reflux irrespective of venous symptoms was significantly more frequent in the UGFS group (35·0 per cent) than in the surgery group (21·0 per cent) (P = 0·003). Mean(s.d.) hospital costs per patient over 2 years were €774(344) per patient for UGFS and €1824(141) for stripping.

CONCLUSION

At 2-year follow-up, UGFS was not inferior to surgery when reflux associated with venous symptoms was the clinical outcome of interest. UGFS has the potential to be a cost-effective approach to a common health problem. Registration numbers: NCT01103258 (http://www.clinicaltrials.gov) and NTR654 (http://www.trialregister.nl).

Search filters for finding prognostic and diagnostic prediction studies in Medline to enhance systematic reviews

Background

The interest in prognostic reviews is increasing, but to properly review existing evidence an accurate search filer for finding prediction research is needed. The aim of this paper was to validate and update two previously introduced search filters for finding prediction research in Medline: the Ingui filter and the Haynes Broad filter.

Methodology/Principal Findings

Based on a hand search of 6 general journals in 2008 we constructed two sets of papers. Set 1 consisted of prediction research papers (n = 71), and set 2 consisted of the remaining papers (n = 1133). Both search filters were validated in two ways, using diagnostic accuracy measures as performance measures. First, we compared studies in set 1 (reference) with studies retrieved by the search strategies as applied in Medline. Second, we compared studies from 4 published systematic reviews (reference) with studies retrieved by the search filter as applied in Medline. Next – using word frequency methods – we constructed an additional search string for finding prediction research. Both search filters were good in identifying clinical prediction models: sensitivity ranged from 0.94 to 1.0 using our hand search as reference, and 0.78 to 0.89 using the systematic reviews as reference. This latter performance measure even increased to around 0.95 (range 0.90 to 0.97) when either search filter was combined with the additional string that we developed. Retrieval rate of explorative prediction research was poor, both using our hand search or our systematic review as reference, and even combined with our additional search string: sensitivity ranged from 0.44 to 0.85.

Conclusions/Significance

Explorative prediction research is difficult to find in Medline, using any of the currently available search filters. Yet, application of either the Ingui filter or the Haynes broad filter results in a very low number missed clinical prediction model studies.

Diagnostic Accuracy and User-Friendliness of 5 Point-of-Care D-Dimer Tests for the Exclusion of Deep Vein Thrombosis

BACKGROUND

Point-of-care D-dimer tests have recently been introduced to enable rapid exclusion of deep venous thrombosis (DVT) without the need to refer a patient for conventional laboratory-based D-dimer testing. Before implementation in practice, however, the diagnostic accuracy of each test should be validated.

METHODS

We analyzed data of 577 prospectively identified consecutive primary care patients suspected to have DVT, who underwent 5 point-of-care D-dimer tests—4 quantitative (Vidas®, Pathfast™, Cardiac®, and Triage®) and 1 qualitative (Clearview Simplify®)—and ultrasonography as the reference method. We evaluated the tests for the accuracy of their measurements and submitted a questionnaire to 20 users to assess the user-friendliness of each test.

RESULTS

All D-dimer tests showed negative predictive values higher than 98%. Sensitivity was high for all point-of-care tests, with a range of 0.91 (Clearview Simplify) to 0.99 (Vidas). Specificity varied between 0.39 (Pathfast) and 0.64 (Clearview Simplify). The quantitative point-of-care tests showed similar and high discriminative power for DVT, according to calculated areas under the ROC curves (range 0.88–0.89). The quantitative Vidas and Pathfast devices showed limited user-friendliness for primary care, owing to a laborious calibration process and long analyzer warm-up time compared to the Cardiac and Triage. For the qualitative Clearview Simplify assay, no analyzer or calibration was needed, but interpretation of a test result was sometimes difficult because of poor color contrast.

CONCLUSIONS

Point-of-care D-dimer assays show good and similar diagnostic accuracy. The quantitative Cardiac and Triage and the qualitative Clearview Simplify D-dimer seem most user-friendly for excluding DVT in the doctor's office.

»Point-of-Care« D-Dimer Testing

D-dimer testing is efficient in the exclusion of venous thromboembolism (VTE). D-dimer laboratory assays are predominantly performed in centralised laboratories in intra-hospital settings although most patients with suspected VTE are presented in primary care. On the other hand decreasing turnaround time for laboratory testing may significantly improve efficacy in emergency departments. Therefore an introduction of a rapid, easy to perform point of care (POC) assay for the identification of D-dimer may offer improvement in diagnostics flow of VTE both in primary care and emergency departments while it could also improve our diagnostic possibilities in some other severe clinical conditions (e.g. disseminated intra-vascular coagulation (DIC) and aortic aneurism (AA)) associated with increased D-dimer. Several POC D-dimer assays have been evaluated and majority of them have met the criteria for rapid and safe exclusion of VTE. In our hands three assays (Stratus, Pathfast and Cardiac) have the laboratory performance profile comparable with our routine D-dimer laboratory assay (Tinaqaunt).