Johan L Severens

Erasmus Universiteit Rotterdam, Rotterdam, South Holland, Netherlands

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Publications (281)1056.2 Total impact

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    ABSTRACT: Most studies on birth settings investigate the association between planned place of birth at the start of labor and birth outcomes and intervention rates. To optimize maternity care it also is important to pay attention to the entire process of pregnancy and childbirth. This study explores the association between the initial preferred place of birth and model of care, and the course of pregnancy and labor in low-risk nulliparous women in the Netherlands. As part of a Dutch prospective cohort study (2007-2011), we compared medical indications during pregnancy and birth outcomes of 576 women who initially preferred a home birth (n = 226), a midwife-led hospital birth (n = 168) or an obstetrician-led hospital birth (n = 182). Data were obtained by a questionnaire before 20 weeks of gestation and by medical records. Analyses were performed according to the initial preferred place of birth. Low-risk nulliparous women who preferred a home birth with midwife-led care were less likely to be diagnosed with a medical indication during pregnancy compared to women who preferred a birth with obstetrician-led care (OR 0.41 95% CI 0.25-0.66). Preferring a birth with midwife-led care - both at home and in hospital - was associated with lower odds of induced labor (OR 0.51 95% CI 0.28-0.95 respectively OR 0.42 95% CI 0.21-0.85) and epidural analgesia (OR 0.32 95% CI 0.18-0.56 respectively OR 0.34 95% CI 0.19-0.62) compared to preferring a birth with obstetrician-led care. In addition, women who preferred a home birth were less likely to experience augmentation of labor (OR 0.54 95% CI 0.32-0.93) and narcotic analgesia (OR 0.41 95% CI 0.21-0.79) compared to women who preferred a birth with obstetrician-led care. We observed no significant association between preferred place of birth and mode of birth. Nulliparous women who initially preferred a home birth were less likely to be diagnosed with a medical indication during pregnancy. Women who initially preferred a birth with midwife-led care - both at home and in hospital - experienced lower rates of interventions during labor. Although some differences can be attributed to the model of care, we suggest that characteristics and attitudes of women themselves also play an important role.
    BMC Pregnancy and Childbirth 12/2015; 15(1):455. DOI:10.1186/s12884-015-0455-x · 2.15 Impact Factor
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    Olena Mandrik, Saskia Knies, Johan L Severens
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    ABSTRACT: An economic value calculation was performed to estimate the lifetime net present value of in vitro fertilization (IVF) in Ukraine, Belarus, and Kazakhstan. Net lifetime tax revenues were used to represent governmental benefits accruing from a hypothetical cohort of an IVF population born in 2009 using the methodology of generational accounting. Governmental expenses related to this population included social benefits, education and health care, unemployment support, and pensions. Where available, country-specific data referencing official sources were applied. The average health care cost needed to achieve one additional birth from the governmental perspective varied from $2,599 in Ukraine to $5,509 in Belarus. The net present value from the population born using IVF was positive in all countries: for Ukraine ($9,839), Belarus ($21,702), and Kazakhstan ($2,295). The break-even costs of drugs and supplies per IVF procedure is expected to be $3,870, $8,530, and $1,780, respectively. Probabilistic sensitivity analyses based on 5,000 simulations show that the average net present value per person remains positive: $1,894±$7,619, $27,925±$12,407, and $17,229±$24,637 in Ukraine, Belarus, and Kazakhstan, respectively. Financing IVF may represent a good investment in terms of governmental financial returns, even in lower-income countries with state-financed health care systems such as Ukraine, Belarus, and Kazakhstan.
    ClinicoEconomics and Outcomes Research 06/2015; 7:347—356. DOI:10.2147/CEOR.S79513
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    ABSTRACT: The study aimed to determine the room for improvement of a perfect cerebrospinal fluid (CSF) biomarker and the societal incremental net monetary benefit of CSF in subjects with mild cognitive impairment (MCI) assuming a hypothetical disease-modifying Alzheimer's disease (AD) treatment. A decision model compared current practice to a perfect biomarker and to two strategies positioning CSF as add-on test when current practice concluded the presence or absence of AD. The simulated MCI population was aged on average 68.3% and 49% had AD. The room for improvement by the perfect CSF test was 0.39 quality adjusted life years, €33,622 ($43,372) savings, 2.0 potential beneficial treatment years, and 1.3-year delay in dementia conversion. The results indicated more potential benefit from a biomarker positioned to verify subjects who are not expected to have AD (i.e., to prevent undertreatment) rather than to verify subjects expected to have AD (prevent overtreatment). Sensitivity analyses explored different CSF positions. Copyright © 2015 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.
    Alzheimer's & dementia: the journal of the Alzheimer's Association 06/2015; DOI:10.1016/j.jalz.2015.02.009 · 17.47 Impact Factor
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    ABSTRACT: - There is increasing discussion in the Netherlands about the introduction of a threshold value for the costs per extra year of life when reimbursing costs of new drugs. - The Medicines Committee ('Commissie Geneesmiddelen'), a division of the Netherlands National Healthcare Institute ('Zorginstituut Nederland'), advises on reimbursement of costs of new drugs. - This advice is based upon the determination of therapeutic value of the drug and the results of economic evaluations.- Mathematical models that predict future costs and effectiveness are often used in economic evaluations; these models can vary greatly in transparency and quality due to author assumptions.- Standardisation of cost-effectiveness models is one solution to overcome the unwanted variation in quality.- Discussions about the introduction of a threshold value can only be meaningful if all involved are adequately informed, and by high quality in cost-effectiveness research and, particularly, economic evaluations.- Collaboration and discussion between medical specialists, patients or patient organisations, health economists and policy makers, both in development of methods and in standardisation, are essential to improve the quality of decision making.
    Nederlands tijdschrift voor geneeskunde 01/2015; 159:A7728.
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    Ties Hoomans, Johan L Severens
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    ABSTRACT: Economic evaluations can inform decisions about the efficiency and allocation of resources to implementation strategies¿strategies explicitly designed to inform care providers and patients about the best available research evidence and to enhance its use in their practices. These strategies are increasingly popular in health care, especially in light of growing concerns about quality of care and limits on resources. But such concerns have hardly motivated health authorities and other decision-makers to spend on some form of economic evaluation in their assessments of implementation strategies. This editorial addresses the importance of economic evaluation in the context of implementation science¿particularly, how these analyses can be most efficiently incorporated into decision-making processes about implementation strategies.
    Implementation Science 12/2014; 9(1):168. DOI:10.1186/s13012-014-0168-y · 3.47 Impact Factor
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    ABSTRACT: Currently, no country-specific metastatic breast cancer (MBC) observational costing data are available for the Netherlands and Belgium. Our aim is to describe country-specific resource use and costs of human epidermal receptor 2 (HER-2)-positive MBC in the Netherlands and Belgium, making use of real-world data.The eligibility period for patient selection was from April 2004 to April 2010. Inclusion and retrospective data collection begins at the time of first diagnosis of HER-2-positive MBC during the eligibility period and ends 24 months post-index diagnosis of MBC or at patient death.We identified 88 eligible patients in the Netherlands and 44 patients in Belgium. The total costs of medical treatment and other resource use utilisation per patient was €48 301 in the Netherlands and €37 431 in Belgium. Majority of costs was related to the use of trastuzumab in both countries, which was 50% of the total costs in the Netherlands and 56% in Belgium respectively.Our study provides estimates of resource use and costs for HER-2-positive MBC in the Netherlands and Belgium. We noticed various differences in resource use patterns between both countries demonstrating caution is needed when transferring cost estimates between countries.
    European Journal of Cancer Care 12/2014; 24(3). DOI:10.1111/ecc.12266 · 1.76 Impact Factor
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    ABSTRACT: Patients with large abdominal aortic aneurysms (AAAs) are usually offered reparative treatment given the high mortality risk. There is uncertainty about how to treat juxtarenal AAAs (JRAAAs) or thoracoabdominal aortic aneurysms (TAAAs). Endovascular repair of an abdominal aortic aneurysm (EVAR) is often seen as safer and easier than open surgical repair (OSR). However, endovascular treatment of JRAAAs or TAAAs requires specially manufactured stent grafts, with openings to allow blood to reach branches of the aorta. Commissioners are receiving increasing requests for fenestrated EVAR (fEVAR) and branched EVAR (bEVAR), but it is unclear whether or not the extra cost of fEVAR or bEVAR is justified by advantages for patients. To assess the clinical effectiveness, safety and cost-effectiveness of fEVAR and bEVAR in comparison with conventional treatment (i.e. no surgery) or OSR for two populations: JRAAAs and TAAAs. Resources were searched from inception to October 2013, including MEDLINE (OvidSP), EMBASE (OvidSP) and the Cochrane Central Register of Controlled Trials (Wiley) and, additionally, for cost-effectiveness, NHS Economic Evaluation Database (NHS EED; Wiley) and EconLit (EBSCOhost). Conference abstracts were also searched. Studies were included based on an intervention of either fEVAR or bEVAR and a comparator of either OSR or no surgery. For clinical effectiveness, observational studies were excluded only if they were not comparative, i.e. explicitly selected on the basis of prognosis. For clinical effectiveness, searches retrieved 5253 records before deduplication. Owing to overlap between the databases, 1985 duplicate records were removed. Of the remaining 3268 records, based on titles and abstracts, 3244 records were excluded, leaving 24 publications to be ordered. All 24 studies were excluded as none of them satisfied the inclusion criteria. Sixteen studies were excluded on study design, six on intervention and two on comparator. Five out of 16 studies excluded on study design reported a comparison. However, all of the studies acknowledged that they had groups that were not comparable at baseline given that they had selectively assigned younger, fitter patients to OSR. Therefore, these studies were considered 'non-comparative'. For cost-effectiveness, searches identified 104 references before deduplication. Owing to overlap between the databases, 34 duplicate records were removed. Of the remaining 70 records, seven were included for the full assessment based on initial screening. After a full-text review, no studies were included. Because of the lack of clinical effectiveness evidence and difficulty in estimating costs given the rapidly changing and variable technology, a cost-effectiveness analysis (CEA) was not performed. Instead a detailed description of modelling methods was provided. Despite a thorough search, no studies could be found that met the inclusion criteria. All studies that compared either fEVAR or bEVAR with either OSR or no surgery explicitly selected patients based on prognosis, i.e. essentially the populations for each comparator were not the same. Despite not being able to conduct a CEA, we have provided detailed methods for the conduct if data becomes available. We recommend at least one clinical trial to provide an unbiased estimate of effect for fEVAR/bEVAR compared with OSR or no surgery. This trial should also collect data for a CEA. This study is registered as PROSPERO CRD42013006051. The National Institute for Health Research Health Technology Assessment programme.
    Health technology assessment (Winchester, England) 12/2014; 18(70):1-66. DOI:10.3310/hta18700 · 5.12 Impact Factor
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    Saskia Knies, Annelies Boonen, Johan L Severens
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    ABSTRACT: The question of how to value lost productivity in economic evaluations has been subject of debate in the past twenty years. According to the Washington panel, lost productivity influences health-related quality of life and should thus be considered a health effect instead of a cost to avoid double counting. Current empirical evidence on the inclusion of income loss when valuing health states is not decisive. We examined the relationship between three aspects of lost productivity (work-status, absenteeism and presenteeism) and patient or social valuation of health-related quality of life (HRQoL). Cross-sectional survey data were collected from a total of 830 respondents with a rheumatic disorder from four West-European countries. Health-related quality of life was expressed in either the European societal utility using EQ-5D-3L or the patient valuation using EQ-VAS. The impact of work-status (four categories), absenteeism (absent from paid work during the past three months), and presenteeism (QQ method) on EQ-5D utilities and VAS scores was examined in linear regression analyses taking into account demographic characteristics and disease severity (duration, pain and restriction). The relationship between work-status, absenteeism or presenteeism and HRQoL was stronger for patient valuation than societal valuation. Compared to work-status and presenteeism the relationship between absenteeism and HRQoL was even less explicit. However, results for all measures of lost productivity are only marginally significant and negligible compared to the influence of disease-related restrictions. This survey study in patients with a rheumatic disorder in four European countries, does not fully support the Washington panel's claim that lost productivity is a significantly related with HRQoL, and this is even more apparent for absenteeism than for work-status and presenteeism. For West-European countries, there is no reason, to include absenteeism in the QALY. Findings need to be confirmed in other disease areas.
    Cost Effectiveness and Resource Allocation 11/2014; 12:24. DOI:10.1186/1478-7547-12-24 · 0.87 Impact Factor
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    ABSTRACT: Background In the absence of a gold standard, a panel of experts can be invited to assign a reference diagnosis for use in research. Available literature offers limited guidance on assembling and working with an expert panel for this purpose. We aimed to develop a protocol for an expert panel consensus diagnosis and evaluated its applicability in a pilot project.Methods An adjusted Delphi method was used, which started with the assessment of clinical vignettes by 3 experts individually, followed by a consensus discussion meeting to solve diagnostic discrepancies. A panel facilitator ensured that all experts were able to express their views, and encouraged the use of argumentation to arrive at a specific diagnosis, until consensus was reached by all experts. Eleven vignettes of patients suspected of having a primary neurodegenerative disease were presented to the experts. Clinical information was provided stepwise and included medical history, neurological, physical and cognitive function, brain MRI scan, and follow-up assessments over 2 years. After the consensus discussion meeting, the procedure was evaluated by the experts.ResultsThe average degree of consensus for the reference diagnosis increased from 52% after individual assessment of the vignettes to 94% after the consensus discussion meeting. Average confidence in the diagnosis after individual assessment was 85%. This did not increase after the consensus discussion meeting. The process evaluation led to several recommendations for improvement of the protocol.ConclusionA protocol for attaining a reference diagnosis based on expert panel consensus was shown feasible in research practice.
    BMC Neurology 10/2014; 14(1):190. DOI:10.1186/PREACCEPT-1702688938102976 · 2.49 Impact Factor
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    ABSTRACT: Bowel cancer is the third most common cancer in the UK. Most bowel cancers are initially treated with surgery, but around 17% spread to the liver. When this happens, sometimes the liver tumour can be treated surgically, or chemotherapy may be used to shrink the tumour to make surgery possible. Kirsten rat sarcoma viral oncogene (KRAS) mutations make some tumours less responsive to treatment with biological therapies such as cetuximab. There are a variety of tests available to detect these mutations. These vary in the specific mutations that they detect, the amount of mutation they detect, the amount of tumour cells needed, the time to give a result, the error rate and cost.
    Health technology assessment (Winchester, England) 10/2014; 18(62):1-132. DOI:10.3310/hta18620 · 5.12 Impact Factor
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    ABSTRACT: Backgroud The 2012 European guidelines recommend statins for intermediate-risk individuals with elevated cholesterol levels. Improved discrimination of intermediate-risk individuals is needed to prevent both cardiovascular disease (CVD) and statin side-effects (e.g. myopathy) efficiently since only 3-15 in every 100 individuals actually experience a cardiovascular event in the next 10 years. We estimated the potential cost-effectiveness of a hypothetical test which helps to determine which individuals will benefit from statins. Methods and Results Prognosis of different age- and gender-specific cohorts with an intermediate risk was simulated with a Markov model to estimate the potential costs and quality-adjusted life-years for four strategies: treat all with statins, treat none with statins, treat according to the European guidelines, or use a test to select individuals for statin treatment. The test-first strategy dominated the other strategies if the hypothetical test was 100% accurate and cost no more than €237. This strategy and the treat-all strategy were equally effective but the test generated lower costs by reducing statin usage and side-effects. The treat-none strategy was the least effective strategy. Threshold analyses show that the test must be highly accurate (especially sensitive) and inexpensive to be the most cost-effective strategy, since myopathy has a negligible impact on cost-effectiveness and statin costs are low. Conclusion Use of a highly accurate prognostic test could reduce overall CVD risk, frequency of drug side-effects and lifetime costs. However, no additional test would add usefully to risk prediction over SCORE when it does not satisfy the costs and accuracy requirements.
    International Journal of Cardiology 09/2014; 176(3). DOI:10.1016/j.ijcard.2014.08.134 · 6.18 Impact Factor
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    ABSTRACT: Aim: The objective of this study was to explore the cost–effectiveness of D-dimer biomarker and the societal value (headroom) of a hypothetical perfect biomarker for risk assessment and subsequent treatment stratification of prophylactic treatment for peripheral arterial disease (PAD). Patients & methods: Decision analytic modeling. Results: Use of the D-dimer biomarker to prescribe oral anticoagulants in the high-risk subset of patients is a cost-effective healthcare intervention. The headroom (societal willingness to pay multiplied by incremental quality-adjusted life years) available for the hypothetical perfect biomarker amounted to €83,877. Conclusion: D-dimer-based PAD risk assessment and treatment tailoring is cost effective. Identification of high-risk PAD patients and prescription of oral anticoagulants could potentially save substantial costs and improve chances of survival for high-risk PAD patients. However, further research of risk stratifying biomarkers test accuracy is needed to support and strengthen the results of this modeling study.
    Biomarkers in Medicine 08/2014; 8(8-8):989-999. DOI:10.2217/bmm.14.45 · 2.86 Impact Factor
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    ABSTRACT: Objective To use contingent valuation (CV) to derive individual consumer values for both health and broader benefits of a public-health intervention directed at lifestyle behaviour change (LBC) and to examine the feasibility and validity of the method.Method Participants of a lifestyle intervention trial (n = 515) were invited to complete an online CV survey. Respondents (n = 312) expressed willingness to invest money and time for changes in life expectancy, health-related quality of life (HRQOL) and broader quality of life aspects. Internal validity was tested for by exploring associations between explanatory variables (i.e. income, paid work, experience and risk factors for cardiovascular diseases) and willingness to invest, and by examining ordering effects and respondents' sensitivity to the scope of the benefits.ResultsThe majority of respondents (94.3%) attached value to benefits of LBC, and 87.4% were willing to invest both money and time. Respondents were willing to invest more for improvements in HRQOL (€42/month; 3 h/week) and broader quality of life aspects (€40/month; 2.6 h/week) than for improvements in life expectancy (€24/month; 2 h/week). Protest answers were limited (3%) and findings regarding internal validity were mixed.Conclusion The importance of broader quality of life outcomes to consumers suggests that these outcomes are relevant to be considered in the decision making. Our research showed that CV is a feasible method to value both health and broader outcomes of LBC, but generalizability to other areas of public health still needs to be examined. Mixed evidence regarding internal validity pleads for caution to use CV as only the base for decision making.
    Health expectations: an international journal of public participation in health care and health policy 08/2014; DOI:10.1111/hex.12195 · 2.85 Impact Factor
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    ABSTRACT: Objectives Many national colorectal cancer screening campaigns have a similar structure. First, individuals are invited to take a noninvasive screening test, and, second, in the case of a positive screening test result, they are advised to undergo a more invasive follow-up test. The objective of this study was to investigate how much individuals’ participation decision in noninvasive screening is affected by the presence or absence of detailed information about invasive follow-up testing and how this effect varies over screening tests. Methods We used a labeled discrete choice experiment of three noninvasive colorectal cancer screening types with two versions that did or did not present respondents with detailed information about the possible invasive follow-up test (i.e., colonoscopy) and its procedure. We used data from 631 Dutch respondents aged 55 to 75 years. Each respondent received only one of the two versions (N = 310 for the invasive follow-up test information specification version, and N = 321 for the no-information specification version). Results Mixed logit model results show that detailed information about the invasive follow-up test negatively affects screening participation decisions. This effect can be explained mainly by a decrease in choice shares for the most preferred screening test (a combined stool and blood sample test). Choice share simulations based on the discrete choice experiment indicated that presenting invasive follow-up test information decreases screening participation by 4.79%. Conclusions Detailed information about the invasive follow-up test has a negative effect on individuals’ screening participation decisions in noninvasive colorectal cancer screening campaigns. This result poses new challenges for policymakers who aim not only to increase uptake but also to provide full disclosure to potential screening participants.
    Value in Health 07/2014; 17(5). DOI:10.1016/j.jval.2014.04.007 · 2.89 Impact Factor
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    ABSTRACT: Management of rheumatoid arthritis (RA) is characterised by a sequence of disease-modifying antirheumatic drugs (DMARDs) and biological response modifiers (BRMs). In most of the Western countries, the drug sequences are determined based on disease activity and treatment history of the patients. A model for realistic patient outcomes should reflect the treatment pathways relevant for patients with specific characteristics.
    PharmacoEconomics 06/2014; DOI:10.1007/s40273-014-0184-4 · 3.34 Impact Factor
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    ABSTRACT: General recommendations for a reference case for economic studies in rheumatic diseases were published in 2002 in an initiative to improve the comparability of cost-effectiveness studies in the field. Since then, economic evaluations in osteoarthritis (OA) continue to show considerable heterogeneity in methodological approach.
    Seminars in Arthritis and Rheumatism 06/2014; 44(3). DOI:10.1016/j.semarthrit.2014.06.005 · 3.63 Impact Factor
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    ABSTRACT: Delayed diagnosis and treatment of Acute Myocardial Infarction (AMI) has a major adverse impact on prognosis in terms of both morbidity and mortality. Since conventional cardiac Troponin assays have a low sensitivity for diagnosing AMI in the first hours after myocardial necrosis, high-sensitive assays have been developed. The aim of this study was to assess the cost effectiveness of a high-sensitive Troponin T assay (hsTnT), alone or combined with the heart-type fatty acid-binding protein (H-FABP) assay in comparison with the conventional cardiac Troponin (cTnT) assay for the diagnosis of AMI in patients presenting to the hospital with chest pain.
    BMC Cardiovascular Disorders 06/2014; 14(1):77. DOI:10.1186/1471-2261-14-77 · 1.50 Impact Factor
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    ABSTRACT: Non-small cell lung cancer (NSCLC) is the most common form of lung cancer. Some epidermal growth factor receptor tyrosine kinase (EGFR-TK) mutations make tumours responsive to treatment with EGFR-TK inhibitors (EGFR-TKIs) but less responsive to treatment with standard chemotherapy. Patients with NSCLC are therefore tested for EGFR-TK tumour gene mutations to inform treatment decisions. There are a variety of tests available to detect these mutations. The different tests vary in the specific mutations that they attempt to detect, the amount of tumour cells needed for the test to work, the time that it takes to give a result, the error rate of the test, and the cost of the test. To compare the performance and cost-effectiveness of EGFR-TK mutation tests used to identify previously untreated adults with locally advanced or metastatic NSCLC, who may benefit from first-line treatment with TKIs. Twelve databases to August 2012 [including MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations and Daily Update (OvidSP), EMBASE, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment database (HTA), Science Citation Index (SCI), Latin American and Caribbean Health Sciences Literature (LILACS), BIOSIS Previews, NIHR Health Technology Assessment programme, PROSPERO (International Prospective Register of Systematic Reviews)], research registers and conference proceedings. A web-based survey gathered data on technical performance of EGFR-TK mutation tests. Randomised controlled trials were assessed for methodological quality using the Cochrane risk of bias tool. Diagnostic accuracy studies were assessed using QUADAS-2. There were insufficient data for meta-analysis. For accuracy studies, we calculated sensitivity and specificity together with 95% confidence intervals (CIs). Survival data were summarised as hazard ratios and tumour response data as relative risks, with 95% CIs. The health-economic analysis considered the long-term costs and quality-adjusted life-years (QALYs) associated with different tests followed by treatment with either standard chemotherapy or a TKI. Direct sequencing was taken as the comparator. The de novo model consisted of a decision tree and a Markov model. The survey indicated no differences between tests in batch size, turnaround time, number of failed samples or cost. Six studies provided data on the accuracy of EGFR-TK mutation testing for predicting response to treatment with TKIs. Estimates of accuracy were similar across studies. Six analyses provided data on the clinical effectiveness of TKIs compared with standard chemotherapy. There were no clear differences in the treatment effects reported by different studies, regardless of which EGFR mutation test was used to select patients. Cost-effectiveness analysis using 'Evidence on comparative effectiveness available' and 'Linked evidence' approaches: Therascreen(®) EGFR polymerase chain reaction (PCR) Kit (Qiagen, Venlo, the Netherlands) was both less effective and less costly than direct sequencing of all exon 19-21 mutations at an incremental cost-effectiveness ratio of £32,167 (comparative) and £32,190 (linked) per QALY lost. 'Assumption of equal prognostic value' approach: the lowest total strategy cost was [commercial-in-confidence (CiC) information has been removed] [Sanger sequencing or Roche cobas EGFR Mutation Testing Kit(®) (Roche Molecular Systems, Inc., Branchburg, NJ, USA)] compared with (CiC information has been removed) for the most expensive strategy (fragment length analysis combined with pyrosequencing). The cost-effectiveness analysis assumed that the differences in outcomes between the results of the trials were solely attributable to the different mutation tests used to distinguish between patients; this assumption ignores other factors that might explain this variation. There was no strong evidence that any one EGFR mutation test had greater accuracy than any other test. Re-testing of stored samples from previous studies, where patient outcomes are already known, could be used to provide information on the relative effectiveness of TKIs and standard chemotherapy in patients with EGFR mutation-positive and mutation-negative tumours, where mutation status is determined using tests for which adequate data are currently unavailable. PROSPERO CRD42012002828. The National Institute for Health Research Health Technology Assessment programme.
    05/2014; 18(32):1-166. DOI:10.3310/hta18320
  • Laura T Burgers, William K Redekop, Johan L Severens
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    ABSTRACT: Decision analytic modelling is essential in performing cost-effectiveness analyses (CEAs) of interventions in cardiovascular disease (CVD). However, modelling inherently poses challenges that need to be dealt with since models always represent a simplification of reality. The aim of this study was to identify and explore the challenges in modelling CVD interventions. A document analysis was performed of 40 model-based CEAs of CVD interventions published in high-impact journals. We analysed the systematically selected papers to identify challenges per type of intervention (test, non-drug, drug, disease management programme, and public health intervention), and a questionnaire was sent to the corresponding authors to obtain a more thorough overview. Ideas for possible solutions for the challenges were based on the papers, responses, modelling guidelines, and other sources. The systematic literature search identified 1,720 potentially relevant articles. Forty authors were identified after screening the most recent 294 papers. Besides the challenge of lack of data, the challenges encountered in the review suggest that it was difficult to obtain a sufficiently valid and accurate cost-effectiveness estimate, mainly due to lack of data or extrapolating from intermediate outcomes. Despite the low response rate of the questionnaire, it confirmed our results. This combination of a review and a survey showed examples of CVD modelling challenges found in studies published in high-impact journals. Modelling guidelines do not provide sufficient guidance in resolving all challenges. Some of the reported challenges are specific to the type of intervention and disease, while some are independent of intervention and disease.
    PharmacoEconomics 04/2014; 32(7). DOI:10.1007/s40273-014-0155-9 · 3.34 Impact Factor

Publication Stats

4k Citations
1,056.20 Total Impact Points


  • 2010–2015
    • Erasmus Universiteit Rotterdam
      • Institute of Health Policy & Management (iBMG)
      Rotterdam, South Holland, Netherlands
  • 2013
    • Utrecht University
      • Department of Pharmaceutical Sciences
      Utrecht, Utrecht, Netherlands
  • 2002–2013
    • Maastricht University
      • • CAPHRI School for Public Health and Primary Care
      • • Faculty of Health, Medicine and Life Sciences
      Maestricht, Limburg, Netherlands
  • 2005–2011
    • Maastricht Universitair Medisch Centrum
      • Central Diagnostic Laboratory
      Maestricht, Limburg, Netherlands
  • 2009
    • University of Leipzig
      Leipzig, Saxony, Germany
  • 2008
    • Maastro Clinic
      Maestricht, Limburg, Netherlands
  • 2007
    • University of Zurich
      Zürich, Zurich, Switzerland
    • Bronovo Hospital
      's-Gravenhage, South Holland, Netherlands
  • 1997–2004
    • Radboud University Nijmegen
      • Department of Gastroenterology and Hepatology
      Nymegen, Gelderland, Netherlands
  • 2000–2003
    • Radboud University Medical Centre (Radboudumc)
      • Department of Human Genetics
      Nymegen, Gelderland, Netherlands