Identification of Evidence for Key Parameters in Decision-Analytic Models of Cost-Effectiveness : A Description of Sources and a Recommended Minimum Search Requirement

This paper proposes recommendations for a minimum level of searching for data for key parameters in decision-analytic models of cost effectiveness and describes sources of evidence relevant to each parameter type. Key parameters are defined as treatment effects, adverse effects, costs, resource use, health state utility values (HSUVs) and baseline risk of events. The recommended minimum requirement for treatment effects is comprehensive searching according to available methodological guidance. For other parameter types, the minimum is the searching of one bibliographic database plus, where appropriate, specialist sources and non-research-based and non-standard format sources. The recommendations draw on the search methods literature and on existing analyses of how evidence is used to support decision-analytic models. They take account of the range of research and non-research-based sources of evidence used in cost-effectiveness models and of the need for efficient searching. Consideration is given to what constitutes best evidence for the different parameter types in terms of design and scientific quality and to making transparent the judgments that underpin the selection of evidence from the options available. Methodological issues are discussed, including the differences between decision-analytic models of cost effectiveness and systematic reviews when searching and selecting evidence and comprehensive versus sufficient searching. Areas are highlighted where further methodological research is required

Economics of tandem mass spectrometry screening of neonatal inherited disorders

Objectives: The aim of this study was to evaluate the cost-effectiveness of neonatal screening for phenylketonuria (PKU) and medium-chain acyl-coA dehydrogenase (MCAD) deficiency using tandem mass spectrometry (tandem MS). Methods: A systematic review of clinical efficacy evidence and cost-effectiveness modeling of screening in newborn infants within a UK National Health Service perspective was performed. Marginal costs, life-years gained, and cost-effectiveness acceptability curves are presented. Results: Substituting the use of tandem MS for existing technologies for the screening of PKU increases costs with no increase in health outcomes. However, the addition of screening for MCAD deficiency as part of a neonatal screening program for PKU using tandem MS, with an operational range of 50,000 to 60,000 specimens per system per year, would result in a mean incremental cost of −£17,298 (−£129,174, £66,434) for each cohort of 100,000 neonates screened. This cost saving is associated with a mean incremental gain of 57.3 (28.0, 91.4) life-years. Conclusions: Cost-effectiveness analysis using economic modeling indicates that substituting the use of tandem MS for existing technologies for the screening of PKU alone is not economically justified. However, the addition of screening for MCAD deficiency as part of a neonatal screening program for PKU using tandem MS would be economically attractive

Ultrasonic locating devices for central venous cannulation: meta-analysis

OBJECTIVES: To assess the evidence for the clinical effectiveness of ultrasound guided central venous cannulation. DATA SOURCES: 15 electronic bibliographic databases, covering biomedical, science, social science, health economics, and grey literature. DESIGN: Systematic review and meta-analysis of randomised controlled trials. POPULATIONS: Patients scheduled for central venous access. INTERVENTION REVIEWED: Guidance using real time two dimensional ultrasonography or Doppler needles and probes compared with the anatomical landmark method of cannulation. DATA EXTRACTION: Risk of failed catheter placement (primary outcome), risk of complications from placement, risk of failure on first attempt at placement, number of attempts to successful catheterisation, and time (seconds) to successful catheterisation. DATA SYNTHESIS: 18 trials (1646 participants) were identified. Compared with the landmark method, real time two dimensional ultrasound guidance for cannulating the internal jugular vein in adults was associated with a significantly lower failure rate both overall (relative risk 0.14, 95% confidence interval 0.06 to 0.33) and on the first attempt (0.59, 0.39 to 0.88). Limited evidence favoured two dimensional ultrasound guidance for subclavian vein and femoral vein procedures in adults (0.14, 0.04 to 0.57 and 0.29, 0.07 to 1.21, respectively). Three studies in infants confirmed a higher success rate with two dimensional ultrasonography for internal jugular procedures (0.15, 0.03 to 0.64). Doppler guided cannulation of the internal jugular vein in adults was more successful than the landmark method (0.39, 0.17 to 0.92), but the landmark method was more successful for subclavian vein procedures (1.48, 1.03 to 2.14). No significant difference was found between these techniques for cannulation of the internal jugular vein in infants. An indirect comparison of relative risks suggested that two dimensional ultrasonography would be more successful than Doppler guidance for subclavian vein procedures in adults (0.09, 0.02 to 0.38). CONCLUSIONS: Evidence supports the use of two dimensional ultrasonography for central venous cannulation

Newborn screening using tandem mass spectrometry: A systematic review

Objectives: To evaluate the evidence for the clinical effectiveness of neonatal screening for phenylketonuria (PKU) and medium-chain acyl-coA dehydrogenase (MCAD) deficiency using tandem mass spectrometry (tandem MS). Study design: Systematic review of published research. Data sources: Studies were identified by searching 12 electronic bibliographic databases; conference proceedings and experts consulted. Results: Six studies were selected for inclusion in the review. The evidence of neonatal screening for PKU and MCAD deficiency using tandem MS was primarily from observational data of large-scale prospective newborn screening programmes and systematic screening studies from Australia, Germany and the USA. Tandem MS based newborn screening of dried blood spots for PKU and/or MCAD deficiency was shown to be highly sensitive (>93.220%) and highly specific (>99.971%). The false positive rate for PKU screening was less than 0.046% and for MCAD deficiency the false positive rate was less than 0.023%. The positive predictive values ranged from 20 to 32% and 19 to 100%, respectively. Conclusions: This review suggests that neonatal screening of dried blood spots using a single analytical technique (tandem MS) is highly sensitive and specific for detecting cases of PKU and MCAD deficiency, and provides a basis for modelling of the clinical benefits and potential costeffectiveness

Choice and judgement in developing models for health technology assessment; a qualitative study

Introduction: The role of models in supporting health policy decisions is reliant on model credibility. Credibility is fundamentally determined by the choices and judgements that people make in the process of developing a model. However, the method of uncovering choices and making judgements in model development is largely unreported and is not addressed by modelling methods guidance. Methods: This qualitative study was part of a project examining errors in health technology assessment models. In-depth interviews with academic and commercial modellers were used to obtain descriptions of the model development process. Data were analysed using framework analysis and interpreted in the context of the methodological literature. Results: The activities involved in developing models were characterised according to the themes; understanding the decision problem, conceptual modelling, model implementation, model checking, and engaging with the decision maker. Finding and using evidence was frequently mentioned across these themes. There was marked variation between practitioners in the extent to which conceptual modelling was recognised as an activity distinct from model implementation. Discussion: Methodological approaches to addressing model credibility described in the wider modelling literature highlight the necessity to disentangle the conceptual modelling and implementation activities. Whilst interviewees talked of judgements and choice making throughout model development, discussion indicated that these were based upon skills and experience with no discussion of formal approaches. Methods are required that provide for a systematic approach to uncovering choices, to generating a shared view of consensus and divergence, and for making judgements and choices in model development

How do individuals value health states? A qualitative investigation.

Despite the importance of health state values in informing resource allocation in health care, there is arguably little known about how individuals value health. Previous studies have shown that a variety of non-health factors and beliefs are important in valuing health, but there is less evidence in the literature about how individuals' beliefs affect their preferences or what role non-health factors play in the process of forming preferences. This study investigated the thought processes of 21 U.K. based participants in March 2013 who valued health states using semi-structured interviews and a think-aloud protocol, with the aim to better understand the relationship between health states, the individual's underlying beliefs, and the individual's preferences. Participants followed several stages in valuing health. First, participants interpreted the health states more concretely, relying on their imagination and their experience of ill health. Participants judged how the concrete health problems combined with their personal interests, circumstances, and environment would affect them personally. Ultimately, participants valued health by estimating and weighing the non-health consequences of the health states. Six consequences were most frequently mentioned: activities, enjoyment, independence, relationships, dignity, and avoiding being a burden. At each stage participants encountered difficulties and expressed concerns. The findings have implications for methods of describing health, for example, whether the focus should be on health or a broader notion of well-being and capability. This is because the consequences are similar to the domains of broader measures such as the ICECAP measures for adults and older people, and the Warwick-Edinburgh Mental Wellbeing Scale. The findings suggest the need for testing whether individuals are informed about the health states they are valuing. Participants valued health by estimating the non-health consequences of health states and these estimates relied on individuals' beliefs about the interaction of the health state and their personal and social circumstances

Can Carbon Find a Home on the Range?

Resource /Energy Economics and Policy,

Systematic review of the evidence on housing interventions for ‘housing-vulnerable’ adults and its relationship to wellbeing

Access to safe, good quality affordable housing is essential to wellbeing and housing related factors can have an important influence on neighbourliness and sense of community belonging. A recent scoping review on housing and wellbeing identified a lack of review-level evidence around the impact of housing interventions on wellbeing of people who are vulnerable to discrimination or exclusion in relation to housing (Preston et al., 2016). This systematic review was commissioned to address that gap. We synthesise and consider the quality of evidence on how housing interventions can contribute to improving the lives of adults who are vulnerable in relation to the security of their housing tenure (‘housing-vulnerable’ adults)