3,916 research outputs found
Economic evaluation of minimal access surgery: The case of surgical treatment for menorrhagia
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The purpose of this thesis is to explore the methodological and empirical issues relating to the economic evaluation of minimal access surgery (MAS). Given the likely increase in the utilisation of economic analysis in this area, it is crucial to explore whether the methods of economic evaluation have limitations in the face of the particular characteristics of MAS. The comparison of abdominal hysterectomy
(AH) and transcervical endometrial resection (TCRE), for the treatment of menorrhagia, is used as a vehicle to develop methods in relation to MAS. Having reviewed the literature and issues relating to the economic analysis of this group of technologies, the empirical starting point of the thesis is the assessment of the limitations of economic evaluations alongside clinical trials, using a trial comparing AH and TCRE. Three major areas of weakness are identified, and alternative ways of addressing these weaknesses are explored in the remainder of the thesis. The first area of methodological development relates to the measure of benefit used in economic evaluation of MAS. In this clinical context, it is argued that the trade-offs that exist between MAS and conventional surgery, in terms of process characteristics and outcomes, should result in an important role for patients' preferences in the construction of a benefit measure. A cost-utility analysis using the standard quality-adjusted life year (GALY) is undertaken, using trial data augmented with valuation data from a further study. The lack of consistency between individual preferences and standard QALYs suggests a major weakness with this measure of benefit. The strengths and weaknesses of an alternative measure of benefit in cost-utility analysis - the ex ante healthy years equivalent (HYE) - are assessed based on a further valuation study. It is shown that it is feasible to elicit ex ante HYEs from patients and that this measure of benefit exhibits some consistency with other expressions of patients' preferences. However, the HYE is likely to impose a greater measurement burden than the standard QALY. The second area of methodological development in the thesis is the analysis of the generalisability of trial-based economic evaluation, given the limitations that often exist with the external validity of trials. A framework is
developed within which trial and observational data can be synthesised. This facilitates the use of sensitivity analysis to explore the robustness of base-case
(trial-generated) results to alternative sources of data, which may be more representative of routine practice. The third area of methodological development
stems from the importance of patients' preferences in relation to MAS. This element relates to the use of methods to model and to evaluate management strategies which use patients' preferences to determine treatment allocation. It is concluded that preference-based decision making has the potential to be cost effective in relation to TCRE and AH, and MAS applications more generally. The thesis demonstrates the importance of continued development in the detailed methods of economic evaluation.Funding was obtained from the Department of Healt
Mark versus Luke? Appropriate Methods for the Evaluation of Public Health Interventions
No full textThe purpose of this paper is to demonstrate that a social decision making approach to evaluation can be generalised to interventions such as public health and national policies which have multiple objectives and impact on multiple constraints within and beyond the health sector. We demonstrate that a mathematical programming solution to this problem is possible, but the information requirements make it impractical. Instead we propose a simple compensation test for interventions with multiple and cross-sectoral effects. However, rather than compensation based on individual preferences, it can be based on the net benefits falling on different sectors. The valuation of outcomes is based on the shadow prices of the existing budget constraints, which are implicit in existing public expenditure and its allocation across different sectors. A ‘welfarist’ societal perspective is not sufficient; rather, a multiple perspective evaluation which accounts for costs and effects falling on each sector is required.cost-effectiveness analysis, decision rules, public health
Changing case order to optimise patterns of performance in mammography screening (CO-OPS) : study protocol for a randomized controlled trial
No full textBackground: X-ray mammography remains the predominant test for screening for breast cancer, with the aim of reducing breast cancer mortality. In the English NHS Breast Screening Programme each woman’s mammograms are examined separately by two expert readers. The two readers read each batch in the same order and each indicates if there should be recall for further tests. This is a highly skilled, pressurised, repetitive and frequently intellectually unchallenging activity where readers examine one or more batches of 30–50 women’s mammograms in each session. A vigilance decrement or performance decrease over time has been observed in similar repetitive visual tasks such as radar operation.
Methods/Design: The CO-OPS study is a pragmatic, multi-centre, two-arm, double blind cluster randomised controlled trial of a computer software intervention designed to reduce the effects of a vigilance decrement in breast cancer screening. The unit of randomisation is the batch. Intervention batches will be examined in the opposite order by the two readers (one forwards, one backwards). Control batches will be read in the same order as one another, as is current standard practice. The hypothesis is that cancer detection rates will be higher in the intervention group because each readers’ peak performance will occur when examining different women’s mammograms. The trial will take place in 44 English breast screening centres for 1 year and 4 months. The primary outcome is cancer detection rate, which will be extracted from computer records after 1 year of the trial. The secondary outcomes include rate of disagreement between readers (a more statistically powerful surrogate for cancer detection rate), recall rate, positive predictive value, and interval cancer rate (cancers found between screening rounds which will be measured three years after the end of the trial).
Discussion: This is the first trial of an intervention to ameliorate a vigilance decrement in breast cancer screening
The value of implementation and the value of information: combined and uneven development
No full textIn a budget constrained healthcare system the decision to invest in strategies to improve the implementation of cost-effective technologies must be made alongside decisions regarding investment in the technologies themselves and investment in further research. This paper presents a single, unified framework that simultaneously addresses the problem of allocating funds between these separate but linked activities. The framework presents a simple 4 state world where both information and implementation can be either at the current level or ‘perfect’. Through this framework it is possible to determine the maximum return to further research and an upper bound on the value of adopting implementation strategies. The framework is illustrated through case studies of health care technologies selected from those previously considered by the UK National Institute for Health and Clinical Excellence (NICE). Through the case studies, several key factors that influence the expected values of perfect information and perfect implementation are identified. These factors include the maximum acceptable cost-effectiveness ratio, the level of uncertainty surrounding the adoption decision, the expected net benefits associated with the technologies, the current level of implementation and the size of the eligible population. Previous methods for valuing implementation strategies have confused the value of research and the value of implementation. This framework demonstrates that the value of information and the value of implementation can be examined separately but simultaneously in a single framework. This can usefully inform policy decisions about investment in healthcare services, further research and adopting implementation strategies which are likely to differ between technologies.Value of information analysis; value of implementation; healthcare decisionmaking, Bayesian analysis
Bridging the gap between methods research and the needs of policy makers: A review of the research priorities of the National Institute for Health and Clinical Excellence
No full textObjectives: The aim of this study was to establish a list of priority topics for methods research to support decision making at the National Institute for Health and Clinical Excellence (NICE).
Methods: Potential priorities for methods research topics were identified through a focused literature review, interviews, an email survey, a workshop and a Web-based feedback exercise. Participants were members of the NICE secretariat and its advisory bodies, representatives from academia, industry, and other organizations working closely with NICE. The Web exercise was open to anyone to complete but publicized among the above groups.
Results: A list of potential topics was collated. Priorities for further research differed according to the type of respondent and the extent to which they work directly with NICE. Priorities emerging from the group closest to NICE included: methodology for indirect and mixed treatment comparisons; synthesis of qualitative evidence; research relating to the use of quality-adjusted life-years (QALYs) in decision making; methods and empirical research for establishing the cost-effectiveness threshold; and determining how data on the uncertainty of effectiveness and cost-effectiveness data should be taken into account in the decision-making process. Priorities emerging from the broadest group of respondents (through the Web exercise) included: methods for extrapolating beyond evidence observed in trials, methods for capturing benefits not included in the QALY and methods to assess when technologies should be recommended in the context of further evidence gathering.
Conclusions: Consideration needs to be given to the needs of those who use the outputs of research for decision making when determining priorities for future methods research.NIHR Medical Research Council
The cost-effectiveness of an early interventional strategy in non-ST-elevation acute coronary syndrome based on the RITA 3 trial
No full textThe published version of the aritcle can be found at the link below.Background: Evidence suggests that an early interventional strategy for patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) can improve health outcomes but also increase costs when compared with a conservative strategy.Objective: The aim of this study was to assess the cost-effectiveness of an early interventional strategy in different risk groups from a UK health-service perspective.Design: Decision-analytic model based on randomised clinical trial data.Main outcome measures: Costs in UK Sterling at 2003/2004 prices and quality-adjusted life years (QALYs) combined into an incremental cost-effectiveness ratio.Methods: Data from the third Randomised Intervention Trial of unstable Angina (RITA 3) was employed to estimate rates of cardiovascular death and myocardial infarction, costs and health-related quality of life. Cost-effectiveness was estimated over patients' lifetimes within the decision-analytic model.Results: The mean incremental cost per QALY gained for an early interventional strategy was approximately £55000, £22000 and £12000 for patients at low, intermediate and high risk, respectively. The early interventional strategy is approximately 1%, 35% and 95% likely to be cost-effective for patients at low, intermediate and high risk, respectively, at a threshold of £20000 per QALY. The cost-effectiveness of early intervention in low-risk patients is sensitive to assumptions about the duration of the treatment effect.Conclusion: An early interventional strategy in patients presenting with NSTE-ACS is likely to be considered cost-effective for patients at high and intermediate risk, but this is less likely to be the case for patients at low risk
A cost-utility analysis of a rehabilitation service for people living with and beyond cancer.
No full textBACKGROUND: We conducted a wait-list control randomised trial of an outpatient rehabilitation service for people living with and beyond cancer, delivered in a hospice day care unit. We report the results of an economic evaluation undertaken using the trial data. METHODS: Forty-one participants were recruited into the study. A within-trial stochastic cost-utility analysis was undertaken using Monte-Carlo simulation. The outcome measure for the economic evaluation was quality adjusted life years (QALYs). Costs were measured from the perspective of the NHS and personal social services. Uncertainty in the observed data was captured through probabilistic sensitivity analysis. Scenario analysis was conducted to explore the effects of changing the way QALYs were estimated and adjusting for baseline difference in the population. We also explore assumptions about the length of treatment benefit being maintained. RESULTS: The incremental cost-effectiveness ratio (ICER) for the base-case analysis was £14,231 per QALY. When QALYs were assumed to change linearly over time, this increased to £20,514 per QALY at three months. Adjusting the estimate of QALYs to account for differences in the population at baseline increased the ICER to £94,748 per QALY at three months. Increasing the assumed length of treatment benefit led to reduced ICERs in all scenarios. CONCLUSIONS: Although the intervention is likely to be cost-effective in some circumstances, there is considerable uncertainty surrounding the decision to implement the service. Further research, informed by a formal value of information analysis, would reduce this uncertainty
Self-compression of 4.9 µm pulses to sub-40 fs with 2 mJ energy in Zinc Sulfide
No full textNonlinear self-compression of few-cycle multi-mJ pulses at 4.9 µm in ZnS is presented. 80 fs input pulses are compressed to 37 fs with 2.1 mJ energy at a 1 kHz repetition rate. © 2024 The Author(s
Defining and characterising structural uncertainty in decision analytic models
No full textAn inappropriate structure for a decision analytic model can potentially invalidate estimates of cost-effectiveness and estimates of the value of further research. However, there are often a number of alternative and credible structural assumptions which can be made. Although it is common practice to acknowledge potential limitations in model structure, there is a lack of clarity about methods to characterize the uncertainty surrounding alternative structural assumptions and their contribution to decision uncertainty. A review of decision models commissioned by the NHS Health Technology Programme was undertaken to identify the types of model uncertainties described in the literature. A second review was undertaken to identify approaches to characterise these uncertainties. The assessment of structural uncertainty has received little attention in the health economics literature. A common method to characterise structural uncertainty is to compute results for each alternative model specification, and to present alternative results as scenario analyses. It is then left to decision maker to assess the credibility of the alternative structures in interpreting the range of results. The review of methods to explicitly characterise structural uncertainty identified two methods: 1) model averaging, where alternative models, with different specifications, are built, and their results averaged, using explicit prior distributions often based on expert opinion and 2) Model selection on the basis of prediction performance or goodness of fit. For a number of reasons these methods are neither appropriate nor desirable methods to characterize structural uncertainty in decision analytic models. When faced with a choice between multiple models, another method can be employed which allows structural uncertainty to be explicitly considered and does not ignore potentially relevant model structures. Uncertainty can be directly characterised (or parameterised) in the model itself. This method is analogous to model averaging on individual or sets of model inputs, but also allows the value of information associated with structural uncertainties to be resolved.
Palliative radiotherapy in addition to self-expanding metal stent for improving dysphagia and survival in advanced oesophageal cancer (ROCS: Radiotherapy after Oesophageal Cancer Stenting):study protocol for a randomized controlled trial
No full textBackgroundThe single most distressing symptom for patients with advanced esophageal cancer is dysphagia. Amongst the more effective treatments for relief of dysphagia is insertion of a self-expanding metal stent (SEMS). It is possible that the addition of a palliative dose of external beam radiotherapy may prolong the relief of dysphagia and provide additional survival benefit. The ROCS trial will assess the effect of adding palliative radiotherapy after esophageal stent insertion.Methods/DesignThe study is a randomized multicenter phase III trial, with an internal pilot phase, comparing stent alone versus stent plus palliative radiotherapy in patients with incurable esophageal cancer. Eligible participants are those with advanced esophageal cancer who are in need of stent insertion for primary management of dysphagia. Radiotherapy will be administered as 20 Gray (Gy) in five fractions over one week or 30 Gy in 10 fractions over two weeks, within four weeks of stent insertion. The internal pilot will assess rates and methods of recruitment; pre-agreed criteria will determine progression to the main trial. In total, 496 patients will be randomized in a 1:1 ratio with follow up until death. The primary outcome is time to progression of patient-reported dysphagia. Secondary outcomes include survival, toxicity, health resource utilization, and quality of life. An embedded qualitative study will explore the feasibility of patient recruitment by examining patients’ motivations for involvement and their experiences of consent and recruitment, including reasons for not consenting. It will also explore patients’ experiences of each trial arm.DiscussionThe ROCS study will be a challenging trial studying palliation in patients with a poor prognosis. The internal pilot design will optimize methods for recruitment and data collection to ensure that the main trial is completed on time. As a pragmatic trial, study strengths include collection of all follow-up data in the usual place of care, and a focus on patient-reported, rather than disease-orientated, outcomes. Exploration of patient experience and health economic analyses will be integral to the assessment of benefit for patients and the NHS
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