Martin Buxton

Modelling in Ecomomic Evaluation: An Unavoidable Fact of Life

The role of modelling in economic evaluation is explored by discussing, with examples, the uses of models. The expanded use of pragmatic clinical trials as an alternative to models is discussed. Some suggestions for good modelling practice are made.

Transmyocardial laser revascularisation in patients with refractory angina: a randomised controlled trial

BACKGROUND Transmyocardial laser revascularisation (TMLR) is used to treat patients with refractory angina due to severe coronary artery disease, not suitable for conventional revascularisation. We aimed in a randomised controlled trial to assess the effectiveness of TMLR compared with medical management. METHODS 188 patients with refractory angina were randomly assigned TMLR plus normal medication or medical management alone. At 3 months, 6 months, and 12 months after surgery (TMLR) or initial assessment (medical management) we assessed exercise capacity with the treadmill test and the 12 min walk. FINDINGS Mean treadmill exercise time, adjusted for baseline values, was 40 s (95% CI -15 to 94) longer in the TMLR group than in the medical-management group at 12 months (p=0.152). Mean 12 min walk distance was 33 m (-7 to 74) further in TMLR patients than medical-management patients (p=0.108) at 12 months. The differences were not significant or clinically important. Perioperative mortality was 5%. Survival at 12 months was 89% (83-96) in the TMLR group and 96% (92-100) in the medical-management group (p=0.14). Canadian Cardiovascular Society score for angina had decreased by at least two classes in 25% of TMLR and 4% of medical-management patients at 12 months (p<0.001). INTERPRETATION Our findings show that the adoption of TMLR cannot be advocated. Further research may be appropriate to assess any potential benefit for sicker patients.

Long-term results of RITA-1 trial: clinical and cost comparisons of coronary angioplasty and coronary-artery bypass grafting

Summary Background Percutaneous transluminal coronary angioplasty (PTCA) and coronary-artery bypass grafting (CABG) are both effective intervention strategies for patients with coronary heart disease. We report comparative long-term clinical and health-service cost findings for these interventions in the first Randomised Intervention Treatment of Angina (RITA-1) trial. Methods 1011 patients with coronary heart disease (45% single-vessel, 55% multivessel) were randomly assigned initial treatment strategies of PTCA or CABG. Information on clinical events, subsequent intervention, symptomatic status, exercise testing, and use of health-care resources is available for a median 6·5 years of follow-up. Analyses were by intention to treat. Findings The predefined primary endpoint of death or nonfatal myocardial infarction occurred in 87 (17%) PTCA-group patients and 80 (16%) CABG-group patients (p=0·64). Similarly, there was no significant treatment difference in deaths alone (39 PTCA, 45 CABG), of which 46% were cardiac related. In both groups, the risk of cardiac death or myocardial infarction was more than five times higher in the first year than in subsequent years of follow-up. 26% of patients assigned PTCA subsequently also had CABG, and a further 19% required additional nonrandomised PTCA. Most of these reinterventions occurred within a year of randomisation, and from 3 years onwards the reintervention rate averaged 4% per year. In the CABG group the reintervention rate averaged 2% per year. The prevalence of angina was consistently higher in the PTCA group, with an absolute average 10% excess compared with the CABG group (p Interpretation Initial strategies of PTCA and CABG led to similar long-term results in terms of survival and avoidance of myocardial infarction and to similar long-term healthcare costs. Choice of approach, therefore, rests on weighing the more invasive nature of CABG against the greater risk of recurrent angina and reintervention over many years after PTCA.

How Can Payback from Health Services Research Be Assessed

Throughout the world there is a growing recognition that health care should be research-led. This strengthens the requirement for expenditure on health services research to be justified by demonstrating the benefits it produces. However, payback from health research and development is a complex concept and little used term. Five main categories of payback can be identified: Knowledge; research benefits; political and administrative benefits; health sector benefits; and broader economic benefits. Various models of research utilization together with previous assessments of payback from research helped in the development of a new conceptual model of how and where payback may occur. The model combines an input-output perspective with an examination of the permeable interfaces between research and its environment. The model characterizes research projects in terms of Inputs, Processes, and Primary Outputs. The last consist of knowledge and research benefits. There are two interfaces between the project and its environment. The first (Project Specification, Selection and Commissioning) is the link with Research Needs Assessment. The second (Dissemination) should lead to Secondary Outputs (which are policy or administrative decisions), and usually Applications (which take the form of behavioural changes), from which Impacts or Final Outcomes result. It is at this final stage that health and wider economic benefits can be measured. A series of case studies were used to assess the feasibility both of applying the model and the payback categorization. The paper draws various conclusions from the case studies and identifies a range of issues for further work.

A review of health utilities using the EQ-5D in studies of cardiovascular disease

BackgroundThe EQ-5D has been extensively used to assess patient utility in trials of new treatments within the cardiovascular field. The aims of this study were to review evidence of the validity and reliability of the EQ-5D, and to summarise utility scores based on the use of the EQ-5D in clinical trials and in studies of patients with cardiovascular disease.MethodsA structured literature search was conducted using keywords related to cardiovascular disease and EQ-5D. Original research studies of patients with cardiovascular disease that reported EQ-5D results and its measurement properties were included.ResultsOf 147 identified papers, 66 met the selection criteria, with 10 studies reporting evidence on validity or reliability and 60 reporting EQ-5D responses (VAS or self-classification). Mean EQ-5D index-based scores ranged from 0.24 (SD 0.39) to 0.90 (SD 0.16), while VAS scores ranged from 37 (SD 21) to 89 (no SD reported). Stratification of EQ-5D index scores by disease severity revealed that scores decreased from a mean of 0.78 (SD 0.18) to 0.51 (SD 0.21) for mild to severe disease in heart failure patients and from 0.80 (SD 0.05) to 0.45 (SD 0.22) for mild to severe disease in angina patients.ConclusionsThe published evidence generally supports the validity and reliability of the EQ-5D as an outcome measure within the cardiovascular area. This review provides utility estimates across a range of cardiovascular subgroups and treatments that may be useful for future modelling of utilities and QALYs in economic evaluations within the cardiovascular area.

Value based pricing for NHS drugs: an opportunity not to be missed?

The policy debate about price, value, and innovation in pharmaceuticals is at a critical stage for the NHS. Claxton and colleagues describe the key principles of value based pricing and consider some of the concerns about such a scheme

The iterative use of economic evaluation as part of the process of health technology assessment.

The Economic evaluation of health care technologies has a key role within the new National Health Service health technology assessment process. There has, however, been little discussion of the best way of combining economic and clinical research. Economic evaluation should be iterative, generating progressively firmer estimates of cost-effectiveness and helping to maximise the efficiency of health care R&D. Here, four stages of economic analysis are suggested, starting with stage I when the basic clinical science is complete, and finishing with stage IV analysis to generalise the results of earlier studies to routine clinical practice.

Cost effectiveness of clinically appropriate decisions on alternative treatments for angina pectoris: prospective observational study

Objective To assess whether revascularisation that is considered to be clinically appropriate is also cost effective. Design Prospective observational study comparing cost effectiveness of coronary artery bypass grafting, percutaneous coronary intervention, or medical management within groups of patients rated as appropriate for revascularisation. Setting Three tertiary care centres in London. Participants Consecutive, unselected patients rated as clinically appropriate (using a nine member Delphi panel) to receive coronary artery bypass grafting only (n=815); percutaneous coronary intervention only (n=385); or both revascularisation procedures (n=520). Main outcome measure Cost per quality adjusted life year gained over six year follow-up, calculated with a National Health Service cost perspective and discounted at 3.5%/year. Results Coronary artery bypass grafting cost �22 000 (€33 000;

Measuring the effectiveness of heart transplant programmes: quality of life data and their relationship to survival analysis.

43 000) per quality adjusted life year gained compared with percutaneous coronary intervention among patients appropriate for coronary artery bypass grafting only (59% probability of being cost effective at a cost effectiveness threshold of �30 000 per quality adjusted life year) and �19 000 per quality adjusted life year gained compared with medical management among those appropriate for both types of revascularisation (probability of being cost effective 63%). In none of the three appropriateness groups was percutaneous coronary intervention cost effective at a threshold of �30 000 per quality adjusted life year. Among patients rated appropriate for percutaneous coronary intervention only, the cost per quality adjusted life year gained for percutaneous coronary intervention compared with medical management was �47 000, exceeding usual cost effectiveness thresholds; in these patients, medical management was most likely to be cost effective (probability 54%). Conclusions Among patients judged clinically appropriate for coronary revascularisation, coronary artery bypass grafting seemed cost effective but percutaneous coronary intervention did not. Cost effectiveness analysis based on observational data suggests that the clinical benefit of percutaneous coronary intervention may not be sufficient to justify its cost.

Proposed methods for reviewing the outcomes of health research: the impact of funding by the UK's 'Arthritis Research Campaign'

This paper explores the problems of benefit measurement in the economic evaluation of heart transplant programmes. We present data from our evaluation of the U.K. heart transplant programmes on both survival and quality of life and we examine the relationship between the two. The quality of life measure used, the Nottingham Health Profile (NHP), is described and results presented. We attempt to aggregate this profile measure into a single index score and combine these data with life expectancy gains to produce estimates of Quality Adjusted Life Years (QALYs) gained for heart transplantation. In addition we examine the extent to which pre-transplant NHP scores can be used as predictors of post-transplant survival.