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Enhanced external counterpulsation for stable angina or heart failure: a systematic review and economic evaluation |
McKenna C, McDaid C, Suekarran S, Hawkins N, Claxton K, Light K, Chester M, Cleland J, Woolacott N, Sculpher M |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. CRD summary The objective was to determine the clinical effectiveness and cost-effectiveness of enhanced external counterpulsation, compared with usual care, for refractory stable angina. The authors concluded that its cost-effectiveness was difficult to determine without long-term randomised controlled trial evidence on the quality of life gained. Full details of the methods and results were provided and the methods were very good. There was a lack of available effectiveness data and the authors’ conservative conclusions are appropriate. Type of economic evaluation Study objective The objective was to determine the effectiveness and cost-effectiveness of enhanced external counterpulsation (EECP) compared with usual care for refractory stable angina. Interventions This study compared EECP with the usual care without EECP. The average course of EECP was 35 sessions that lasted for one hour and were given over seven weeks. Methods Analytical approach:A decision analytic Markov model was used to assess the costs and outcomes in patients with chronic stable angina. The time horizon was the lifetime of the patient. The authors reported that the perspective was that of the National Health Service (NHS) and Personal Social Services (PSS).
Effectiveness data:The main clinical effectiveness estimate was the improvement in quality of life after treatment. A systematic review of the literature was undertaken to obtain the measures of clinical effectiveness and this included searches of MEDLINE, EMBASE, and CINAHL. The review identified studies published between 1980 and March 2008 and there were no language and geographical restrictions. The inclusion and exclusion criteria were adequately reported; only randomised controlled trials (RCTs), cohort studies with contemporary control groups (not historic controls), and case-control studies were included. One RCT was identified and this measured quality of life over one year; opinion from five experts was sought for the probability of sustaining treatment benefits after the first year. The opinions of each expert were pooled to generate a distribution of values. Mortality associated with cardiovascular disease was derived from a trial and from Framingham risk equations. Other cause mortality was derived from age-gender adjusted risk tables.
Monetary benefit and utility valuations:Quality of life in the identified RCT was based on the Short Form 36 (SF-36) Health Survey and an algorithm was used to convert the summary scores of the eight SF-36 dimensions to the preference-based European Quality of life (EQ-5D) questionnaire scores.
Measure of benefit:Quality-adjusted life-years (QALYs) were the measure of benefit and, as the benefits were generated over the lifetime of the patient, they were discounted at an annual rate of 3.5%.
Cost data:Based on the literature review, the authors assumed that EECP did not alter the risk of developing cardiovascular disease events and death, compared with no treatment, and the only costs were those associated with initial, and any subsequent, treatment with EECP. These costs included the capital costs of the machine; equipment replacement costs; consumable costs, such as gel and ultrasound scan; and staffing costs, including nurse and doctor time, receptionist, and other overhead costs. The resource use and unit costs were mainly from personal communication with the providers of EECP and the suppliers of the EECP machine. The price year was 2008 and, as the costs were incurred over the lifetime of the patient, future costs were discounted at an annual rate of 3.5%. All costs were reported in UK pounds sterling (£).
Analysis of uncertainty:A series of one-way sensitivity analyses was undertaken by varying: the expert values on the maintenance of the treatment effect; the costs of EECP; the probability of repeat EECP; the age and gender of the population receiving treatment; and the discount rate. A probabilistic sensitivity analysis was also undertaken by fitting frequency distributions around each model parameter. A Monte-Carlo simulation was performed and the results were presented in cost-effectiveness acceptability curves. An analysis of the expected value of perfect information (EVPI) was undertaken to assess the potential value of future research on EECP. Results The additional cost of treatment with EECP, over usual care, was £4,750. The discounted QALYs gained were 7.492 with EECP and 7.237 with usual care.
Compared with usual care, the additional cost per QALY gained with EECP was £18,643.
The probabilistic sensitivity analysis showed that, at a willingness-to-pay of £20,000 per QALY, the probability of EECP being cost-effective was 44.4%, and when the willingness-to-pay was increased to £30,000, it was 69.8%.
The one-way sensitivity analysis showed that the results were most sensitive to variations in the expert values on the maintenance of the treatment effect. The EVPI analysis suggested that further research to obtain more precise estimates of the quality of life following EECP treatment, and the duration of these benefits, would be of value. Authors' conclusions The authors concluded that the overall cost-effectiveness of EECP was finely balanced and difficult to determine without long-term RCT evidence on the quality of life gained from EECP. CRD commentary Interventions:The interventions were reported clearly and in detail.
Effectiveness/benefits:The authors provided full details of the methods used to obtain the clinical effectiveness data. They undertook a very broad systematic literature review and it is likely that all the relevant information was considered. There was a lack of available data and they had to use an expert panel to extrapolate the results from the identified trial. The full methods for eliciting the opinions were appropriately reported and the limitations of this approach were highlighted in the authors’ conclusions.
Costs:The perspective was explicitly reported. There was no evidence that EECP had any influence on the risk of developing cardiovascular events and mortality and so only the costs of EECP were included. The methods used to derive the unit costs and resource quantities were adequately reported, as were their sources. The price year, time horizon, discount rate, and currency were all explicitly reported.
Analysis and results:All the available evidence was synthesised, using a decision analytic Markov model. Appropriate details of the model were provided, including a diagram. The impact of uncertainty on the results was exhaustively evaluated and estimates on the value of future research into EECP were reported. The authors adequately reported some limitations of their study, particularly the lack of long-term effectiveness estimates, and they fully accounted for this in their conservative conclusions.
Concluding remarks:Full details of the methods and results were provided and the methods were very good. There was a lack of available effectiveness data and the authors’ conservative conclusions are appropriate. Funding NIHR Health Technology Assessment programme. Bibliographic details McKenna C, McDaid C, Suekarran S, Hawkins N, Claxton K, Light K, Chester M, Cleland J, Woolacott N, Sculpher M. Enhanced external counterpulsation for stable angina or heart failure: a systematic review and economic evaluation. Health Technology Assessment 2009; 13(24): 1-90 Other publications of related interest Arora R, Chou T, Jain D, Fleishman B, Crawford L, McKiernan T, et al. The multicentre study of enhanced external counterpulsation (MUST-EECP): effect of EECP on exercise induced myocardial ischemia and angina episodes. Journal of the American College of Cardiology 1999; 33: 1833-1840.
Arora R, Chou T, Jain D, Fleishman B, Crawford L, McKiernan T, et al. Effects of enhanced external counterpulsation on health-related quality of life continue 12 months after treatment: a substudy of the Multicentre Study of Enhanced External Counterpulsation. Journal of Investigative Medicine 2002; 50: 25-32. Indexing Status Subject indexing assigned by NLM MeSH Adult; Aged; Angina Pectoris /therapy; Counterpulsation; Female; Heart Failure /therapy; Humans; Male; Middle Aged AccessionNumber 22009102453 Date bibliographic record published 20/01/2010 Date abstract record published 19/05/2010 |
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