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Therapeutic options and cost considerations in the treatment of ischemic heart disease |
Cleland J G, Walker A |
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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. Health technology Therapeutic options in the treatment of ischemic heart disease.
Study population Hypothetical cohort of 100 patients with ischemic heart disease.
Setting Hospital. The study was set in the UK.
Dates to which data relate Effectiveness and resource use data were collected from studies published between 1982 and 1994. Cost data were collected from 1994-1995 sources. The price year was not reported.
Source of effectiveness data The effectiveness data were derived from a literature review.
Modelling A decision analytic model was used to determine the cost-effectiveness of the therapeutic options in the treatment of ischemic heart disease.
Outcomes assessed in the review The review assessed mortality rates, operation rates, non-fatal MI rates, drug management, impact of aspirin and simvastatin, quality of life, follow-up visits, and hospitalisation.
Study designs and other criteria for inclusion in the review Effectiveness estimates were mainly derived from a meta-analysis of published, randomised, controlled trials.
Sources searched to identify primary studies Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data Summary statistics from individual studies.
Number of primary studies included At least 4 studies were included.
Methods of combining primary studies Investigation of differences between primary studies Results of the review Mild activity restriction had a health status 95% of normal, whereas moderate-to-severe restriction was valued at 80% of normal. Aspirin reduced the rate of non-fatal MI by 39% (p=0.006) after 5 years of follow-up. There was no mortality benefit from aspirin. Simvastatin reduced all-cause mortality by 30% (p=0.0003) after 5 years of follow-up as well as reducing the need for coronary surgery by 37% and non-fatal MIs by 30% (both p<0.00001). 94% of patients randomised to surgery would be operated on in the first year. Of those patients randomised to medical treatment, 5% would be operated on each year for the first 5 years and 2-3% thereafter. Following surgery, the annual rate of a second operation was 0.93%. Follow-up visits were twice as frequent for the medical management group. Surgical patients were seen twice a year in the clinic, whereas all medical management patients received four visits per year.
Measure of benefits used in the economic analysis Quality-adjusted life years (QALYs) were used as the measure of benefits. Benefits were discounted at an annual rate of 6%. Utility weights were derived from published sources using generic health status measures.
Direct costs Direct costs were discounted at an annual rate of 6%. Quantities and costs were reported separately. Direct costs included the costs of CABG surgery, drug treatment, routine follow-up, and non-fatal MI. The quantity/cost boundary adopted was that of the health service. The estimation of quantities and costs was based on actual data. Drug costs were taken from the British National Formulary. The price year was not reported.
Statistical analysis of costs Sensitivity analysis Results for subgroups of patients with particular diagnoses and characteristics were also constructed.
Estimated benefits used in the economic analysis At 5 years, the estimated life-years gained were 10 for surgery versus medical management plus aspirin and 2 for surgery versus medical management plus aspirin and simvastatin. At 10 years, the estimated life-years gained was 28 for surgery versus medical management plus aspirin and -3 for surgery versus medical management plus aspirin and simvastatin. At 5 years, the estimated quality adjusted life-years gained was 25 for surgery versus medical management plus aspirin, 9 for surgery versus medical management plus aspirin and simvastatin, and 16 for medical management plus aspirin and simvastatin versus medical management plus aspirin. At 10 years, the estimated quality adjusted life-years gained was 36 for surgery versus medical management plus aspirin, -3 for surgery versus medical management plus aspirin and simvastatin, and 39 for medical management plus aspirin and simvastatin versus medical management plus aspirin.
Cost results Over 5 years, total costs amounted to 691,946 for surgery, 276,085 for medical management plus aspirin, and 486,521 for medical management plus aspirin and simvastatin. Over 10 years, total costs were 786,461 for surgery, 484,465 for medical management plus aspirin, and 836,263 for medical management plus aspirin and simvastatin.
Synthesis of costs and benefits At 5 years, the cost per QALY gained was 19,508 for surgery versus medical management plus aspirin, 26,555 for surgery versus medical management plus aspirin and simvastatin, and 14,500 for medical management plus aspirin and simvastatin versus medical management plus aspirin. Surgery only proved cost-effective at the 10,000/QALY threshold for those with severe angina. At 10 years, the cost per QALY gained was 10,001 for surgery versus medical management plus aspirin and 7,383 for medical management plus aspirin and simvastatin versus medical management plus aspirin. Medical management plus aspirin and simvastatin was less expensive and saved QALYs compared with surgery. The conclusions were sensitive to the assumptions and duration of follow-up.
Authors' conclusions For patients with intractable symptoms, surgery is highly effective and has benefits on prognosis. In patients with well-controlled symptoms on medical therapy, the benefits of surgery are small and uncertain, and therefore, medical therapy is the most cost-effective option. The preferred cost-effective option favoured medical treatment.
CRD COMMENTARY - Selection of comparators A justification was given for the comparator used, namely potential therapies. You, the user of the database, should decide if these health technologies are relevant to your setting.
Validity of estimate of measure of benefit The authors did not state that a systematic review of the literature had been undertaken. More details could have been provided about the design of the review and the method of combining primary effectiveness estimates. The estimation of benefits was modelled and utility weights were derived from other sources.
Validity of estimate of costs Some good features of the cost analysis were that all relevant cost categories were included, and quantities and costs were reported separately. However, no sensitivity analyses were conducted on costs or quantities, and the price year was not reported. The analysis may have under-estimated the costs of adopting an anatomical approach in selecting patients for surgery due to the costs of unnecessary angiograms, and because the survival benefits of patients with triple-vessel disease and few symptoms are better than those with severe angina.
Other issues The authors did not make appropriate comparisons of their findings with those from other studies. The issue of generalisability to other settings was not addressed. The authors did not present their results selectively. The study enrolled patients with ischemic heart disease and this was reflected in the authors' conclusions.
Implications of the study The authors conclude that all patients should receive a statin in addition to medical therapy and aspirin. The only reason for surgery would be for the relief of symptoms and, therefore, angiography is an inappropriate way to select patients for surgery.
Bibliographic details Cleland J G, Walker A. Therapeutic options and cost considerations in the treatment of ischemic heart disease. Cardiovascular Drugs and Therapy 1998; 12(Supplement 3): 225-232 Indexing Status Subject indexing assigned by NLM MeSH Anti-Inflammatory Agents, Non-Steroidal /economics /therapeutic use; Anticholesteremic Agents /economics /therapeutic use; Aspirin /economics /therapeutic use; Coronary Artery Bypass /economics; Cost-Benefit Analysis; Drug Therapy, Combination; Humans; Models, Economic; Myocardial Ischemia /drug therapy /economics /surgery /therapy; Quality-Adjusted Life Years; Simvastatin /economics /therapeutic use AccessionNumber 21998001591 Date bibliographic record published 31/05/2001 Date abstract record published 31/05/2001 |
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