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Preventing cardiovascular disease among Canadians: is the treatment of hypertension or dyslipidemia cost-effective? |
Grover S, Coupal L, Lowensteyn I |
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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 examine the cost-effectiveness of hypertension and dyslipidaemia therapy for the prevention of cardiovascular disease, in asymptomatic individuals, aged 40 to 70 years. Preventive treatment appeared to be cost-effective in many eligible individuals, but the costs were high for the nationwide implementation of the two programmes, according to Canadian guidelines. The study was well conducted and generally well described. The authors’ conclusions appear to be valid, but a more extensive analysis of uncertainty would have been useful. Type of economic evaluation Cost-effectiveness analysis Study objective The objective was to examine the cost-effectiveness of treatment for hypertension and dyslipidaemia, in asymptomatic individuals aged 40 to 70 years, for the prevention of cardiovascular disease. Interventions Lipid and hypertension therapies, according to Canadian guidelines, aimed to reduce cardiovascular disease. Each strategy was compared with no prevention. Methods Analytical approach:The analysis was based on the published Cardiovascular Life Expectancy Model; a Markov model of the risks of cardiovascular disease and the potential benefits of treating these risk factors. A lifetime horizon was considered and the authors stated that the perspective of the health care system was adopted.
Effectiveness data:The clinical data came from a selection of known, relevant studies. Treatment efficacy was from two randomised controlled trials (RCTs): one for lipid treatment, and one for hypertension therapy. The baseline clinical characteristics of the eligible patient population were from the Canadian heart health surveys, which covered the period between 1986 and 1992. The impact of risk factors on cardiovascular disease was from the MyHealthCheckUp national survey. The key clinical input was the efficacy of treatment.
Monetary benefit and utility valuations:Not included.
Measure of benefit:Life-years (LYs) were the summary benefit measure and were discounted at 3% per annum.
Cost data:The economic analysis included drugs and treatment of cardiovascular disease, including in-patient and out-patient services, physician fees, and emergency services. Consumption and the costs of drugs were based on a survey carried out in Canada and official prices, including retail mark-up and dispensing fees. Data for the other costs were from a published economic evaluation, the details of which were not reported, the Canadian Institute for Health Information methodology (covering over 85% of all Canadian acute care in-patient discharges), and the Quebec and Ontario reimbursement fee schedule. All costs were in Canadian dollars (CAD) and the price year was 2002. A 3% annual discount rate was applied.
Analysis of uncertainty:A best-case scenario was considered in which the drug efficacy for the treatment of hypertension and dyslipidaemia was set at the higher value from the RCTs. Subgroup analyses were also conducted, with different patient age groups. Results For dyslipidaemia therapy, the lifetime net costs per patient were CAD 7,100 for women and CAD 8,200 for men. The LYs saved were 0.37 for women and 0.52 for men. The incremental cost per LY saved with the preventive treatment over no intervention was CAD 19,200 (ranging from CAD 7,100 to CAD 43,800 depending on age group) for women, and CAD 15,900 (range CAD 10,900 to CAD 20,100) for men. The incremental cost per LY saved for preventive treatment of dyslipidaemia for all patients was CAD 16,700.
For hypertension therapy, the lifetime net costs per patient were CAD 6,800 for women and CAD 8,100 for men. The LYs saved were 0.20 for women and 0.21 for men. The incremental cost per LY saved with the preventive treatment over no intervention was CAD 34,900 (range CAD 19,300 to CAD 70,500) for women and CAD 39,000 (range CAD 18,000 to CAD 63,900) for men. The incremental cost per LY saved for preventive treatment of hypertension for all patients was CAD 37,100.
The sensitivity analysis showed that, in the best-case scenarios, the incremental costs per LY saved for dyslipidaemia therapy were CAD 9,900 and for hypertension therapy they were CAD 10,200. Authors' conclusions The authors concluded that the preventive treatment of dyslipidaemia and hypertension appeared to be cost-effective for many eligible patients, but the costs were high due to the nationwide implementation of the two programmes. CRD commentary Interventions:The selection of the comparator (no intervention) was appropriate, but the costs and benefits of this strategy were not explicitly modelled. The authors provided a clear description of the Canadian treatment guidelines for the two health conditions.
Effectiveness/benefits:Country-specific sources appear to have been used to select the most appropriate risk factors and patient characteristics for the model. National databases were the best source for the authors’ setting and some information on these databases was provided. The drug efficacy was appropriately taken from the RCTs, but the authors did not address the issue of mixing data from different sources. LYs were a valid benefit measure, given the impact of the disease on survival. Moreover, they allow cross-disease comparisons to be made with the benefits of other health care interventions. Conventional discounting was applied.
Costs:The categories of costs were consistent with the perspective. Extensive details of the unit costs and quantities of resources used were provided for the drugs, but little information on the other cost categories was given. The published sources for some costs were not described. Cost estimates were treated deterministically, but the key costs were varied in the sensitivity analysis. Other details of the analysis, such as the price year and use of discounting, were reported. The unit costs of the studied drugs were reported.
Analysis and results:The model outputs associated with the two preventive strategies were appropriately reported and were well analysed. Key details of the analytic model were reported. Only a best-case scenario was included in the sensitivity analysis, and the authors acknowledged that the results of their analysis were optimistic for the treatments considered. They compared their findings with those of other published economic evaluations, which showed similar results.
Concluding remarks:The study was well conducted and generally well described. The authors’ conclusions appear to be valid, but a more extensive analysis of uncertainty would have been useful. Funding Supported by a grant from AstraZeneca Canada. Bibliographic details Grover S, Coupal L, Lowensteyn I. Preventing cardiovascular disease among Canadians: is the treatment of hypertension or dyslipidemia cost-effective? Canadian Journal of Cardiology 2008; 24(12): 891-898 Other publications of related interest Grover SA, Paquet S, Levinton C, Coupal L, Zowall H.. Estimating the benefits of modifying risk factors of cardiovascular disease: a comparison of primary vs secondary prevention. Archives of Internal Medicine 1998; 158: 655-662.
Grover SA, Coupal L, Kaouache M, Lowensteyn I. Preventing cardiovascular disease among Canadians: what are the potential benefits of treating hypertension or dyslipidemia? Canadian Journal of Cardiology 2007; 23: 467-473. Indexing Status Subject indexing assigned by NLM MeSH Adult; Age Factors; Aged; Antihypertensive Agents /economics /therapeutic use; Cardiovascular Diseases /economics /etiology /prevention & Cohort Studies; Cost of Illness; Cost-Benefit Analysis; Dyslipidemias /complications /drug therapy /economics; Economics, Pharmaceutical; Female; Health Care Costs; Health Care Surveys; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors /economics /therapeutic use; Hypertension /complications /drug therapy /economics; Male; Middle Aged; Ontario; Primary Prevention /economics; Quality-Adjusted Life Years; Quebec; Risk Factors; Sex Factors; control AccessionNumber 22009100801 Date bibliographic record published 02/09/2009 Date abstract record published 14/04/2010 |
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