|Health economic evaluation of controlled and maintained physical exercise in the prevention of cardiovascular and other prosperity diseases
|Annemans L, Lamotte M, Clarys P, Van den Abeele E
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.
The study investigated the costs and outcomes of a fitness setting intervention to maintain and control physical exercise. This intervention was compared with a do nothing approach.
Type of intervention
Primary prevention and health promotion.
The study population comprised a hypothetical cohort of three target populations, ranked from low to high risk as follows:
30 years old, body mass index (BMI) 26, cholesterol 190, systolic blood pressure (SBP) 120;
40 years old, BMI 30, cholesterol 210, SBP 130; and
50 years old, BMI 32, cholesterol 250, SBP 140.
The study setting was community care. The economic study was undertaken in Belgium.
Dates to which data relate
The effectiveness data were derived from studies published between 1996 and 2003. The cost data were derived from studies published between 1998 and 2003. The price year was not reported.
A decision analytic model was developed using Tree Age 2004 software to determine the costs and outcomes for both interventions.
Study designs and other criteria for inclusion in the review
The clinical and epidemiological data used in the economic evaluation included:
the risk of cardiovascular events;
the percentage of fatal coronary heart disease (CHD) and cerebrovascular disease;
the annual risk of nonfatal stroke, myocardial infarction (MI) and death given a previous history of either MI or stroke;
the relative risk for CHD and cerebrovascular disease with exercise;
the risk of colon and breast cancer;
the survival rates for breast and colon cancer;
the relative risk for breast and colon cancer with exercise;
the incidence of diabetes;
the relative risk for diabetes with exercise; and
the annual risks of developing microvascular disease in diabetics.
Sources searched to identify primary studies
The impact of exercise on cerebrovascular disease was derived from a meta-analysis. The impact of exercise on CHD was derived from a large long-term cohort study provided by the Harvard Alumni Health study. The impact of exercise on cancer and diabetes was derived from a published study evaluating the costs of physical inactivity in Canada (Katzmarzyk et al. 2000, see 'Other Publications of Related Interest' for more bibliographic details). Data to populate other model parameters were derived from published studies.
Methods used to derive estimates of effectiveness
The authors did not report the methods used to obtain the data with which to populate the model. For example, they did not provide the search methods or the inclusion criteria, or state whether data from different studies were combined.
Measure of benefits used in the economic analysis
The measure of benefits used was the quality-adjusted life-years (QALYs) gained. Utility values associated with cardiovascular disease and diabetes were derived from a published study, which estimated the independent effect of BMI and complications on quality of life in a group of diabetic patients. The utilities for breast and colon cancer were derived from another two studies. Since the benefits could be generated over a 25-year period, discounting was relevant and was appropriately performed using an annual rate of 3%.
The direct costs to the public payer were included in the analysis. These comprised the costs of acute care for MI and stroke, follow-up after an MI or stroke, the treatment of colon and breast cancer, diabetes, microvascular complications related to diabetes, and the annual subscription to a fitness centre, which the authors assumed to be EUR 500. The authors reported that travel costs and opportunity costs of time spent exercising were not included. The costs were derived from published studies. Since the costs could be incurred over a 25-year period, discounting was relevant and was appropriately performed using an annual rate of 3%. The price year was not reported. The authors reported the incremental costs.
Statistical analysis of costs
The costs were treated as point estimates (i.e. the data were deterministic).
The authors considered the indirect costs, mainly those related to absenteeism as a result of a poor health condition. Such costs included acute MI and stroke; diabetes and microvascular complications related to diabetes; colon and breast cancer; and the costs associated with the long-term effects of an MI or stroke. The costs were derived from published studies. Since the costs could be incurred over a 25-year period, discounting was relevant and was appropriately performed using an annual rate of 3%. The price year was not reported. The authors reported the incremental costs.
In the analysis, the authors simulated different values between EUR 0 and 500, depending on what percentage of the total cost of a fitness centre the government would subsidise. In addition, a series of one-way sensitivity analyses were conducted by varying the time horizon and the impact of compliance. Multivariate sensitivity analyses were performed by varying the cost of complications and the effectiveness of physical exercise in reducing events.
Estimated benefits used in the economic analysis
The incremental QALYs gained when the physical exercise intervention was compared with no intervention were 1.15, 1.16 and 1.23 for cohorts 1, 2 and 3, respectively.
For cohort 1, the incremental societal costs of the physical exercise intervention compared with no intervention ranged from EUR -3,086 (i.e. savings of EUR 3,086) when the public payment was EUR 0 to EUR 16,008 when the public payment was EUR 500.
For cohort 2, the incremental societal costs of the physical exercise intervention compared with no intervention ranged from EUR -7,114 when the public payment was EUR 0 to EUR 10,847 when the public payment was EUR 500.
For cohort 3, the incremental societal costs of the physical exercise intervention compared with the no intervention ranged from EUR -13,240 when the public payment was EUR 0 to EUR 2,889 when the public payment was EUR 500.
Synthesis of costs and benefits
The costs and benefits were combined using an incremental cost-utility ratio (ICUR; i.e. the additional cost per QALY gained when the physical intervention was compared with no intervention).
For cohort 1, the ICUR ranged from dominant when the public payment was EUR 0 to EUR 13,920 when the public payment was EUR 500.
For cohort 2, the ICUR ranged from dominant when the public payment was EUR 0 to EUR 9,351 when the public payment was EUR 500.
For cohort 3, the ICUR ranged from dominant when the public payment was EUR 0 to EUR 2,349 when the public payment was EUR 500.
The sensitivity analyses showed that the results were relatively robust, with no scenario having an ICUR of more than EUR 20,000 per QALY gained.
The authors concluded that controlled and maintained physical exercise was projected to be cost-effective, the likely explanation for which was its simultaneous effect on several diseases and the associated weight loss.
CRD COMMENTARY - Selection of comparators
A justification was given for the comparator used. The do nothing approach was current practice in Belgium. You should decide if the comparator used represents current practice in your own setting.
Validity of estimate of measure of effectiveness
The parameters were derived from published studies. The authors did not report the methods used to identify the studies, nor did they state whether the results from different studies were combined, and if so how.
Validity of estimate of measure of benefit
The estimation of health benefit (QALYs) was derived appropriately using a decision analytic model. Since QALYs could be incurred over a long time period, discounting was appropriately performed. The utility values used to generate QALYs were derived from previous research. However, the authors did not report the method used in the previous studies to elicit utility values.
Validity of estimate of costs
The analysis of the costs was performed from the perspectives of both the public payer and society. For both these perspectives, it would appear that all the relevant cost categories were included in the analysis. The authors reported that travel costs and opportunity costs of exercise were not included. These omissions, however, are unlikely to have affected the authors' conclusions. All other relevant costs were included. The costs were derived from published studies and, since they could be incurred over a long time period, were appropriately discounted. The price year was not reported, which will hamper any future inflation exercises.
The authors reported that, at the time of their study, no other health economic evaluation of controlled and maintained physical exercise, simulating the resultant future health and economic consequences, had been conducted. The issue of generalisability to other settings was partly addressed through the sensitivity analyses. The authors do not appear to have presented their results selectively and their conclusions reflected the scope of their analysis. The authors acknowledged a number of further limitations to their study. First, in the base-case, the model assumed 100% compliance with physical exercise, which is very difficult to obtain in real life. Second, since only three cohorts were considered, the results should not be extrapolated to the entire population. Third, the costs of travel or time spent exercising were not included in the analysis.
Implications of the study
The authors reported that the exact level of government intervention would depend on the importance the government assigns to the avoided diseases.
Source of funding
Supported by a grant from the Fitness Organisation.
Annemans L, Lamotte M, Clarys P, Van den Abeele E. Health economic evaluation of controlled and maintained physical exercise in the prevention of cardiovascular and other prosperity diseases. European Journal of Cardiovascular Prevention and Rehabilitation 2007; 14(6): 815-824
Other publications of related interest
Because readers are likely to encounter and assess individual publications, NHS EED abstracts reflect the original publication as it is written, as a stand alone paper. Where NHS EED abstractors are able to identify positively that a publication is significantly linked to or informed by other publications, these will be referenced in the text of the abstract and their bibliographic details recorded here for information.
Katzmarzyk PT, Gledhill N, Shephard RJ. The economic burden of physical inactivity in Canada. CMAJ 2000;163:1435-40.
Lamotte M, Annemans L, Levefer A, et al. A health economic model to assess the long-term effects and cost-effectiveness of orlistat in obese type 2 diabetic patients. Diabetes Care 2002;25:303-8.
Van den Hout WB, de Jong Z, Munneke M, et al. Cost-utility and cost-effectiveness of a long-term, high-intensity exercise program compared with conventional physical therapy in patients with rheumatoid arthritis. Arthritis Rheum 2005;53:39-47.
Subject indexing assigned by NLM
Adult; Aged; Belgium /epidemiology; Cardiovascular Diseases /economics /epidemiology /prevention & Cost of Illness; Cost-Benefit Analysis; Exercise /physiology; Exercise Therapy /methods; Female; Follow-Up Studies; Humans; Male; Middle Aged; Models, Economic; Prevalence; Quality of Life; Time Factors; control
Date bibliographic record published
Date abstract record published