ArticlesEffectiveness and costs of interventions to lower systolic blood pressure and cholesterol: a global and regional analysis on reduction of cardiovascular-disease risk
Introduction
Cardiovascular disease is a major contributor to the global burden of disease. It accounts for 20·3% of disability-adjusted life years (DALYs) lost in more developed countries and already for 8·1% of those lost in less-developed countries. The World Health Report 20021 quantified the major contributions of tobacco use, alcohol consumption, high blood pressure, high cholesterol concentrations, low intake of fruit and vegetables, physical inactivity, and high body-mass index to the global burden of disease and of cardiovascular disease in particular.1, 2
Improved data on degree of exposure and reassessments of the magnitude of hazards, have led to the recognition that high blood pressure and high cholesterol concentrations have much greater influence on population health than previously thought.3 About two-thirds of strokes and almost half of cases of ischaemic heart disease can be attributed to systolic blood pressure greater than 115 mm Hg. Total cholesterol concentrations over 3·8 mmol/L account for about 18% of strokes and 55% of cases of ischaemic heart disease. The joint effects of blood pressure and cholesterol concentration would, of course, be less than additive because of the multicausality of cardiovascular disease and the joint action of these two risk factors.1 Regional analyses have also shown that high blood pressure and high cholesterol concentrations are major risks to health in all regions of the world, not just high-income countries.
Given the burden of disease caused by these factors, assessment of the costs and effects of the available intervention strategies to reduce these risks is important. These strategies should, however, be seen in the context of more comprehensive approaches to the control of cardiovascular disease that focus on several inter-related risks to health including blood pressure, cholesterol concentration, tobacco use, body-mass index, physical activity, diet, and diabetes.4, 5 Here we take advantage of the development of standard methods and companion tools for the assessment of costs, effects, and cost-effectiveness of different interventions within and across regions.6, 7, 8, 9, 10, 11, 12, 13 These methods and tools mean that results of intervention analyses can be compared more meaningfully across interventions and across locations.
Assessment of the costs and effects of the major intervention strategies for reducing the burden attributable to blood pressure and cholesterol concentrations must address two key issues. First, what are the relative roles of non-personal health services—such as mass-media messages to change diet, or legislation to lower the salt content of processed foods—and personal health services—such as the pharmacological management of cholesterol concentration and hypertension?4, 5, 14 Second, should management of blood pressure and cholesterol concentrations be based on thresholds for each risk factor seen in isolation (such as treatment for a systolic blood pressure above 160 mm Hg), or should management be based on the absolute risk of cardiovascular disease for a given individual taking into account all his or her known determinants of risk?15 We analyse the population health effects and costs of non-personal health measures, treatment of individual risk factors, and treatment based on various values of absolute risk.16, 17, 18
Section snippets
Interventions
17 non-personal and personal health-service interventions or combinations have been included in this analysis (table 1). Non-personal health interventions included health education through the mass media (focusing on blood pressure, cholesterol concentration, and body mass), and either legislation or voluntary agreements on salt content to ensure appropriate labelling and stepwise decreases in the salt content of processed foods. Personal health-service interventions included detection and
Results
Table 2 gives the total annualised costs, total annual health effect in terms of DALYs averted, and the average cost-effectiveness ratio for each of the 17 interventions in three subregions with differing levels of adult and child mortality and different patterns of risks to health (EurA, AmrB, and SearD; the full set of results for all 14 subregions is given in webtable 2). The health benefits of all interventions follow a roughly bell-shaped curve when plotted against age. Depending on the
Discussion
In all regions, these selected non-personal and personal health interventions to lower blood pressure and cholesterol concentration are very cost effective. This finding is at odds with the perception that strategies to prevent cardiovascular disease should strictly be the concern of the very wealthy. Implied in these results is a further frameshift in thinking about priorities and public-health strategies for less developed regions. Even though the benefits documented here are large, the
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