Cost-Effectiveness of Interventions to Promote Physical Activity: A Modelling Study

Linda Cobiac and colleagues model the costs and health outcomes associated with interventions to improve physical activity in the population, and identify specific interventions that are likely to be cost-saving.Background: Physical inactivity is a key risk factor for chronic disease, but a growing number of people are not achieving the recommended levels of physical activity necessary for good health. Australians are no exception; despite Australia's image as a sporting nation, with success at the elite level, the majority of Australians do not get enough physical activity. There are many options for intervention, from individually tailored advice, such as counselling from a general practitioner, to population-wide approaches, such as mass media campaigns, but the most cost-effective mix of interventions is unknown. In this study we evaluate the cost-effectiveness of interventions to promote physical activity. Methods and Findings: From evidence of intervention efficacy in the physical activity literature and evaluation of the health sector costs of intervention and disease treatment, we model the cost impacts and health outcomes of six physical activity interventions, over the lifetime of the Australian population. We then determine cost-effectiveness of each intervention against current practice for physical activity intervention in Australia and derive the optimal pathway for implementation. Based on current evidence of intervention effectiveness, the intervention programs that encourage use of pedometers (Dominant) and mass media-based community campaigns (Dominant) are the most cost-effective strategies to implement and are very likely to be cost-saving. The internet-based intervention program (AUS$3,000/DALY), the GP physical activity prescription program (AUS$12,000/DALY), and the program to encourage more active transport (AUS$20,000/DALY), although less likely to be cost-saving, have a high probability of being under a AUS$50,000 per DALY threshold. GP referral to an exercise physiologist (AUS$79,000/DALY) is the least cost-effective option if high time and travel costs for patients in screening and consulting an exercise physiologist are considered. Conclusions: Intervention to promote physical activity is recommended as a public health measure. Despite substantial variability in the quantity and quality of evidence on intervention effectiveness, and uncertainty about the long-term sustainability of behavioural changes, it is highly likely that as a package, all six interventions could lead to substantial improvement in population health at a cost saving to the health sector. : Please see later in the article for Editors' Summary Background: The human body needs regular physical activity throughout life to stay healthy. Physical activity—any bodily movement produced by skeletal muscles that uses energy—helps to maintain a healthy body weight and to prevent or delay heart disease, stroke, type 2 diabetes, colon cancer, and breast cancer. In addition, physically active people feel better and live longer than physically inactive people. For an adult, 30 minutes of moderate physical activity—walking briskly, gardening, swimming, or cycling—at least five times a week is sufficient to promote and maintain health. But at least 60% of the world's population does not do even this modest amount of physical activity. The daily lives of people in both developed and developing countries are becoming increasingly sedentary. People are sitting at desks all day instead of doing manual labor; they are driving to work in cars instead of walking or cycling; and they are participating less in physical activities during their leisure time. Why Was This Study Done?: In many countries, the chronic diseases that are associated with physical inactivity are now a major public-health problem; globally, physical inactivity causes 1.9 million deaths per year. Clearly, something has to be done about this situation. Luckily, there is no shortage of interventions designed to promote physical activity, ranging from individual counseling from general practitioners to mass-media campaigns. But which intervention or package of interventions will produce the optimal population health benefits relative to cost? Although some studies have examined the cost-effectiveness of individual interventions, different settings for analysis and use of different methods and assumptions make it difficult to compare results and identify which intervention approaches should be give priority by policy makers. Furthermore, little is known about the cost-effectiveness of packages of interventions. In this study, the researchers investigate the cost-effectiveness in Australia (where physical inactivity contributes to 10% of deaths) of a package of interventions designed to promote physical activity in adults using a standardized approach (ACE-Prevention) to the assessment of the cost-effectiveness of health-care interventions. What Did the Researchers Do and Find?: The researchers selected six interventions for their study: general practitioner “prescription” of physical activity; general practitioner referral to an exercise physiologist; a mass-media campaign to promote physical activity; the TravelSmart car use reduction program; a campaign to encourage the use of pedometers to increase physical activity; and an internet-based program. Using published data on the effects of physical activity on the amount of illness and death caused by breast and colon cancer, heart disease, stroke, and type 2 diabetes and on the effectiveness of each intervention, the researchers calculated the health outcomes of each intervention in disability-adjusted life years (DALY; a year of healthy life lost because of premature death or disability) averted over the lifetime of the Australian population. They also calculated the costs associated with each intervention offset by the costs associated with the five conditions listed above. These analyses showed that the pedometer program and the mass-media campaign were likely to be the most cost-effective interventions. These interventions were also most likely to be cost-saving. Referral to an exercise physiologist was the least cost-effective intervention. The other three interventions, though unlikely to be cost-saving, were likely to be cost-effective. Finally, a package of all six interventions would be cost-effective and would avert 61,000 DALYs, a third of what could be achieved if every Australian did 30 minutes of physical activity five times a week. What Do These Findings Mean?: As in all modeling studies, these findings depend on the quality of the data and on the assumptions included by the researchers in their calculations. Unfortunately, there was substantial variability in the quantity and quality of evidence on the effectiveness of each intervention and uncertainty about the long-term effects of each intervention. Nevertheless, the findings presented in this study suggest that the assessment of the cost-effectiveness of a combination of interventions designed to promote physical activity might provide policy makers with some guidance about the best way to reduce the burden of disease caused by physical inactivity. More specifically, for Australia, these findings suggest that the package of the six interventions considered here is likely to provide a cost-effective way to substantially improve the health of the nation. Additional Information: Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000110.