Cost-effectiveness implications of GP intervention to promote physical activity: evidence from Perth, Australia

BACKGROUND: Physical inactivity is a major risk factor for many chronic diseases including diabetes, cardiovascular diseases and some cancers. It is estimated that, in Australia, physical inactivity contributes to 13,500 annual deaths and incurs an annual cost of AU$ 21 billion to the health care system. The cost of physical inactivity to the Western Australian (WA) economy is estimated to be about AU$ 2.1 billion. Increased burden of physical inactivity has motivated health professionals to seek cost effective intervention to promote physical activity. One such strategy is encouraging general practitioners (GPs) to advocate physical activity to the patients who are at high risk of developing chronic diseases associated with physical inactivity. This study intends to investigate the cost-effectiveness of a subsidy program for GP advice to promote physical activity. METHODOLOGY: The percentage of population that could potentially move from insufficiently active to sufficiently active, on GP advice was drawn from the Western Australian (WA) Premier's Physical Activity Taskforce (PATF) survey in 2006. Population impact fractions (PIF) for diseases attributable to physical inactivity together with disability adjusted life years (DALYs) and health care expenditure were used to estimate the net cost of intervention for varying subsidies. Cost-effectiveness of subsidy programs were evaluated in terms of cost per DALY saved at different compliance rates. RESULTS: With a 50% adherence to GP advice, an annual health care cost of AU$ 24 million could be potentially saved to the WA economy. A DALY can be saved at a cost of AU $ 11,000 with a AU$ 25 subsidy at a 50% compliance rate. Cost effectiveness of such a subsidy program decreases at higher subsidy and lower compliance rates. CONCLUSION: Implementing a subsidy for GP advice could potentially reduce the burden of physical inactivity. However, the cost-effectiveness of a subsidy program for GP advice depends on the percentage of population who comply with GP advice.