In 1999 physical inactivity was identified as the leading contributor to the overall burden of disease in Australian women, and second only to tobacco smoking in men (Mathers, Vos, & Stevenson, 1999). Indeed, inactivity is independently associated with many chronic health problems, as described in part one of this report, and exacerbates the metabolic, structural and functional declines of ageing (Singh, 2002). In 2002 the annual direct health care costs of inactivity-related health problems in Australia were conservatively estimated to be AUD 377 million per year (Stephenson, Bauman, Armstrong, Smith, & Bellew, 2000). In the US, health care costs have been shown to be inversely associated with physical activity, after adjustment for body mass index (Wang, McDonald, Reffott, & Edington, 2005), and it is estimated that individual health care costs are USD300 per year less in regularly active than in sedentary adults (Pratt, Macera, Wang, 2000).
The aim of the final analysis in this report was to quantify the relationships between physical activity and Medicare costs in the mid-age and older cohorts of the ALSWH, using data from M3 and O2.
Data from women who responded to either M3 (2001) or O2 (1999), and who gave permission for linkage to the Medicare data-base (see below) were included in these analyses. Data from women who reported being unable to walk 100m, with BMI<18.5, or with missing data for one or more of the weight, height, body mass index or physical activity variables, were excluded, leaving data from 7,004 mid-age and 5,161 older women in the analysis sample.
In Australia, the universal health insurance system, Medicare, covers all permanent residents, regardless of age or circumstances, for medical services including general practitioner (GP) and specialist consultations, pathology and radiology and limited additional primary health care services. Medicare provides a fixed rebate of 85% of the fee set by the government for services provided outof-hospital, or 75% for services provided in hospital for private patients. There is no legislation restricting the amount that doctors can charge for services.
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All the women whose data are included in these analyses gave written consent for the release of Medicare claims data to the research team. Total costs for Medicare-subsidised health services were recorded for each woman; these cover costs to both the government (the rebate) and the additional charge paid by the patient. Pharmaceutical and hospital services are not covered by Medicare and were not available for inclusion in these analyses.
Mean annual costs of Medicare reimbursable services for women in each physical activity category were calculated (2001 costs were used for the mid-age women, and 1999 costs for the older women; see Figure 4.8). Although the older women made approximately 60% more claims than the mid-age women, costs were only about 30% more, because many older women were charged only the Medicare rebateable fee (ie the cost per service was lower than for the mid-age women). Fewer than 10% of the mid-age women and 2% of the older women did not visit a GP; and fewer than 5% and 1% respectively made no claims and therefore had no costs.
The greatest differences in costs were between the
none and
very low physical activity categories, indicating that even low levels of physical activity (less than meeting the national guidelines) are associated with lower health care costs. For the mid-age women mean costs were 26.3% ($134 per annum) higher in those in the
none category than in moderately active women. For older women mean costs were 23.5% ($156 per annum) higher in the sedentary women.
The Medicare costs reported here (an average of $536 and $715 for the mid-age and older women respectively) include only the costs of visits to general practitioners, medical specialists and outpatient pathology and radiology services. As such, they represent only a fraction of total health care costs, which were estimated to be AUD 3,931 per person per annum in 2003/04 (Australian Institute of Health and Welfare, 2005). We did not have access to the costs of hospital services or pharmaceuticals, which make up the bulk of health care costs in Australia. Similarly, the costs reported here do not include the costs of work days lost due the chronic health problems that are associated with both inactivity and overweight.
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Although it is not possible to directly compare the costs reported here with those reported in studies from other countries, it is possible to compare the relative differences reported for health care costs of people in different physical activity categories (26.3% more in sedentary than in moderately active mid-age women and 23.5% more for corresponding categories in older women). These percentage differences are similar to those reported by Pronk, Goodman, O'Connor, & Martinson (1999) for a sample of participants (40 years or older) in a Minnesota health plan. In that study each additional
active day each week (defined as any activity reported that day) was associated with a 4.7% reduction in costs (ie a 23.5% reduction for those routinely active on 5 days each week), compared with those who reported no days of physical activity (Pronk et al., 1999). Another US study, which included all health care and pharmaceutical costs incurred by a large sample (N=196,000) of employees in the automotive industry, also found a 23.7% decrease in costs among those who reported
brisk physical activity 3 times a week or more, compared with those who reported none, with an average per person difference in costs of USD 514 (Wang, McDonald, Champagne, & Edington, 2004). Estimates made by Pratt, Macera, & Wang (2000) using data from a national sample of US adults in 1987 were somewhat higher. They estimated that the mean net annual benefit of regular physical activity was USD 330 per person, or a reduction in costs of 32.4%.
Figure 4.8: Mean annual costs of Medicare rebateable health services by physical activity category for mid-age women in 2001 (pale bars, N=7,204; M3 survey) and older women in 1999 (darker bars, N=4161; O2 survey).
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Additional analyses using these data found that the expected cost savings of
activating the most sedentary women would be greater than those from reducing body mass index. The three-way relationships between physical activity, body mass index, and health service costs were interesting, as they showed that costs were not significantly increased in overweight (BMI 25 to <30) mid-age or older women who reported sufficient physical activity to meet the national guidelines, compared with healthy weight active women. Regardless of body mass index category, the highest costs were seen in the women who reported
no physical activity.
On a population basis, it is clear from our findings that the greatest relative cost savings could accrue if sedentary women could improve both their physical activity and body mass index. However, in light of the fact that many women have difficulty changing their weight, and that there would be significant cost savings from increasing only physical activity (in sedentary women), our advice would be to encourage women to focus on increasing physical activity rather than only on losing weight. Significant benefits in terms of health care costs, both for women and for Medicare, may result if all women could achieve just 60-150 minutes of moderate intensity physical activity each week (our
low category). In other words, sedentary women would have to walk briskly for 12-30 minutes on five days each week. Small changes in social support, as well as in workplace, transport and safety policies, would help these women to achieve this modest goal.