Excess body weight is strongly associated with the risk of diabetes. In Australia, the latest data suggests that 11 million adults have overweight or obesity and 1.2 million adults have diabetes. The respective costs of obesity and diabetes were estimated previously, but the cost associated with both obesity and diabetes combined have not been reported in Australia. The aim of the study was to assess and compare the total direct (healthcare plus non-healthcare) cost and government subsidies by body weight and diabetes status.
The Australian Diabetes, Obesity and Lifestyle study collected health service utilisation and health related expenditure data at the 2011-12 follow-up survey. The World Health Organization body mass index cut-points were used to define normal weight, overweight and obesity. Participants with fasting plasma glucose ≥7.0 mmol/L, 2 hour plasma glucose ≥11.1 mmol/L, or self-reported having diabetes and on pharmacotherapy were considered to have diabetes. Costing data were available on 4409 participants aged ≥36 years in 2011-12. Unit costs for 2016-17 were used where available or were otherwise inflated to 2016-17 dollars. Age- and sex-adjusted costs per person were estimated using generalised linear models.
The annual total direct cost ranged from $1998 per person with normal weight to $2501 per person with obesity in participants without diabetes. For those with diabetes, total direct costs ranged from $2353 per person with normal weight to $3131 with obesity. Additional expenditure as government subsidies ranged from $5681 per person with normal weight and no diabetes to $8067 per person with obesity and diabetes.
The annual total excess cost was 26% for obesity alone and 46% with the addition of diabetes. Lifestyle modification programs targeting people with excess body weight may reduce the risk of diabetes, thereby, reducing the financial burden for both individuals and the government