Four in 10 adults may be eligible to use GLP-1 RA treatment for obesity in Australia

Overweight and obesity affects approximately 13.2 million Australian adults and is now the leading contributor of illness and premature death in Australia. It contributes substantially to the burden of chronic disease, including type 2 diabetes, chronic kidney disease, and osteoarthritis. It is also associated with increased cardiovascular risk, with approximately 80% of Australian adults with cardiovascular disease also living with overweight or obesity.

GLP-1 receptor agonist (GLP-1 RA) medications were first approved by the Therapeutic Goods Administration (TGA) for treatment of type 2 diabetes. More recently, large randomised controlled trials have demonstrated that some GLP-1 RAs can lead to clinically meaningful weight loss and reduce the risk of major adverse cardiovascular events in people with established cardiovascular disease. These findings have supported the expansion of TGA-approved indications. Semaglutide was approved by the TGA for chronic weight management in early-2022, and in late-2024 it also gained approval for secondary prevention of cardiovascular disease. Tirzepatide was also approved by the TGA for chronic weight management in 2024.

These medications have transformed the landscape for managing patients with overweight or obesity beyond traditional treatment options such as lifestyle modification and bariatric surgery. The World Health Organization recently recommended the need for “safe, equitable and appropriate” integration of GLP-1 RAs into “multimodal obesity chronic care models.” However, the high out-of-pocket cost of the medication ($200-$700 per month) has raised important questions, both in Australia and internationally, about how these medications should be subsidised.

Potential changes to subsidisation 

In Australia, the Pharmaceutical Benefits Scheme (PBS) currently subsidises semaglutide and dulaglutide for some adults with type 2 diabetes, reducing the maximum out-of-pocket cost for those meeting subsidy conditions to $31.60 ($7.70 for concession card holders). However, no GLP-1 RA medication is currently listed on the PBS for the treatment of chronic weight management or the secondary prevention of cardiovascular disease in adults with overweight or obesity.

This may change following a recent Pharmaceutical Benefits Advisory Committee (PBAC) recommendation to subsidise semaglutide for adults with established cardiovascular disease and a body mass index (BMI) of 35kg/m² or higher. An additional BMI threshold of 32.5kg/m² or higher was recommended for adults of Asian or Aboriginal or Torres Strait Islander ethnicity, due to the greater health burden of established cardiovascular disease and obesity at lower BMI thresholds in these populations.

Our research group estimated how many Australian adults are eligible for GLP-1 RA treatment based on indications approved by the TGA for chronic weight management and secondary prevention of cardiovascular disease. We also estimated eligibility under different coverage scenarios based on BMI and relevant comorbidities. Knowing how many adults may be eligible for GLP-1 RA treatment can help us better understand the potential impact of these medications on our nation’s health and inform ongoing discussions about expanding subsidised access.

How many people are eligible?

Approximately 39.7% of the Australian adult population were eligible to use a GLP-1 RA medication for chronic weight management, representing 7.8 million people.

In addition, 338 900 Australian adults with overweight or obesity and established cardiovascular disease but without diabetes were eligible to use a GLP-1 RA to reduce their risk of major adverse cardiovascular events.

Population eligibility under various coverage scenarios

Eligibility varied substantially depending on the coverage criteria applied. Restricting subsidised access based on BMI threshold alone reduced the number of adults eligible for chronic weight management. For example:

Requiring individuals to have one or more weight-related comorbidity listed in the TGA indication for chronic weight management (ie, hypertension, dyslipidaemia, cardiovascular disease, or type 2 diabetes) reduced eligibility even further. Although obstructive sleep apnoea was among the listed weight-related comorbidities, it could not be reliably identified using the available survey data.

Similarly, restricting subsidised access to people with established cardiovascular disease across different BMI thresholds further reduced the number of adults qualifying for treatment.

While subsidising treatment for all eligible adults has implications for national healthcare expenditure, overweight and obesity and associated comorbidities already place a significant economic and productivity burden on Australia’s healthcare system, estimated to cost our economy approximately $39 billion annually. 

Weighing costs of expanded access against the potential health and economic benefits of wider and more equitable treatment access will be essential to future policies regarding how best to integrate these medications into the Australian healthcare system.

Jasmin Castrillon is a PhD candidate in the Department of Surgery at The University of Melbourne. 

Professor Michelle Dowsey is an Epidemiologist, Registered Nurse and Dame Kate Campbell Fellow in the Department of Surgery at the University of Melbourne.

Dr Cade Shadbolt is a Postdoctoral Research Fellow in the Department of Surgery at the University of Melbourne.