The impact of sodium glucose co-transporter 2 inhibitors and glucagon-like peptide 1 receptor agonists on insulin utilisation and costs in Australia: a national retrospective observational cross-sectional study

Background

Global insulin requirements for type 2 diabetes were predicted to increase by more than 20% from 2018 to 2030. However, this did not anticipate the rapid increase in use of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors that has occurred over recent years. The current study aims to examine changes in insulin utilisation and costs in Australia from 2003 to 2023.

Methods

We conducted a large-scale observational study of national insulin utilisation and expenditure in Australia from 2003 to 2023 using the Australian Pharmaceutical Benefits Scheme. The proportion of insulin-treated people with type 2 diabetes between 2013 and 2023 was estimated using National Diabetes Services Scheme data. Joinpoint models and interrupted time series analysis were used to examine utilisation trends.

Findings

Insulin utilisation (units of insulin per person with diabetes) increased by an average of 2.71% per annum (95% CI 1.97, 3.73) from 2003 to 2015, then fell by 2.70% per annum (95% CI −4.55, −1.39) from 2015 to 2023. The proportion of insulin-treated people with type 2 diabetes increased by 1.00% per annum (95% CI 0.81, 1.25) from 2013 to 2020, then fell by 0.66% per annum (95% CI −1.62, −0.04) from 2020 to 2023. A 43% reduction in inflation-adjusted insulin expenditure was observed between 2015 and 2023 due to a combination of reduced utilisation and reduction in the price of insulin glargine.

Interpretation

Projected global insulin requirements and costs may be less than previously anticipated if reduced use of insulin in Australia is similarly observed in other countries.

Funding

No funding was received for this study.