Background: Healthcare spending is concentrated, with a minority of the population accounting for the majority of healthcare costs.

Methods: The authors modelled the impact of high resource user (HRU) prevention strategies within five years using the validated High Resource User Population Risk Tool.

Results: The authors estimated 758,000 new HRUs in Ontario from 2013–2014 to 2018–2019, resulting in $16.20 billion in healthcare costs (Canadian dollars 2016). The prevention approach that had the largest reduction in HRUs was targeting health-risk behaviours.

Conclusions: This study demonstrates the use of a policy tool by decision makers to support prevention approaches that consider the impact on HRUs and estimated healthcare costs.