Do State Out-Of-Pocket Caps On Insulin Costs Improve Access?

Perhaps not. At least that is according to a paper by Anderson et al. (2024). The authors use a difference-in-difference approach with 2018-2021 claims data. A summary of the results are below.

Approximately one-quarter of patients who use insulin report underuse because of cost. In response, more than twenty states have implemented monthly caps on insulin out-of-pocket spending, ranging from $25 to $100…
State-level caps on insulin out-of-pocket spending for commercial enrollees did not significantly increase insulin use; that may be in part because of out-of-pocket expenses being lower than cap amounts.

We could see potentially two things going on here. As the authors mentioned, the out-of-pocket (OOP) caps may be higher than the OOP caps private insurers already had in place. Additionally, demand for insulin is likely fairly inelastic since these patients are at high risk for serious complications or death without insulin. This does not mean that the caps weren’t a good idea; just that they had a small impact on patient behavior.