State Out-Of-Pocket Caps On Insulin Costs: No Significant Increase In Claims Or Utilization

Nearly all patients with type 1 diabetes and 20-30 percent of patients with type 2 diabetes use insulin to manage glycemic control. 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. Using a difference-in-differences approach, this study evaluated whether state-level caps on insulin out-of-pocket spending change insulin usage among commercially insured enrollees. The study included 33,134 people ages 18-64 who had type 1 diabetes or who used insulin to manage type 2 diabetes with commercial insurance coverage that was subject to state-level oversight and was included in the 25 percent sample of the IQVIA PharMetrics database during 2018-21. Insulin out-of-pocket caps did not significantly increase quarterly insulin claims for enrollees who had type 1 diabetes or who used insulin to manage type 2 diabetes. 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.