State out-of-pocket insulin caps decrease costs

Key takeaways:

• Patients in states with out-of-pocket insulin price caps ranging from $25 to $100 saw a 17.4% relative reduction in OOP costs.
• The caps were not associated with changes in insulin use.

Insulin out-of-pocket caps were associated with reduced insulin costs but not increased insulin use, according to a study published in the Annals of Internal Medicine.

Laura F. Garabedian, PhD, MPH, an assistant professor at Harvard Medical School, and colleagues noted that since 2020, 25 states have capped insulin out-of-pocket (OOP) expenses at $25 to $100 for a 30-day supply for those enrolled in commercial health plans.

“Data about the effectiveness of state insulin caps can inform state and federal policymaking, but the effect of state insulin caps on OOP costs and use among commercially insured populations is uncertain,” they wrote.

The researchers conducted a pre-post study of commercially insured patients with diabetes under the age of 65 years who used insulin.

The insulin users were either from eight intervention states that had insulin OOP caps of $25 to $30, $50, or $100 as of January 2021 (n = 16,043), or from 17 control states (n = 63,751).

Garabedian and colleagues also focused on specific subgroups in the study:

• people from states with insulin OOP caps of $25 to $30;
• enrollees with health savings accounts (HSAs) that require high insulin OOP payments; and
• lower income people.

State insulin caps were not associated with changes in mean 30-day insulin fills per month among the overall population or when examined by plan type, Garabedian and colleagues said.

However, overall, insulin users in intervention states saw a –17.4% (95% CI, 23.9%-10.9%) relative reduction in OOP costs, which the researchers noted was significantly driven by reductions among HSA enrollees (relative change = –43.4%; 95% CI, –51.6% to –35.2%).

In their analysis, the researchers looked at changes in insulin use and OOP costs by specific cap levels — focusing on $25 to $30 and $100 caps (there was only one state with a $50 cap).

They found that in states with caps between $25 to $30, the caps were associated with OOP cost reductions of –40% (95% CI, 62.5%-17.6%), which was again driven by reductions among HSA enrollees (relative change = –46.5%; 95% CI, –63.1% to –29.9%). In states with caps of $100, the caps were associated with a –13.6% (95% CI, –21.1% to –6%) relative reductions in OOP costs.

Low-income people in intervention states with caps of $25 to $30 saw a –8.3% (95% CI, –40.1% to 23.6%) relative change in OOP costs compared with a relative change of –50.3% (95% CI, –55.4% to –45.1%) among higher income people. In states with caps of $100, lower income people had a relative change of –9.9% (95% CI, –28.6% to 8.7%) vs. –14.3% (95% CI, –20.9% to –7.7%) among higher income people.

The researchers noted that the large OOP decreases in the HSA subgroup were not surprising “because HSA plans have higher baseline cost-sharing than other plan types, overall and specifically for insulin.”

They added that there were several possible reasons why insulin use did not increase in almost all subgroups.

For example, the OOP reductions may not have been large enough to increase use, whereas patients with diabetes who were undertreated with insulin may not have been aware of state cap policies, “and longer-term follow-up could ultimately reveal increased use,” they wrote.

According to Garabedian and colleagues, although the proposed $35 national cap would significantly reduce OOP costs for HSA members, it would have a small effect for nonaccount plan members, “who comprise the vast majority of the commercial market.”

“Other policies might be needed to improve access to affordable insulin among commercially insured patients with diabetes who have cost-related underuse,” they concluded. “In addition, clinicians and population health managers should be aware of their state's insulin OOP cost caps and should facilitate appropriate therapy among patients with cost-related insulin underuse.”