Mar 26, 2024 - Health

Insulin caps lowered costs but didn't improve access, study finds

Illustration of a syringe pulling from a vial with a hundred dollar bill as a label.

Illustration: Aïda Amer/Axios

State caps on insulin costs lowered privately insured patients' out-of-pocket spending, but they didn't appear to increase insulin use, according to a new Annals of Internal Medicine study.

Why it matters: The research suggests increasingly popular insulin caps alone aren't enough to improve insulin uptake among patients with diabetes in commercial insurance.

  • At least half of states in recent years have limited monthly insulin costs in the commercial market, and leading insulin manufacturers have followed suit as the Biden administration pushes a national cap for privately insured patients.

What they found: State insulin caps, which range from $25 to $100 for a month's supply, were associated with 17.4% relative decrease in consumer out-of-pocket costs, researchers from Harvard Medical School and Harvard Pilgrim Health Care Institute found.

  • The savings were over twice as large (40%) among patients using health savings accounts, while patients in states with caps between $25 and $30 were most likely to see a drop in costs.
  • However, insulin use remained constant for nearly all populations, though it increased for lower-income patients with HSAs in states with $25-$30 caps.

The intrigue: Previous studies found Medicare enrollees' prescription fills rose after Medicare implemented a new $35 cap on monthly insulin costs.

  • Researchers said those with private insurance are on average healthier and less likely to need insulin, and they might be less affected by caps because they have more resources to afford the medication.

What they're saying: "Other policies might be needed to improve access to affordable insulin among commercially insured patients with diabetes who have cost-related underuse," the authors wrote.

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