Capping Insulin at $35 Per Month Significantly Improves Treatment Adherence in Type 2 Diabetes

How Does a $35 Insulin Cap Improve Diabetes Treatment?

For millions of Americans living with type 2 diabetes, the cost of insulin has long been a critical barrier to consistent treatment. New research adds to a growing body of evidence showing that when out-of-pocket insulin costs are capped at $35 per month, patients are significantly more likely to fill their prescriptions on time and adhere to their treatment regimens. Cost-related non-adherence — skipping doses, splitting pills, or delaying refills — is a well-documented problem in diabetes care, and affordability interventions appear to directly address it.

The Inflation Reduction Act, signed into law in 2022, established a $35 per month cap on insulin copays for Medicare beneficiaries beginning in January 2023. Since then, researchers have been tracking the real-world impact of this policy. The latest findings suggest that removing the financial sting of insulin costs translates into measurable improvements in how consistently patients use their medication, which is a key factor in preventing the serious complications of poorly managed diabetes, including cardiovascular disease, kidney failure, and neuropathy.

Why Is Insulin Affordability a Public Health Crisis?

The United States has long been an outlier in insulin pricing. According to a RAND Corporation study published in 2024, insulin prices in the US were roughly two to three times higher than in comparable high-income nations. Before recent policy interventions, some patients reported paying several hundred dollars per month for insulin, leading to well-documented cases of dose rationing. The CDC has estimated that approximately 1 in 4 insulin users have reported rationing due to cost, a practice that can lead to diabetic ketoacidosis, hospitalization, and even death.

The three major insulin manufacturers — Eli Lilly, Novo Nordisk, and Sanofi — all announced voluntary price reductions or $35 cap programs in 2023, extending some cost relief beyond Medicare to commercially insured and even uninsured patients. While these corporate actions and the Medicare cap have meaningfully reduced out-of-pocket costs, advocacy groups continue to push for broader federal legislation that would extend the $35 cap to all insured Americans, not just those on Medicare. The new study's findings strengthen the case that price caps are not merely a financial convenience but a clinically meaningful intervention.

What Are the Long-Term Health Benefits of Better Insulin Adherence?

The clinical importance of medication adherence in type 2 diabetes is well established. The landmark United Kingdom Prospective Diabetes Study (UKPDS) demonstrated that intensive blood glucose control significantly reduces the risk of microvascular complications such as retinopathy and nephropathy. More recent evidence also links sustained glycemic control to reduced cardiovascular events, which remain the leading cause of death among people with diabetes. When patients can afford their insulin and take it consistently, the downstream savings in averted hospitalizations and emergency care are substantial.

Health economists have long argued that investing in medication affordability yields significant returns. The American Diabetes Association estimates that diabetes costs the US healthcare system over $400 billion annually when direct medical costs and lost productivity are combined. Policies that improve adherence at relatively modest cost — such as a $35 copay cap — represent one of the more efficient public health interventions available. As policymakers debate expanding these caps beyond Medicare, studies like this one provide critical evidence that affordability directly shapes health outcomes.