American Diabetes Association Scientific Sessions

American Diabetes Association Scientific Sessions

June 23, 2018
2 min read

Cost-related insulin underuse raises risk for poor glycemic control

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ORLANDO, Fla. —  Patients with type 1 or type 2 diabetes who reported using less insulin than prescribed due to cost concerns were more likely to have poor glycemic control compared with those who report regular insulin use, according to findings from cross-sectional study.

“Insulin is a lifesaving medication,” Darby M. Herkert, BS, a former undergraduate researcher at Yale University, said during her presentation. “It has been listed as an essential medicine by the World Health Organization and its use has been associated with lower rates of hospitalization and emergency department utilization. However, the high cost of medication has been shown to be associated with reduced adherence.”

Over the past decade, the cost of insulin has increased dramatically, Herkert said: cash prices for a 10-mL vial of insulin have increased almost 600% from 2004 to 2018.

To examine factors associated with cost-related insulin underuse, Herkert and colleagues administered a cross-sectional survey to 199 outpatients at the Yale Diabetes Center with type 1 and type 2 diabetes who were prescribed insulin within 6 months from June to August 2017 (50.8% women; 60.8% white; 41.7% with type 1 diabetes). The primary outcome was cost-related underuse of insulin in the past 12 months, defined by a positive response to any one of six questions. Participants were asked if, in the past 12 months, they used less insulin than prescribed, tried to “stretch out” insulin, took smaller doses of insulin than prescribed, stopped taking insulin, did not fill an insulin prescription or did not start insulin therapy due to cost. Poor glycemic control was defined as an HbA1c of at least 9%, determined by medical records.

Overall, 51 patients (25.5%) reported cost-related insulin underuse.

“This means that 1 in 4 patients was using less of an essential medicine because it cost too much for them to take the prescribed amount,” Herkert said.

Patients reporting cost-related underuse had lower income levels, variable drug coverage and employment, Herkert said. Enrollment in an employer-sponsored health plan did not appear to have a protective effect against cost-related insulin underuse vs. other prescription drug plans.

In multivariable analyses, researchers found that patients also had threefold higher odds of having an HbA1c of at least 9% vs. patients who did not report insulin underuse (P = .03), Herkert said.

Herkert noted that because the sample was small, there was limited power to test associations with insulin underuse, and a causal relationship between cost-related insulin underuse and poor glycemic control could not be established.

“Access to more affordable insulin is urgently needed, and we need greater transparency with regards to the way insulin is priced and greater advocacy for those patients who are unable to afford their prescriptions,” Herkert said.

As previously reported by Endocrine Today, stakeholders from the diabetes community in May addressed concerns regarding insulin pricing before the U.S. Senate Special Committee on Aging, outlining the complex problems that place insulin out of reach for some patients with diabetes and seeking help from legislators to demand more accountability in drug pricing. The American Diabetes Association simultaneously published in Diabetes Care a white paper on insulin access and affordability. In his testimony in May, William T. Cefalu, MD, chief scientific, medical and mission officer for the ADA, said the ADA will soon release a follow-up paper with more specific public policy recommendations on lowering out-of-pocket costs for people with diabetes. – by Regina Schaffer


Herkert DM, et al. 2-OR. Presented at: American Diabetes Association 78th Scientific Sessions; June 22-26, 2018; Orlando, Fla.

Disclosure: Herkert reports no relevant financial disclosures.