In a clinical study published in JAMA Internal Medicine, researchers found that roughly 30% of patients ration insulin. Lead author Darby Herkert, BS, of Yale College, New Haven, Connecticut, and colleagues affiliated with Yale School of Medicine, Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine; Brigham and Women’s Hospital; Harvard Medical School, Boston, Massachusetts; and Department of Internal Medicine, Yale School of Medicine explored the potential cost-related underuse of insulin in the past 12 months, defined as a positive response to any of the six questions on a survey distributed to roughly 350 eligible patients included in their study sample. 

The survey questions included the following: Have you used less insulin than prescribed? Have you tried to stretch out your insulin?  Have you taken smaller doses of insulin than prescribed? Have you stopped using insulin? Have you not filled an insulin prescription or not started insulin because of cost?

According to senior author and endocrinologist at Yale University, Dr. Kasia Lipska, “You might have heard stories of patients rationing their insulin.” She added, “The stories are really powerful, but they don't tell us how common this problem has become. Our findings show that these are not isolated incidents and that skimping on insulin is frighteningly common. As clinicians, we have to advocate for change because the status quo is simply cruel and not acceptable.” 

The research team highlighted findings that not only does one in four patients use less insulin than prescribed because of cost, but also only one in three of those who do ration does not share this cost-related underuse with their prescribers. The team also explored the clinical impact of this underuse by examining its association with poor glycemic control (HbA1c 9% or greater) using multivariable logistic regression that also considered sex, body-mass index, duration of diabetes, and income. As predicted, patients who reported underuse versus those who were using insulin as directed were more likely to have poor glycemic control (43.1% [n = 22] vs. 28.1% [n = 41]; odds ratio = 2.96; 95% CI, 1.14-8.16; P = .03).

“It was really eye-opening to hear patients’ stories as they turned in completed surveys,” said Darby Herkert, first coauthor of the study and Yale undergraduate. “I’ve worked in various global health settings, but this brought home to me how much patients struggle with costs right here in New Haven.”
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