Cost Issues Prevent a Quarter of Patients From Taking Insulin

Becky McCall

June 23, 2018

ORLANDO — Cost issues related to insulin use prevent a full quarter of patients with diabetes taking insulin as prescribed, and this is associated with poorer glycemic control, shows a new study.

Low to middle income patients were worse off, the data indicate. Patients in the $25,000 to $99,000 income bracket were significantly more likely to underuse insulin because of cost barriers, Darby Herkert, BS, from Yale University, New Haven, Connecticut, reported here today at the American Diabetes Association (ADA) 2018 Scientific Sessions.

"We were shocked to find that 25.2% of patients surveyed were underusing insulin in some way in the past year due to cost, and we found this was common across different drug prescription plans," Herkert said in an interview with Medscape Medical News. "Such a high number of patients using less of a life-saving medication is tragic."

Those patients who underused insulin because of cost were found to have a three-fold higher odds of poor glycemic control compared with those not underusing (odds ratio, 3.12; P = .03).

"Not only are patients using less of this medicine due to high cost, but this is having a tangible, detrimental health effect," Herkert added.

One delegate, Carolyn Cox, RD, from Sharp Healthcare in San Diego, California, who spoke to Medscape Medical News, explained that patients struggling with the high costs of insulin was an everyday experience at her center.

"Patients might go to the pharmacy and find that the [insulin] analog they are discharged on is extremely expensive, at $300 to $400 per vial. These patients don't take insulin as prescribed, or not at all, but they don't have a prescription for anything else and end up being rehospitalized."

"These prices are irrational because these insulins have not changed for years...I live on the Mexico border, and we have patients going across the border to buy their insulin for less," she noted.

"We tell people to go to Walmart to get the human insulin ReliOn, which is much less expensive. Also, you can buy regular insulin without a prescription, but many people don't realize this," she added.

First Study to Relate Cost, Insulin Underuse, and Poor HbA1c

Extortionate price rises for insulin analogs have taken effect in recent years in the United States in particular. Between 2002 and 2013, prices rose from an average of $4.34/mL to $12.92/mL, according to one study (JAMA2016;315:1400-1402).

No generic insulin is available; there are biosimilar insulins but the price for these isn't much lower than for the regular analogs.

"Take insulin lispro, for example. It used to cost $59 per vial in 2004 but now costs $359 per vial," Herkert said during her talk.

She explained that although prior studies have pointed to the potential role of medication cost in insulin underuse, to her knowledge there had not previously been research that examined cost-related insulin underuse, associated factors, and subsequent effects.

In light of this, Herkert and her Yale colleagues set out to try to dissect three aspects of the problem: the proportion of patients who use less than their prescribed insulin because of cost, the factors associated with insulin underuse, and the association between insulin underuse and poor glycemic control.

To achieve this, they conducted a cross-sectional survey and cognitive interviews with patients from Yale Diabetes Center.

Out of 354 eligible patients with type 1 or type 2 diabetes, 199 (56.2%) completed the questionnaire. Patients had to have been prescribed insulin in the past 6 months and made an outpatient visit between June and August 2017. Demographic and socioeconomic factors were collated along with information on insulin underuse because of cost and subsequent glycemic control.

Questions about insulin use included whether the patient had used less insulin than prescribed, had tried to "stretch out" their insulin, or did not fill a prescription.

An HbA1c ≥ 9% was considered poor glycemic control.

After stratification of patients who underused insulin because of cost, the analysis showed that "around 50% were female, and primarily white, followed by African American, then Hispanic, and then other races/ethnicities; 41.7% of patients had type 1 diabetes."

"The numbers show us that patients who are more likely to underuse are those in the middle-income range of $25,000 to $100,000."

"Above a $100,000 income and below $10,000 the odds of underuse drop again. We speculate that this is due to insurance plan coverage and inability to pay out-of-pocket."

"These results highlight an urgent need to address high insulin prices in the United States," they conclude.

More Research and Greater Advocacy Needed

Herkert remarked that the small, single-site study "has some limitations regarding generalizability; however, the Yale Diabetes Center covers New Haven, which is well known as a microcosm of the US general population."

Ideally, she would like to do a much larger prospective nationwide study.

"We'd like to look at more outcomes beyond just HbA1c levels as a measure of diabetes management. For example, it would be helpful to look at hospitalizations and ketoacidosis or hypoglycemia —the type of data that we cannot obtain from the small study conducted here."

The study findings are all the more pertinent given recent renewed efforts to highlight the excessive high cost of insulin in the United States.

Last month, a white paper by the ADA Insulin Access and Affordability Working Group, entitled Insulin Access and Affordability: The Rising Costs of Treatment, was released to coincide with a hearing by the US Senate Special Committee on Aging.

And, as reported by Medscape Medical News, the American Medical Association has just issued a statement calling for price transparency and for the Federal Trade Commission and Justice Department to monitor insulin pricing.

Physicians are joining their patients in protest too, taking to the streets back in April to help draw attention to the issue.

"This is a huge problem," said Cox.

The authors and Cox have reported no relevant financial relationships.

American Diabetes Association 2018 Scientific Sessions. June 22, 2018; Orlando, Florida. Abstract 2-OR.

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