Expensive Insulins, Pen Devices Dominate Diabetes Care in US

Despite the extensive recent focus on its cost, insulin use in the United States remains dominated by insulin glargine and other analogs, as well as pen devices for delivery, new research shows.

The findings come from a nationally representative audit of outpatient care with input from nearly 5000 physicians who prescribed insulin to patients with type 2 diabetes in 2016-2020.

The dramatic rise in the price of insulin in the United States has been extensively discussed in recent years, particularly with the newer analogs as compared with older human insulins.

Few Studies Indicate Analog Insulins Better Than Human Insulins

"Our findings suggest that even with increased public scrutiny for insulin products...[the market is] dominated by the use of insulin analogs and insulin pen delivery devices, with persistent uptake of newer products as they are approved," lead author Rita R. Kalyani, MD, told Medscape Medical News.

"Though newer insulins offer potentially greater flexibility with reduced hypoglycemia for many patients, they are also much more costly, with minimal to no head-to-head studies suggesting significant differences in glucose-lowering efficacy when compared to human insulins," she stressed.

"We found it surprising that, despite the much-publicized concerns regarding insulin costs, analog insulins continue to represent more than 80% of insulin visits in the US," added Kalyani, of the Division of Endocrinology, Diabetes & Metabolism at Johns Hopkins University School of Medicine, Baltimore, Maryland.

However, as expected, the study also revealed a gradual increased uptake in the use of biosimilar insulins as more have been introduced to the market.

Kalyani advised, "Clinicians should be aware of their individual prescribing patterns for insulin and consider the affordability of insulin for patients as part of shared decision-making during clinic visits, particularly given the greater financial strain that many patients have faced during the ongoing COVID-19 pandemic and the rising societal costs for diabetes care."

The research was published online October 12 in JAMA Network Open by Kalyani and colleagues.

Analogs Prevailed, While Biosimilar Use Rose

The data come from the Health National Disease and Therapeutic Index, a quarterly sampling of approximately 4800 physicians that provides nationally representative diagnostic and prescribing information on patients treated by office-based physicians in the United States.

Overall, there were 27,860,691 insulin treatment visits for type 2 diabetes in 2016-2020. Of those, long-acting analog insulins (glargine [Lantus], detemir [Levemir], and degludec [Tresiba]) accounted for 67.3% of treatment visits in 2016 and 74.8% of treatment visits in 2020.

Rapid-acting insulin analogs (lispro [Humalog], aspart [Novolog], faster aspart [Fiasp], and glulisine [Apidra]) accounted for about 21.2% of visits in 2016 and about 16.5% in 2020.

On the other hand, intermediate- and short-acting human insulins (NPH and regular) accounted for just 3.7% of visits in 2016 and 2.6% in 2020.

Grouped together, the long- and short-acting analogs accounted for 92.7% of visits in 2016 and 86.3% in 2020, while the human insulins represented just 7.3% of visits in 2016 and 5.5% in 2020.

The biosimilar analog insulins (glargine and lispro) first appeared in the database in 2017, accounting for 2.6% of visits that year and 8.2% by 2020.

Overall, the number of visits for insulin treatment declined by 18% between 2016 and 2020, from 6.0 million to 4.9 million. That drop may be due to multiple factors, Kalyani said.

"Recently updated clinical practice guidelines from professional societies such as the American Diabetes Association recommend the use of glucagon-like peptide-1 (GLP-1) receptor agonists prior to insulin when injectable medications are being considered [for type 2 diabetes]," she noted.

"In addition, during the pandemic, patients may not have been seeing their healthcare providers for routine diabetes care as often as before...These and other factors may have contributed to the decrease in insulin visits that we observed."

By specific insulins, glargine has topped the list all along, accounting for about half of all treatment visits, at 52.6% in 2020. Degludec came in second, at 17.4%, and lispro third, at 9.5%.

Use of Pen Devices Also Increased

The proportion of treatment visits for insulin vials/syringes declined from 63.9% in 2016 to 41.1% in 2020, while visits for insulin pens rose from 36.1% to 58.7%.

"Many pens are more costly compared to vials of the same insulin product. Interestingly, some studies have found that use of insulin pens may promote greater patient adherence to insulin and, as a result, more broadly decrease healthcare costs associated with diabetes. However, we did not specifically investigate the cost of insulin in our study," Kalyani noted.

The proportion of visits for "newer" insulins, defined as those approved in 2010 or later, rose from 18.1% in 2016 to 40.9% in 2020, while the concurrent drop for insulins approved prior to 2010 was from 81.9% to 59.1%.

"The findings of our study provide insight into potential drivers of insulin costs in the US and may inform health policy," the researchers conclude.

Funded in part by the National Heart, Lung, and Blood Institute. Kalyani currently serves on the Endocrinologic and Metabolic Drugs Advisory Committee of the US Food and Drug Administration .

JAMA Netw Open. Published online October 12, 2021. Full text

Miriam E. Tucker is a freelance journalist based in the Washington, DC, area. She is a regular contributor to Medscape, with other work appearing in the Washington Post, NPR's Shots blog, and Diabetes Forecast magazine. She is on Twitter @MiriamETucker.

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