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Despite advancements in insulin treatments over the past three decades, disparities in outcomes have widened among people with diabetes taking them, a new study found.

For example, the share of Mexican Americans taking insulin who achieved good blood-sugar control sharply dropped to 10% during the period of 2013 to 2020 from 25% during 1988 to 1994, researchers reported Tuesday in JAMA Network Open.


With that, the group’s outcomes have increasingly diverged from those of white adults. The proportion of non-Hispanic white people with good blood-sugar management — defined as an A1C below 7% — has stayed roughly the same over time, with 33% achieving it in the most recent period. (The researchers pooled data from multiple years to ensure large enough sample sizes.)

The share of people experiencing severe hyperglycemia — very high blood sugar defined as an A1C over 10% — has been largely unchanged within racial groups, but big gaps have persisted. In the most recent seven years studied, 24% of Mexican Americans and 23% of Black adults taking insulin experienced the condition, while 9% of white adults did, the study said.

The study doesn’t include Asian Americans, because the survey that it’s based on — the National Health and Nutrition Examination Survey — only recently started sampling large numbers of Asian Americans.


Insulin is the primary treatment for people with type 1 diabetes and a critical later-line therapy for those with type 2 diabetes, but the study shows patients have vastly different experiences while on it. This comes even with the development of new insulin formulations and better ways of administering the medication.

“What we want is for all these technologies and all these advances to improve public health,” said Elizabeth Selvin, one of the study’s authors and a professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health. “What we’re actually seeing is a widening of disparities in diabetes.”

The gaps spell serious health consequences, as extended periods of high blood sugar can lead to complications such as kidney disease, vision impairment, and nerve damage.

Groups with lower proportions of glycemic control may be experiencing slower intensification in their treatments, the study said. They may also be skipping doses as insulin prices have surged, and they may have less access to technologies that help manage and monitor blood sugar, such as continuous glucose monitors.

A study published in Diabetes Technology & Therapeutics last month found that even though use of insulin pumps for type 1 diabetes has grown in the past two decades, there were no improvements in racial gaps.

“The health care disparity has been very persistent for diabetes care,” said Frank Hu, professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health. “This is another indication that health disparities in the U.S. have actually exacerbated in the last one or two decades despite great efforts to reduce health disparities.”

STAT’s coverage of chronic health issues is supported by a grant from Bloomberg Philanthropies. Our financial supporters are not involved in any decisions about our journalism.

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