Only 20% With Type 1 Diabetes Are Meeting HbA1c Goals

Miriam E. Tucker

January 28, 2019

Only about one in five people with type 1 diabetes in the United States is achieving optimal glycemic control despite increased use of technologies such as insulin pumps and continuous glucose monitors (CGMs), new data show. 

The findings, from the T1D Exchange registry, were recently published online in Diabetes Technology & Therapeutics by Nicole C. Foster, MS, Jaeb Center for Health Research, Tampa, Florida, and colleagues. 

Of particular concern, glycemic control actually appears to have worsened among adolescents and young adults between the periods of 2010-2012 and 2016-2018, and racial disparities remain in both use of diabetes technologies and glycemic control.

What's more, the T1D Exchange is comprised of centers that focus on the care of type 1 diabetes in both adults and children, representing "30,000 patients followed at the leading centers in the United States," notes senior author Satish Garg, MD, professor of medicine and pediatrics at the University of Colorado Denver, Aurora, in a statement by Diabetes Technology & Therapeutics.

So glycemic control among individuals cared for outside of these settings would be expected to be even worse, the researchers note.

A Snapshot of What's Happening: Pump and CGM Use Have Risen

With their article, Foster and colleagues set out to provide a snapshot of the profile of adults and youth with type 1 diabetes in the United States and to assess longitudinal changes in management and clinical outcomes in the registry.

Insulin pump use increased from 57% in 2010-2012 to 63% in 2016-2018, particularly among children younger than 6 years (from 50% to 60%) and those aged 6-12 years (58% to 68%). Pump use also increased among adults.

At the same time, CGM use rose even more dramatically, from 7% to 30% overall during the two time periods, particularly during 2013 and 2014.

Uptake among children younger than 6 years of age was "most prominent," rising more than tenfold, from 4% to 51%, and CGM use among 6 to 12 year olds jumped from 3% to 37%.

"This is presumably related to the ability of a parent to monitor the CGM glucose data remotely," the authors note.

Increases in CGM use were fairly steep among adults as well, from 15% to more than a third of those aged 26 and older.   

But device usage varied dramatically by race and income level. For example, 81% of white children younger than 13 years of age with annual household incomes of $75,000 or greater were using insulin pumps, compared with just 37% of black children of the same age with annual household incomes less than $50,000. For CGM use, those proportions were 54% versus 8%, respectively.

However, most participants never downloaded blood glucose meters, CGM devices, or insulin pumps at home. With the exception of the Dexcom "share" feature, use of mobile applications was uncommon.

The authors expect that to change with time, though.

"With recent greater emphasis on seamless transmission of data to the cloud and enhancements in reporting and decision-support tools, the integration of device data into self-management can be expected to increase."

Despite Devices, Metabolic Control Far From Ideal

Among 9657 participants with data for both 2010-2012 and 2016-2018, overall adjusted mean HbA1c was actually higher in the more recent period, averaging 7.8% in 2010-2012 and 8.4% in 2016-2018 (P < .001).

The increase was particularly dramatic among adolescents and young adults.  

Specifically, during 2016-2018, mean HbA1c levels were highest, at 9.3%, among teens aged 15-18 years, with averages of 8.1% and 8.0%, respectively, for those aged 5 years and 28 years, and levels remained steady, at about 7.5%-7.9%, beyond age 30 years.

Foster and colleagues call the data on adolescents and young teens a "surprising finding," noting, "we do not have an explanation for this increase," other than that it could be because of "unmeasured confounding factors."

Proportions achieving American Diabetes Association targets of less than 7.5% for youth and less than 7.0% for adults were just 17% and 21%, respectively.

And mean HbA1c levels were higher in African Americans than white or Hispanic patients across all age groups, even after adjustment for socioeconomic status.

HbA1c and Acute Complications Lower in Pump/CGM Users

HbA1c was significantly lower in insulin pump and CGM users than non-users after adjustment for age, diabetes duration, race/ethnicity, and annual income, however (P < .001).

But among CGM users, HbA1c didn't differ significantly between those using pumps versus multiple daily insulin injections, except among adolescents and young adults, in whom HbA1c was lower in pump users. 

With regard to acute complications, in 2016-2018 the adjusted frequency of severe hypoglycemia was lower for pump users versus non-users (5% vs 9%; P < .001) and those using versus not using CGM (5% vs 7%; P = .06).

Diabetic ketoacidosis also occurred less often in those using pumps compared with injections (2% vs 4%; P = .002) and those using versus not using CGM (1% vs 3%; P = .04).

"There is no indication from these data that HbA1c levels in the registry as a whole have improved over this 5-year period despite an increase in the use of insulin pumps and CGM," the authors summarize. 

"We hope that these data will stimulate further research and efforts to find ways to improve glucose control and bridge the gap in different racial backgrounds," they conclude.

The authors have reported no relevant financial relationships.

Diabetes Technol Ther. Published online January 18, 2019. Full text

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