The more technology, the lower the A1c
Over the study period, the proportion of stand-alone CGM users rose from 26.9% to 44.1%, while use of AIDs rose from 0% in 2014 and 2015 to 38.6% in 2021. The latter group included patients who used first-generation Medtronic 670G and 770G devices and second-generation Tandem t:slim X2 with Control-IQ devices.
Between 2017 and 2021, AIDs users had significantly lower A1c levels than nontechnology users: 7.4% vs. 8.1% in 2017, and 7.3% vs. 8.4% in 2021 (P < .001 for every year). CGM users also had significantly lower A1c levels than nonusers at all time points (P < .001 per year).
The proportions achieving an A1c less than 7% differed significantly across users of CGMs, AIDs, and no technology (P < .01 for all years). In 2021, the percentage of people who achieved an A1c less than 7% were 50.9% with AIDs and 44.1% for CGMs vs, just 15.2% with no technology.
Work to be done: Why aren’t more achieving < 7% with AIDs?
Asked why only slightly more than half of patients who used AIDs achieved A1c levels below 7%, Dr. Shah listed three possibilities:
First, the 7% goal doesn’t apply to everyone with type 1 diabetes, including those with multiple comorbidities or with short life expectancy, for whom the recommended goal is 7.5%-8.0% to prevent hypoglycemia. “We didn’t separate out patients by A1c goals. If we add that, the number might go up,” Dr. Shah said.
Second, AID technology is continually improving, but it’s not perfect. Users still must enter carbohydrate counts and signal the devices for exercise, which can lead to errors. “It’s a wonderful technology for overnight control, but still, during the daytime, there are so many factors with the user interface and how much a person is engaged with the technology,” Dr. Shah explained.
Third, he said, “Unfortunately, obesity is increasing in type 1 diabetes, and insulin doses are increasing. Higher BMI [body mass index] and more insulin resistance can mean higher A1c. I really think for many patients, we probably will need an adjunct therapy, such as an SGLT2 [sodium-glucose cotransporter-2] inhibitor or a GLP-1 [glucagonlike peptide-1] agonist, even though they’re not approved in type 1 diabetes, for both glycemic and metabolic control including weight. I think that’s another missing piece.”
He also pointed out, “If someone has an A1c of 7.5%, I don’t expect a huge change. But if they’re at 10%, a drop to 8% is a huge change.”
Overall, Dr. Shah said, the news from the study is good. “In the past, only 30% were achieving an A1c less than 7%. Now we’re 20% above that. ... It’s a glass half full.”
Dr. Karakus has disclosed no relevant financial relationships. Dr. Shah has received, through the University of Colorado, research support from Novo Nordisk, Insulet, Tandem Diabetes, and Dexcom, and honoraria from Medscape, Lifescan, Novo Nordisk, and DKSH Singapore for advisory board attendance and from Insulet and Dexcom for speaking engagements.
A version of this article first appeared on Medscape.com.