Orlando, FLORIDA — Use of continuous glucose monitoring (CGM) and automated insulin delivery (AID) systems doesn’t guarantee achievement of A1c targets or avoidance of severe hypoglycemia in people with type 1 diabetes (T1D), new survey data suggested.

In a follow-up survey of > 1000 adults with T1D from the T1D Exchange, about 90% were using CGMs and two thirds were using AIDs. Yet, about a third were still unable to reach A1c levels below the recommended 7%, nearly a third had impaired awareness of hypoglycemia (IAH), and about one in five said they’d had at least one severe hypoglycemia episode (SHE) in the past year. Those two hypoglycemia metrics were nearly identical to those reported in a previous survey of over 2000 participants, from whom the current group is a subset.

“These results highlight the need for innovative approaches to enable people with type 1 diabetes to reach glycemic targets whilst also avoiding hypoglycemia to decrease the risk of complications and improve quality of life,” Jennifer L. Sherr, MD, PhD, professor of pediatrics at Yale University School of Medicine, New Haven, Connecticut, said in her presentation of the data at the 2024 annual American Diabetes Association Scientific Sessions.

This follow-up survey was the first to ask patients what had happened that led to the low blood sugar episode. The most common reasons given were miscalculation of insulin dose, overestimation of carbohydrates, physical activity, and missing a meal. “The technology right now can’t fix any of that. What this tells me is that we have much better tools today, but there’s so much that still leaves us at risk,” Sherr, who has T1D herself, told Medscape Medical News.

Asked to comment, session moderator Ilias (Elias) Spanakis, MD, Associate Professor of Medicine at the University of Maryland, Baltimore, told Medscape Medical News, “This is an important study evaluating severe hypoglycemic events and impaired hypoglycemic awareness among patients with type 1 diabetes using advanced diabetes technologies. The study design is based on surveys and as the authors correctly acknowledged, the results can be affected by recall bias.”

Nonetheless, Spanakis, who is also chief of the Endocrinology, Diabetes and Nutrition Section of the VA Maryland Health Care System, added, “these results can also mean that IAH and SHE have multifactorial causes, and the use of CGMs and AIDs can have only a modest impact in these important and complicated conditions.”

Hypoglycemia Still a Problem, Despite High CGM Use

In the previous survey of 2074 participants, conducted between February and April 2021, > 40% had not achieved an A1c level below 7.0%, about 20% had experienced at least one SHE within a 12-month period, and about 30% had reported IAH.

The new survey of 1056 (about 50%) from the original group was conducted between April and May of 2023. Current measures of A1c were the most recent one in the 12 months prior to the survey, while IAH was assessed by the Gold Score (1 = always aware of lows to 7 = never aware, with IAH defined as a score ≥ 4). Severe hypoglycemia was measured with the question “In the past 12 months, how many times did you experience low blood sugars that you were unable to treat yourself and needed help from others?”

Nearly all the 1056 participants who had been using CGM at the time of the first survey were still using it, with only 2.1% having stopped CGM and 6.6% initiating it, bringing the total using CGM from 91.8% to 94.4% from the previous to the current survey. There was a greater increase in AID use, from 53.5% to 69.0%, with just 1.6% stopping AID use and 18.0% initiating it between the two surveys.

Yet, the proportions achieving A1c levels less than 7% barely moved, from 62.1% previously to 67.4% in the current survey. The proportions experiencing IAH dropped insignificantly from 30.6% to 29.1%. And, despite the high use of CGM and greater use of AIDs, the proportions reporting one or more SHEs actually rose slightly from 16.8% to 19.0%. The proportions reporting at least two SHEs were nearly identical at the two time periods, 9.6% previously and 10.0% in the newer survey.

When the 201 participants who reported SHEs were asked about the causes, the most common was overestimation of insulin dose or carbohydrate count. Physical activity was second, at 36.3%, and delayed or smaller meal was endorsed by 20.9%.

The majority of SHEs, 88.6%, were treated outside of healthcare settings, typically by a spouse or friend, while just 14.4% were treated by an emergency medical professional. Smaller proportions, 2.5% each, were treated during outpatient or inpatient visits. “This suggests that many severe hypo events may not be captured by healthcare data, and the prevalence of these events are likely significantly underrepresented,” Sherr said in her presentation.

She told Medscape Medical News, “The technology has been great. But these data highlight that there is still going to be human error, severe hypo is still prevalent, and we do see impaired awareness in a number of individuals. How do we identify those individuals and give them the training, education, and treatment necessary to avoid severe hypo events? And then how do we look at the future of treatment, cell-based therapies and other things that will make us less reliant on technology?”

Sherr received research support, served as a consultant, and/or served on advisory boards for Abbott Diabetes, Breakthrough T1D, Medtronic, NIH, Provention Bio, Insulet, Zealand, Cecelia Health, Mannkind, StartUp Health T1D Moonshot, and Vertex Pharmaceuticals. Spanakis received research support to his institutions from Dexcom and Tandem Diabetes for the conduction of clinical studies.

Miriam E. Tucker is a freelance journalist based in the Washington DC area. She is a regular contributor to Medscape Medical News, with other work appearing in the Washington Post, NPR’s Shots blog, and Diatribe. She is on X @MiriamETucker.