Automated Insulin Delivery Benefits Adults with Type 2 Diabetes Regardless of C-Peptide Levels: Study Finds
USA: A new study published in Diabetes Care revealed that automated insulin delivery (AID) systems lowered A1C levels and increased time in the glucose range for adults with type 2 diabetes, regardless of their C-peptide levels. Researchers concluded that having a low C-peptide level should not be a prerequisite for AID therapy.
The study addresses a key policy issue: the Centers for Medicare & Medicaid Services (CMS) currently requires a low C-peptide level for insulin pump coverage unless the individual is β-cell autoantibody positive. This requirement limits access to automated insulin delivery systems for many adults with type 2 diabetes, even when they could benefit from the technology.
Researchers performed a secondary analysis of the Randomized Trial Evaluating the Efficacy and Safety of Control-IQ+ Technology in Adults With Type 2 Diabetes Using Basal-Bolus Insulin Therapy. The trial assessed the t:slim X2 insulin pump with Control-IQ+ technology in adults with insulin-treated type 2 diabetes.
Participants were grouped based on C-peptide levels according to CMS criteria: 195 patients had high C-peptide levels, while 59 were classified as having low C-peptide levels. All participants had blood glucose ≤225 mg/dL at the time of C-peptide measurement and were negative for antiglutamic acid decarboxylase antibodies.
Key Findings:
- Over the 13-week study, adults using AID systems experienced significant improvements in glycemic control.
- Mean A1C levels in the AID group decreased by 0.8% from baseline, a significantly greater reduction than in the control group for both high and low C-peptide subgroups.
- Patients using AID spent more time in the target glucose range (70–180 mg/dL) than those in the control group, with significant improvements in both high and low C-peptide categories.
- Among adults aged 65 years or older, AID therapy led to larger A1C reductions for those with high C-peptide levels compared with the control group.
- Although reductions for older patients with low C-peptide levels were not statistically significant, overall glycemic improvements were observed across all C-peptide groups.
The study highlights that the benefits of automated insulin delivery are not limited to patients with low C-peptide levels. “A benefit of AID is present with high C-peptide levels and low C-peptide levels. Thus, requiring a low C-peptide level as a prerequisite for AID therapy is not warranted,” the authors wrote.
The study was led by Dr. Irl B. Hirsch of the University of Washington School of Medicine in Seattle. The researchers noted certain limitations, including the small number of participants in the low C-peptide subgroup, the 13-week duration of the trial, and the fact that C-peptide measurements were not always taken in fasting conditions.
Overall, the findings suggest that automated insulin delivery systems can improve glycemic outcomes for adults with type 2 diabetes regardless of residual insulin production, supporting broader access to AID technology and challenging current CMS coverage requirements.
Reference:
Irl B. Hirsch, Yogish C. Kudva, David T. Ahn, Thomas Blevins, Michael R. Rickels, Dan Raghinaru, John W. Lum, Craig Kollman, Jordan E. Pinsker, Roy W. Beck, 2IQP Study Group; Adults With Type 2 Diabetes Benefit From Automated Insulin Delivery Irrespective of C-Peptide Level. Diabetes Care 2025; dc251125. https://doi.org/10.2337/dc25-1125
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