Does early closed-loop therapy preserve pancreas function in youth with type 1 diabetes?

The researchers reported that youth who started on a hybrid closed-loop system within 21 days of diagnosis versus standard insulin therapy did not have less decline in residual C-peptide secretion (mean adjusted difference -0.06 pmol/mL) at 12 months.

Roman Hovorka, Wellcome–Medical Research Council Institute of Metabolic Science, Addenbrooke's Hospital, United Kingdom, and colleagues sought to clarify whether improved glucose control with hybrid closed-loop therapy can help to preserve C-peptide secretion compared to standard insulin therapy in people with new-onset type 1 diabetes in a multicenter, open-label, parallel-group, randomized trial.

Youths (n=97) aged 10.0 to 16.9 years of age (mean age, 12 years) were assigned within 21 days after type 1 diagnosis to receive hybrid closed-loop therapy (n=51) or standard insulin therapy (control; n=46) for 24 months. The analysis was done on an intention-to-treat basis. The study's primary endpoint was the curve (AUC) for the plasma C-peptide level (after a mixed-meal tolerance test) 12 months after diagnosis.

The study yielded the following findings:

• There was no notable difference between the two groups in the AUC for the C-peptide level at 12 months (primary endpoint) (geometric mean, 0.35 pmol per milliliter with closed-loop therapy and 0.46 pmol per milliliter with control therapy; mean adjusted difference, −0.06 pmol per milliliter).
• There was no substantial between-group difference in the AUC for the C-peptide level at 24 months (geometric mean, 0.18 pmol per milliliter with closed-loop therapy and 0.24 pmol per milliliter with control therapy; mean adjusted difference, −0.04 pmol per milliliter).
• The arithmetic means glycated hemoglobin level was lower in the closed-loop group than in the control group by four mmol per mole (0.4 percentage points) at 12 months and by 11 mmol per mole (1.0 percentage points) at 24 months.
• Five cases of severe hypoglycemia occurred in the closed-loop group (in 3 participants), and one occurred in the control group; one case of diabetic ketoacidosis occurred in the closed-loop group.

In an accompanying editorial, Jan Bolinder, the Karolinska Institute in Stockholm, commented, "Currently, hybrid closed-loop therapy is the most efficient option for treating type 1 diabetes, so is it not surprising that superior glucose control was achieved in the closed-loop group."

He further added, "despite this benefit, users of the closed loop system still weren't able to achieve the recommended HbA1c target of 6.5% or below, instead hovering at 6.9% after 12 and 24 months."

According to him, although the trial findings are "somewhat disappointing," it was good that closed-loop therapy aided in long-term glucose control after being introduced close to the time of diagnosis.

"Intensive glucose control for 24 months did not appear to prevent the decline in residual C-peptide secretion in youths with new-onset type 1 diabetes," the study authors concluded.

Reference:

Boughton CK, et al. "Closed-loop therapy and preservation of C-peptide secretion in type 1 diabetes" N Engl J Med 2022; DOI: 10.1056/NEJMoa2203496.