Patients living with highly unstable type 1 diabetes (T1D) are eligible for beta-cell replacement (βCR) therapy (islet or pancreas transplantation). This study aimed to evaluate glycemic control in patients treated with automated insulin delivery (AID) following failed βCR therapy, defined as secondary graft failure or marginal function.

A national, multicenter, retrospective study was conducted with 23 patients who had βCR failure treated with AID for at least three months. The primary outcome was the proportion of patients achieving recommended glucose targets (time in 70-180mg/dl range [TIR] > 70%, time below range [TBR] < 4% and HbA1c < 7%). Secondary outcomes included TIR, glycemia risk index (GRI), HbA1c, coefficient of variation (CV), body weight, insulin doses, severe hypoglycemia and AID discontinuation.

The proportion of patients achieving recommended glucose targets under AID increased from 5.0% to 57.1% after 12 months. TIR increased from 54.2 ± 18.0% to 75.5 ± 9.6% after 12-month AID, while GRI decreased from 45.8 ± 22.2% to 25.6 ± 10.3%. HbA1c levels decreased from 7.5 ± 0.9% to 7.0 ± 1.1% after 12-month AID. CV, body weight and insulin doses did not change. All patients were free from severe hypoglycemia under AID, including those who had experienced severe hypoglycemia after βCR failure. No patient discontinued the AID.

This study highlights the effectiveness of AID in achieving glucose control targets and preventing severe hypoglycemia in patients with T1D following βCR failure. AID may serve as a valuable therapeutic option to improve glucose control when graft function declines.