Three-Year Real-World Performance of Bihormonal Fully Closed-Loop Therapy in Type 1 Diabetes

Type 1 diabetes management continues to advance through novel treatment options, such as bihormonal fully closed-loop (FCL) systems. Real-world data on these systems are currently limited to a maximum of 1 year. Extended follow-up spanning several years would provide valuable insights into long-term performance of a bihormonal FCL.

In a retrospective, observational, real-world cohort study, adults with type 1 diabetes who were treated with the bihormonal FCL system for 3 years were included. Endpoints were determined per 6 months (semester) and included continuous glucose monitoring-derived outcomes. Linear mixed-effects models were used to evaluate changes in outcome measures over time.

A total of 102 users were included in the study. Limited availability of initial glucagon (GlucaGen [GG]) led to a necessary switch to an alternative (Glugon) for a part of the users. GG-only users (n = 60) demonstrated stable glucose outcomes over the 3-year period, whereas a decline was observed in the total group during the final period. In the GG-only group, time in range (TIR; 3.9-10.0 mmol/L [70-180 mg/dL]) ranged from 79.5% to 80.8% and from 77.4% to 80.8% in the total group. For time below range (<3.9 mmol/L [<70 mg/dL]), this was 0.95%-1.56% (GG-only) versus 1.03%-1.69% (total). TIR decreased from 79.3 ± 7.1 to 75.8 ± 7.9 in the 3-month period after the glucagon switch compared to the period before (P < 0.001).

Real-world data demonstrated long-term stability of bihormonal FCL system performance among individuals treated with GG. A slight decline in performance was observed in the total population, and outcomes significantly deteriorated for users after the glucagon switch, indicating a negative effect on FCL performance of the alternative glucagon. Overall, the long-term findings point toward the benefits of the bihormonal FCL to maintain adequate glycemic control in people with type 1 diabetes over several years.