Hybrid Closed-Loop Therapy in Adults with Type 1 Diabetes in England: Long-Term Outcomes from a Real-World Observational Study

Objective: To evaluate longitudinal real-world outcomes in adults with type 1 diabetes initiating hybrid closed loop (HCL).

Methods: Adults with type 1 diabetes, managed with an insulin pump and intermittently scanned continuous glucose monitoring with hemoglobin A1c (HbA1c) ≥8.5% (69 mmol/mol), were started on HCL between August and December 2021 as part of the National Health Service England HCL pilot. We collected outcomes, including change in HbA1c, sensor glucometrics, Gold score (hypoglycemia awareness), diabetes distress score, acute event rates, and user opinion of HCL.

Results: In total, 420 HCL users across 30 diabetes centers in the United Kingdom were included (median age 40 [interquartile range or IQR 29–50] years, 68% female, 85% White British). Over a median follow-up of 12 months (IQR 8–28) (range 6–38 months), mean adjusted HbA1c reduced by 1.4% (95% confidence interval [CI] −1.5, −1.3; P < 0.001) (16 mmol/mol [95% CI −17, −14]; P < 0.001). Time in range (70–180mg/dL) increased from 33.7% to 60.4% (P < 0.001). The proportion of individuals achieving HbA1c ≤7.5% (58 mmol/mol) increased from 0% to 33.1% (P < 0.001). Diabetes distress score reduced (−1.1; 95% CI −1.3, −1.0; P < 0.001) and Gold score reduced (−0.4; 95% CI −0.5, −0.2; P < 0.001). The percentage of individuals with impaired hypoglycemia awareness (Gold score ≥4) decreased (16.6% [baseline] vs. 9.2% [follow-up]; P < 0.001). Almost all participants stated that HCL had a positive impact on quality of life (94.5%; 361/382). The number of hospital admissions was low.

Conclusions: Long-term real-world use of HCL is associated with sustained improvements in glycemic and person-reported outcomes in adults with type 1 diabetes and above-target HbA1c levels.