Long-Term Improvements in Glycemia and User-Reported Outcomes Associated with Open-Source Automated Insulin Delivery Systems in Adults with Type 1 Diabetes in the United Kingdom: A Real-World Observational Study

<b><i>Objective:</i></b> To evaluate real-world outcomes in adults with type 1 diabetes initiating open-source automated insulin delivery systems (OS-AID). <b><i>Methods:</i></b> Adults with type 1 diabetes who commenced OS-AID, between May 2016 and April 2021, across 12 centers in the United Kingdom were included. Anonymized clinical data, collected during routine clinical care between December 2019 and November 2023, were submitted to a secure web-based tool within the National Health Service network. Outcomes included change in hemoglobin A1c (HbA1c), sensor glucometrics, diabetes distress score, Gold score (hypoglycemia awareness), user opinion of OS-AID, and event rates (hospital admissions, paramedic callouts, severe hypoglycemia, and adverse events) between baseline and follow-up. <b><i>Results:</i></b> In total, 81 OS-AID users were included (51.9% male; 90.1% White British; mean age 41.4 years; median diabetes duration 25 years [IQR 17-32]). Over a mean follow-up of 1.7 years, HbA1c reduced by 0.8% (9 mmol/mol) (7.3 ± 1.1% vs. 6.5 ± 0.7%; <i>P</i> < 0.001), and the percentage of individuals achieving HbA1c ≤ 7.0% (53 mmol/mol) increased from 48.6% to 75.7% (<i>P</i> < 0.001). Diabetes-related distress score reduced by 0.9 (95% confidence interval [CI] -0.3, -1.5; <i>P</i> = 0.006), and Gold score reduced by 0.7 (95% CI -0.1, -1.3; <i>P</i> = 0.022). The percentage of individuals with impaired hypoglycemia awareness (Gold score ≥4) reduced (27.8% at baseline vs. 8.3% at follow-up; <i>P</i> = 0.039). Of those asked, all participants stated that OS-AID had a positive impact on quality of life. The number of hospital admissions was low. <b><i>Conclusions:</i></b> The use of OS-AID is associated with long-term improvements in HbA1c, hypoglycemia awareness, and diabetes-related distress in type 1 diabetes. These benefits were achieved without increased rates of hospital admissions, diabetic ketoacidosis, or severe hypoglycemia.