In adults with type 2 diabetes, the benefits of fully closed-loop insulin delivery, which does not require meal bolusing, are unclear. In an open-label, single-center, randomized crossover study, 26 adults with type 2 diabetes (7 women and 19 men; (mean ± s.d.) age, 59 ± 11 years; baseline glycated hemoglobin (HbA1c), 75 ± 15 mmol mol−1 (9.0% ± 1.4%)) underwent two 8-week periods to compare the CamAPS HX fully closed-loop app with standard insulin therapy and a masked glucose sensor (control) in random order, with a 2-week to 4-week washout between periods. The primary endpoint was proportion of time in target glucose range (3.9–10.0 mmol l−1). Analysis was by intention to treat. Thirty participants were recruited between 16 December 2020 and 24 November 2021, of whom 28 were randomized to two groups (14 to closed-loop therapy first and 14 to control therapy first). Proportion of time in target glucose range (mean ± s.d.) was 66.3% ± 14.9% with closed-loop therapy versus 32.3% ± 24.7% with control therapy (mean difference, 35.3 percentage points; 95% confidence interval (CI), 28.0–42.6 percentage points; P < 0.001). Time > 10.0 mmol l−1 was 33.2% ± 14.8% with closed-loop therapy versus 67.0% ± 25.2% with control therapy (mean difference, −35.2 percentage points; 95% CI, −42.8 to −27.5 percentage points; P < 0.001). Mean glucose was lower during the closed-loop therapy period than during the control therapy period (9.2 ± 1.2 mmol l−1 versus 12.6 ± 3.0 mmol l−1, respectively; mean difference, −3.6 mmol l−1; 95% CI, −4.6 to −2.5 mmol l−1; P < 0.001). HbA1c was lower following closed-loop therapy (57 ± 9 mmol mol−1 (7.3% ± 0.8%)) than following control therapy (72 ± 13 mmol mol−1 (8.7% ± 1.2%); mean difference, −15 mmol mol−1; 95% CI, −11 to −20 mmol l−1 (mean difference, −1.4%; 95% CI, −1.0 to −1.8%); P < 0.001). Time < 3.9 mmol l−1 was similar between treatments (a median of 0.44% (interquartile range, 0.19–0.81%) during the closed-loop therapy period versus a median of 0.08% (interquartile range, 0.00–1.05%) during the control therapy period; P = 0.43). No severe hypoglycemia events occurred in either period. One treatment-related serious adverse event occurred during the closed-loop therapy period. Fully closed-loop insulin delivery improved glucose control without increasing hypoglycemia compared with standard insulin therapy and may represent a safe and efficacious method to improve outcomes in adults with type 2 diabetes. This study is registered with ClinicalTrials.gov (NCT04701424).

We evaluated the safety and efficacy of fully closed-loop insulin therapy compared with standard insulin therapy in adults with type 2 diabetes requiring dialysis. In an open-label, multinational, two-center, randomized crossover trial, 26 adults with type 2 diabetes requiring dialysis (17 men, 9 women, average age 68 ± 11 years (mean ± s.d.), diabetes duration of 20 ± 10 years) underwent two 20-day periods of unrestricted living, comparing the Cambridge fully closed-loop system using faster insulin aspart (‘closed-loop’) with standard insulin therapy and a masked continuous glucose monitor (‘control’) in random order. The primary endpoint was time in target glucose range (5.6–10.0 mmol l−1). Thirteen participants received closed-loop first and thirteen received control therapy first. The proportion of time in target glucose range (5.6–10.0 mmol l−1; primary endpoint) was 52.8 ± 12.5% with closed-loop versus 37.7 ± 20.5% with control; mean difference, 15.1 percentage points (95% CI 8.0–22.2; P < 0.001). Mean glucose was lower with closed-loop than control (10.1 ± 1.3 versus 11.6 ± 2.8 mmol l−1; P = 0.003). Time in hypoglycemia (<3.9 mmol l−1) was reduced with closed-loop versus control (median (IQR) 0.1 (0.0–0.4%) versus 0.2 (0.0–0.9%); P = 0.040). No severe hypoglycemia events occurred during the control period, whereas one severe hypoglycemic event occurred during the closed-loop period, but not during closed-loop operation. Fully closed-loop improved glucose control and reduced hypoglycemia compared with standard insulin therapy in adult outpatients with type 2 diabetes requiring dialysis. The trial registration number is NCT04025775.