Aims: A retrospective observational cohort study evaluating real-world outcomes in adults with type 1 diabetes and gastroparesis using automated hybrid closed loop insulin delivery systems (HCL).

Materials and methods: All adults with type 1 diabetes and gastroparesis attending King's College Hospital diabetes service and using continuous glucose monitoring (CGM) from 5 October 2023 to 16 January 2025 were included. Glycaemic data (HbA_1c, CGM metrics), hypoglycaemia awareness (Gold score), diabetes distress (DDS2), and acute complications (DKA, severe hypoglycaemia) were collected from electronic health records and glucose platforms for 12 months pre- and post-HCL initiation.

Results: From 1827 clinic attendees, 36 adults with gastroparesis were identified, with 17 initiating HCL. HCL and non-HCL groups had comparable baseline characteristics and metrics (HCL: Mean(SD) HbA_1c 70(21)mmol/mol [8.6(1.9)%]; Time in range (TIR) 36.8 (21.9) % vs. non-HCL: HbA_1c 71 (25) mmol/mol [8.6(2.3)%]; TIR 37.1(19.2)%, p = 0.73). Post-HCL, HbA_1c median(IQR) fell to 57(52.5-65.0) mmol/mol [7.4(7.0-8.1)%] (p < 0.001). TIR increased to 55.7(19.9)% (p < 0.001), with a significant reduction in Time above range Level 2 (TAR2) [>13.9 mmol/L/>250 mg/dL](32.7% to 14.5%, p = 0.014). Gold score improved (2.5 to 1.5, p = 0.019), but DDS2 remained unchanged. No increase in DKA or severe hypoglycaemia occurred.

Conclusions: Within a specialist multidisciplinary team setting, HCL systems significantly reduce HbA_1c without increasing risk of severe hypoglycaemia or DKA in people with type 1 diabetes and gastroparesis.