Glycaemic control in individuals with type 1 diabetes using an open source artificial pancreas system (OpenAPS).

Open source artificial pancreas systems (OpenAPS) have gained considerable interest in the diabetes community. We analyzed continuous glucose monitoring (CGM) records of 80 OpenAPS users with type 1 diabetes (T1D). A total of 19 495 days (53.4 years) of CGM records were available. Mean glucose was 7.6 ± 1.1 mmol/L, time in range 3.9-10 mmol/L was 77.5 ± 10.5%, <3.9 mmol/L was 4.3 ± 3.6%, <3.0 mmol/L was 1.3 ± 1.9%, >10 mmol/L was 18.2 ± 11.0% and > 13.9 mmol/L was 4.1 ± 4.0%, respectively. In 34 OpenAPS users, additional CGM records were obtained while using sensor-augmented pump therapy (SAP). After changing from SAP to OpenAPS, lower mean glucose (-0.6 ± 0.7; P < 0.0001), lower estimated HbA1c (-0.4 ± 0.5%; P < 0.0001), higher time in range 3.9-10 mmol/L (+9.3 ± 9.5%; P < 0.0001), less time < 3.0 mmol/L (-0.7 ± 2.2%; P = 0.0171), lower coefficient of variation (-2.4 ± 5.8; P = 0.0198) and lower mean of daily differences (-0.6 ± 0.9 mmol/L; P = 0.0005) was observed. Glycaemic control using OpenAPS was comparable with results of more rigorously developed and tested AP systems. However, OpenAPS was used by a highly selective, motivated and technology-adept cohort, despite not being approved for the treatment of individuals with T1D.