Faster insulin action is associated with improved glycaemic outcomes during closed‐loop insulin delivery and sensor‐augmented pump therapy in adults with type 1 diabetes

We aimed to evaluate the relationship between insulin pharmacodynamics and glycaemic outcomes during closed‐loop insulin delivery and sensor‐augmented pump therapy. We retrospectively analysed data from a multicentre randomized control trial involving 32 adults with type 1 diabetes receiving day‐and‐night closed‐loop insulin delivery and sensor‐augmented pump therapy over 12 weeks. We estimated time‐to‐peak insulin action (t _{max, IA} ) and insulin sensitivity ( S _I ) during both interventions, and correlated these with demographic factors and glycaemic outcomes. During both interventions, t _{max, IA} was positively correlated with pre‐ and post‐intervention HbA1c (r = 0.50‐0.52, P < .01) and mean glucose (r = 0.45‐0.62, P < .05), and inversely correlated with time sensor glucose, which was in target range 3.9 to 10 mmol/L (r = ?0.64 to ?0.47, P < .05). Increased body mass index was associated with higher t _{max, I} and lower S _I (both P < .05). During closed‐loop insulin delivery, t _{max, IA} was positively correlated with glucose variability ( P < .05). Faster insulin action is associated with improved glycaemic control during closed‐loop insulin delivery and sensor‐augmented pump therapy.