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.