The effect of the optimal use of rapid-acting insulin analogues on insulin secretion in Type 2 diabetes

The abnormal glucose tolerance of Type 2 diabetes is characterized by post-prandial hyperglycaemia. We aimed to examine whether the restoration of a more physiological insulin profile using rapid-acting insulin analogues might, through effects on glucose toxicity, improve endogenous insulin secretion rate (ISR) and secondly improve markers of vascular risk. Eighteen people with insulin-treated Type 2 diabetes were recruited into a single centre, cross-over, open-labeled study. The order of pre-meal unmodified human insulin or insulin aspart was randomized: treatment periods lasted at least 8–12 weeks after which ISR was assessed by stepped low-dose glucose infusion and fasting markers of vascular risk measured. Glucose control was good (HbA1c 6.94±0.12 (±S.E.)% versus 7.07±0.13%, NS) with insulin aspart and human insulin. Mean post-prandial self-monitored blood glucose concentration was also good particularly with insulin aspart (7.5±0.41mmol/l versus 8.19±0.34mmol/l) but the difference did not reach statistical significance. Over 160min ISR did not differ between insulin aspart and human insulin and there was also no change in various markers of vascular risk. In conclusion a meal-time+basal insulin regimen gave close to normal post-prandial blood glucose control with both the insulin aspart and human insulin regimens, such that no difference in ISR or markers of vascular risk could be demonstrated.