Aims: To compare the effects of the rapid-acting insulin analogue insulin aspart and soluble human insulin on hypoglycaemia and glycaemic control in patients with Type 1 diabetes when injected immediately before meals as part of intensive insulin therapy.
Methods: In this multinational, double-blind, randomised, crossover trial, 155 patients with Type 1 diabetes (HbA(1c) < 8.0%) were symmetrically randomised to two 16-week treatment periods on either type of insulin, both injected 0-5 min before meals. NPH insulin was given as basal insulin once or twice daily as needed, and insulin dosages were regularly adjusted using pre-defined algorithms to maintain tight glycaemic control. Treatment periods were separated by a 4-week washout.
Results: The rate of major nocturnal (24.00-06.00 h) hypoglycaemic episodes was 72% lower with insulin aspart than with human insulin (0.067 vs. 0.225 events/month; P = 0.001). Total rate of major hypoglycaemia did not differ significantly between treatments (insulin aspart/human insulin relative risk 0.72; 95% CI 0.47-1.09, P = 0.12). The rate of minor events was significantly reduced by 7% with insulin aspart (P = 0.048). Reductions in rate of hypoglycaemia were achieved with maintained overall glycaemic control: Mean HbA(1c) remained constant, slightly below 7.7% on both treatments.
Conclusions: The use of insulin aspart in an intensive insulin regimen in patients with tightly controlled Type 1 diabetes led to clinically significant reductions in major nocturnal hypoglycaemia with no deterioration in glycaemic control. Major nocturnal hypoglycaemia appears to be a strong clinical indication for the use of rapid-acting insulin analogues during intensive insulin therapy.