Twice daily biphasic insulin aspart improves postprandial glycaemic control more effectively than twice daily NPH insulin, with low risk of hypoglycaemia, in patients with type 2 diabetes.

OBJECTIVE: Biphasic insulin aspart 30 (BIAsp30) is a dual release formulation, containing 30% soluble and 70% protamine-crystallized insulin aspart. This study compared the glycaemic control and safety profiles achieved with either twice daily BIAsp30 or NPH insulin in patients with type 2 diabetes not optimally controlled by oral hypoglycaemic agents (OHAs), NPH insulin or a combination of both.

METHODS: In this 16-week multinational, parallel-group, double-blind trial, 403 such patients were randomized to receive either BIAsp30 or NPH insulin immediately before breakfast and evening meals. OHAs were discontinued at randomization. Efficacy was assessed by glycosylated haemoglobin (HbA1c) and self-recorded daily 8-point blood glucose (BG) profiles. Hypoglycaemic and other adverse events were the chosen safety parameters.

RESULTS: HbA1c concentration decreased by >0.6% (p < 0.0001 vs. baseline) in both groups, with metabolic control continuing to improve throughout the trial without reaching a stable level. Patients who switched from once or twice daily NPH monotherapy to twice daily BIAsp30 achieved a significantly greater reduction in HbA1c (0.78%) than those randomized to twice daily NPH insulin (0.58%; p = 0.03). BIAsp30 decreased mean daily postprandial glycaemic exposure to a greater extent than NPH insulin (mean difference = 0.69 mmol/l; p < 0.0001), reflecting greater decreases in the postbreakfast and postdinner increments (of 1.26 and 1.33 mmol/l, respectively), although postlunch increment was relatively increased (by 0.56 mmol/l). Despite the greater reduction in overall postprandial glycaemic exposure in the BIAsp30 group, the overall safety profile of BIAsp30 was equivalent to that of NPH insulin with <2% of patients experiencing major hypoglycaemia, and approximately 33% reporting minor hypoglycaemic episodes, in both groups.

CONCLUSION: Twice daily BIAsp30 reduced postprandial glucose exposure to a significantly greater extent than NPH insulin and was at least as effective at reducing HbA1c in patients with type 2 diabetes. Both insulins were well tolerated. In patients poorly controlled on OHAs or NPH alone, glycaemic control can be improved by switching to twice daily BIAsp30, without increasing hypoglycaemic risk.