Intensification to biphasic insulin aspart 30/70 (BIAsp 30, NovoMix 30) can improve glycaemic control in patients treated with basal insulins: a subgroup analysis of the IMPROVE observational study.

Aims: The international IMPROVE observational study investigated the safety profile and effectiveness of biphasic insulin aspart 30/70 (BIAsp 30) in the routine treatment of patients with type 2 diabetes. We present analyses for the subgroup of patients who switched from basal insulin to BIAsp 30.

Methods: Patients in routine care who started insulin therapy with or switched to BIAsp 30 from existing insulin regimens were eligible for this 26-week study. This analysis includes only patients previously treated with basal insulin. Outcomes including adverse events, hypoglycaemic events and glycaemic profile were recorded from patients' notes, recall and diaries.

Results: Of the 748 patients included (age 59.7+/-11.8 years, diabetes duration 11.4+/-7.3 years, baseline HbA1c 9.1+/-1.6%), 497 were previously using human neutral protamine Hagedorn (NPH) insulin and 245 analogue basal insulin. Overall, major and minor hypoglycaemia rates decreased from baseline to final visit (major: 0.171 to 0.011; minor: 9.70 to 5.89 events/patient-year) and were similar between the subgroups. HbA1c and fasting blood glucose were significantly reduced from baseline (NPH prestudy: -1.6%, -2.4 mmol/l; analogue basal prestudy: -1.8%, -2.4 mmol/l), as was postprandial blood glucose, with 33.8% of patients achieving the HbA1c target < 7% without hypoglycaemia. Insulin dose increased slightly from prestudy (0.33+/-0.21 U/kg), baseline (0.40+/-0.20 U/kg) to final visit (0.52+/-0.26 U/kg); most patients (76%) followed a twice-daily regimen at final visit. Body weight did not change significantly and treatment satisfaction increased.

Conclusions: Patients with type 2 diabetes inadequately controlled on basal insulins may improve their glycaemic control by intensification to BIAsp 30 therapy.