Comparison of insulin lispro mixture 25/75 with insulin glargine during a 24-h standardized test-meal period in patients with Type 2 diabetes.

AIM: To compare insulin lispro mixture (25% insulin lispro and 75% NPL; Mix 25/75) twice-daily plus oral glucose-lowering medications (metformin and/or sulphonylurea) with once-daily insulin glargine plus oral agents with respect to postprandial glycaemic control and other glucose and lipid parameters in patients with Type 2 diabetes inadequately controlled with insulin and/or oral glucose-lowering agents.

METHODS: This was a randomized, open-label, crossover study. Prestudy oral agents were continued and patients not already on oral agents were treated with metformin. Mix 25/75 and insulin glargine were adjusted over 3 months to attain premeal plasma glucose (PG) < 6.0 mmol/l and were then given during a 24-h in-patient test meal period with frequent PG, serum triglyceride (TG) and free fatty acid (FFA) measurements.

RESULTS: Twenty patients (10 F/10 M; mean +/-sd age 54.0 +/- 10.7 years, body mass index 37.0 +/- 8.6 kg/m2, HbA1c 8.4 +/- 1.01%) participated. Mean doses were 23 U before the morning and 37 U before the evening meal for Mix 25/75 and 44 U for insulin glargine. The combined 2-h morning and evening meal postprandial plasma glucose (PPG) was not different between groups (9.2 +/- 2.04 vs. 9.9 +/- 1.66 mmol/l, P = 0.161). Mix 25/75 was associated with a lower mean 2-h PPG for all meals combined (9.0 +/- 1.88 vs. 9.9 +/- 1.80 mmol/l, P < 0.05) and lower mean 24-h PG (6.7 +/- 1.00 vs. 7.5 +/- 1.32 mmol/l, P < 0.01). Eight patients experienced mild hypoglycaemia (PG < 3.5 mmol/l) with Mix 25/75 and 3 with insulin glargine. The endpoint HbA1c was lower with Mix 25/75 (6.9 +/- 0.52% vs. 7.3 +/- 0.81%, P < 0.05).

CONCLUSIONS: In a 24-h test-meal setting in 20 patients, Mix 25/75 insulin plus oral glucose-lowering agents was associated with lower mean PPG and 24-h PG, more mild hypoglycaemia and similar TG, FFA and fasting PG concentrations. HbA1c was lower with Mix 75/25 plus oral agents, although it may not have reached steady state due to ongoing dose adjustment.