Non-glycemic effects of insulin therapy: a comparison between insulin aspart and regular human insulin during two consecutive meals in patients with type 2 diabetes

Abstract

ObjectiveTo control postprandial hyperglycemia in insulin-treated type 2 diabetic patients, prandial therapy with regular human insulin (HI) or fast acting insulin analogs is used. Postprandial hyperglycemia seems to be reduced more effectively with insulin analogs than with normal insulin, but there are no data concerning the effect on lipolysis or pancreatic insulin and proinsulin secretion of normal insulin in comparison to insulin analogs.Design and methodsWe included 13 patients with type 2 diabetes mellitus (age 62.2±10.3 years) with preexisting insulin therapy in this crossover, prospective, open-labeled, randomized trial comparing regular HI with insulin aspart (IA) in the setting of a standardized breakfast and a standardized lunch 4 h later. Blood samples for determination of glucose, free fatty acids (FFA), triglycerides, C-peptide, and intact proinsulin were drawn during fasting and every 30 min until 4 h after the second test meal. Statistical analysis was performed with ANOVA for repeated measurements and paired Student's t-test.ResultsThe mean increase in blood glucose was significantly lower after IA (24.18±16.33 vs 34.92±29.07 mg/dl, P=0.02) compared with HI. Both therapies reduced FFA; however, the mean reduction was significantly higher after IA than after HI (−0.47±0.16 vs −0.35±0.15 μmol/l, P<0.001). The mean increase in intact proinsulin was significantly lower after IA than after HI (10.53±5 vs 15.20±6.83 pmol/l, P<0.001). No differences were observed in the C-peptide levels between the two groups.ConclusionIn the setting of two consecutive meals, IA reduces lipolysis and proinsulin secretion more effectively than HI.