Observations on blood lipid and intermediary metabolite concentrations during conventional insulin treatment or CSII

An objective of The Kroc Collaborative Study Group trial of the feasibility of maintaining improved control of plasma glucose concentrations with continuous subcutaneous insulin infusion (CSII) was to test the non-glycemic aspects of metabolic control in relation to microvascular disease. Serum lipid levels were assessed in the 68 patients completing the 8-mo trial, before and after randomization to conventional insulin treatment (CIT) or CSII. During CSII, fasting serum cholesterol concentrations, normal at baseline (186 +/- 7 mg/dl), were unchanged at 4 and 8 mo (183 +/- 8 and 186 +/- 10 mg/dl). Fasting serum triglyceride concentrations fell on treatment with CSII (baseline 90 +/- 12 mg/dl, 8 mo 60 +/- 7 mg/dl, P less than 0.01), but were unchanged during CIT (baseline 88 +/- 8 mg/dl, 8 mo 83 +/- 10 mg/dl). Thirty-two patients in three centers had 24-h profiles of intermediary metabolites measured at baseline (0), 4, and 8 mo. Mean 24-h venous blood lactate levels fell during CSII (baseline 1.28 +/- 0.12 mmol/L, 4 mo 0.99 +/- 0.4 mmol/L, P less than 0.05; 8 mo 1.05 +/- 0.11 mmol/L), but blood alanine levels were unchanged. Venous blood 3-hydroxybutyrate fell from 0.12 X /divided by 1.18 mmol/L at baseline to 0.06 X /divided by 1.22 mmol/L at 8 mo during CSII (P less than 0.01), mainly due to decreases at 0400 and 0600 h. Decreases in fasting serum triglyceride levels confirm previous investigations of insulin-dependent diabetic subjects treated with CSII; decreases of venous blood lactate and 3-hydroxybutyrate levels toward normal indicate that these metabolic effects of CSII recognized in short-term studies are sustained over an 8-mo period.