HIGH-DOSE INTRAVENOUS INSULIN INFUSION VERSUS INTENSIVE INSULIN-TREATMENT IN NEWLY-DIAGNOSED IDDM

High-dose intravenous insulin infusion at the onset of IDDM has been s uggested to improve beta-cell function during the 1st year of insulin treatment. To test this hypothesis, we randomly assigned newly diagnos ed IDDM patients to receive either an experimental 2-week high-dose in travenous insulin infusion (n = 9; age, 25 +/- 7 years; HbA(1c), 10.5 +/- 2.0%) or an intensive insulin therapy of four injections per day ( n = 10; age, 28 +/- 7 years; HbA(1c), 12.3 +/- 3.0%). The experimental -therapy group received three times more insulin (1.2 +/- 0.4 U . kg(- 1) day(-1)) than the intensive-therapy group (0.4 +/- 0.1 U . kg(-1) . day(-1), P < 0.0005). By week 3, both groups were treated similarly w ith intensive insulin therapy and were followed for 1 year. beta-cell function was evaluated with fasting plasma C-peptide and glucagon-stim ulated and mixed meal-stimulated C-peptide concentrations. In both gro ups, insulin doses were comparable, and HbA(1c) levels were near norma l during follow-up. At diagnosis of IDDM, fasting C-peptide was 0.40 /- 0.13 nmol/l in the experimental-therapy group and 0.39 +/- 0.23 nmo l/l in the intensive-therapy group. Irrespective of treatment, a sligh t decline of fasting C-peptide was observed in sequential measurements up to 12 months in both groups (Delta, -0.13 and -0.08 nmol/l, respec tively; NS), Glucagon-stimulated C-peptide concentrations decreased fr om 0.54 +/- 0.18 and 0.70 +/- 0.39 nmol/l at month 0 to 0.41 +/- 0.20 and 0.61 +/- 0.52 nmol/l, respectively, at month 12. In the experiment al-therapy group, mixed meal-stimulated C-peptide concentrations (area under the curve over 2 h) increased from 82.10 +/- 43.72 to 101.20 +/ - 32.53 nmol/l and in the intensive-therapy group, from 75.05 +/- 46.0 1 to 107.20 +/- 102.51 nmol/l. Changes in stimulated C-peptide concent rations between month 0 and 12 were not significant in both groups. Du ring follow-up, fasting and stimulated C-peptide concentrations were n ot significantly different between the experimental-therapy group and the intensive-therapy group. We conclude that as initial treatments of newly diagnosed IDDM, high-dose intravenous insulin infusion and inte nsive insulin therapy equally preserve beta-cell function during the 1 st year of insulin therapy.