Metabolic Control in Diabetic Patients: Effect of Insulin-secretory Reserve (Measured by Plasma C-Peptide Levels) and Circulating Insulin Antibodies

We measured circulating hemoglobin A₁ (HbA₁) and fasting plasma C-peptide concentrations in 100 diabetic patients. Pancreatic insulin reserve showed a negative correlation with HbA₁ concentrations in nonobese, insulin-treated patients but not in obese patients, whether they were treated with insulin, oral agent, or diet alone. Patients with fasting C-peptide concentrations above 0.1 pmol/ml had significantly better metabolic control than did those with lower values.

Anti-insulin antibodies were measured in 37 patients. There was no correlation between metabolic control and the affinity constants or binding capacities of these antibodies.