The relevance of persistent C-peptide secretion in type 1 (insulin-dependent) diabetes mellitus to glycaemic control and diabetic complications

Diabetes Res Clin Pract. 1990 Apr;9(1):23-35. doi: 10.1016/0168-8227(90)90005-e.


The effect of residual C-peptide secretion in longer standing IDDM on glycaemic control and the prevalence and evolution of complications over 2 years was evaluated. Thirty-one subjects with IDDM of 15.4 (1.5) years duration (mean SEM)) and residual C-peptide secretion, were matched for age, duration of diabetes and body mass index with 31 subjects without detectable C-peptide secretion. At trial entry and over 2 years, levels of HbA1, fructosamine and mean blood glucose were essentially similar in both groups. Levels of glycated albumin (GSA) were significantly higher in the C-peptide negative group after 3 and 9 months (P less than 0.05). An increased prevalence of proliferative retinopathy in the C-peptide negative group and of peripheral vascular disease in the C-peptide secretor group was apparent at entry to the study (both P less than 0.05), although no significant differences were observed after 1 or 2 years. There was no difference in the prevalence of peripheral or autonomic neuropathy, hypertension, nephropathy or ischaemic heart disease. Subjects with C-peptide concentrations greater than 0.100 pmol/ml at entry to this study had lower daily insulin requirements after 1 and 2 years, but behaved like the larger group with any detectable C-peptide secretion in all other respects. Residual C-peptide secretion was lost after 1 year in 7 patients, in whom glycaemic control during the year had been particularly poor. Insulin antibody titres were no different in the 2 groups at any time point. This study suggests that residual C-peptide secretion in longer standing IDDM confers the potential for limited improvements in glycaemic control. This effect appears to be insufficient to prevent the evolution of microvascular complications over a 2-year period. Residual C-peptide secretion and relative hyperinsulinaemia may be associated with an excess of peripheral vascular disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Albuminuria
  • Biomarkers / blood*
  • Blood Glucose / metabolism*
  • Blood Glucose Self-Monitoring
  • Blood Pressure
  • C-Peptide / blood*
  • C-Peptide / metabolism
  • Coronary Disease / diagnosis
  • Diabetes Mellitus, Type 1 / blood*
  • Diabetes Mellitus, Type 1 / complications
  • Diabetes Mellitus, Type 1 / physiopathology
  • Diabetic Angiopathies / diagnosis
  • Diabetic Nephropathies / diagnosis
  • Diabetic Neuropathies / diagnosis
  • Diabetic Retinopathy / diagnosis
  • Follow-Up Studies
  • Fructosamine
  • Glycated Hemoglobin A / analysis
  • Hexosamines / blood
  • Humans
  • Hypertension / diagnosis
  • Middle Aged


  • Biomarkers
  • Blood Glucose
  • C-Peptide
  • Glycated Hemoglobin A
  • Hexosamines
  • Fructosamine