C-peptide response in patients on insulin therapy.

This study was undertaken to document clinical features and presentation of Type I diabetes and to study beta cell response in these patients. It provides data on 30 insulin treated patients. Type I diabetes presents most commonly in the 20-40 year age group. A positive family history in first degree relatives was noted in 40%. The commonest complications were retinopathy (63%) and peripheral neuropathy (53%). Proteinuria (10%), ischaemic heart disease (13%) and peripheral vascular disease (13%) were less common. Three kinds of response to C-peptide were noted: 1) no response 2) blunted response (below the normal range) and 3) peak response to glucose within the low normal range. Group 3 probably represents Type II insulin treated diabetes. There was poor correlation between fasting blood glucose and basal or peak C-peptide response, or with duration or complications of diabetes. C-peptide response may be used to differentiate Type I from Type II diabetes.