Why Is a New Trial Required to Define the Role of Insulin Reserve in Newly Diagnosed Adult Type 1 Diabetes?

Endogenous Insulin Reserve

In patients with type 1 diabetes endogenous insulin production recovers after the initiation of insulin therapy. This remission is characterised by a significant reduction of therapeutic insulin dosage, sometimes patients are even completely “off insulin”. Although not proved by clinical studies it is assumed that reduction of the glucotoxic effects on pancreatic cells has the potential to preserve a significant insulin reserve over a longer period of time. Plasma C-peptide concentration is used to measure insulin reserve in patients because it is secreted in equimolar amounts with insulin. The C-peptide antibody does not crossreact with injected insulin circulating in the blood stream. Recently, intrinsic biological activity was described after years of general belief that C-peptide was not biologically active ([Forst, 1998]). Adult-onset patients with type 1 diabetes were found to have a longer period of residual insulin secretion than children ([Schiffrin, 1992]). Clinical experience suggested that patients with residual insulin had stable blood glucose concentrations and lower glycosylated hemoglobin levels.

References

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• 5 Schiffrin A, Suissa S, Weitzner G. et al . Factors predicting course of B-cell function in IDDM.  Diabetes Care. 1992;  15 997-1001
• 6 The Diabetes Control and Complications Trial Study Group . The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus.  N Engl J Med. 1993;  329 977-989
• 7 The Diabetes Control and Complications Trial Study Group . Effect of intensive therapy on residual beta-cell function in patients with type 1 diabetes in the diabetes control and complications trial.  Ann Intern Med. 1998;  128 517-523
• 8 Torgerson D J, Sibbald B. What is a patient preference trial?.  Brit Med J. 1998;  316 360