Serum fructosamine level as a marker of glycemic control in diabetic patients with and without a residual C-peptide secretion.

Serum fructosamine was determined in 115 diabetic patients with a C-Peptide secretion (0.84 +/- 0.06 pmol/ml, mean +/- SEM) (Group A) and in 30 type I C-peptide negative totally insulin-dependent subjects (less than 0.05 pmol/ml) (Group B). A significant correlation between fructosamine and HbA1 values (r = 0.70, p less than 0.001) was evidenced in Group A. In contrast, such a correlation was not found in Group B (r = 0.33, p greater than 0.05). Fructosamine levels were also in good agreement with the physician's ratings of the degree of glycemic control in Group A, but not in Group B. It is concluded that the fructosamine measurement represents a complement rather than an alternative to HbA1, in particular in unstable diabetic patients.