Glycosylated serum proteins and glycosylated hemoglobin in the assessment of glycemic control in insulin-dependent and non-insulin-dependent diabetes mellitus.

To evaluate the relative value of glycosylated serum proteins (GSPs) versus glycosylated hemoglobin (HbA1c) in assessing glycemic control in diabetes mellitus, we performed regular monitoring of GSPs and HbA1c in 30 subjects with insulin-dependent diabetes mellitus (IDDM) or non-insulin-dependent diabetes mellitus (NIDDM) who performed frequent self-glucose monitoring. Analysis of the relationship between patterns of glycemic control and GSPs and HbA1c demonstrated that subjects with IDDM and NIDDM appeared similar when the more traditional indicators of glycemic control such as mean blood glucose level (166.9 +/- 20.9 v 177.4 +/- 39.6 mg/dL) or HbA1c (83.57 +/- 12.8 v 80.24 +/- 15.7 mmol hydroxymethyl furfuraldehyde [HMF]/mol hemoglobin [Hgb]) were used. However, when GSP levels or the standard deviation of mean glucose levels (SDMG) were used to assess glycemic control, higher levels were found in subjects with IDDM (52 +/- 10.3 mg/g protein and 28.59 +/- 7.60 mg/dL) versus NIDDM (44.6 +/- 15.2 mg/g protein and 21.6 +/- 15.9 mg/dL). Using multivariate analysis, GSPs were predictive of SDMG (P = .046), whereas HbA1c added no significant further information (P = .27). Our results suggest that GSPs may be more sensitive than HbA1c assay to the greater fluctuations in blood glucose levels generally associated with IDDM.

Longitudinal assessment of glycosylated blood protein concentrations in normal pregnancy and gestational diabetes.

Longitudinal changes in glycosylated hemoglobin concentration (GlyHb) and glycosylated serum protein concentration (GSP) in both normal pregnancy and pregnancy complicated by gestational diabetes were determined using affinity chromatography, a method in which nonenzymatically glycosylated proteins are specifically measured. At 7-10 wk gestation, GlyHb in women who developed diabetes (N = 21) was higher than GlyHb in normal women (N = 49) (6.7 +/- 0.2% versus 5.7 +/- 0.2%, respectively, P less than 0.001) and remained elevated throughout gestation. In normal pregnancy, GlyHb decreased to a nadir at 23-26 wk and returned to baseline concentration by 31-34 wk. In gestational diabetes, there was an initial increase in GlyHb to 7.1 +/- 0.5% at 11-14 wk followed by a steady decrease. At 7-10 wk, GSP in women who developed diabetes was not elevated compared with normal concentration, although at 11-14 wk there was significant difference between the two groups (P less than 0.02). In normal women, GSP remained constant throughout gestation. In gestational diabetes, GSP decreased to early pregnancy values (P less than 0.02). Glycosylated blood proteins were elevated in early gestation in women who developed gestational diabetes and may have predictive value in identifying women who will develop diabetes in pregnancy.

Comparison of serum fructosamine with glycosylated serum protein (determined by affinity chromatography) for the assessment of diabetic control.

Glycosylated total protein (GTP) and glycosylated albumin (GALb) were measured in serum using aminophenylboronic acid affinity chromatography and the results were compared with those found using the fructosamine assay. The percentage GTP and GALb found by affinity chromatography correlated well with fructosamine values in the sera of a group of non-diabetic and diabetic patients (fructosamine vs GTP, r = 0.91, p less than 0.001; fructosamine vs GALb, r = 0.91, p less than 0.001). Results of each method gave similar correlations when compared with the degree of diabetic control assessed by glycosylated haemoglobin (GHb) and fasting plasma glucose (FPG) (fructosamine vs FPG, r = 0.74, p less than 0.001; GTP vs FPG, r = 0.75, p less than 0.001; GALb vs FPG, r = 0.79, p less than 0.001; fructosamine vs GHb, r = 0.79, p less than 0.001; GTP vs GHb, r = 0.81, p less than 0.001; GALb vs GHb, r = 0.84, p less than 0.001). Both methods could equally discriminate between groups of non-diabetics and diabetic patients (p less than 0.001) and showed similar temporal changes after starting insulin therapy.