Do glycoalbumin levels preferentially reflect changes in postprandial glucose excursions?

AIMS: To evaluate whether plasma glycated albumin, which provides an integrated measure of plasma glucose levels over the preceding 2-4 weeks, better reflects changes in postprandial glucose excursions than HbA1c .

METHODS: People with suboptimum glycaemic control on dual oral therapy were enrolled in the Treating-to-Target-in-Type 2 diabetes (4-T) trial, in which participants were randomized to the addition of once-daily basal insulin, twice-daily biphasic insulin or thrice-daily prandial insulin. Glycated albumin levels were assayed enzymatically from baseline and 1-year fasting plasma samples. We evaluated robust correlations of glycated albumin and HbA1c both with fasting and postprandial glucose levels at these two time points, and with insulin-induced changes in the postprandial excursion.

RESULTS: Requisite data were available for 625 of the participants in the 4-T trial. Their mean (±sd) age was 62 ± 10 years and body weight was 85.8 ± 15.9 kg, and their median (interquartile range) diabetes duration was 9 (6, 13) years. Partial correlations at baseline and 1 year between postprandial glucose excursions and glycated albumin/HbA1c , after adjusting for fasting glucose, were 0.27/0.15 and 0.22/0.18, respectively. Glycated albumin, compared with HbA1c , explained 66% more of the variation in postprandial glucose excursions at baseline. At 1 year, postprandial glucose excursions on basal, biphasic and prandial and insulin therapy were reduced by 0.43, 0.78 and 1.88 mmol/l, respectively. These reductions were associated with changes in both glycated albumin and HbA1c (P < 0.01), with a stronger association for glycated albumin.

CONCLUSION: Changes in glycated albumin and HbA1c reflect changes in postprandial glucose excursions to a similar extent.