The ratio of glycated albumin to glycated haemoglobin correlates with insulin secretory function

Objective Although glycated haemoglobin (A1c) levels are similar among patients with type 2 diabetes, the glycated albumin (GA)/A1c ratio varies considerably. On the basis of the hypothesis that endogenous insulin secretion might be correlated with the GA/A1c ratio, we investigated whether insulin secretory function or insulin resistance has different effects on the GA/A1c ratio in patients with type 2 diabetes using the standardized liquid meal test. Design A clinical, retrospective study. Patients and measurements A total of 758 patients with type 2 diabetes ingested a standardized liquid meal (i.e. 500 kcal, 17.5 g fat, 68.5 g carbohydrate and 17.5 g protein). The subjects were divided into two groups: those with GA/A1c ratio <2.5 (n = 414) and those with GA/A1c ratio =2.5 (n = 344). We compared the A1c and GA levels, and the GA/A1c ratio and evaluated the relationships between the glycaemic indices and other parameters. Effects of beta-cell function [homeostasis model assessment (HOMA-beta), insulinogenic index (IGI)] and insulin resistance (HOMA-IR) on the GA/A1c ratio were also examined. Results The GA/A1c ratio was significantly correlated with HOMA-beta, IGI and body mass index (BMI) but not with HOMA-IR. Furthermore, after adjusting for age, gender, BMI, haemoglobin and albumin levels, the GA/A1c ratio was still inversely correlated with both HOMA-beta and IGI. Conclusions The GA/A1c ratio is significantly correlated with insulin secretory function but not with insulin resistance.