Sitagliptin Significantly Decreases the Ratio of Glycated Albumin to HbA1c in Patients with Type 2 Diabetes Mellitus

Abstract

Background: Since glycated albumin (GA) is a glycemic control marker which reflects more postprandial plasma glucose (PPPG) and/or glycemic excursions than HbA1c, the GA/HbA1c ratio is a useful indicator for PPPG and/or glycemic excursions. In this study, we investigated the clinical significance of the GA/HbA1c ratio by administration of sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, in patients with type 2 diabetes mellitus. Methods: Sitagliptin (50 mg/day) was administered for 24 weeks to 69 patients with type 2 diabetes mellitus with stable glycemic control. Results: With sitagliptin administration, both HbA1c and GA significantly decreased from baseline to the periods of week 4 and week 24. The GA/HbA1c ratio also significantly decreased (baseline 2.72 ± 0.42 vs. 24 weeks 2.60 ± 0.38, P<0.0001). The change in the GA/HbA1c ratio with the sitagliptin administration for 24 weeks was inversely correlated with baseline GA (R=-0.425, P<0.001) and baseline GA/HbA1c ratio (R=-0.354, P=0.003), but not with baseline HbA1c (R=-0.222, P=0.066). By tertile analysis based on the baseline GA/HbA1c ratio, the GA/HbA1c ratios were significantly associated with GA (P<0.0001), but not fasting plasma glucose (FPG) and HbA1c. Furthermore, changes in GA (P=0.010), but not FPG and HbA1c, were significantly correlated with the baseline GA/HbA1c ratio. Conclusions: Sitagliptin significantly decreased the GA/HbA1c ratio and this effect was more pronounced in patients with the higher baseline GA/HbA1c ratio. Our findings suggest that the effect of sitagliptin on the GA/HbA1c ratio might reflect improvement of PPPG levels and/or glycemic excursion.