Glucose variability and glycated hemoglobin HbA1c in type 1 and type 2 diabetes

Introduction. The ultimate goal of diabetes therapy is to prevent chronic complications of the disease. HbA 1c level is closely related to the risk of development of micro- and macrovascular complications, however blood glucose variability (BGV) has emerged recently as yet another possible risk factor for vascular, particularly endothelial damage in diabetes. Continuous glucose monitoring systems (CGMS) are currently used for the BGV assessment, however due to their costs they are rarely utilised in daily clinical practice. The aim of the study was to assess BGV and its relationship with HbA 1c in patients with well (HbA 1c ∼7%) and poorly (HbA 1c ∼10%) controlled type 1 and type 2 diabetes. Material and methods. 131 patients subdivided in 4 groups according to diabetes type and level of metabolic control were enrolled into the study. All patients underwent continuous glucose monitoring with the use of iPRO2 system (Medtronic). Results. BGV was lower in type 2 than in type 1 diabetes patients. There was no statistically significant relationship between BGV and HbA 1c in well or poorly controlled patients with type 1 or type 2 diabetes. However, well controlled type 1 diabetes patients presented with greater degree of BGV than poorly controlled type 1 diabetes subjects. Conclusions. HbA 1c does not reflect blood glucose variability as assessed with CGMS in type 1 or type 2 diabetes subjects. BGV is significantly greater in type 1 diabetes than in type 2 diabetes, therefore the use CGMS might be of particular benefit for the former group of patients, especially those with good glycemic control.