Relationship between mean blood glucose and glycated haemoglobin in Type 2 diabetic patients

Aims To correlate the values of MBG to HbA(1c) in Greek patients with Type 2 diabetes and/or metabolic syndrome. Methods We followed up 140 Greek adult patients: 92 patients with Type 2 diabetes treated with insulin or oral glucose-lowering medication, and 48 patients with newly diagnosed Type 2 diabetes or metabolic syndrome not receiving any treatment. MBG was calculated for each patient from self-measurements of blood glucose using a portable glucometer, made six times a day (before eating and 2 h after a meal), three times a week for 1 month. HbA(1c) was determined by HPLC at 0 and 12 weeks. Results HbA(1c) at 0 (x) and 12 weeks (y) correlated strongly (y = 0.790x + 1.115, r = 0.92), confirming that the patient's glycaemic status remained stable during the whole period of follow-up. Linear regression was performed on MBG values; HbA(1c) at 12 weeks, sex, age, body mass index (BMI) and patient status (Type 2 diabetes treated or not) were used as independent variables. None of the independent variables reached statistical significance in the model, with the exception of HbA(1c) at 12 weeks. The final model was: MBG (mg/dl) = (34.74 x HbA(1c)) - 79.21, r = 0.93; or MBG (mmol/l) = 1.91 x HbA(1c) - 4.36, r = 0.93. Conclusions Our results establish for the first time a strong correlation between MBG and HbA(1c) in Type 2 diabetic patients and support the idea of expressing HbA(1c) results as MBG. This will help patients to gain a clearer interpretation of the result, with less confusion. This simplification will allow every person with diabetes using home glucose-monitoring to understand his or her own target level.