HbA1c Is Not Potent Glucose Control Assessment Tool in Type 2 Diabetes Patients Treated With Insulin

Glycated haemoglobin (HbA1c) is used for defining of glucose control in diabetic patients nevertheless its insufficiency to present overall control in some specific cases. Continuous Glucose Monitoring (CGM) is usually used for adjustment of insulin doses but the derived data are helpful for exact glucose control. We assess the potency of HbAc for defining of real glucose control in subgroup of type 2 diabetes patients treated with different insulin regimens. We studied 54 diabetic patients (33 men, 21 women; age 60.23±5.99 years, disease duration 12.64±5.02 years) - 33 with type 2 diabetes on pre-mixed insulin, 21 with type 2 on multiple insulin injection (MII). Patients performed multiple daily blood glucose measurements of fasting and prandial blood glucose for three months period. HbA1c was measured and CGM by using iProTM for seven days was performed at the end of this period. In pre-mixed insulin treated group and in intensified regimen group, moderate positive correlation was found between HbA1c and mean blood glucose derived from CGM (7.64±1.40% and 7.69±1.23%, respectively 7.64±1.48mmol/l and 7.60±1.30mmol/l), with r1=0.642 (p<0.01) and r2=0.570 (p<0.05). Even lower was correlation between HbA1c and time-in-range (r1=0.431 and r2 =0.401). There were no correlations between HbA1c and percentage of time spent below the target and number of hypoglycemic episodes in each group. Same trend of correlations was found comparing HbA1c and mean BG level in eight-point profile. Based on HbA1c assessment 36.36% of patients on premixed insulin, 19.05% of type 2 patients on MII were with good control. After estimation of results from SMBG these percentage were respectively 28.14% and 12.11%. CGM defined 27.27% of patients on premixed insulin, 13.80% of type 2 patients on MII as well controlled. We conclude that in insulin treated type 2 patients HbA1c gives relative information about overall control with no precise presenting of glucose fluctuations and out-of-range values of blood glucose with no information about hypoglycemic episodes. Nevertheless, short observed period CGM data could give much information that is comparable to three months blood glucose measurement and could replace the use of HbA1c for assessment of overall control. Reference: (1) Chehregosha H, et al. Diabetes Ther. 2019; 10, 853–863 (2) Beyond A1c Writing Group. Diab Care. 2018; 41: e92-e94 (3) Hirsch I et al. Diabetes Tech Ther 2017, 19 (3): S38-S48