Correlation between glycated hemoglobin and continuous glucose monitoring-derived metrics in children with type 1 diabetes mellitus

Abstract:

Objective：To analyze the correlation between glycated hemoglobin (HbA1c) and continuous glucose monitoring（CGM）-derived metrics in children with type 1 diabetes mellitus（T1DM）. Methods：Children with T1DM who wore flash glucose monitoring system（FGMS） for more than 3 months were collected from the Department of Endocrinology，Genetics and Metabolism，Children’s Hospital Affiliated to Zhengzhou University from August 2019 to October 2020. The clinical data including age，gender，diabetic duration，body mass index（BMI），insulin delivery method，fasting blood glucose，fasting C-peptide，HbA1c，time in target glucose range（TIR），time above target glucose range（TAR），time below target glucose range（TBR） and mean glucose（MG） were collected，and the correlation of HbA1c with TIR，TAR，TBR and MG was analyzed. Results：A total of 118 children were included in the study，including 54 boys and 64 girls，with an average age of 7.7 years，mean diabetic duration of 2.5 years，mean fasting C peptide of 0.1 ng/mL，mean HbA1c 6.7%，mean TIR of 67.4%，mean TAR of 21.4%，mean TBR of 11.2%，mean MG of 7.4 mmol/L. Compared with children using subcutaneous insulin injection，children using insulin pump had older age（P=0.01），longer diabetic duration（P=0.01），higher BMI（P=0.03），but lower fasting blood glucose（P=0.03） and higher TIR（P=0.03）. HbA1c was in general negatively correlated with TIR（r=-0.571，P < 0.01)，and positively correlated with TAR（r=0.720，P < 0.01) and MG（r=0.799，P < 0.01)，but not correlated with TBR（P=0.210）. HbA1c was correlated with TIR，TAR and MG in children with insulin pump（r=-0.519，0.688，0.783） and children with subcutaneous insulin injection（r=-0.648，0.763，0.820)，all of which were not correlated with TBR. HbA1c levels corresponded to the recommended frequency in TIR of 60% and 70% were 6.59% and 6.22% respectively. Conclusion：The glycemic control of children with T1DM should be evaluated by combining HbA1c and CGM-derived metrics.