Case of type 1 diabetes mellitus with decreased hemoglobin glycation index after switching insulin pump

This case report described a 78-year-old woman with type 1 diabetes who experienced a significant decrease in the hemoglobin glycation index (HGI) after switching her insulin pump from MiniMed™770G to 780G. Despite minimal changes in glycemic control, including a slight decrease in the average sensor glucose and % coefficient of variation (%CV) from continuous glucose monitoring metrics, her glycated hemoglobin level decreased from 8.2% to 7.3%, and HGI decreased from approximately 1.3-0.5. Previous reports have shown that HGI indicates differences in the glycation rate of hemoglobin between individuals. Moreover, a high HGI is a risk factor for diabetic complications. However, there are no reports on changes in HGI within an individual. Therefore, the significance of intraindividual HGI changes, as in this case, should be investigated.