Relation Between Hypoglycemia and Glycemic Variability in Type 2 Diabetes Patients with Insulin Therapy: A Study Based on Continuous Glucose Monitoring

To determine the factors associated with hypoglycemia in patients with type 2 diabetes mellitus (T2DM) on insulin therapy.This retrospective study included 62 inpatients with T2DM on insulin therapy who underwent 5-day continuous glucose monitoring (CGM). We analyzed the relation between hypoglycemia (defined as blood glucose below 70 mg/dL, as determined by the CGM) and time spent in hypoglycemia with fasting blood glucose, mean blood glucose (MBG), standard deviation (SD), coefficient of variation, minimum blood glucose level, maximum blood glucose level, and the percent time spent with blood glucose levels of >180 mg/dL.Twelve patients (19.4%) developed hypoglycemia, and most were maintained on mix insulin therapy alone. In the hypoglycemic group, MBG was lower and SD was higher, than in the non-hypoglycemic group, although HbA1c was not different. Multivariate logistic regression analysis identified MBG and SD as factors related to hypoglycemia. Receiver operating characteristic curve analysis showed that the optimal MBG and SD cutoff values for prediction of hypoglycemia were 150.9 and 41.1 mg/dL, respectively. When subjects were divided into four groups according to these values, time at blood glucose <70 mg/dL was longest, and total insulin dosage highest, in the MBG-low/SD-high group.MBG and SD of glucose levels were identified as significant and independent determinants of hypoglycemia in T2DM on insulin therapy. It is important to use the least insulin dose, with the target of minimizing glycemic variability, to achieve good glycemic control without hypoglycemia.