AbstractBackgroundTreatment for type 1 diabetes mellitus (T1DM) has greatly changed by the general use of insulin analogs and continuous subcutaneous insulin infusion (CSII). To investigate whether these advances have been translated into continued improvement in glycemic control in Japanese children and adolescents, we analyzed the registration data of the two consecutive recent cohorts of Japanese childhood-onset T1DM patients.MethodsThe registration data including hemoglobin A1c(HbA1c), hypoglycemia and insulin regimen were compared between the two cohorts (862 patients in the 2008 cohort and 1090 in the 2013 cohort).ResultsThe proportion of subjects with multiple daily insulin injection therapy (MDI) and CSII significantly increased (p<0.0001) from 67.4% and 9.7% to 71.8% and 23.4%, respectively. In the 2013 cohort, almost all patients were treated with basal-bolus treatment using insulin analogs. The use of CSII increased in all age groups, especially in the age group 0–5 years. The rates of overall, moderate and severe hypoglycemia significantly declined from 10.24, 10.18 and 0.056 events/100 persons/period in the 2008 cohort to 0.66, 0.62 and 0.033 in the 2013 cohort (p<0.0001, <0.0001, 0.04), respectively. Contrarily, there were no significant changes in HbA1cvalues between the two cohorts.ConclusionsThe popularization of the basal-bolus treatment using insulin analogs hascontributed to a significant decrease in hypoglycemia. In contrast, the intensive insulin treatment may not be enough for the satisfactory improvement of glycemic control in Japanese children and adolescents with T1DM. Considerable points remain, such as diabetic education and support to motivate patients.