Decreasing trends in mean HbA_1c are not associated with increasing rates of severe hypoglycemia in children: A longitudinal analysis of two contemporary population-based pediatric type 1 diabetes registries from Australia and Germany/Austria between 1995 and 2016

OBJECTIVE To investigate temporal trends in glycemic control and severe hypoglycemia rates for pediatric patients with type 1 diabetes from 1995 to 2016 by analyzing data from the longitudinal, prospective, population-based German/Austrian (Diabetes Patient History Documentation [DPV]) and Western Australian (Western Australian Children's Diabetes Database [WACDD]) diabetes registries. RESEARCH DESIGN AND METHODS Patients diagnosed with type 1 diabetes aged 1c and severe hypoglycemia (self-reported loss of consciousness/convulsion) rates were calculated per 100 patient-years. RESULTS Between 1995 and 2016, the annual mean HbA_1c decreased from 8.3 to 7.8% in the DPV cohort and from 9.2 to 8.3% in the WACDD cohort. Over the same period, the severe hypoglycemia rate decreased by an annual average of 2% (relative risk 0.983 [95% CI 0.981, 0.986]) in the DPV cohort and 6% (relative risk 0.935 [95% CI 0.934, 0.937]) in the WACDD cohort. Concomitant decreasing trends in both HbA_1c and severe hypoglycemia rates were observed in boys and girls, all age-groups, and injection therapy/pump regimen groups. CONCLUSIONS Over the past two decades, there have been concurrent improvements in HbA_1c and decreasing severe hypoglycemia rates in two contemporary, longitudinal, population-based pediatric cohorts of type 1 diabetes. Translation of these data into clinical practice and patient education may reduce fear of hypoglycemia and enable better glycemic control.