In this study, patients with type 1 diabetes and a glycated hemoglobin level of 6.9% or lower (≤52 mmol per mole) were found to have a risk of death from any cause or from cardiovascular causes that was twice as high as that for matched controls. Type 1 diabetes is associated with a substantially increased risk of premature death as compared with that in the general population. 1 – 8 Among persons with diabetes who are younger than 30 years of age, excess mortality is largely explained by acute complications of diabetes, including diabetic ketoacidosis and hypoglycemia 7 – 9 ; cardiovascular disease is the main cause of death later in life. 7 – 9 Improving glycemic control in patients with type 1 diabetes substantially reduces their risk of microvascular complications and cardiovascular disease. 10 , 11 Accordingly, diabetes treatment guidelines emphasize good glycemic control, 12 – 15 which is indicated by the glycated hemoglobin level, . . .