Treatment Goals and Outcomes
The most important measure of treatment outcome in type 1 diabetes is the level of glycemic control. Periodic measurement of hemoglobin A1c (HbA1c or in short A1c) in a blood test gives a picture of the blood sugar level in the most recent period (long-term blood sugar). For many years, glycemic control in type 1 diabetes has been primarily assessed with the HbA1c test, and it is still considered the most important metric, although new technology has made other relevant metrics accessible.
The general aim is for HbA1c to be as close to the limit value (48 mmol/mol) for healthy individuals as possible, while avoiding episodes of hypoglycemia (acute low blood sugar). The American Diabetes Association (ADA) recommends a clinical treatment target for HbA1c in type 1 diabetes at ≤53 mmol/mol . Recommendations in many EU countries and the Nordic countries, are at the same level.
The landmark Diabetes Control and Complications Trial (DCCT), together with several follow-up studies, have shown that reaching the 53 mmol/mol target, versus an HbA1c level of 75 mmol/mol, is associated with 50–76% reductions in rates of development and progression of microvascular (retinopathy, neuropathy, and diabetic kidney disease) complications .
The diagrams above show HbA1c outcomes by age group as reported in two registers on each side of the Atlantic . Diagram 1 shows patients' mean HbA1c and diagram 2 the percentage of patients reaching the target of 53 mmol/mol. The data indicate that the teenage period is the most difficult, and that patients in Europe seem to obtain better results than in the US. Most importantly, the data clearly demonstrates that only a minority of patients with type 1 diabetes achieve the goals for HbA1c. The explanation for this should be sought in the challenges in living with type 1 diabetes.
HbA1C does not provide a measure of glycemic variability or hypoglycemia. By using CGM technology (Continuous Glucose Monitor), patients and caregivers gain access to metrics such as time in, above, and below range (TIR), mean glucose, and glycemic variability, which are important to assess glycemic control more precisely.
If better treatments were available, so that treatment goals were reached, life with type 1 diabetes would be significantly less burdensome, and many people would be saved from debilitating complications.
- American Diabetes Association (ADA). Standards of Medical Care in Diabetes - 2020, 6. Glycemic Targets. Diabetes Care. 2020 Jan. S68-S69.
- J. M. Hermann, K. M. Miller, S. E. Hofer, M. A. Clements, W. Karges, N. C. Foster, et al. The Transatlantic HbA1c gap: differences in glycaemic control across the lifespan between people included in the US T1D Exchange Registry and those included in the German/Austrian DPV registry. Diabetic Medicine. 2019 Sep. 850.