Why are people with T1D regularly asked to measure their hemoglobin A1C?

The duration of diabetes and the quality of blood sugar control affects the likelihood that one would develop complications such as retinopathy and nephropathy. Retinopathy is caused by a damage to the blood vessels of the tissue at the back of the eye (retina). It might show no symptoms or only mild vision problems.  However, as it progresses, it can eventually cause blindness. Nephropathy is damage to the kidneys damage that eventually leads to their incapacity to filter the blood properly, which can culminate to the need for dialysis.

A recent report confirms adequate blood sugar limits risks of complications

Reports from one of the most important studies in type 1 diabetes, The Diabetes Control and Complications Trial (DCCT) that lasted 10 years, demonstrated that intensive therapy (with a goal to achieve blood sugar levels as close to non-diabetic ranges as possible) reduced the development and progression of retinopathy compared with conventional therapy (with a goal to prevent hypo and hyperglycemia symptoms without a fixed glucose targets). Participants from the DCCT were followed over an additional 20 years in the Epidemiology of Diabetes Interventions and Complications (EDIC) study, which also showed that the benefits of intensive therapy persisted for a total of 30 years. They also found that the two greatest risk factors for eye and kidney related complications were a higher hemoglobin A1c and a longer duration of T1D.

This is why people with type 1 diabetes have their hemoglobin A1c checked regularly. This blood test shows the average blood sugar level of the past 2 to 3 months.

These findings are consistent with current risk reduction recommendations for eye, kidney, and heart complications in T1D. In order to reach these recommendations and promote better eye, kidney, and cardiac health in T1D, more efficient and targeted strategies are needed to ensure the best control of blood sugars, starting with better therapy lines and technologies as well as better hypoglycemia management and prevention tools.


1- Hainsworth DP, Bebu I, Aiello LP, et al. Risk factors for retinopathy in type 1 diabetes: the dcct/edic study. Diabetes care. 2019;2019 Mar 04. doi:10.2337/dc18-2308

2- Perkins BA, Bebu I, de Boer IH, et al. Risk factors for kidney disease in type 1 diabetes. Diabetes care. 2019;Dc182062:182062. doi:10.2337/dc18-2062

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