How is prediabetes defined?

People with prediabetes have a high risk of developing cardiovascular disease and of premature death. The size of this risk depends on how prediabetes is defined. This has been demonstrated in research carried out by Steno Diabetes Center Copenhagen.


​Various methods are currently applied when attempting to define prediabetes. However, these various methods differ as regards to which people they define as being at risk. At the same time there are well-established links between cardiovascular disease, premature death and prediabetes. It is therefore relevant to examine whether cardiovascular diseases develop differently from one person to the next depending on which method has been used to define prediabetes.

Dorte Vistisen and Kristine Færch from the Department of Clinical Epidemiology at Steno Diabetes Center Copenhagen (SDCC) have examined this question in a study recently published in the international journal Diabetes Care.


"Our conclusion is basically that there is a significant difference between the risk of cardiovascular diseases in people with prediabetes, depending on how prediabetes is defined. The highest risk of developing a cardiovascular disease or of dying was observed in people with prediabetes defined on the basis of the marker for longer-term blood sugar levels, HbA1c. This indicates that this method identifies the right people, at least within the age group 50-80 years," said Dorte Vistisen, who is senior researcher and team leader at the Department of Clinical Epidemiology at the SDCC, and she continued:


"However, the good news is that this increased risk is primarily due to factors such as smoking, high cholesterol levels and high blood pressure, i.e. common risk factors for cardiovascular disease. Assuming these risk factors are addressed, prediabetes ought not to give rise to a significantly higher risk of cardiovascular disease and premature death than that of the general population."

Fasting blood glucose and HbA1c

Researchers have looked at differences in the risk of cardiovascular disease and premature death in people with prediabetes aged 50-80 years, depending on how prediabetes is defined. In addition, they have examined whether the increased risk can be explained by the existence of other risk factors for cardiovascular disease. The study is based on data from participants in the London-based Whitehall II population. Prediabetes can be determined by measuring blood sugar level after fasting (fasting blood glucose), or based on a blood sample that indicates the average blood sugar level for a longer period (HbA1c). Both fasting blood glucose and HbA1c were measured in the participants in the study, together with a number of other risk factors.


"When we took into account other risk factors for cardiovascular disease, the increased risk for people with prediabetes was considerably reduced. This calls into question the applicability of prediabetes as an independent risk assessment tool for cardiovascular disease and premature death," said Dorte Vistisen.


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