medwireNews: The risk for cardiovascular disease (CVD) and death is higher among individuals with prediabetes defined by glycated hemoglobin (HbA1c) level compared with fasting plasma glucose (FPG) or 2-hour plasma glucose (2hPG), study data show.
But any excess risk associated with prediabetes, regardless of the definition used, was attenuated when demographic and cardiovascular risk factors were taken into account.
“These findings indicate that there is no obvious optimal glycemic cut-off for risk stratification, and the higher risk for CVD and death among individuals with prediabetes is mainly explained by its clustering with other risk factors associated with hyperglycemia,” Dorte Vistisen (Steno Diabetes Center Copenhagen, Denmark) and co-investigators remark.
They add: “This challenges the use of the prediabetes classification as a stand-alone tool for risk stratification among older adults.”
The researchers studied data for 5427 members of the Whitehall II cohort who did not have diabetes and were aged 50–79 years at baseline.
They found that the proportion of participants with prediabetes was approximately three times higher when defined according to American Diabetes Association (ADA) criteria (FPG 5.6–6.9 mmol/L and/or HbA1c 5.7–6.4%) than when World Health Organization (WHO)/International Expert Committee (IEC) criteria (FPG 6.1–6.9 mmol/L and/or HbA1c 6.0–6.4%) were used, at 36.8% versus 11.6%.
When defined by 2hPG (7.8–11.0 mmol/L), 14% of 4730 individuals who had this measurement taken were classified as having prediabetes.
During a median 11.5 years of follow-up, the incidence of CVD and death was a significant 54% higher in individuals with prediabetes according to the WHO/IEC definition than among those with normoglycemia, at 22.7 vs 14.8 cases per 1000 person–years.
And it was a significant 37% higher with the ADA definition (18.9 vs 13.8 cases per 1000 person–years), but both associations lost significance after adjustment for previous CVD, smoking, cholesterol level, systolic blood pressure, and use of antihypertensive treatments.
When Vistisen and team looked at the associations by specific measurements, they found that, compared with individuals with normoglycemia, the incidence of CVD or death was approximately twofold higher in participants with HbA1c-defined prediabetes, around a 1.3-fold higher in those with FPG levels 6.1–6.9 mmol/L, and 1.44-fold higher in those with elevated 2hPG.
The authors conclude in Diabetes Care that their study “shows that a substantial part of the excess risk in prediabetes is explained by other CVD risk factors, suggesting that the use of prediabetes as an independent factor for risk stratification is questionable.”
By Laura Cowen
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