Glycosylated Hemoglobin and Cardiovascular Risk in Nondiabetic Adults

Even within the normal range, HbA1c level correlated with diabetes risk.

Glycosylated hemoglobin (HbA1c) is used most commonly as an indicator of glycemic control in patients with known diabetes. But do variations of HbA1c level within the "normal" range predict diabetes and other clinical outcomes? To answer this question, researchers measured HbA1c in 11,000 adults (mean age, 57) who had no histories of diabetes or cardiovascular disease and correlated HbA1c levels with long-term outcomes.

When participants were grouped by baseline HbA1c level, 15-year cumulative incidences of self-reported diabetes ranged from 6% for those with HbA1c <5.0% to 44% for those with HbA1c 6.0% to 6.5%. This association persisted after adjustment for baseline fasting glucose levels and other variables. Baseline HbA1c also was associated with 15-year risk for cardiovascular disease: For example, those with HbA1c levels of 6.0% to 6.5% had twofold higher 15-year risk for both coronary disease and stroke than did those with HbA1c levels of 5.0% to 5.5%. However, the association between baseline HbA1c level and mortality was J-shaped: Compared with HbA1c of 5.0% to 5.5%, those with either lower or higher HbA1c levels had greater risk for death from any cause.


Citation(s):

Selvin E et al. Glycated hemoglobin, diabetes, and cardiovascular risk in nondiabetic adults. N Engl J Med 2010 Mar 4; 362:800.