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. 2010 Jul;33(7):1665-73.
doi: 10.2337/dc09-1939.

A1C level and future risk of diabetes: a systematic review

Xuanping Zhang  1 , Edward W Gregg, David F Williamson, Lawrence E Barker, William Thomas, Kai McKeever Bullard, Giuseppina Imperatore, Desmond E Williams, Ann L Albright
Affiliations

A1C level and future risk of diabetes: a systematic review

Xuanping Zhang et al. Diabetes Care. 2010 Jul.

Abstract

We examined ranges of A1C useful for identifying persons at high risk for diabetes prior to preventive intervention by conducting a systematic review. From 16 included studies, we found that annualized diabetes incidence ranged from 0.1% at A1C <5.0% to 54.1% at A1C >or=6.1%. Findings from 7 studies that examined incident diabetes across a broad range of A1C categories showed 1) risk of incident diabetes increased steeply with A1C across the range of 5.0 to 6.5%; 2) the A1C range of 6.0 to 6.5% was associated with a highly increased risk of incident diabetes, 25 to 50% incidence over 5 years; 3) the A1C range of 5.5 to 6.0% was associated with a moderately increased relative risk, 9 to 25% incidence over 5 years; and 4) the A1C range of 5.0 to 5.5% was associated with an increased incidence relative to those with A1C <5%, but the absolute incidence of diabetes was less than 9% over 5 years. Our systematic review demonstrated that A1C values between 5.5 and 6.5% were associated with a substantially increased risk for developing diabetes.

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Figures

Figure 1
Figure 1
Study flow chart.
Figure 2
Figure 2
A1C modeled as a function of annualized incidence. The dashed lines are pointwise 95% confidence limits for the fitted curve.
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