title: A1C level and future risk of diabetes: a systematic review.
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.
authors.affiliation: Division of Diabetes Translation, National Center for Chronic Disease Prevention and HealthPromotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. Xuanping Zhang, xbz2@cdc.gov
authors.forename: Xuanping
authors.initials: X
authors.lastname: Zhang
authors.forename: Edward W
authors.initials: EW
authors.lastname: Gregg
authors.forename: David F
authors.initials: DF
authors.lastname: Williamson
authors.forename: Lawrence E
authors.initials: LE
authors.lastname: Barker
authors.forename: William
authors.initials: W
authors.lastname: Thomas
authors.forename: Kai McKeever
authors.initials: KM
authors.lastname: Bullard
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Imperatore
authors.forename: Desmond E
authors.initials: DE
authors.lastname: Williams
authors.forename: Ann L
authors.initials: AL
authors.lastname: Albright
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D015994:Incidence; D012307:Risk Factors
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human