title: Diabetes diagnostic thresholds of the glycated hemoglobin A1c and fasting plasma glucose levels considering the 5-year incidence of retinopathy.
abstract: OBJECTIVE
  As retinopathy is used as a defining threshold of diabetes, we assessed the glycated hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) values associated with an increased risk of 5-year incidence of retinopathy.
  
  
  METHODS
  We studied HbA1c, FPG, and optic fundus findings of 2605 individuals without previously diagnosed diabetes annually during a 5-year period. Retinopathy was examined using non-mydriatic, 45° digital fundus photography. Baseline levels were stratified as <5.3 [34], 5.3-5.6 [34-38], 5.7-6.0 [39-42], 6.1-6.4 [43-47], and ⩾6.5% [48mmol/mol] for HbA1c and <5.0, 5.0-5.5, 5.6-6.0, 6.1-6.9, and ⩾7.0mmol/L for FPG. Cox proportional hazard models were used to analyze hazard ratios (HRs) associated with HbA1c or FPG for incident retinopathy.
  
  
  RESULTS
  During a total of 11845 person-years, we identified 50 (1.9%) cases of incident retinopathy. The adjusted HRs for incident retinopathy associated with a one-standard deviation increase in HbA1c and FPG were 1.2 (95% confidence intervals: 1.1-1.4) and 1.2 (1.1-1.4), respectively. These HRs were significantly higher for a HbA1c level ⩾6.5% (48mmol/mol) (3.4 [1.1-10.2]) or FPG level ⩾7.0mmol/L (3.6 [1.1-11.6]) than for a HbA1c level <5.3% (34mmol/mol) or FPG level <5.0mmol/L.
  
  
  CONCLUSIONS
  A HbA1c value of 6.5% (48mmol/mol) and FPG value of 7.0mmol/L might be proper as diabetes diagnostic thresholds that indicate a high risk of future retinopathy.
authors.affiliation: Diabetes Center, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku 162-8666, Tokyo, Japan. Electronic address: nakagami.dmc@twmu.ac.jp.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nakagami
authors.affiliation: Diabetes Center, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku 162-8666, Tokyo, Japan; Internal Medicine, Yoyogi Hospital, 1-30-7, Sendagaya, Shibuya-ku, Tokyo 151-8556, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Department of Ophthalmology, Tokyo Women's Medical University Medical Center East, 2-1-10, Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan; Department of Ophthalmology, Saitama-ken Saiseikai Kurihashi Hospital, 714-6, Kouemon, Kuki, Saitama 349-1105, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Suto
authors.affiliation: Diabetes Center, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku 162-8666, Tokyo, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Oya
authors.affiliation: Diabetes Center, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku 162-8666, Tokyo, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Diabetes Center, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku 162-8666, Tokyo, Japan.
authors.forename: Moritoshi
authors.initials: M
authors.lastname: Kurita
authors.affiliation: Diabetes Center, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku 162-8666, Tokyo, Japan.
authors.forename: Chisato
authors.initials: C
authors.lastname: Isago
authors.affiliation: Diabetes Center, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku 162-8666, Tokyo, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Hasegawa
authors.affiliation: Diabetes Center, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku 162-8666, Tokyo, Japan.
authors.forename: Arata
authors.initials: A
authors.lastname: Ito
authors.affiliation: Diabetes Center, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku 162-8666, Tokyo, Japan.
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Uchigata
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D003930:Diabetic Retinopathy / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D005215:Fasting / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D005951:Glucose Tolerance Test / Q000592:standards; D006442:Glycated Hemoglobin / Q000032:analysis* / Q000592:standards; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012016:Reference Values
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin
keywords: Diabetes; Diagnostic criteria; Fasting plasma glucose; HbA1c; Incidence; Retinopathy