title: Subclassification of preproliferative diabetic retinopathy and glycemic control: relationship between mean hemoglobin A1C value and development of proliferative diabetic retinopathy.
abstract: OBJECTIVE
  We evaluated the relationship between long-term glycemic control and the proportion of patients developing proliferative diabetic retinopathy (PDR) among cases with mild type preproliferative diabetic retinopathy (PPDR).
  
  
  METHODS
  The relationship was evaluated between the mean hemoglobin A1C (HbA1C) value during a period of at least 2 years and the proportion of patients developing PDR among cases with mild type PPDR, based on our previously proposed subclassification.
  
  
  RESULTS
  During follow-up, 27% of the total PPDR cases developed PDR. The mean HbA1C value in those patients who had developed PDR was 9.4% and was significantly higher than the 7.6% in those who had not developed PDR. The proportion developing PDR was 48% of the cases with a mean HbA1C value of 8.6% or more. By comparison, the proportion developing PDR was 8% among those with a mean HbA1C value below 8.6%. The proportion developing PDR was estimated to approximately double with each 1% increase in the mean HbA1C value. The cumulative occurrence rates of PDR at 2, 5, and 10 years were estimated to be 5%, 28%, and 60% in cases with a mean HbA1C value of 8.6% or more, and 0%, 7%, and 14% in those with a mean HbA1C value below 8.6%, respectively.
  
  
  CONCLUSIONS
  Stricter systemic and ophthalmological control is indicated for cases with a mean HbA1C value exceeding 8.6%.
authors.affiliation: Department of Ophthalmology, Nihon University, School of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sato
authors.forename: Z
authors.initials: Z
authors.lastname: Lee
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000097:blood / Q000145:classification / Q000209:etiology*; D018450:Disease Progression; D005451:Fluorescein Angiography; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D006943:Hyperglycemia / Q000517:prevention & control*; D015994:Incidence; D017075:Laser Coagulation; D008875:Middle Aged; D015861:Retinal Neovascularization / Q000097:blood / Q000145:classification / Q000209:etiology*
chemical_list: D006442:Glycated Hemoglobin