Glycemic Thresholds for Diabetes-Specific Retinopathy: Implications for Diagnostic Criteria for Diabetes
- The DETECT-2 Collaboration Writing group,
- Stephen Colagiuri, (MBBS) ()1,
- Crystal M.Y. Lee, (PhD)1,
- Tien Y. Wong, (PhD)2,3,
- Beverley Balkau, (PhD)4,5,
- Jonathan E. Shaw, (MD)6 and
- Knut Borch-Johnsen, (DMSc)7,8
- 1 Boden Institute of Obesity, Nutrition and Exercise, University of Sydney, Australia
- 2 Center for Eye Research Australia, University of Melbourne, Australia
- 3 Singapore Eye Research Institute, National University of Singapore, Singapore
- 4 INSERM, CESP Centre for Research in Epidemiology and Population Health, U1018, Epidemiology of diabetes, obesity and chronic kidney disease over the lifecourse, F-94807, France
- 5 Université Paris Sud 11, UMRS 1018, F-94807, France
- 6 Baker IDI Heart and Diabetes Institute, Australia
- 7 Steno Diabetes Center, Denmark
- 8 Faculty of Health Science, Univ. Aarhus, Denmark
Objective: To re-evaluate the relationship between glycemia and diabetic retinopathy.
Research design and methods: We conducted a data pooling analysis of nine studies from five countries with 44623 participants aged 20 to 79 years with gradable retinal photographs. The relationship between diabetes-specific retinopathy (defined as moderate or more severe retinopathy) and three glycemic measures: fasting plasma glucose (FPG; n=41411), 2-hour post oral glucose load plasma glucose (2-h PG; n=21334), and glycated hemoglobin (HbA1c; n=28010), was examined.
Results: When diabetes-specific retinopathy was plotted against continuous glycemic measures, a curvilinear relationship was observed for FPG and HbA1c. Diabetes-specific retinopathy prevalence was low for FPG < 6.0 mmol/L and HbA1c < 6.0% but increased above these levels. Based on vigintile (20 groups with equal numbers) distributions, glycemic thresholds for diabetes-specific retinopathy were observed over the range 6.4-6.8 mmol/L for FPG, 9.8-10.6 mmol/L for 2-h PG, and 6.3-6.7% for HbA1c. Thresholds for diabetes-specific retinopathy from receiver operating characteristic curve analyses were 6.6 mmol/L for FPG, 13.0 mmol/L for 2-h PG, and 6.4% for HbA1c.
Conclusion: This study broadens the evidence-base on diabetes diagnostic criteria. A narrow threshold range for diabetes-specific retinopathy was identified for FPG and HbA1c but not for 2-h PG. The combined analyses suggest that the current diabetes diagnostic level for FPG could be lowered to 6.5 mmol/L and that an HbA1c of 6.5% is a suitable alternative diagnostic criterion.
- Received June 23, 2010.
- Accepted October 8, 2010.
- Copyright © American Diabetes Association