Abstract P048: Prediabetes Range Fasting Glucose and Hemoglobin A1C Levels and Their Associations with Subclinical Atherosclerosis: Observations from the Dallas Heart Study
Background Over 1/3 of US adults have “prediabetes” defined by impaired fasting glucose (IFG) and/or “at risk” hemoglobin A1c (A1C) - criteria criticized by some for being too liberal. Their associations with subclinical atherosclerosis remain poorly defined.
Methods/Results Prediabetes was determined (fasting plasma glucose (FPG) 100-125mg/dL and/or A1C 5.7-6.4%) and coronary artery calcium (CAC) was measured in 2,373 adults age 30-70 free from medically-treated diabetes or cardiovascular disease in the Dallas Heart Study 2, a population-based cohort with mean age 49 years, mean BMI 30.5 kg/m2; 60% women and 64% non-white. Those with vs. without prediabetes were older (52 vs. 48 yrs; p<0.001), and more likely to be men (63% vs. 53%), non-white (71 vs. 61%;), and obese (58% vs. 40%; p<0.001 for each). CAC prevalence (Agatston score >10) was higher in those with vs. without prediabetes (31 vs. 21%; p<0.001), with no statistical difference in CAC prevalence between prediabetes sub-groups with IFG-only, A1C-only, or both (p<0.877) (FIGURE). Analyzing FPG and A1C each continuously as univariable predictors of CAC, the optimized threshold for FPG was 96 mg/dl and for A1C was 5.5%. The optimized FPG threshold to predict the composite: mortality, MI, stroke or coronary revascularization over a median 8.4 yrs of follow-up (169 total events) among 2,880 DHS-1 participants enrolled 2001-2002 was 106 mg/dl; A1C was not measured in DHS-1.
Conclusions Glycemic thresholds presently used to identify prediabetes are associated with increased atherosclerosis, and perhaps even lower thresholds might be considered to capture the spectrum of increased clinical risk associated with dysglycemia below the diabetes range.
- © 2013 by American Heart Association, Inc.