454-P: Risk Stratification of Cerebrocardiovascular Disease (CVD) according to HbA1c, Fasting Plasma Glucose (FPG), and Their Combinations in People with Prediabetes (preDM)

Association between preDM, defined by HbA1c or FPG alone, and CVD has remained controversial whereas impaired glucose tolerance (IGT) defined according to 2-h blood glucose level in the oral glucose tolerance test has been consistently associated with CVD. However, a glucose tolerance test is not practical in all persons. Thus, we attempted to identify a high-risk group for CVD in those with PreDM using HbA1c and FPG combinations. We analyzed data from a nationwide claims database on 1,140,096 Japanese with no CVD history or glucose abnormality from 2008 to 2022. Multivariate Cox regression analysis showed that compared with normal HbA1c (≤5.6%), CVD risk increased significantly and linearly from HbA1c 5.9% to HbA1c 6.8% in the diabetic range. Conversely, compared with normal FPG (70-99 mg/dl), CVD risk did not increase in the preDM range at each FPG level. Analysis of combinations of HbA1c and FPG showed that with FPG levels 70-99 mg/dl compared with HbA1c ≤5.6%, those with HbA1c 6.0-6.4% had an increased risk of CVD. Risk was higher than with HbA1c 6.5-6.8% (hazard ratio [HR] 1.30 [95% CI 1.11-1.52], 1.11 [0.63-1.96]) (Table). Results suggest that preDM with high HbA1c and normal FPG might have potential postprandial hyperglycemia or lack treatment interventions due to undiagnosed diabetes, which could increase risk of CVD.