Longer time to peak glucose during the oral glucose tolerance test increases cardiovascular risk score and diabetes prevalence

INTRODUCTION The pattern of glucose levels during an oral glucose tolerance test (OGTT) may be useful for predicting diabetes or cardiovascular disease (CVD). Our aim was to determine whether the time to peak glucose during the OGTT is associated with CVD risk scores and diabetes. METHODS Individuals with impaired fasting glucose (IFG) were enrolled in this observational study. Participants were grouped by the measured time to peak glucose (30, 60, 90 and 120 min) during the 75g OGTT. The primary outcome was 10-year CVD risk scores (using the Framingham risk score calculator). Secondary outcomes evaluated effect of time to peak glucose on prevalence of diabetes and indicators of glucose homeostasis. RESULTS A total of 125 patients with IFG underwent OGTTs. Framingham 10-year risk score for the 90-min group was 1.7 times higher than for the 60-min group (6.98±6.56% vs. 4.05±4.60%, P = 0.023). Based on multivariate linear regression, time to peak glucose at 90 min was associated with a higher Framingham risk score than 60-min group (β coefficient: 2.043, 95% confidence interval: 0.067-6.008, P = 0.045). The percentages of patients with HbA1c ≥6.5%, isolated post-challenge hyperglycemia (IPH) and diabetes (combined IPH and HbA1c ≥6.5%) were significantly increased with longer times to peak glucose. Prevalence of diabetes was higher in the 90-min group than in the 60-min group (31.5% vs. 5.7%, P = 0.001). CONCLUSIONS In subjects with IFG, those with a longer time to peak glucose had a higher Framingham 10-year risk score and were associated with a greater likelihood of IPH and diabetes.