Discriminatory ability of anthropometric measurements of central fat distribution for prediction of post‑prandial hyperglycaemia in patients with normal fasting glucose: the DICAMANO Study

Abstract

Background and aims: Obesity is associated with impaired glucose tolerance which is a risk factor for cardiovascular risk. However, the oral glucose tolerance test (OGTT) is not usually performed in patients with normal fasting glycae‑ mia, thus ofering false reassurance to patients with overweight or obesity who may have post-prandial hyperglycae‑ mia. As an alternative to resource demanding OGTTs, we aimed to examine the predictive value of anthropometric measures of total and central fat distribution for post-prandial hyperglycaemia in patients with overweight and obesity with normal fasting glycaemia enrolled in the DICAMANO study. Methods: We studied 447 subjects with overweight/obesity with a fasting glucose value ≤5.5 mmol l −1 (99 mg dl−1 ) and BMI≥25 kg/m2 who underwent a 75-g OGTT. Post-prandial hyperglycaemia was defned as a glucose level≥7.8 mmol l −1 (140 mg dl−1 ) 2-h after the OGTT. The anthropometric measurements included body mass index, body adiposity index, waist circumference, neck circumference, waist-to-hip ratio and waist-to-height ratio. Results: The prevalence of post-prandial hyperglycaemia was 26%. Mean 1-h OGTT glucose levels, insulin resistance and beta cell dysfunction was higher in those subjects in the highest tertile for each anthropometric measurement, irrespective of fasting glucose level. Central fat depot anthropometric measurements were strongly and indepen‑ dently associated with an increased risk of post-prandial hyperglycaemia. After multivariable-adjustment for fasting plasma glucose level, smoking, and physical activity level, the odds ratio (95% confdence intervals) for the presence of post-prandial hyperglycaemia for neck circumference, waist circumference and waist-to-height ratio were 3.3 (1.4, 7.7), 2.4 (1.4, 4.4) and 2.5 (1.4, 4.5), respectively. Conclusions: In this large and comprehensively phenotyped cohort, one in four subjects had post-prandial hyper‑ glycaemia despite normal fasting glycaemia. Anthropometric indices of central fat distribution were strongly and independently associated with an increased risk of post-prandial hyperglycaemia. These results support the associa‑ tion between central adiposity and glucose derangements and demonstrate the clinical usefulness of anthropometric measurements as screening tools for the selection of patients who are most likely to beneft from an OGTT.