A formula to simplify the screening for impaired glucose tolerance in youths with overweight or obesity

Aim: To develop a low cost formula as screening tool for identifying youths with overweight/obesity (OW/OB) at risk for impaired glucose tolerance (IGT). Methods and Results: A retrospective observational study was performed in 1189 Caucasian youths with OW/OB aged 5-17 years, in whom information about family history for diabetes (FD), fasting glucose (FG), 2-hour glucose levels post-oral glucose tolerance test, alanine aminotransferase (ALT), and lipids were available at their first visit. Youths with impaired fasting glucose and high HbA1c were excluded from the study. Prevalence of isolated IGT was 6.6% (n =78). Youths with IGT were older, showed higher prevalence of FD, higher levels of FG and post-load glucose, ALT, triglycerides, and low HDL-Cholesterol compared to youths without IGT. The sample was divided into training set (TS) (n = 883) and validation set (VS) (n =306). The formula predicting IGT was obtained by logistic regression analysis in the TS, as it follows: 0.043*ALT+0.064*FG+0.87*FD-0.06*HDL. The cut-off of 5.7 showed sensitivity 0.29, specificity 0.95, and overall accuracy 0.91 (0.89-0.93) for detecting IGT. Similar results were found in the VS. Conclusions: Using low cost variables, this simple formula can help pediatricians to select young people with OW/OB who should perform the OGTT for the screening of IGT.