USING COMMON CLINICAL DATA IMPROVES THE AGREEMENT BETWEEN THE NEW CRITERIA OF IMPAIRED FASTING GLUCOSE AND DYSGLYCEMIA

The aim of this study was to determine the level of agreement between the impaired fasting glucose (IFG) and abnormal glucose tolerance before and after application of the new IFG definition and to evaluate the impact of adding common clinical data on this agreement. A cross sectional population based study was carried out in an Iranian urban population which enrolled 8766 men and women over 20 years. Fasting and 2-hour plasma glucose were measured in all subjects excluding those with previously diagnosed diabetes and fasting plasma glucose ≥126 mg/dl. The diagnostic parameters and kappa coefficient between the previous and revised definitions of IFG for detecting impaired glucose tolerance (IGT) and dysglycemia (IGT and diabetes) were calculated. Logistic regression and ROC curve analysis were used to determine the independent clinical risk factors and their optimal cut-points associated with IGT and dysglycemia. After using the new criteria, sensitivity of IFG for detecting IGT or dysglycemia increased but specificity and positive likelihood ratio (LR+) decreased and the κ slightly improved (0.16 to 0.29 for IGT and 0.24 to 0.35 for dysglycemia). Adding the clinical data to the revised criteria considerably improved the agreement between IFG with IGT and dysglycemia (κ increased from 0.286 to 0.470 for IGT and from 0.354 to 0.574 for dysglycemia). This also increased the LR+ from 3.86 to 14.5 and from 4.46 to 17.4 respectively for detecting IGT or dysglycemia. The new IFG definition in combination with common clinical risk factors most likely predicts IGT and dysglycemia.