Urinary Myoinositol 2h after 75g Glucose Loading as A Sensitive Marker of Glucose Intolerance

Abstract

To assess the possibility of using urinary myoinositol (UMI) at 2h after glucose loading as a marker for mass screening of glucose intolerance, a total of 390 volunteers were classified according to the 1998 WHO and 1999 JDS criteria. Cases of NGT with a 1h post-loaded plasma glucose level of more than 180mg/dl were classified as the pre-borderline type. Urine samples were collected before and 2h after glucose loading and UMI was measured using the enzymatic cycling method. We examined the ability to detect glucose intolerance between the UMI level at 2h after glucose loading (2hUMI) and the UMI increment between before and 2h after glucose loading (ΔUMI). The 2hUMI values showed a good correlation with ΔUMI. Both areas under the receiver operating characteristic curves between 2hUMI and ΔUMI were nearly equal and no significant differences were found. The optimum cutoff value for 2hUMI to detect glucose intolerance was 25mg/gCr. Applying this cutoff value, sensitivity and specificity were respectively 74% and 73% (as for ΔUMI, sensitivity; 74%, specificity; 80%). The positive rates for 2hUMI were 93.3% in DM and 72.6% in impaired glucose tolerance (IGT). Conversely, the positive rates for ΔUMI were 91.1% in DM and 72.6% in IGT. It would therefore appear to be possible to detect abnormal glucose tolerance effectively using the 2hUMI measurement.