Simple Screening for Glucose Intolerance Based on Myoinositol Levels in Self-Collected Urine Samples at Home

Background: Urinary myoinositol (UMI) is a molecule with a structure similar to D-glucose. In the presence of hyperglycemia, reabsorption of MI in the renal tubules is inhibited by urinary glucose (UG), resulting in high concentrations of MI excreted into the urine. Unlike UG, UMI is highly stable at room temperature (RT) for over a week. Therefore, we conducted a study to establish a simple screening method for glucose intolerance (GI) based on UMI levels in self-collected pre- and postprandial urine samples at home.

Methods: First, to diagnose GI, we performed a 75gOGTT at the hospital in 115 volunteers without a past history of diabetes (DM). Within a week, each volunteer collected urine samples before and 2h after consuming the test meal (500kcal, energy bar) at home, and these samples were shipped to a single laboratory at RT. UMI was measured using an enzymatic method.

Results: To assess the usefulness of UMI for screening GI (IGT+DM), we performed statistical analyses using receiver-operating characteristic (ROC) curve. It revealed that the area under the curve of ROC (AUCROC) for 2h-postprandial UMI/creatinine (Cr) was 0.74 for diagnostic accuracy of GI (IGT+DM). The optimal cut-off was 27 mg/gCr with a sensitivity of 60%, and a specificity of 81%. For diagnostic accuracy of DM, AUCROC for 2h-postprandial UMI/Cr was 0.83, with a sensitivity of 80%, and a specificity of 74% at the cut-off value of 27 mg/gCr.

Conclusions: UMI measurement of urine samples self-collected at home may be a non-invasive, inexpensive, and valuable screening method for GI. This strategy may be suitable for subjects in area with limited access to medical care including developing countries, and could be the first step towards further medical examinations such as blood glucose (OGTT when required), and HbA1c.