Simple and non-invasive screening method for diabetes based on myoinositol levels in urine samples collected at home

OBJECTIVE: To establish a simple screening method for diabetes based on myoinositol (MI) in urine samples collected at home. RESEARCH DESIGN AND METHODS: Initially, we evaluated the stability of urinary MI (UMI) at room temperature (RT; 25°C) and 37°C in 10 outpatients with type 2 diabetes. We then enrolled 115 volunteers without a current or history of diabetes. In all subjects, glucose intolerance was diagnosed by 75 g oral glucose tolerance test (75gOGTT). To assess the association between UMI or urine glucose (UG) and plasma glucose (PG), urine samples were also collected at 0 and 2 hours during 75gOGTT. All the subjects collected urine samples at home before and 2 hours after consuming the commercially available test meal. UMI levels at wake-up time (UMI(wake-up)), before (UMI(premeal)) and 2 hours after the test meal (UMI(2h-postprandial)) were measured using an enzymatic method. ΔUMI was defined as UMI(2h-postprandial) minus UMI(premeal). RESULTS: Differing from UG, UMI was stable at RT and 37°C. UMI was increased linearly along with an increase in PG, and no threshold for UMI was observed. UMI was closely associated with blood glucose parameters obtained from a 75gOGTT and hemoglobin A1c (HbA1c) at hospital after adjustment for age, sex, body mass index and serum creatinine. UMI(wake-up), UMI(premeal), UMI(2h-postprandial) and ΔUMI at home were higher in diabetic subjects than non-diabetic subjects even after the above adjustment. Receiver operating characteristics curve (ROC) analyses revealed that for the screening of diabetes, the area under the curve for ROC for UMI(2h-postprandial) and ΔUMI (0.83 and 0.82, respectively) were not inferior to that for HbA1c ≥48 mmol/mol, which is the American Diabetes Association (ADA) criteria for diabetes. CONCLUSIONS: MI measurement in urine samples collected at home before and after the meal would be a simple, non-invasive and valuable screening method for diabetes.