ABSTRACT
AIMS/INTRODUCTION: The objective of the present study was to clarify the validity of ß-cell function-related parameters for predicting the insulin requirement of Japanese type 2 diabetic patients. MATERIALS AND METHODS: In 188 patients with type 2 diabetes who had been admitted to the University of Toyama Hospital (Toyama, Japan) without receiving insulin therapy, we carried out a cross-sectional study examining the relationship between the homeostasis model assessment of ß-cell function (HOMA-ß) and C-peptide-based indices, and also carried out a retrospective study to examine the utility for predicting insulin requirement of several ß -cell function-related indices using a receiver operating characteristic (ROC) curve analysis. RESULTS: The secretory units of islets in transplantation index (SUIT) had the strongest correlation with HOMA-ß, followed by the fasting serum C-peptide immunoreactivity index (CPI); the fasting serum C-peptide immunoreactivity itself (F-CPR) had the least correlation. The CPI, HOMA-ß and SUIT were significantly lower in the insulin-requiring group than in the non-insulin-requiring group, even after adjustments for confounding factors (P < 0.01). The areas under the ROC curve for insulin requirement were 0.622, 0.774, 0.808, and 0.759 for F-CPR, CPI, SUIT, and HOMA-ß, respectively. The cut-off values of SUIT, CPI, and HOMA-ß for an over 80% specificity for the prediction of insulin therapy were 23.5, 1.00, and 14.9, respectively. CONCLUSIONS: The present study shows that SUIT is the best predictor of insulin requirement among these ß-cell function-related markers.
