Risk assessment by post-challenge plasma glucose, insulin response ratio, and other indices of insulin resistance and/or secretion for predicting the development of type 2 diabetes.

ABSTRACT

OBJECTIVE: To find useful indices to identify subjects at high risk for developing diabetes. METHODS: We retrospectively reviewed 75-g oral glucose tolerance test (OGTT) surveys conducted during 1980 to 2001 in a Japanese community. Using personal charts of the surveys, 230 non-diabetics were followed for progression to type 2 diabetes. The usefulness of HbA(1C), fasting (Glucose(0)) and 1-hour (Glucose(60)) glucose levels during OGTT, and indices for insulin resistance and/or secretion to identify high risk subjects for diabetes were then analyzed. MATERIALS Data described in personal charts of the OGTT program for residents of Nishikawa Town, Niigata Prefecture, Japan. RESULTS: During the 4.3+/-2.7 years of follow-up, 52 subjects progressed to type 2 diabetes. Assessing glucose and insulin levels during OGTT, Glucose(0), Glucose(60), "Insulin Response Ratio" (IRR(30), Insulin at 30 minutes / Fasting insulin; IRR(60), insulin at 60 minutes / fasting insulin), and insulin secretion / insulin resistance index (ISIRI(30)) were significantly associated with progression to type 2 diabetes even after the result for OGTT, body mass index, and familial history of diabetes were adjusted. These were also able to identify still higher risk subjects for type 2 diabetes from those with impaired glucose tolerance (IGT) although other indices for insulin resistance or secretion and hemoglobin A(1C) were less contributable for this purpose. CONCLUSION: A combination of Glucose(0) and Glucose(60) can most cost effectively identify high risk subjects for type 2 diabetes from IGT. IRR(30), IRR(60) and ISIRI(30) can also be used for such identification. However, further studies are needed to clarify whether these indices are superior to Glucose(0) and Glucose(60).