An Assessment of the New NIH Diagnostic Criteria for Diabetes Mellitus According to Insulin Response in a 75 g Oral Glucose Tolerance Test and Levels of Hemoglobin AIC

Summary

This study reviews the new diagnostic criteria for diabetes mellitus proposed by NIH. We measured insulin levels during 75 g oral glucose tolerance test (75 g OGTT) and hemoglobin AIC levels in patients diagnosed as having impaired glucose tolerance (IGT) or non-insulin dependent diabetes (NIDDM) according to the NIH criteria. In a 75 g oral glucose tolerance test, there was no significant difference in insulin-glucose ratio between nonobese IGT and nonobese NIDDM who had fasting blood glucose levels of less than 120 mg/dl (NIDDM-A group). However, in nonobese NIDDM with fasting blood glucose higher than 120 mg/dl (NIDDM-B group), the insulin-glucose ratio was significantly lower than in the IGT or NIDDM-A group. The NIDDM-B group had a higher hemoglobin AIC levels than the IGT and NIDDM-A groups, with no significant difference between the levels of the two latter groups. These observations suggest that the impairment in the function of pancreatic B cells and the state of chronic hyperglycemia are the same in IGT & NIDDM-A groups. Therefore, the NIH standards do not appear refined enough to truly differentiate between IGT and nonobese NIDDM with fasting blood glucose of less than 120 mg/dl.

Key-Words:

New Diagnostic Criteria - Diabetes Mellitus - Insulin Response - Hemoglobin AIC