[Study on blood glucose control of subjects with borderline type abnormality in 75 G oral glucose tolerance test values. The establishment of a high risk group on the basis of yearly observations].

SUBJECTS AND METHODS

227 of subjects with a 2-hour plasma glucose concentration of 120-199 mg/dl were selected from 413 participants who had two or more 75 g OGTT in health examinations from 1987-1995. From these subjects we established 8 groups according to initial 2-hour plasma glucose concentration 120-199 mg/dl stratified by 10 mg/dl, and calculated the total percentages of participants whose 2-hour plasma glucose concentration reached 200 mg/dl or greater over a 1-8 years (2.7 +/- 1.7 years, mean +/- SD) observation period. In 36 subjects who were tested annually over a four year period (4 times), the mean values of their 4 values were analyzed for relationships to coefficients of variation of the 2-hour plasma glucose.

RESULTS

By stratified groups (from lowest to highest) of those with an initial plasma glucose concentration of 120-159 mg/dl, 7.4%, 12.1%, 16.1%, and 15.0% attained values of 200 mg/dl and higher, respectively in 1-8 years. On the other hand, 29.6%, 29.6%, 39.1%, and 47.4% of those with an initial plasma glucose concentration of 160-199 mg/dl moved to a diabetic type after 1-8 years, respectively. The percentages of those who ended up with levels of 200 mg/dl and greater at 2-hours tended to increase in subjects whose initial 2-hour plasma glucose concentration was over 160 mg/dl in comparison with patients below that initial level.

CONCLUSIONS

From these results, it appears that subjects with 160-199 mg/dl 2-hour glucose concentration, which is considered a borderline status, are at high risk for future abnormal levels (> 200 mg/dl at 2-hours) and should be managed as a high risk level group for prevention of diabetes.