HYPERGLYCEMIC PROGRESSION IN SUBJECTS WITH IMPAIRED GLUCOSE-TOLERANCE- ASSOCIATION WITH DECLINE IN BETA-CELL FUNCTION

Impaired glucose tolerance is associated with an increased risk of Typ e 2 diabetes. This prospective cohort study has examined the variables associated with hyperglycaemic progression in order to elucidate the aetiology of this deterioration. The 5 mg glucose.kg ideal body weight .min-1 continuous infusion of glucose with model assessment (CIGMA) te st was used to quantitate glucose tolerance, beta cell function, and i nsulin sensitivity. Twenty-two Caucasian subjects who had impaired glu cose tolerance identified on two separate tests underwent repeat testi ng after a median period of 24 months. At follow-up, 2 of the 22 subje cts (9 %) had Type 2 diabetes, 18 (82 %) had impaired glucose toleranc e, and 2 (9 %) were normoglycaemic. The fasting and achieved (60-min) glucose levels were significantly higher at follow-up (mean +/- SD) (5 .7 +/- 0.8 vs 5.5 +/- 0.5 mmol l-1, p = 0.029 and 10.0 +/- 0.9 vs 9.6 +/- 0.6 mmol l-1, p = 0.021, respectively), and beta cell function was significantly lower (median and interquartile range): 75 % (50-93 %) vs 90 % (70-135 %), p = 0.009. The changes in fasting plasma glucose w ere found to correlate with change in body mass index (r(s) = 0.46, p = 0.03). We conclude that impaired glucose tolerance is associated wit h decline in beta cell function, and denotes substantial risk of hyper glycaemic progression. Randomized controlled trials are warranted to d etermine whether exercise programmes, dietary advice, and attentive fo llow-up and effective preventive strategies for subjects with impaired glucose tolerance.