Long-term repeatability of measures of early insulin secretion derived from an intravenous glucose tolerance test and conversion from impaired glucose tolerance to diabetes.
OBJECTIVE
We assessed the long-term repeatability of the acute insulin response (AIR) and sensitivity index (S(I)) derived from the frequently sampled intravenous glucose tolerance test (FSIGT).


METHODS
An FSIGT was performed in 20 women who participated in a 6.5-month rye- and wheat-bread intervention trial, 70 men and women with impaired fasting glycaemia (IFG) or impaired glucose tolerance (IGT) who participated in the Genobin study, and 81 men and women with IGT who participated in the Finnish Diabetes Prevention Study (DPS).


RESULTS
The correlation of AIR and S(I) at base-line with respective values after the 6.5-8.5-month trials was 0.86-0.88 and 0.71-0.84, and before and after 4 years in the DPS substudy, 0.86 and 0.53. In multivariate analyses, AIR (relative risk for a 1-SD change, 0.67; 95% confidence intervals 0.46-0.97) predicted the conversion from IGT to diabetes in the DPS substudy.


CONCLUSIONS
AIR is highly repeatable even after 4 years of follow-up. The long-term repeatability of S(I) is moderate. Our findings emphasize the importance of impaired early insulin secretion in the transition from IGT to diabetes, and the high degree of tracking of measures of early insulin secretion derived from the FSIGT.
Laaksonen
David E
DE
Department of Medicine, Kuopio University Hospital, Kuopio, Finland.
Niskanen
Leo
L
Mykkänen
Hannu
H
Juntunen
Katri S
KS
Schwab
Ursula
U
Kolehmainen
Marjukka
M
Rauramaa
Rainer
R
Tuomilehto
Jaakko
J
Uusitupa
Matti
M
D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D016001:Confidence Intervals; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000503:physiopathology*; D005215:Fasting; D005260:Female; D005387:Finland / Q000453:epidemiology; D005500:Follow-Up Studies; D018149:Glucose Intolerance; D005951:Glucose Tolerance Test / Q000379:methods*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D001786:Blood Glucose; D007328:Insulin