Background:
We investigated the concordance between glucose effectiveness (sg) and insulin sensitivity (si), derived from the unmodified dynamic non-insulin-assisted intravenous glucose tolerance test (ivgtt) implemented by sg(mm) and si(mm); simulation analysis and modelling/conversational interaction (saam/consam) versus the eu/hyperglycaemic basal insulinaemic and the euglycaemic hyperinsulinaemic clamp (sg(clamp) and si(clamp)).
Methods:
Twenty-seven of 30 normoglycaemic subjects completed a (1) euglycaemic hyperinsulinaemic clamp, (2) 6-h eu/hyperglycaemic near-normoinsulinaemic pancreatic clamp with hyperglycaemia present over the final 2 h of the clamp (day 2 study), (3) identical clamp to (2) but with euglycaemia maintained over the entire 6 h (day 3 study) and (4) ivgtt. sg(clamp) was calculated in two ways based on data from study (2) alone (day 2 sg(clamp210-240')) or from data from study day (2) and (3) (day 2-3 sg(clamp330-360')).
Results:
Sg(mm) was unrelated to the magnitude of endogenous insulin release (air). the single-day (day 2) and two-day (day 2 and 3) sg(clamp) protocols correlated (r = 0.72, p = 0.003), but sg(clamp210-240') was significantly (p = 0.001) higher than sg(clamp330-360'). employing the day 2 and 3 sg(clamp) protocol, the whole body sg(clamp330-360') was similar to sg(mm) (1.80 ± 0.82 versus 1.73 ± 0.58 dl/min) and correlated (r = 0.45, p < 0.02). sg(clamp210-240') did not correlate with sg(mm) (r = 0.24). si(mm) and si(clamp) were similar (0.093 ± 0.060 versus 0.087 ± 0.029 dl/min per mu/l) and correlated (r = 0.76, p < 0.001).
Conclusions:
The time-dependent increase in glucose disposal observed during a prolonged 6-h clamp significantly influences the estimation of sg(clamp), and significant concordance coefficients are observed between sg(mm), and sg(clamp330-360'), and si(mm) and si(clamp).