NORMALIZATION OF INSULIN SENSITIVITY IN THE OBESE PATIENT AFTER STABLE WEIGHT-REDUCTION WITH BILIOPANCREATIC DIVERSION

Insulin resistance is a common feature in obese patients. To evaluate the modifications in insulin sensitivity after a bariatric operation s uch as Bilio-pancreatic diversion (BPD), three groups of subjects (14 normal controls (N); seven eX-obese patients (X) with at least 2 years at weight-stable conditions after BPD surgery; and eight morbidly obe se patients (0)) were studied with intravenous (IVGTT) and oral (OGTT) glucose tolerance tests. The ratio of the area under the curve (AUC) for glucose over that of insulin was used as a measure of insulin sens itivity. All the following tests were conducted as Bonferroni-correcte d pairwise t-tests, in case overall ANOVA was significant. No signific ant difference was found between N and X subjects, while obese patient s showed a reduced AUCg/AUCi ratio with respect to the normal controls (O vs N: 0.01164 +/- 0.00039 vs 0.02392 +/- 0.0039, p < 0.05). IVGTT, AUCs: significant differences were found in each case: N vs X: 0.0591 +/- 0.0075 vs 0.1402 +/- 0.0399, p < 0.05; N vs O: 0.0591 +/- 0.0075 vs 0.0223 +/- 0.0031, p < 0.01; X vs O: 0.1402 +/- 0.0399 vs 0.0223 +/ - 0.0031, p < 0.05. IVGTT-derived data were also analyzed using the mi nimal model of glucose kinetics; with this method, glucose effectivene ss was significantly different between normal subject and obese subjec ts (0.0248 +/- 0.00288 vs 0.00905 +/- 0.00135 per min, p < 0.001). The insulin sensitivity index was not significantly different between nor mal and ex-obese subjects, while both of these groups were significant ly different from obese patients (N vs 0: 12.04 x 10(-5) +/- 2.61 x 10 (-5) vs 3.29 x 10(-5) +/- 0.61 x 10(-5), p < 0.066; X vs 0: 16.42 x 10 (-5) +/- 4.23 x 10(-5) vs 3.29 x 10(-5) +/- 0.61 x 10(-5) per min per pM, p < 0.02). In conclusion, the present study indicates that, after a body weight reduction operation capable of almost re-establishing id eal body weight like BPD, obese individuals with a family history of o besity show a normalization of insulin response to glucose load.