A STUDY OF INSULIN-RESISTANCE USING THE MINIMAL MODEL IN NONDIABETIC FAMILIAL COMBINED HYPERLIPIDEMIC PATIENTS

The presence of insulin resistance in 20 male nondiabetic patients wit h familiar combined hyperlipidemia (FCH) and 20 controls of similar ag e and body mass index (BMI) was investigated using the minimal model m ethod modified by the administration of insulin and an oral glucose to lerance test. The peripheral sensitivity of insulin, expressed as the insulin sensitivity index (Si), was 1.91 +/- 1.05 and 2.86 +/- 1.19 x 10(-4) . min(-1) . mU/L in FCH patients and controls, respectively (P <.01), and the corresponding value for the peripheral utilization of g lucose independently of insulin (Sg) was 1.70 +/- 1.13 in FCH patients and 2.35 +/- 0.60 x 10(-2) . min(-1) in controls (P <.02). In the FCH group, the Si value correlated significantly (P <.05) with the waist to hip ratio (WHR), plasma triglycerides (TG), free fatty acids (FFA), and the area under the curve of glucose (AUCg) and insulin (AUCi). In the control group, the correlation also reached statistical significa nce (P <.05) with age, BMI, WHR, blood pressure, TG, AUCg, and AUCi. S ubgrouping the subjects with respect to central obesity defined as a W HR of 0.95 or greater, we observed lower Si values in obese and non-ob ese FCH subjects relative to controls (P <.02). The mean Si value in o bese subjects was significantly lower than in non-obese FCH subgroups (1.40 +/- 0.79 v 2.68 +/- 0.95 x 10(-4) . min(-1) . mU/L, respectively , P <.01). In conclusion, a higher degree of insulin resistance relati ve to control values appears to be an integral part of the metabolic d erangements observed in FCH, and central-trunk obesity exacerbates the insulin resistance syndrome. Copyright (C) 1998 by W.B. Saunders Comp any.