Association of Albuminuria With Intraglomerular Hydrostatic Pressure and Insulin Resistance in Subjects With Impaired Fasting Glucose and/or Impaired Glucose Tolerance

Abstract

OBJECTIVE Little is known about the relationships between insulin resistance, intrarenal hemodynamics, and urinary albumin excretion (UAE) in humans with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT). The aim of the current study was to examine intrarenal hemodynamic abnormalities, insulin resistance, and UAE in subjects with IFG or IGT. We hypothesized that intrarenal hemodynamic abnormalities would be associated with insulin resistance. RESEARCH DESIGN AND METHODS Fifty-four kidney donors underwent 75-g oral glucose tolerance and inulin and para-aminohippuric acid clearance testing. Insulin sensitivity index (ISI) was evaluated by the Matsuda index. Intrarenal hemodynamic parameters were calculated by the Gomez formulae. RESULTS Of the 54 subjects, 33 exhibited IFG or IGT and 31 exhibited normal glucose tolerance (NGT). Glomerular hydrostatic pressure (Pglo) and UAE were significantly higher in the IFG or IGT subjects with obesity (P = 0.015 and 0.0001, respectively). Log ISI correlated significantly and negatively with Pglo (r = −0.351, P = 0.009) in all subjects. In multiple regression analyses among all subjects, log ISI was associated significantly and independently with Pglo (β = −0.316, P = 0.015), after adjustment for age, sex, and systolic blood pressure. Further, BMI (β = 0.517, P = 0.0004), Pglo (β = 0.420, P = 0.004), and log ISI (β = −0.366, P = 0.008) were each associated significantly and independently with UAE after adjustment. CONCLUSIONS We demonstrated that increased insulin resistance is associated with increased Pglo and UAE in IFG or IGT subjects. These hemodynamic burdens and insulin resistance may cause injury to the glomeruli even in subjects with IFG or IGT.