Prognostic importance of insulin-mediated glucose uptake in aged patients with congestive heart failure secondary to mitral and/or aortic valve disease

Previous studies have demonstrated that insulin resistance is a common feat ure of congestive heart failure (CHF), hut the clinical significance of suc h insulin resistance is still debated. We tested the hypothesis that insuli n-mediated glucose uptake (IMGU) is a prognostic factor in CHF in aged pati ents. For this purpose 174 aged patients with GHF participated in a cross-s ectional and a longitudinal study of 24 months' duration. In this latter st udy survival analysis was calculated comparing subjects at the first and se cond tertile of IMGU with chose at third tertile. All subjects underwent an thropometric (body mass index, waist/hip ratio), cardiovascular (arterial b lood pressure, 24-hour Holier monitoring, peak VO2, left ventricular electi on fraction, echocardiography), and metabolic (determination of fasting pla sma glucose, insulin, catecholamine, free fatty acids, tumor necrosis facto r-alpha concentrations, and assessment of IMGU by euglycemic hyperinsulinem ic glucose clamp) investigations. In the cross-sectional study, IMGU correl ated with age (r = -0.33, p < 0.001), body mass index (r = -0.46 p < 0.001) , ventricular premature complexes (r = -0.78, p < 0.001), left ventricular ejection fraction (r = -0.15, p < 0.05), fasting plasma norepinephrine (r = -0.75, p < 0.001), tumor necrosis factor-alpha (r = -0.45, p < 0.001), fre e fatty acids (r = -0.54 p < 0.001), and peak VO2 (r = 0.67, p < 0.001). In the longitudinal study patients at the first and second tertile of IMGU ha d a lower probability of survival than patients at the third tertile (p < 0 .03). Cox regression analysis showed IMGU to be a prognostic factor indepen dent of fasting plasma norepinephrine, tumor necrosis factor-alpha free fat ty acid concentration, New York Heart Association class, peak VO2, and left ventricle ejection fraction (relative risk 1.1, 95% confidence intervals 1 .0 to 2.1). In conclusion, our study demonstrates that insulin resistance i s a common feature of CHF most likely due to elevated plasma norepinephrine and tumor necrosis factor-alpha concentrations, and that IMGU is an indepe ndent prognostic factor in CHF. (C) 1999 by Excerpta Medica, Inc.