Metabolic syndrome, but not insulin resistance, is associated with an increased risk of renal function decline

Background & aims: The purpose of this study was to evaluate the effect of metabolic syndrome (Mets) and insulin resistance (IR) on the risk of renal function decline (RFD) in a rural Chinese cohort. Methods: A total of 2696 subjects aged 40-71 years with normal renal function were followed-up for 7 years. RFD was defined using the Kidney Disease: Improving Global Outcome definition, i.e., a drop in estimated glomerular filtration rate (eGFR) category accompanied by a 25% or greater drop in eGFR from baseline or a sustained decline in eGFR of more than 5 mL/min/1.73 m(2)/year. Results: During the 7-year follow-up, 9.0% of the subjects developed RFD. Subjects with Mets at baseline had an increased risk of RFD with an adjusted odds ratio (OR) of 1.77 (95%Cl: 1.25-2.52), and there was a graded relationship between the numbers of Mets components and the risk for RFD. Exclusion of the subjects with hypertension (1.65; 0.99-2.75) or diabetes (1.86; 1.30-2.67) at baseline or further adjustment for IR (1.72; 1.15-2.57) did not substantially change the association between Mets and the risk of RFD. Moreover, the ORs of Mets status for RFD in the older group (>= 55 years) were 2.14 (1.06 -4.33) times of that in the younger group (<55 years) and 2.26 (1.07-4.78) times in hypercholesterolemia group (>= 5.2 mmol/L) of that in the normal (<5.2 mmol/L) group. The baseline IR was not associated with the risk for RFD. Conclusions: Mets, but not IR, was associated with an increased risk for RFD. And there was a detrimental interaction of Mets with older age and hypercholesterolemia on the risk of RFD. (C) 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.