Correlates of insulin resistance in older individuals with and without kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is associated with insulin resistance (IR). Prior studies have found that in individuals with CKD, leptin is associated with fat mass but resistin is not and the associations with adiponectin are conflicting. This suggests that the mechanism and factors associated with IR in CKD may differ. METHODS: Of the 2418 individuals without reported diabetes at baseline, participating in the Health, Aging and Body Composition study, a study in older individuals aged 70-79 years, 15.6% had CKD defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) based on cystatin C. IR was defined as the upper quartile of the homeostasis model assessment. The association of visceral and subcutaneous abdominal fat, percent body fat, muscle fat, lipids, inflammatory markers and adiponectin were tested with logistic regression. Interactions were checked to assess whether the factors associated with IR were different in those with and without CKD. RESULTS: Individuals with IR had a lower eGFR (80.7 ± 20.9 versus 75.6 ± 19.6, P < 0.001). After multivariable adjustment, eGFR (odds ratio per 10 mL/min/1.73 m(2) 0.92, 95% confidence interval 0.87-0.98) and CKD (1.41, 1.04-1.92) remained independently associated with IR. In individuals with and without CKD, the significant predictors of IR were male sex, black race, higher visceral fat, abdominal subcutaneous fat and triglycerides. In individuals without CKD, IR was associated with lower high-density lipoprotein and current nonsmoking status in multivariate analysis. In contrast, among individuals with CKD, interleukin-6 (IL-6) was independently associated with IR. There was a significant interaction of eGFR with race and IL-6 with a trend for adionectin but no significant interactions with CKD (P > 0.1). In the fully adjusted model, there was a trend for an interaction with adiponectin for eGFR (P = 0.08) and significant for CKD (P = 0.04 ), where adiponectin was associated with IR in those without CKD but not in those with CKD. CONCLUSIONS: In mainly Stage 3 CKD, kidney function is associated with IR; except for adiponectin, the correlates of IR are similar in those with and without CKD.