Context: Studies addressing the association of metabolic syndrome and insulin resistance with the risks of incident chronic kidney disease (CKD) and the progression of renal function were either lacking or inconclusive.
Objective: The aim of this study was to define the effect of metabolic syndrome and insulin resistance on the development of new CKD and the decline in renal function.
Design and setting: A prospective cohort study was conducted at a tertiary university-based hospital in Taiwan.
Patients and other participants: We studied a total of 1456 Asians 65 or older who were followed for an average of 3.15 yr. Within the cohort, we measured insulin resistance using the homeostasis model assessment formula in 652 nondiabetic participants.
Interventions: There were no interventions.
Main outcome measures: We measured the prevalence and incidence of CKD and the annual decline of the estimated glomerular filtration rate.
Results: We found that the adjusted odds ratio for prevalent CKD in association with metabolic syndrome was 1.778 (95% confidence interval, 1.188 to 2.465), the hazard ratio for rapid decline in renal function was 1.042 (0.802-1.355), and the hazard ratio for incident CKD was 1.931 (1.175-3.174). With each one-unit increment of insulin resistance, the odds ratio of prevalent CKD and proteinuria were raised 1.312-fold (1.114 to 1.545) and 1.278-fold (1.098 to 1.488), respectively. Insulin resistance was not associated with incident CKD. Increment of insulin resistance per unit was associated with 1.16-fold (1.06 to 1.26) elevation in the hazard ratios of the decline in renal function.
Conclusions: Metabolic syndrome predicts the risks of prevalent and incident CKD, whereas insulin resistance is associated with prevalent CKD and rapid decline in renal function in elderly individuals.