Metabolic syndrome, insulin resistance, and chronic allograft dysfunction

Metabolic syndrome (MS) is a cluster of cardiovascular (CV) risk factors (hypertension, dyslipidemia, obesity, and glucose homeostasis alterations), and insulin resistance (IR) is suggested to be a common pathogenic background. In the general population, MS and IR have been proven to be risk factors for diabetes, CV disease, and chronic kidney disease. In the renal transplant setting, few studies have analyzed the relevance of MS and IR. According to the few data available, the prevalence of MS in renal transplant patients has been described as 22.6% at 12 months, 37.7% at 36 months, and 64% at 6 years after transplantation. Importantly, MS has been shown to be an independent risk factor for chronic allograft dysfunction (CAD), graft failure, new-onset diabetes, and CV disease. Also, persistent hyperinsulinemia during the first posttransplant year has been related to an increase in glomerular filtration rate, probably reflecting glomerular hyperfiltration as observed in prediabetes and early type 2 diabetes. Importantly, prediabetes (impaired fasting glucose and impaired glucose tolerance), a state hallmarked by IR, proved to be highly frequent among stable renal transplant recipients (30%), which is nearly three times its incidence in the general population. Posttransplant IR has been associated with subclinical atheromatosis as assessed by carotid intima-media thickness, and with chronic subclinical inflammation. In conclusion, MS and IR are important modifiable risk factors in renal transplant recipients, and prompt interventions to avoid its deleterious effects at the metabolic, CV, and graft function levels are needed.