Inflammation in end-stage renal disease: the hidden enemy.

Cardiovascular disease (CVD) remains the major cause of morbidity and mortality in end-stage renal disease (ESRD) patients. As traditional risk factors cannot alone explain the unacceptable high prevalence and incidence of CVD in this high-risk population, inflammation (interrelated to insulin resistance, oxidative stress, wasting and endothelial dysfunction) has been suggested to be a significant contributor. Indeed, several different inflammatory biomarkers, such as high sensitivity C-reactive protein (hs-CRP), have been shown to independently predict mortality in ESRD patients. As CRP is so strongly associated with vascular disease it has been suggested that this hepatic-derived protein is not only a marker, but also a mediator, of vascular disease. Although in vitro data from studies on endothelial cells, monocytes-macrophages and smooth muscle cells support a direct role for CRP in atherogenesis, data from studies performed in vivo have been controversial. The causes of the highly prevalent state of inflammation in ESRD are multiple, including inflammatory signals associated with the dialysis procedure, decreased renal function, volume overload, comorbidity and intercurrent clinical events. As the prevalence of inflammation varies considerably between continents and races, dietary and/or genetic factors may have an impact on inflammation in ESRD. Elevated CRP in dialysis patients could be evaluated at three different levels: (i) national/regional level; (ii) dialysis unit level; and (iii) individual patient level.