Inflammatory syndrome in chronic kidney disease: pathogenesis and influence on outcomes

Morbidity and mortality are markedly elevated in chronic kidney disease (CKD) patients as consequence of cardiovascular risk factors clustering. Non-traditional risk factors such as inflammation are far more prevalent in this population and contribute significantly to atherosclerosis and cardiovascular disease (CVD). CKD results in a chronic, low-grade inflammatory process that becomes evident even in the early stages of the disease. C-reactive protein (CRP) and interleukin-6 (IL-6) are the most extensively studied inflammatory biomarkers in CVD. Circulating levels of both of these factors are elevated in CKD patients and increase with renal function deterioration. In end-stage renal disease (ESRD), elevated CRP levels are a strong predictor of all-cause and cardiovascular mortality. Recent studies showed IL-6 to predict more reliably CVD and mortality in ESRD patients. However, the issue of the ideal inflammatory marker remains open. Several factors are involved in triggering the inflammatory process including patient-related factors, such as underlying disease, comorbidity, oxidative stress, infectious, genetic or immunologic factors and uremia per se, as well as those arising from dialysis treatment itself, mainly membrane and dialysate biocompatibility. This inflammatory state is associated with adverse outcomes, such as malnutrition, anemia and erythropoietin hyporesponsiveness, high rate of CVD, decreased quality of life, as well as increased mortality and hospitalization in CKD patients. There is currently no consensus on how to manage the inflammatory syndrome in this population. However, adequate knowledge of its causes and their potential prevention or treatment may improve poor clinical outcome in CKD patients.