Impact of Residual Renal Function on Complications in Chronic Hemodialysis Patients

Chronic kidney disease (CKD) is a progressive loss in renal function over a period of months or years. As kidney function declines, there is progressive deterioration in mineral homeostasis manifesting as disruption of serum and tissue concentrations of phosphorus and calcium (Ca), as well as changes in circulating levels of hormones such as parathyroid hormone (PTH). These mineral and endocrine functions are critically important in the regulation of both initial bone formation during growth (bone modeling) and bone structure and function during adulthood (bone remodeling) Residual renal function (RRF) plays an important role in maintaining fluid balance, phosphorus control, nutrition, and removal of middle molecular uremic toxins. Decline of RRF also contributes significantly to anemia, inflammation, and malnutrition in patients on dialysis.

Inflammation and activation of acute-phase responses are common in chronic kidney disease patients.

The causes of inflammation in HD patients are multifactorial. Inflammatory reaction may originate from several sources, including graft or fistula infections, bioincompatible dialysis membrane, dialysate, endotoxin exposure, back filtration, chronic infections, and malnutrition. High-sensitivity C-reactive protein (hsCRP) assay is useful for sensitive detection of the inflammatory state.

Residual renal function (RRF) in patients with end-stage renal disease (ESRD) receiving renal replacement therapy is defined as the ability of native kidneys to eliminate water and uremic toxins. In clinical practice, it is considered synonymous with such parameters as daily diuresis and/or glomerular filtration rate (GFR). The optimal method to measure RRF has not been established . RRF remains important even after beginning of dialysis. RRF contributes significantly to the overall health and well-being of patients on dialysis Residual Renal (RRF) plays an important role in maintaining fluid balance, phosphorus control, nutrition, and removal of middle molecular uremic toxins and shows inverse relationships with valvular calcification and cardiac hypertrophy in patients on dialysis.

Decline in RRF also contributes significantly to anemia, inflammation, and malnutrition in patients on dialysis . RRF may allow for a reduction in the duration of hemodialysis (HD) sessions and the need for dietary and fluid restrictions in both patients on peritoneal dialysis (PD) and patients on HD. More importantly, the loss of RRF is a powerful predictor of mortality. Much of RRF is lost during the first 18 months of HD, and appears to depend on the primary cause(s) of kidney failure as well as on other patient-related and treatment-related factors