Strategies for preserving residual renal function in peritoneal dialysis patients

Abstract

Although there have been many advancements in the treatment of patients with chronic kidney disease (CKD) over the last 50 years, in terms of reducing cardiovascular risk, mortality remains unacceptably high, particularly for those patients who progress to stage 5 CKD and initiate dialysis (CKD5d). As mortality risk increases exponentially with progressive CKD stage, the question arises as to whether preservation of residual renal function once dialysis has been initiated can reduce mortality risk. Observational studies to date have reported an association between even small amounts of residual renal function and improved patient survival and quality of life. Dialysis therapies predominantly provide clearance for small water-soluble solutes, volume and acid-base control, but cannot reproduce the metabolic functions of the kidney. As such, protein-bound solutes, advanced glycosylation end-products, middle molecules and other azotaemic toxins accumulate over time in the anuric CKD5d patient. Apart from avoiding potential nephrotoxic insults, observational and interventional trials have suggested that a number of interventions and treatments may potentially reduce the progression of earlier stages of CKD, including targeted blood pressure control, reducing proteinuria and dietary intervention using combinations of protein restriction with keto acid supplementation. However, many interventions which have been proven to be effective in the general population have not been equally effective in the CKD5d patient, and so the question arises as to whether these treatment options are equally applicable to CKD5d patients. As strategies to help preserve residual renal function in CKD5d patients are not well established, we have reviewed the evidence for preserving or losing residual renal function in peritoneal dialysis patients, as urine collections are routinely collected, whereas few centres regularly collect urine from haemodialysis patients, and haemodialysis dialysis patients are at risk of sudden intravascular volume shifts associated with dialysis treatments. On the other hand, peritoneal dialysis patients are exposed to a variety of hypertonic dialysates and episodes of peritonitis. Whereas blood pressure control, using an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB), and low-protein diets along with keto acid supplementation have been shown to reduce the rate of progression in patients with earlier stages of CKD, the strategies to preserve residual renal function (RRF) in dialysis patients are not well established. For peritoneal dialysis patients, there are additional technical factors that might aggravate the rate of loss of residual renal function including peritoneal dialysis prescriptions and modality, bio-incompatible dialysis fluid and over ultrafiltration of fluid causing dehydration. In this review, we aim to evaluate the evidence of interventions and treatments, which may sustain residual renal function in peritoneal dialysis patients.

C reactive protein and depressive symptoms in hemodialysis patients: A questionable association

“…Our results are in keeping with previous smaller single centre reports, suggesting that younger healthier dialysis patients are more likely to self-report depressive symptoms, whereas older more co-morbid patients report fewer symptoms [23,25]. We also found an association with diabetes and increasing BDI-II score, this may be because both dialysis and diabetes impose restrictions on dietary intake, and on one hand dialysis impacts on diabetic control, and on the other residual renal function is often more rapidly lost with diabetic kidney disease [26]. Although an increased CRP was retained in the model, CRP was not a significant independent factor.…”

Serum Endocan as a Predictive Marker for Decreased Urine Volume in Peritoneal Dialysis Patients

“…Because body fluid control is mainly influenced by RRF, the decline of RRF causes poor body fluid control in PD patients. Moreover, many studies have demonstrated that preserving RRF is associated with improved survival in PD patients [6]. Urine volume is a useful indicator of RRF, and a decline in urine volume suggests a decrease in RRF [1,7,8].…”

Management of hypertension for patients undergoing dialysis therapy

“…Therefore, preserving RRF is particularly important for patients on PD. For the purpose of RRF preservation, some strategies have been reported effective [66]. These include keeping proper body fluid volume and controlling BP.…”