Rationale and Strategies for Preserving Residual Kidney Function in Dialysis Patients.

BACKGROUND: Residual kidney function (RKF) conveys a survival benefit among dialysis patients, but the mechanism remains unclear. Improved volume control, clearance of protein-bound and middle molecules, reduced inflammation and preserved erythropoietin and vitamin D production are among the proposed mechanisms. Preservation of RKF requires techniques to measure it accurately to be able to uncover factors that accelerate its loss and interventions that preserve it and ultimately to individualize therapy. The average of renal creatinine and urea clearance provides a superior estimate of RKF in dialysis patients, when compared with daily urine volume. However, both involve the difficult task of obtaining an accurate 24-h urine sample. SUMMARY: In this article, we first review the definition and measurement of RKF, including newly proposed markers such as serum levels of beta2-microglobulin, cystatin C and beta-trace protein. We then discuss the predictors of RKF loss in new dialysis patients. We review several strategies to preserve RKF such as renin-angiotensin-aldosterone system blockade, incremental dialysis, use of biocompatible membranes and ultrapure dialysate in hemodialysis (HD) patients, and use of biocompatible solutions in peritoneal dialysis (PD) patients. Despite their generally adverse effects on renal function, aminoglycoside antibiotics have not been shown to have adverse effects on RKF in well-hydrated patients with end-stage renal disease (ESRD). Presently, the roles of better blood pressure control, diuretic usage, diet, and dialysis modality on RKF remain to be clearly established. Key Messages: RKF is an important and favorable prognostic indicator of reduced morbidity, mortality, and higher quality of life in both PD an HD patients. Further investigation is warranted to uncover factors that protect or impair RKF. This should lead to improved quality of life and prolonged lifespan in patients with ESRD and cost-reduction through patient centeredness, individualized therapy, and precision medicine approaches.

In-Hospital Mortality in Cirrhotic Patients with End-Stage Renal Disease Treated with Hemodialysis Versus Peritoneal Dialysis: A Nationwide Study.

BACKGROUND: Cirrhotic patients often develop end-stage renal disease (ESRD) requiring renal replacement therapy in the form of hemodialysis (HD) or peritoneal dialysis (PD). Studies comparing the outcomes and difference in in-hospital mortality between these 2 groups, particularly among those with ascites, are sparse. We set our objective to determine the dialysis modality with a better in-hospital survival rate among cirrhotic patients with ESRD (ESRD-cirrhosis). METHODS: Data was extracted from the 2005 to 2012 Nationwide Inpatient Sample (NIS). Using propensity score matching, ESRD-cirrhosis patients on PD were matched with patients on HD at a 1:1 ratio. Another subgroup analysis of ESRD-cirrhosis patients with ascites was performed using the same matching algorithm. Analyses were performed using SAS version 9.3 (SAS Institute, Cary, NC, USA). RESULTS: Among 26,135 cirrhotic patients with incident ESRD, 25,686 (98.3%) and 449 (1.7%) were initiated on HD and PD, respectively, during the hospitalization. There was a nonsignificant mortality difference between the ESRD-cirrhosis patients treated with PD and those treated with HD. In a subgroup analysis of these patients with ascites, 18 patients underwent PD while 1,878 patients required HD. Also, PD had a significantly lower in-hospital mortality compared with HD in this subgroup (0% vs 26.67%, p = 0.03). Mean length of stay for those who received HD was 8.34 days compared with 7.06 days for the PD group (p < 0.0001). Similarly, mean hospital charges were greater for those who had HD compared with PD ($74,501 vs $57,460; p < 0.001). CONCLUSION: Cirrhotic patients with ESRD and ascites who undergo PD have a significantly lower mortality than those who are started on HD. However PD is rarely initiated for ESRD in cirrhotic patients with ascites during hospitalization in the United States. Due to the potential advantages of PD, nephrologists should encourage PD when selecting dialysis modality in this subgroup of patients whenever possible.