The relationship between decline rate of residual renal function in the first year and mortality in peritoneal dialysis patients

INTRODUCTION

To assess the relationship between the rate of residual renal function (RRF) decline in the first year and all-cause and cardiovascular mortality in peritoneal dialysis (PD) patients.

METHODS

Incident PD patients were divided into two groups by the corresponding RRF decline value, when hazard ratio (HR) = 1 was found by the restricted cubic spline. The associations of rate of decline of RRF in the first year with mortality were evaluated.

RESULTS

Of 497 PD patients, 122 patients died. After adjusting for confounding factors, patients in fast-decline group had a significant increase risk of all-cause and cardiovascular mortality (HR: 1.97 and 2.09, respectively). Each 0.1-mL/min/1.73 m2 /month decrease in RRF in the first year of PD was associated with a 19% and 20% higher risk of all-cause and cardiovascular mortality, respectively.

CONCLUSIONS

Faster decline of RRF in the first year was independently associated with all-cause and cardiovascular mortality in PD patients.

A Review of Residual Kidney Function in Peritoneal Dialysis Patients

Residual kidney function (RKF) has been associated with better survival, less morbidity, and improved quality of life in peritoneal dialysis (PD) patients. Since higher peritoneal clearance does not lead to better outcomes, more emphasis should be put on preserving kidney function. Many other benefits have been reported, including better volume and blood pressure control, better nutritional status, lower rates of PD peritonitis, preserved erythropoietin and vitamin D production, middle molecule clearance, lower Left Ventricular Hypertrophy, and better serum phosphate level. The most practical method of assessing RKF is the mean of 24-h urinary urea and creatinine clearance. Incremental PD prescription is an ideal option to supplement RKF in PD patients, which also offers more flexibility to the patient and, possibly, improved adherence. Angiotensin converting enzyme inhibitors and angiotensin receptor blockers should be used when possible in PD patients to preserve RKF. Loop diuretics are underutilized in PD patients despite providing an additional means of maintaining fluid balance and reducing the need for higher glucose-containing PD solutions. In this paper, we outline the importance of RKF in PD patients and the different strategies for its preservation.

On the importance of the interplay of residual renal function with clinical outcomes in end-stage kidney disease

Chronic kidney disease (CKD) is one of the most important public health concerns of the century, and is associated with high rates of morbidity, mortality and social costs. CKD evolving towards end-stage kidney disease (ESKD) is on the rise resulting in a greater number of patients requiring peritoneal dialysis (PD) and hemodialysis (HD). The aim of this manuscript is to review the current literature on the interplay of residual renal function (RRF) with clinical outcomes in ESKD. The persistence of RRF is one of the most important predictors of decreased morbidity, mortality, and better quality of life in both PD and HD patients. RRF contributes to the well-being of ESKD patients through various mechanisms including higher clearance of solutes, maintenance of fluid balance, removal of uremic toxins and control of electrolytes. Furthermore, RRF has beneficial effects on inflammation, anemia, malnutrition, diabetes mellitus, obesity, changes in the microbiota, and cardiac diseases. Several strategies have been proposed to preserve RRF, such as blockade of the renin-angiotensin-aldosterone system, better blood pressure control, incremental PD and HD. Several clinical trials investigating the issue of preservation of RRF are ongoing. They are needed to broaden our understanding of the interplay of RRF with clinical outcomes in ESKD.

Association between lipid profile and residual renal function in incident peritoneal dialysis patients

INTRODUCTION

Residual renal function (RRF) is one of the most crucial factor in the management of peritoneal dialysis (PD). The aim of this study was to evaluate the association between lipid profile and preservation of RRF among incident PD patients.

METHODS

This retrospective cohort study investigated 113 patients (male, 72%; age, 59±14 years) who initiated PD between 2006 and 2017. We investigated the relationships between high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) at PD initiation and change in renal Kt/V during the first year after PD initiation.

RESULTS

Alterations in renal Kt/V during the first year after PD initiation correlated negatively with HDL-C at PD initiation, but not with LDL-C. On multivariate analysis, HDL-C at PD initiation was independently associated with change in renal Kt/V during the first year after PD initiation.

CONCLUSION

These results suggests importance of lipid management among incident PD patients for preservation of RRF.

Red blood cell distribution width predicts residual renal function decline in patients undergoing continuous ambulatory peritoneal dialysis

To investigate the relationship between red blood cell distribution width (RDW) and residual renal function (RRF) in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Seventy-seven CAPD patients were enrolled in this study. According to receiver operator characteristic (ROC) curve analysis, patients were divided into high RDW (RDW > 14.95%) and low RDW (RDW ≤ 14.95%) groups. The data of baseline clinical, biochemical parameters, comorbidities, medication status, peritoneal function, and dialysis adequacy were compared. Survival curves were calculated using Kaplan-Meier method. Cox regression model was employed to analyze risk factors of decline in RRF. The overall median survival time was 24 months, the median survival time of high RDW group (46 patients) and low RDW group (31 patients) were 24 and 12 months, respectively. Compared with the low RDW group, patients in the high RDW group were older, higher rate of decline RRF and white blood cells count as well as lower total Kt/V (all p < 0.05). Kaplan-Meier survival curves showed that the low RDW group had higher survival of RRF compared with the high RDW group (p < 0.001). Multivariate Cox regression analysis showed that high RDW was independent risk factor for decline of RRF(hazard ratio = 1.441, 95% confidence interval: 1.089-1.905, p = 0.01). Increased baseline RDW is associated with decline of RRF in CAPD patients and RDW can be stratified as a valuable indicator for the risk of RRF decline.

Rate of decline in residual kidney function pre and post peritoneal dialysis initiation: A post hoc analysis of the IDEAL study

Background

Residual kidney function (RKF) is associated with improved survival and quality of life in dialysis patients. Previous studies have suggested that initiation of peritoneal dialysis (PD) may slow RKF decline compared to the pre-dialysis period. We sought to evaluate the association between PD initiation and RKF decline in the Initiating Dialysis Early And Late (IDEAL) trial.

Methods

In this post hoc analysis of the IDEAL randomized controlled trial, PD participants were included if results from 24-hour urine collections had been recorded within 30 days of dialysis initiation, and at least one value pre- and one value post-dialysis commencement were available. The primary outcome was slope of RKF decline, calculated as mean of urinary creatinine and urea clearances. Secondary outcomes included slope of urine volume decline and time from PD initiation to anuria.

Results

The study included 151 participants (79 early start, 72 late start). The slope of RKF decline was slower after PD initiation (-2.69±0.18mL/min/1.73m²/yr) compared to before PD (-4.09±0.33mL/min/1.73m²/yr; change in slope +1.19 mL/min/1.73m²/yr, 95%CI 0.48–1.90, p<0.001). In contrast, urine volume decline was faster after PD commencement (-0.74±0.05 L/yr) compared to beforehand (-0.57±0.06L/yr; change in slope -0.18L/yr, 95%CI -0.34—-0.01, p = 0.04). No differences were observed between the early- and late-start groups with respect to RKF decline, urine volume decline or time to anuria.

Conclusions

Initiation of PD was associated with a slower decline of RKF compared to the pre-dialysis period.

Effects of exercise on residual renal function in patients undergoing peritoneal dialysis: A post-hoc analysis of a randomized controlled trial

We aimed to investigate the effects of exercise on renal outcomes in patients undergoing peritoneal dialysis (PD). In a post-hoc analysis of a randomized controlled trial of a 12-week home-based exercise program involving 47 patients undergoing PD, we excluded 18 patients with anuria and analyzed 13 and 16 patients in the usual care and exercise groups, respectively. The primary outcomes were weekly renal creatinine clearance (CCr) and urinary biomarkers: liver-type fatty acid-binding protein (L-FABP) and the microalbumin-to-creatinine ratio (ACR). Although the maintenance of weekly renal CCr in the exercise group was not significantly different compared with that in the usual care group (P = .09), urinary L-FABP levels (P = .02) and ACR (P = .04) were significantly decreased in the exercise group. To the best of our knowledge, this is the first study to demonstrate the beneficial effects of exercise on renal outcomes in patients undergoing PD.

Risk factors for loss of residual renal function in children with end-stage renal disease undergoing automatic peritoneal dialysis

BACKGROUND

This study analysed children with end-stage renal disease treated with automated peritoneal dialysis (APD) in our centre to explore the risk factors associated with residual renal function (RRF) loss.

METHODS

Children treated with APD as the initial renal replacement therapy regimen from January 2008 to December 2016 were included. All the children had a daily urine volume of ≥100 ml/m² when APD was initiated and a dialysis follow-up time of ≥12 months. A daily urine volume of <100 ml/m² after 12 months of APD treatment was defined as loss of RRF. Possible risk factors that may be associated with RRF loss were analysed.

RESULTS

A total of 66 children were included in the study. After 12 months of APD treatment, the daily urine volume decreased by 377.45 ± 348.80 ml/m², the residual glomerular filtration rate decreased by 6.39 ± 3.69 ml/min/1.73 m² and 29 of the patients (43.9%) developed RRF loss. The higher risk of RRF loss after 1 year of APD treatment was most pronounced in patients with daily urine volume of ≤400 ml/m² before treatment, higher glucose exposure and higher ultrafiltration volume, while the lower risk of RRF loss was in patients with administration of diuretics. Each increase of 1 g/m²/day glucose exposure was associated with a 5% increase in RRF loss (odds ratio (OR) 1.05, p = 0.023) and each increase of 1 ml/m²/day ultrafiltration volume was associated with a 1% increase in RRF loss (OR 1.01, p = 0.013).

CONCLUSION

In children undergoing APD, the risk for loss of RRF is associated with low urine volume at the start of APD, high glucose loading and high peritoneal ultrafiltration volume, while preservation of RRF is associated with the usage of diuretics.

Incremental peritoneal dialysis

Incremental peritoneal dialysis (PD) has been variably defined. It involves taking advantage of the residual renal function that is usually present at initiation of dialysis to initially prescribe less onerous lower doses of PD while still achieving individualized clearance goals. We propose that incremental PD be defined as a strategy, rather than a particular regime, in which: (1) less than standard “full-dose” PD is initially prescribed in recognition of the value of residual renal function; (2) peritoneal clearance is initially less than the individualized clearance goal but the combination of peritoneal plus renal clearance achieves or exceeds that goal clearance; and (3) there is a clear intention to increase dose of PD as renal clearance declines and/or symptoms appear.

Incremental PD by its nature lessens the workload of dialysis for those doing PD, reduces cost and exposure of the peritoneal membrane to glucose, and may lessen mechanical symptoms. Evidence that incremental PD improves clinical outcomes compared to the use of full-dose PD is lacking but one randomized controlled trial, multiple observational studies, and a systematic review all suggest that outcomes are at least as good. Given that incremental PD costs less and is inherently less onerous, it is reasonable, pending larger randomized trials, to adopt this strategy.

N-Terminal Pro-Brain Natriuretic Peptide Predicts Long-Term Technique Failure in Patients Undergoing Peritoneal Dialysis

It is unclear whether N-terminal pro-brain type natriuretic peptide (NT-proBNP) level can be a biomarker for technique failure among long-term peritoneal dialysis (PD) patients. We prospectively included end-stage renal disease patients undergoing PD from a single center between December 2011 and December 2017. We divided the cohort into high or low NT-proBNP groups and analyzed the risk factors associated with the incidence of technique failure using Cox proportional hazard regression analysis. A total of 258 chronic PD patients (serum NT-proBNP, 582 ± 1216 ng/mL) were included. After a mean follow-up of 3.6 years, 49.6% of PD patients developed technique failure and switched to hemodialysis, while 15.5% died. Cox proportional hazard regression analyses accounting for age, gender, diabetes, renal clearance, C-reactive protein, and hydration status, showed that higher natural log transformed NT-proBNP levels (hazard ratio [HR] 1.13, p < 0.01) were predictive of an increased risk of technique failure, and were also predictive of an increased risk of mortality (HR 1.56, p < 0.01). Consequently, NT-proBNP might be an under-recognized biomarker for estimating the risk of technique failure, and regular monitoring NT-proBNP levels among PD patients may assist in their care.

Rapid Change in Residual Renal Function Decline Is Associated with Lower Survival and Worse Residual Renal Function Preservation in Peritoneal Dialysis Patients

The survival advantage observed among peritoneal dialysis patients early on after dialysis initiation has been largely attributed to residual renal function (RRF) preservation due to higher baseline residual function and fewer comorbidities. We hypothesize that a rapid decline in RRF is associated with higher risk of anuria and mortality. In a retrospective cohort study of 581 subjects on peritoneal dialysis with longitudinal prevalent data, we assessed whether RRF change over time, in addition to baseline RRF, increased risk of mortality and anuria using Kaplan-Meier analysis and Cox proportional hazard analysis to control for known risk factors. Rapid RRF decline (≥ 0.09 decline) over a 12-month period was associated with a 2.6-fold increase in the risk of death (hazard ratio [HR] 2.60, 95% confidence interval [CI] 1.66 - 4.07, compared with < 0.09 decline) and a 2-fold increase in anuria (HR 2.06, 95% CI 1.24 - 3.42). Each quartile of increasing severity of RRF decline over a 12-month period increased risk incrementally for death (2^nd quartile: HR 3.04, CI 1.26 - 7.34; 3^rd quartile: HR 4.01, CI 1.71 - 9.83; 4^th quartile HR 5.78, CI 2.10 - 15.9) and generally for anuria (quartiles with HR 5.72 - 7.21). The escalating risk of mortality and anuria was greater for those with diabetes mellitus. In conclusion, rapid decline in RRF over a 12-month period increased the risk of mortality and likewise anuria, beyond previously established risk factors for mortality and anuria. The impact on mortality and RRF preservation was particularly severe for those with diabetes mellitus.

Baseline and Time-Averaged Values Predicting Residual Renal Function Decline Rate in Japanese Peritoneal Dialysis Patients

Residual renal function (RRF) is a strong prognostic factor of morbidity and mortality in patients undergoing peritoneal dialysis (PD). We determined predictors of the RRF rate of decline using both baseline values and time-averaged ones. We retrospectively analyzed 94 patients being treated with PD at the Japanese Red Cross Medical Center. The decline rate of RRF was calculated by a diminution in the weekly renal Kt/V between the first and last follow up divided by follow-up years. The mean follow-up period was 2.28 years, and the mean decline rate of weekly renal Kt/V was 0.25 per year. A multivariate analysis using baseline parameters identified dialysis-to-plasma ratios of creatinine at 4 h (P = 0.02), urinary protein (P = 0.02), and mean blood pressure (MBP) (P < 0.01) as being positively associated with the RRF rate of decline, while the use of angiotensin converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) had a negative correlation (P = 0.03). When using time-averaged values as independent variables, a lower weekly total renal Kt/V (P < 0.0001), higher urinary protein (P < 0.0001), and higher MBP (P = 0.04) independently predicted a faster RRF rate of decline. We demonstrated that PD patients with a lower MBP and lower urinary protein both at baseline and throughout their PD duration had a slower RRF rate of decline. We recommend strict control of blood pressure and anti-proteinuric therapy for PD patients.

Predictors of Residual Renal Function Decline in Peritoneal Dialysis Patients: The balANZ Trial

Objective

Preservation of residual renal function (RRF) is associated with improved survival. The aim of the present study was to identify independent predictors of RRF and urine volume (UV) in incident peritoneal dialysis (PD) patients.

Methods

The study included incident PD patients who were balANZ trial participants. The primary and secondary outcomes were RRF and UV, respectively. Both outcomes were analyzed using mixed effects linear regression with demographic data in the first model and PD-related parameters included in a second model.

Results

The study included 161 patients (mean age 57.9 ± 14.1 years, 44% female, 33% diabetic, mean follow-up 19.5 ± 6.6 months). Residual renal function declined from 7.5 ± 2.9 mL/min/1.73 m2 at baseline to 3.3 ± 2.8 mL/min/1.73 m2 at 24 months. Better preservation of RRF was independently predicted by male gender, higher baseline RRF, higher time-varying systolic blood pressure (SBP), biocompatible (neutral pH, low glucose degradation product) PD solution, lower peritoneal ultrafiltration (UF) and lower dialysate glucose exposure. In particular, biocompatible solution resulted in 27% better RRF preservation. Each 1 L/day increase in UF was associated with 8% worse RRF preservation ( p = 0.007) and each 10 g/day increase in dialysate glucose exposure was associated with 4% worse RRF preservation ( p < 0.001). Residual renal function was not independently predicted by body mass index, diabetes mellitus, renin angiotensin system inhibitors, peritoneal solute transport rate, or PD modality. Similar results were observed for UV.

Conclusions

Common modifiable risk factors which were consistently associated with preserved RRF and residual UV were use of biocompatible PD solutions and achievement of higher SBP, lower peritoneal UF, and lower dialysate glucose exposure over time.

The Use of Incremental Peritoneal Dialysis in a Large Contemporary Peritoneal Dialysis Program

BACKGROUND

The use of an incremental peritoneal dialysis (PD) strategy in a large contemporary patient population has not been described.

OBJECTIVE

We report the use of this strategy in clinical practice, the prescriptions required, and the clearances achieved in a large center which has routinely used this approach for more than 10 years.

DESIGN

This is a cross-sectional observational study.

SETTING

A single large Canadian academic center.

PATIENTS

This study collected data on 124 prevalent PD patients at a single Canadian academic center.

METHODS AND MEASUREMENTS

The proportion of patients who achieve the clearance target on a low clearance or incremental PD prescription; the actual PD prescriptions and consequent total, peritoneal, and renal urea clearances [Kt/V] achieved; and patient and technique survival and peritonitis rate in comparison with national and international reports.

RESULTS

Of the 124 prevalent PD patients in this PD unit, 106 (86%) were achieving the Kt/V target, and of these, 54 (44% of all patients) were doing so using incremental PD prescriptions. Fifty of these incremental PD patients were using automated PD (APD) with either no day dwell (68%) or less than 7 days a week treatment (12%) or both (20%). Patient survival in our PD unit was not different from that reported in Canada as a whole. Peritonitis rates were better than internationally recommended standards.

LIMITATIONS

This is an observational study with no randomized control group.

CONCLUSIONS

Incremental PD is feasible in a contemporary PD population treated mainly with APD. Almost half of the patients were able to achieve clearance targets while receiving less onerous and less costly low clearance prescriptions. We suggest that incremental PD should be widely used as a cost-effective strategy in PD.

Correlation of Residual Diuresis with MIS Score and Nutritional Status in Peritoneal Dialysis Patients: A Croatian Nationwide Study

Introduction. Residual diuresis (RD) is an important predictor of mortality and cardiovascular (CV) deaths in peritoneal dialysis (PD) patients, and contributes more to overall survival compared to PD clearance. In this study we investigated the correlation between RD and CV outcomes in PD patients.

Methods. A total of 190 PD patients from 13 dialysis centers, a national representation, were included in this analysis. Biomarkers of anemia, nutritional status [malnutrition inflammation score (MIS), subjective global assessment (SGA), serum albumin, anthropometric measurements including body mass index (BMI)], dialysis dose (Kt/V) and laboratory measurements were determined. RD was estimated using the volume of daily urine.

Results. There were 78(41.05 %) females and 112 (58.95 %) males; aged 57.35±14.41 years, on PD for 24.96±24.43 months. Fifty-six patients had diabetes type II (44 as primary kidney disease). The mean RD was 1170±673.6 ml (range 0-3000 mL). Statistically significant correlations between RD and BMI, hip circumference, time on PD, Kt/V, MIS, SGA, erythrocytes (E), Hemoglobin (Hb), PTH, and serum albumin were observed.

Conclusions. We demonstrated a significant correlation between RD and MIS score, SGA, anthropometry and albumin. Every effort should be invested to maintain RD for as long as possible to achieve optimal treatment results and to decrease CV mortality in PD population.

Risk Factors for Decline of Residual Renal Function in Children Treated With Peritoneal Dialysis

♦ BACKGROUND: The aim of the study was to assess risk factors for residual renal function (RRF) decline in children during the first/second year of chronic peritoneal dialysis (PD). ♦ METHODS: The study group included 56 children with end-stage renal disease (ESRD) (age 10.13 ± 4.86 years), including 18 on continuous ambulatory PD (CAPD) and 38 on automated PD (APD), in whom we evaluated RRF (daily diuresis [mL/m2/24 h], residual glomerular filtration rate (rGFR) [mL/min/1.73 m2]), etiology of ESRD, PD fluid volume (mL/m2/24 h), glucose load (g/m2/24 h), ultrafiltration (mL/m2/24 h), peritoneal permeability (D/PCrea 4h, D/D0 Glu 4h), dialysis adequacy (twKt/V, twCCr [L/week/1.73 m2]), blood pressure (BP), biochemical parameters, and medications used. Duration of follow-up was 24 months. ♦ RESULTS: Mean diuresis before initiation of PD was 1,394.93 ± 698.37 (mL/m2/24 h), and mean rGFR was 7.41 ± 3.96 (mL/min/1.73 m2). The rate of daily diuresis decline was -529.34 ± 546.28 in the first year and -107.10 ± 291.54 (mL/m2/24 h) in the second year (p = 0.005), and the rate of rGFR decline was -3.35 ± 3.73 in the first year and -1.63 ± 1.85 (mL/min/1.73 m2) in the second year (p = 0.118). Eleven (19.64%) patients became anuric. In univariate analysis, the rate of daily diuresis decline in the first year was related to baseline diuresis (r = -0.29, p = 0.031), proteinuria (r = -0.43, p = 0.001), and systolic BP (r = -0.31, p = 0.020); 12-month changes (Δ0 - 12) in PD fluid volume (r = -0.37, p = 0.004), glucose load (r = -0.28, p = 0.035), and ultrafiltration (r = -0.38, p = 0.004); serum calcium-phosphorus product (r = -0.41, p = 0.002); and Δ0 - 12 body mass index (BMI) Z-score (r = 0.30, p = 0.024); while the rate of rGFR decline in the first year was related only to baseline rGFR (r = -0.57, p < 0.001). In multivariate analysis, significant predictors of the rate of daily diuresis decline in the first year were baseline diuresis (β = -0.386, p < 0.001) and proteinuria (β = -0.278, p = 0.017), mean systolic BP Z-score (β = -0.237, p = 0.027), and age at the onset of PD (β = -0.224, p = 0.037), while predictors of the rate of rGFR decline were baseline rGFR (β = -0.607, p < 0.001) and baseline proteinuria (β = -0.225, p = 0.046). In the second year, the only predictors of the rate of rGFR decline were D/D0 Glu 4h (r = 0.44, p = 0.033, univariate analysis) and rGFR at 12 months (β = -0.499, p = 0.044). ♦ CONCLUSION: The most important risk factors for rapid RRF decline in children during the first year of chronic PD include higher baseline daily diuresis and proteinuria, and additional factors are systolic BP and age at the onset of PD; while high baseline GFR and low peritoneal transport status may be the only important factors during the second year.

The Impact of Fluid Overload and Variation on Residual Renal Function in Peritoneal Dialysis Patient

BACKGROUND

The effect of fluid overload and variation on residual renal function (RRF) in peritoneal dialysis (PD) patients is controversial.

METHODS

Retrospective cohort study was designed. One-hundred and ninety PD patients with measured glomerular filtration rate (mGFR) ≧ 3 ml/min/1.73 m2 were recruit. Fluid status of every participant was assessed by bioelectrical impedance analysis (BIA) every 3 months for 1 year. The cohort was divided into three hydration groups, namely persistent overhydration (PO) group, intermittent overhydration (IO) group and normal hydration (NH) group. Additionally, participants were also divided into high or low fluid variation groups. The decline rate of RRF and the event of anuria were followed up for 1 year. The association of fluid overload with RRF loss was evaluated by Cox proportional hazard models adjusted for confounders.

RESULTS

Thirty-six (18.9%) patients developed anuria. The decline rate of mGFR in both PO and IO groups were significantly faster than that of NH group (PO vs NH: -0.2 vs -0.1 ml/min/1.73 m2/month, p < 0.01; IO vs NH: -0.2 vs -0.1 ml/min/1.73 m2/month, p < 0.01). Kaplan-Meier analysis showed poorer RRF outcome in both PO and IO groups compared with that of NH group (PO vs NH: p < 0.001; IO vs NH: p = 0.006). Patients with high fluid variation had worse RRF survival than those with low fluid variation (p = 0.04). Adjusted Cox regression models indicated the hazard ratio of RRF loss in PO group was 8.90-folds higher (95% confidence interval 3.07-31.89) than that in NH group.

CONCLUSIONS

These findings suggested fluid overload was independently associated with the decline of RRF in PD patients.

Rate of Decline of Residual Kidney Function Before and After the Start of Peritoneal Dialysis

♦

BACKGROUND

There is a paucity of information on whether peritoneal dialysis (PD) slows the decline of residual kidney function (RKF) compared to the natural slope of RKF decline prior to dialysis start. Our aim was to analyze the RKF decline before and after initiating PD, and to determine the principal factors affecting this decline during the PD period. ♦

METHODS

We determined individual glomerular filtration rates (GFR) for approximately 12 months before and after PD in 77 new PD patients in a large academic medical center (2008 - 2012). The GFR was estimated by the Modification of Diet in Renal Disease (MDRD) equation in the predialysis period and by averaging 24-hour urine creatinine and urea clearances in the PD period. The rate of RKF decline was calculated using unadjusted linear regression analysis. Wilcoxon signed rank test was used to compare RKF decline before and after PD initiation. Multivariate linear regression was used to identify independent risk factors for RKF decline in the PD phase. ♦

RESULTS

A significantly slower mean rate of RKF decline was observed in the PD period compared with the predialysis period (-0.21 ± 0.30 vs -0.59 ± 0.55 mL/min/1.73 m(2)/month, p < 0.01). Higher baseline RKF, higher serum phosphate, and older age were independently associated with faster decline of RKF (all p < 0.01). ♦

CONCLUSIONS

In patients with advanced chronic kidney disease, initiating PD was associated with a slower rate of RKF decline compared to the rate in the predialysis period.

Clinical Significance of the Edema Index in Incident Peritoneal Dialysis Patients

Background

Proper monitoring for volume overload is important to improve prognosis in peritoneal dialysis (PD) patients. The association between volume status and residual renal function (RRF) remains an unresolved issue. The aim of the present study was to evaluate the association between the edema index and survival or RRF in incident PD patients.

Patients and Methods

We identified all adults who underwent PD. The edema index was defined as the ratio of extracellular fluid to total body fluid. Participants with available data regarding survivorship or non-survivorship during the first year after PD initiation were included in the area under the receiver operating characteristic curve analysis. The cutoff value of the edema index for 1-year mortality was >0.371 in men and >0.372 in women. Participants were divided into two groups according to the cutoff value of their baseline edema indices: High (>cutoff value) and Low (≤cutoff value). Survivors during the first year after PD initiation were divided into two groups according to the initial and 1-year edema index: Non-improvement (maintenance of criteria in the initial Low group during the year) and Other (all participants except those in the Non-improvement group).

Results

In total, 631 patients were enrolled in the present study. The cutoff value of the edema index for 1-year mortality was >0.371 in men and >0.372 in women. The respective mean initial RRF values (mL·min^-1·1.73 m^-2) in the Low and High groups, respectively, were 4.88 ± 4.09 and 4.21 ± 3.28 in men (P = 0.108), and 3.19 ± 2.57 and 2.98 ± 2.70 in women (P = 0.531). There were no significant differences between groups in either sex. The respective mean RRF values at 1 year after PD initiation in the Low and High groups, respectively, were 3.56 ± 4.35 and 2.73 ± 2.53 in men, and 2.80 ± 2.36 and 1.85 ± 1.51 in women. RRF at 1 year after PD initiation was higher in the Low group than in the High group (men: P = 0.027; women: P = 0.001). In men, the cumulative 5-year survival rates were 78.7% and 46.2% in the Low and High groups, respectively, whereas in women, rates were 77.2% and 58.8% in the Low and High groups, respectively. For survivors during the first year after PD initiation, the Non-improvement group was associated with a poor survival rate compared with the Other group for both sexes.

Conclusion

A high edema index was associated with mortality in incident PD patients at baseline and follow-up. The edema index may be used as a new marker for predicting mortality in PD patients.

High-sensitivity C-reactive protein, apolipoproteins, and residual diuresis in chronic kidney disease patients undergoing hemodialysis

BACKGROUND

Residual diuresis (RD) is the simplest method for measuring renal residual function in patients with chronic kidney disease (CKD). A reduction in RD is associated with intensification of the inflammatory process caused by uremia. However, little is known regarding the relation between RD and inflammatory markers in these patients. We verify possible associations among the hs-CRP, atherogenic factors, and RD, in patients with CKD undergoing hemodialysis.

METHODS

This study enrolled 80 patients with CKD undergoing hemodialysis. Patients were stratified according to RD in anuric (RD-) group (n = 47) and non-anuric (RD+) group (n = 33). Urine volumes were collected in a 24 h period during the interdialytic period. Serum high-sensitivity C-reactive protein (hs-CRP), and apolipoprotein (Apo) A1 and B levels were measured after fasting for 12 h.

RESULTS

Serum hs-CRP levels were higher in the RD- group than in the RD+ group (P = 0.015). In the total group, hs-CRP was significantly correlated with RD (r = - 0.25, P = 0.025) and Apo AI (r = - 0.25, P = 0.024). A greater proportion of patients had reduced plasma concentrations of Apo AI in the RD- group (31.9 %) compared with the RD+ group (9.1 %) (P = 0.014).

CONCLUSION

This study shows a relationship between RD and the hs-CRP in patients undergoing hemodialysis. Although the inflammatory state was verified in a large part of the CKD population, patients without RD had more elevated hs-CRP serum levels than those with RD.

Extracellular volume expansion and the preservation of residual renal function in Korean peritoneal dialysis patients: a long-term follow up study

INTRODUCTION

In chronic peritoneal dialysis patients, preservation of residual renal function (RRF) is a major determinant of patient survival, and maintaining sufficient intravascular volume has been hypothesized to be beneficial for the preservation of RRF. The present study aimed to test this hypothesis using multifrequency bioimpedence analyzer (MFBIA), in Korean peritoneal dialysis patients.

METHODS

A total of 129 patients were enrolled in this study. The baseline MFBIA was checked, and the patients were divided into the following two groups: group 1, extracellular water per total body water (ECW/TBW) < median, group 2, ECW/TBW > median. We followed up the patients, and then we analyzed the changes in the urine output (UO) and the solute clearance (weekly uKt/V) in each group. Data associated with patient and technical survivor were collected by medical chart review. The volume measurement was made using Inbody S20 equipment (Biospace, Seoul, Korea). We excluded the anuric patients at baseline.

RESULT

The median value of ECW/TBW was 0.396. The mean patient age was 49.74 ± 10.01 years, and 62.1 % of the patients were male; most of the patients were on continuous ambulatory peritoneal dialysis (89.1 %). The mean dialysis vintage was 26.20 ± 28.71 months. All of the patients were prescribed hypertensive medication, and 48.5 % of the patients had diabetes. After 25.47 ± 6.86 months of follow up, ΔUO and Δweekly Kt/V were not significantly different in the two groups as follows: ΔUO (-236.07 ± 185.15 in group 1 vs -212.21 ± 381.14 in group 2, p = 0.756); Δ weekly Kt/v (-0.23 ± 0.43 in group 1 vs -0.29 ± 0.49 in group 2, p = 0.461). The patient and technical survivor rate was inferior in the group 2, and in the multivariable analysis, initial hypervolemia was an independent factor that predicts both of the patient mortality [HR 1.001 (1.001-1.086), p = 0.047] and the technical failure [HR 1.024 (1.001-1.048), p = 0.042].

CONCLUSIONS

Extracellular volume expansion, measured by MFBIA, does not help preserve residual renal function, and is harmful for the technical and patient survival in Korean peritoneal dialysis patients.

Risk factors for loss of residual renal function in children treated with chronic peritoneal dialysis

In dialyzed patients, preservation of residual renal function is associated with better survival, lower morbidity, and greater quality of life. To analyze the evolution of residual diuresis over time, we prospectively monitored urine output in 401 pediatric patients in the global IPPN registry who commenced peritoneal dialysis (PD) with significant residual renal function. Associations of patient characteristics and time-variant covariates with daily urine output and the risk of developing oligoanuria (under 100 ml/m²/day) were analyzed by mixed linear modeling and Cox regression analysis including time-varying covariates. With an average loss of daily urine volume of 130 ml/m² per year, median time to oligoanuria was 48 months. Residual diuresis significantly subsided more rapidly in children with glomerulopathies, lower diuresis at start of PD, high ultrafiltration volume, and icodextrin use. Administration of diuretics significantly reduced oligoanuria risk, whereas the prescription of renin–angiotensin system antagonists significantly increased the risk oligoanuria. Urine output on PD was significantly associated in a negative manner with glomerulopathies (−584 ml/m²) and marginally with the use of icodextrin (−179 ml/m²) but positively associated with the use of biocompatible PD fluid (+111 ml/m²). Children in both Asia and North America had consistently lower urine output compared with those in Europe perhaps due to regional variances in therapy. Thus, in children undergoing PD, residual renal function depends strongly on the cause of underlying kidney disease and may be modifiable by diuretic therapy, peritoneal ultrafiltration, and choice of PD fluid.

Effect of hypertension and antihypertensive medications on residual renal function in children treated with chronic peritoneal dialysis

PURPOSE

To evaluate the effect of hypertension (HTN) and antihypertensive medications (AHM) on residual renal function (RRF) in children on CAPD and APD.

MATERIAL/METHODS

We retrospectively evaluated underlying kidney disease, systolic and diastolic blood pressure (SBP/DBP), presence and control of HTN (SBP/DBP≥95th percentile), AHM, RRF (daily diuresis, residual glomerular filtration rate [rGFR]), biochemical parameters, BMI Z-score, and dialysis parameters during 12-month follow-up in 87 children (38 CAPD, 49 APD) aged 10.22±4.31 years. The rate of RRF loss was expressed as absolute and relative [%] reduction.

RESULTS

At baseline, HTN was found in 74.7% patients (CAPD/APD: 84.2%/67.3%, P=0.06), most commonly in HUS and least frequently in CAKUT. The proportion of CAPD/APD patients with poorly controlled HTN was 70.0%/63.3% (P=0.50). Relative daily diuresis loss in children with uncontrolled HTN was higher (P=0.017) compared to children with SBP/DBP <95th percentile. No effect of AHM on the rate of RRF loss was found. In multivariate analysis, absolute daily diuresis loss was related to baseline diuresis (β=-0.30, P<0.001) and proteinuria (β=-0.31, P=0.004); absolute rGFR loss to baseline rGFR (β=-0.73, P<0.001) and glucose load after 12 months (β=-0.36, P=0.02); relative daily diuresis loss to mean BMI Z-score (β=-0.44, P=0.04); and relative rGFR to baseline rGFR (β=-0.37, P<0.001) and SBP percentile (β=-0.21, P=0.045).

Preserving residual renal function in dialysis: what we know

Residual renal function confers a survival benefit among dialysis patients thought to be related to greater volume removal and solute clearance. Whether the presence of residual renal function is protective or merely a marker for better health is not clear. The basic mechanisms governing the decline or persistence of residual renal function are poorly understood and few studies have examined the role of medical therapy in its preservation. Dialysis modality, inflammatory processes often associated with comorbid diseases (including diabetes mellitus and obesity), volume dysregulation, and vitamin D deficiency are predictive of residual renal function decline. We review potential mechanisms for preservation of remaining glomerular filtration rate among chronic dialysis patients.

Inflammation and myocardial damage markers influence loss of residual renal function in peritoneal dialysis patients

BACKGROUND

Residual renal function (RRF) has been identified as the most important component in dialysis adequacy and has a strong effect on clinical outcomes. This justifies any effort in understanding the mechanism behind the preservation or decline in RRF. The aim of this study was to analyze the possible association of components of cardio-renal syndrome with the rate of decline in RRF.

METHODS

A retrospective cohort study was performed in a group of prevalent adult patients on continuous ambulatory peritoneal dialysis (CAPD). Patients were analyzed at baseline and after a 30-month follow-up. Evaluations included measurements of residual renal function, dialysis adequacy parameters, cardiovascular comorbidity, and measurements of biochemical markers of cardiovascular disease (CVD) and inflammation, as well as resting electrocardiography.

RESULTS

We included 129 patients in the study who were divided into groups according to loss of RRF, considering the cut-off point as 100 mL/day of 24 h urine volume. At baseline, there were no differences between groups: patients who lost RRF showed low values of 24 h urine volume, higher levels of systolic blood pressure, N-terminal pro-brain natriuretic peptide (NT-proBNP), C-reactive protein (CRP), IL-6, and low values of serum albumin. In the multivariate analysis, age, albumin, CRP, and NT-proBNP were significant risk factors for the loss of RRF.

CONCLUSIONS

Data indicate a close relationship between heart and kidney function where chronic kidney disease (CKD) affects and is an effect of, heart function, indicative of a bi-directional influence that leads to a vicious cycle, promoting deleterious effects on both systems.

Ferritin as a predictor of decline in residual renal function in peritoneal dialysis patients

AIMS

Inflammation is an important factor in renal injury. Ferritin, an inflammatory marker, is considered an independent predictor of rapid renal progression in patients with chronic kidney disease. However, the relationship between ferritin and residual renal function (RRF) in patients undergoing peritoneal dialysis (PD) remains unclear.

METHODS

We reviewed the medical records of patients who started PD between June 2001 and March 2012 at Soonchunhyang University Bucheon Hospital, Korea. A total of 123 patients were enrolled in the study. At 1 month after the initiation of PD, RRF was determined by a 24-hour urine collection and measured every 6 months thereafter. Clinical and biochemical data at the time of the initial 24-hour urine collection were considered as baseline.

RESULTS

The RRF reduction rate was significantly greater in patients with high ferritin (ferritin ≥ 250 ng/mL) compared with those with low ferritin (ferritin < 250 ng/mL; -1.71 ± 1.36 mL/min/yr/1.73 m(2) vs. -0.84 ± 1.63 mL/min/yr/1.73 m(2), respectively; p = 0.007). Pearson correlation analysis revealed a significant negative correlation between the baseline serum ferritin level and the RRF reduction rate (r = -0.219, p = 0.015). Using multiple linear regression analysis and adjusting for other risk factors, baseline serum ferritin was an independent factor for the RRF reduction rate (β = -0.002, p = 0.002).

CONCLUSIONS

In this study we showed that a higher ferritin level was significantly associated with a more rapid RRF decline in patients undergoing PD.

Comparison of the impact of "fast decline" in residual renal function and "initial anuria" on long-term outcomes in CAPD patients

BACKGROUND

Residual renal function (RRF) is pivotal to long-term outcomes, while rapid RRF decline (RRFD) is associated with mortality risk for continuous ambulatory peritoneal dialysis (CAPD) patients. This study was conducted to compare the impact of "initial anuria" and rapid RRFD on the long-term prognosis of CAPD patients.

METHOD

According to the timing of anuria and the slope of RRFD, a total of 255 incident CAPD patients were divided into 3 groups. For the "anuria" group, anuria was detected from CAPD initiation and persisted for > 6 months (n = 27). Based on the median of the RRFD slope, the other 228 non-anuric patients were divided into a "slow decliner" group (n = 114), and a "rapid decliner" group (n = 114). The maximal observation period was 120 months.

RESULTS

Logistic regression tests indicated that the "anuria" group was associated with previous hemodialysis > 3 months (odds ratio [OR]: 8.52, 95% confidence interval [CI]: 3.12 - 23.28), and female (OR: 0.29, 95% CI: 0.09 - 0.90), while the "fast decliner" group with higher Davies co-morbidity scores (DCS) (OR: 1.52; 95% CI: 1.08 - 2.14), body mass index (BMI) (OR: 1.12; 95% CI: 1.04 - 1.21), and male (OR: 1.12; 95% CI: 1.04 - 1.21). After adjusting for DCS, the "fast decliner" group (hazard ratio [HR]: 0.37; 95% CI: 0.17 - 0.80) showed a better outcome than that of the "anuria" group (reference = 1). Both baseline RRF (β = -0.24; p < 0.001) and DCS (β = -3.76; p < 0.001) showed inverse linear correlations to the slope of RRFD. From the Cox proportional analyses, higher baseline RRF (HR: 0.92; 95% CI: 0.88 -.97) and higher slope of RRFD (slower decline in RRF) (HR: 0.90; 95% CI: 0.85 - 0.96) were independent factors for less mortality risk in patients with DCS = 0. However, only a higher slope of RRFD (HR: 0.97; 95% CI: 0.94 - 0.99) was significant for better survival in CAPD patients with DCS > 0.

CONCLUSION

Compared to the baseline RRF, CAPD patients with co-morbidities that rapidly deteriorate RRFD are more crucially associated with long-term mortality risk.

Predictors of residual renal function decline in patients undergoing continuous ambulatory peritoneal dialysis

BACKGROUND

Residual renal function (RRF) is an important prognostic indicator in continuous ambulatory peritoneal dialysis (CAPD) patients. We determined the predictors of RRF loss in a cohort of incident CAPD patients.

METHODS

We reviewed the record of 645 incident CAPD patients. RRF loss is represented by the slope of decline of residual glomerular filtration rate (GFR) as well as the time to anuria.

RESULTS

The average rate of residual GFR decline was -0.083 ± 0.094 mL/min/month. The rate of residual GFR decline was faster with a higher proteinuria (r = -0.506, p < 0.0001) and baseline residual GFR (r = -0.560, p < 0.0001). Multivariate analysis showed that proteinuria, baseline residual GFR, and the use of diuretics were independent predictors of residual GFR decline. Cox proportional hazard model showed that proteinuria, glucose exposure, and the number of peritonitis episodes were independent predictors of progression to anuria, while a higher baseline GFR was protective. Each 1 g/day of proteinuria is associated with a 13.2% increase in the risk of progressing to anuria, each 10 g/day higher glucose exposure is associated with a 2.5% increase in risk, while each peritonitis episode confers a 3.8% increase in risk.

CONCLUSIONS

Our study shows that factors predicting the loss of residual solute clearance and urine output are different. Proteinuria, baseline residual GFR, and the use of diuretics are independently related to the rate of RRF decline in CAPD patients, while proteinuria, glucose exposure, and the number of peritonitis episodes are independent predictors for the development of anuria. The role of anti-proteinuric therapy and measures to prevent peritonitis episodes in the preservation of RRF should be tested in future studies.

The negative impact of early peritonitis on continuous ambulatory peritoneal dialysis patients

BACKGROUND

Peritonitis rate has been reported to be associated with technique failure and overall mortality in previous literatures. However, information on the impact of the timing of the first peritonitis episode on continuous ambulatory peritoneal dialysis (CAPD) patients is sparse. The aim of this research is to study the influence of time to first peritonitis on clinical outcomes, including technique failure, patient mortality and dropout from peritoneal dialysis (PD).

METHODS

A retrospective observational cohort study was conducted over 10 years at a single PD unit in Taiwan. A total of 124 patients on CAPD with at least one peritonitis episode comprised the study subjects, which were dichotomized by the median of time to first peritonitis into either early peritonitis patients or late peritonitis patients. Cox proportional hazard model was used to analyze the correlation of the timing of first peritonitis with clinical outcomes.

RESULTS

Early peritonitis patients were older, more diabetic and had lower serum levels of creatinine than the late peritonitis patients. Early peritonitis patients were associated with worse technique survival, patient survival and stay on PD than late peritonitis patients, as indicated by Kaplan-Meier analysis (log-rank test, p = 0.04, p < 0.001, p < 0.001, respectively). In the multivariate Cox regression model, early peritonitis was still a significant predictor for technique failure (hazard ratio (HR), 0.54; 95% confidence interval (CI), 0.30 - 0.98), patient mortality (HR, 0.34; 95% CI, 0.13 - 0.92) and dropout from PD (HR, 0.50; 95% CI, 0.30 - 0.82). In continuous analyses, a 1-month increase in the time to the first peritonitis episode was associated with a 2% decreased risk of technique failure (HR, 0.98; 95% CI, 0.97 - 0.99), a 3% decreased risk of patient mortality (HR, 0.97; 95% CI, 0.95 - 0.99), and a 2% decreased risk of dropout from PD (HR, 98%; 95% CI, 0.97 - 0.99). Peritonitis rate was inversely correlated with time to first peritonitis according to the Spearman analysis (r = -0.64, p < 0.001).

CONCLUSIONS

Time to first peritonitis is significantly correlated with clinical outcomes of peritonitis patients with early peritonitis patients having poor prognosis. Patients with shorter time to first peritonitis were prone to having a higher peritonitis rate.

Comparative outcomes between continuous ambulatory and automated peritoneal dialysis: a narrative review

Automated methods for delivering peritoneal dialysis (PD) to persons with end-stage renal disease continue to gain popularity worldwide, particularly in developed countries. However, the endeavor to automate the PD process has not been advanced on the strength of high-level evidence for superiority of automated over manual methods. This article summarizes available studies that have shed light on the evidence that compares the association of treatment with continuous ambulatory PD or automated PD (APD) with clinically meaningful outcomes. Published evidence, primarily from observational studies, has been unable to demonstrate a consistent difference in residual kidney function loss rate, peritonitis rate, maintenance of euvolemia, technique survival, mortality, or health-related quality of life in individuals undergoing continuous ambulatory PD versus APD. At the same time, the future of APD technology appears ripe for further improvement, such as the incorporation of voice commands and expanded use of telemedicine. Given these considerations, it appears that patient choice should drive the decision about PD modality.

Effect of peritoneal dialysis modality on the 1-year rate of decline of residual renal function

PURPOSE

The effect of different peritoneal dialysis (PD) modalities on the decline in residual renal function (RRF) is unclear due to inconsistencies among studies. In particular, the effect of automated peritoneal dialysis (APD) modalities [continuous cyclic peritoneal dialysis (CCPD) and nightly intermittent peritoneal dialysis (NIPD)] on RRF has not been examined in a large cohort.

MATERIALS AND METHODS

We conducted a single-center retrospective study to investigate the association between PD modalities and decline in RRF in 142 incident PD patients [34 on CCPD, 36 on NIPD, and 72 on continuous ambulatory peritoneal dialysis (CAPD)]. RRF was measured within 2 months from PD start and at 1 year after PD initiation.

RESULTS

The RRF at 1 year after PD initiation was 1.98±2.20 mL/min/1.73 m² in CCPD patients and 3.63±3.67 mL/min/1.73 m² in NIPD patients, which were moderately lower than 4.23±3.51 mL/min/1.73 m² in CAPD patients (p=0.064). Moreover, there was no significant difference in the 1-year rate of decline of RRF between CCPD and NIPD patients, although APD patients had a faster 1-year RRF decline rate than CAPD patients (CCPD and NIPD vs. CAPD: -45.68 and -36.69 vs. 1.17%/year, p=0.045). APD was associated with a more rapid decline in RRF in patients with end-stage renal disease undergoing PD, although multivariate analysis attenuated the significance of this finding (β=-31.50; 95% CI, -63.61 to 0.62; p=0.052).

CONCLUSION

Our results suggest that CAPD might be more helpful than APD for preserving RRF during the first year of dialysis therapy, although there was no significant difference in the 1-year rate of decline of RRF between the two APD modalities.

Geographic and facility-level variation in the use of peritoneal dialysis in Canada: a cohort study

BACKGROUND

Peritoneal dialysis is associated with similar survival and similar improvement in quality of life and is less costly compared with in-centre hemodialysis. We examined facility and geographic variation in the use of peritoneal dialysis in Canada.

METHODS

We analyzed data from the Canadian Organ Replacement Register for the period January 2001 to December 2010. We identified patients for whom peritoneal dialysis was the primary modality at 90 days after initiation of dialysis. We used multilevel models to evaluate variation in use of peritoneal dialysis by facility and geographic region.

RESULTS

We analyzed data for 31 778 incident dialysis patients at 56 facilities in 13 geographic regions across Canada. Use of peritoneal dialysis at 90 days varied considerably across geographic regions (range 19.8%-36.1%) and declined over time, from 28.8% in 2001 to 22.5% in 2010. After adjustment for case mix and facility-level quality indicators, 9.3% and 3.4% of the variability was attributable to facility and geographic factors, respectively. In adjusted models, there was a substantial difference between geographic regions with the lowest and highest peritoneal dialysis use (odds ratio for high use 1.51, 95% confidence interval [CI] 1.33-1.73 v. odds ratio for low use 0.69, 95% CI 0.60-0.79).

INTERPRETATION

In Canada, substantial variability in the use of peritoneal dialysis attributable to facility and geographic region was not explained by differences in patient case mix. An opportunity exists to optimize use of this cost-effective therapy through changes in policy and standardization of criteria for initiation of peritoneal dialysis.

Residual renal function in children treated with chronic peritoneal dialysis

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. Preserved RRF improves survival and quality of life in adult ESRD patients treated with peritoneal dialysis. In children, RRF was shown not only to help preserve adequacy of renal replacement therapy but also to accelerate growth rate, improve nutrition and blood pressure control, reduce the risk of adverse myocardial changes, facilitate treatment of anemia and calcium-phosphorus balance abnormalities, and result in reduced serum and dialysate fluid levels of advanced glycation end-products. Factors contributing to RRF loss in children treated with peritoneal dialysis include the underlying renal disease such as hemolytic-uremic syndrome and hereditary nephropathy, small urine volume, severe proteinuria at the initiation of renal replacement therapy, and hypertension. Several approaches can be suggested to decrease the rate of RRF loss in pediatric patients treated with chronic peritoneal dialysis: potentially nephrotoxic drugs (e.g., aminoglycosides), episodes of hypotension, and uncontrolled hypertension should be avoided, urinary tract infections should be treated promptly, and loop diuretics may be used to increase salt and water excretion.

Diabetic patients could do as well as non-diabetic patients without inflammation on peritoneal dialysis

Background

Diabetic patients on peritoneal dialysis (PD) have lower survival and are more likely complicated with inflammation than their non-diabetic counterparts. Here, we explored the interaction effects between diabetes and inflammation on the survival of PD patients.

Methods

Overall, 2,264 incident patients were enrolled from a retrospective cohort study in China. Patients were grouped according to the baseline levels of high-sensitive C-reactive protein (hsCRP, ≤3 mg/L or >3 mg/L) or serum albumin (SA, ≥38 g/L or <38 g/L). Then, several multivariable adjusted stratified Cox regression models were constructed for these groups to explore the predicted role of diabetes on all-cause or cardiovascular death under inflammatory or non-inflammatory conditions.

Results

Diabetics on PD were more likely to have inflammation than non-diabetics on PD, and they presented with elevated hsCRP (52.7% vs. 47.3%, P = 0.03) or decreased SA (77.9% vs. 62.7%, P < 0.001) levels. After stratification by size of center and controlling for confounding factors, diabetes was found to predict all-cause death in patients with hsCRP >3 mg/L or SA <38 g/L but not in patients with hsCRP ≤3 mg/L or SA ≥38 g/L. Similarly, the presence of diabetes was an indication of cardiovascular death in patients with hsCRP >3 mg/L or SA <38 g/L. However, if further adjusted by baseline cardiovascular disease, the predicted role of diabetes on death related to cardiovascular disease in patients with SA <38 g/L disappeared.

Conclusion

Diabetic patients could do as well as non-diabetic patients without inflammation on peritoneal dialysis. Active strategies should be implemented to improve inflammation status in diabetic patients on PD.

Controversies in timing of dialysis initiation and the role of race and demographics

Dialysis remains the predominant form of renal replacement therapy in the United States, but the optimal timing for the initiation of dialysis remains poorly defined. Not only clinical factors such as signs/symptoms of uremia, co-existing cardiovascular disease, and presence of diabetes but also key demographic characteristics including age, gender, race/ethnicity, and socioeconomics have all been considered as potential modifying factors in the decision for the timing of dialysis initiation. The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for the Evaluation and Management of chronic kidney disease (CKD) suggests that dialysis be initiated when signs/symptoms attributable to kidney failure such as serositis, acid-base or electrolyte abnormalities, pruritus, poorly controlled volume status or blood pressure, deteriorating nutritional status despite dietary intervention, or cognitive impairment are visible or noted. These signs/symptoms typically occur when the glomerular filtration rate (GFR) is in the range of 5-10 ml/minute/1.73 m(2) , although they may occur at higher levels of GFR. We review recent data on the timing of dialysis initiation, their implications for managing patients with late-stage CKD, and the important role of considering key demographics in making patient-centered decisions for the timing of dialysis initiation.

Extracellular volume expansion, measured by multifrequency bioimpedance, does not help preserve residual renal function in peritoneal dialysis patients

Residual renal function is a major survival determinant for peritoneal dialysis patients. Hypovolemia can cause acute kidney injury and loss of residual renal function, and it has been suggested that patients receiving peritoneal dialysis should preferably be maintained hypervolemic to preserve residual renal function. Here we determined whether hydration status predicted long-term changes in residual renal function. Changes in residual renal function and extracellular water (ECW) to total body water (TBW) measured by multifrequency bioimpedance in 237 adult patients who had paired baseline and serial 12 monthly measurements were examined. Baseline hydration status (ECW/TBW) was not significantly associated with preservation of residual renal function, unlike baseline and follow-up mean arterial blood pressure. When the cohort was split into tertiles according to baseline hydration status, there was no significant correlation seen between change in hydration status and subsequent loss in residual renal function. Increased ECW/TBW in peritoneal dialysis patients was not associated with preservation of residual renal function. Similarly, increments and decrements in ECW/TBW were not associated with preservation or reduction in residual renal function. Thus, our study does not support the view that overhydration preserves residual renal function and such a policy risks the consequences of persistent hypervolemia.

Association of overtime urine volume and ultrafiltration changes with patient survival in continuous ambulatory peritoneal dialysis patients

BACKGROUND

Associations between patient survival and baseline urine volume (UV), ultrafiltration (UF) volume, and combined UV and UF were evaluated in Iranian continuous ambulatory peritoneal dialysis (CAPD) patients.

METHODS

From 1995 to 2006, data on 1472 CAPD patients from 26 centers were collected. Demographic, clinical, and laboratory characteristics were analyzed using STATA software. Baseline UV was considered as an indicator of residual renal function and patients with an annual decrease of more than 250 cc/day were placed in decreasing UV group. The role of a new variable, net positive fluid removal, which defines as the combination of baseline UV and UF, was also evaluated.

RESULTS

Patients with higher baseline UV were significantly more married and educated and candidate for CAPD based on positive selection criteria. In dichotomous categorization, mean of serum creatinine was lower and albumin was higher in patients with UV ≥ 1000 cc/day compared with UV < 250 cc/day. A significant correlation was found between baseline UV <250 cc/day and ≥1000 cc/day and patient survival. Patients with stable UV had better survival compared with patients with decreasing UV (p = 0.04). There was no correlation between UF and patient survival. Remarkable association with patient and technique survival and net positive fluid removal ≥2000 cc/day and <500 cc/day was observed. Multiple Cox regression analysis revealed significant correlation between net positive fluid removal ≥2000 cc/day and higher patient survival [p = 0.01, hazard ratio (HR) = 13.2], higher first albumin (albumin ≥ 3.5 mg/dL, p = 0.01, HR = 0.02), and lower negative selection (p = 0.0001, HR = 11.8).

CONCLUSION

Loss of UV over time and lower net positive fluid removal increase mortality of PD patients.

Time course of peritoneal function in automated and continuous peritoneal dialysis

BACKGROUND AND OBJECTIVES

In automated peritoneal dialysis (APD), a patient's peritoneal membrane is more intensively exposed to fresh dialysate than it is in continuous ambulatory peritoneal dialysis (CAPD). Our aim was to study, in incident peritoneal dialysis (PD) patients, the influence of APD-compared with that of CAPD-on peritoneal transport over 4 years.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Patients were included if at least 2 annual standard permeability analyses (SPAs) performed with 3.86% glucose were available while the patient was using the same modality with which they had started PD (APD or CAPD). Patients were followed until their first modality switch. Differences in the pattern of SPA outcomes over time were tested using repeated-measures models adjusted for age, sex, comorbidity, primary kidney disease, and year of PD start.

RESULTS

The 59 CAPD patients enrolled were older than the 47 APD patients enrolled (mean age: 58 ± 14 years vs 49 ± 14 years; p < 0.01), and they had started PD earlier (mean start year: 2000 vs 2002). Over time, no differences in solute (p > 0.19) or fluid transport (p > 0.13) were observed. Similarly, free water transport (p = 0.43) and small-pore transport (p = 0.31) were not different between the modalities. Over time, patients on APD showed a faster decline in effective lymphatic absorption rate (ELAR: p = 0.02) and in transcapillary ultrafiltration (TCUF: p = 0.07, adjusted p = 0.05). Further adjustment did not change the results.

CONCLUSIONS

Compared with patients starting on CAPD, those starting on APD experienced a faster decline in ELAR and TCUF. Other transport parameters were not different over time between the groups.

Relation of ankle-brachial index to the rate of decline of residual renal function in peritoneal dialysis patients

AIM

The aim of this study was to determine whether ankle-brachial index (ABI) predicts the rate of decline of residual renal function (RRF) in peritoneal dialysis (PD) patients. Previous studies demonstrated the importance of loss of RRF in predicting all-cause risk and cardiovascular mortality in PD patients. It is also known that patients with a low ABI value have a greater risk for deteriorating renal function in the general population. The relationship between ABI and the declining rate of RRF in PD patients with an additional dialysis-specific risk factor is uncertain.

METHODS

Seventy-four PD patients with RRF of more than 1 mL/min per 1.73 m(2) were analyzed. ABI was used as the surrogate measure of pre-existing cardiovascular disease and atherosclerosis burden to further determine the outcome of RRF in this study. The slope of decline of RRF was used to determine the outcome.

RESULTS

Based on the multivariate analysis, only ABI (P < 0.001), diabetes (P = 0.02) and baseline RRF (P = 0.009) independently predicted a faster decline in RRF. A stepwise multiple linear regression analysis demonstrated that ABI was an independent predictor for the slope of decline of RRF (P < 0.001).

CONCLUSION

A low ABI is an independent predictor of not only the known atherosclerotic events, but also of the rate of decline of RRF over time in PD patients.

Presence of peripheral arterial disease predicts loss of residual renal function in incident CAPD patients

BACKGROUND

Accelerated cardiovascular disease (CVD), including peripheral arterial disease (PAD), is very common in patients with end-stage renal disease. Residual renal function (RRF) is a strong predictor of patient survival that is suggested to be linked to the degree of CVD. However, the relationship between PAD and decline in RRF has not previously been measured.

METHODS

We studied incident continuous ambulatory peritoneal dialysis patients from Peking University Third Hospital. An ankle brachial index of less than 0.9 was used to diagnose PAD. Residual renal function (RRF) was determined as the mean of 24-hour urea and creatinine clearances (glomerular filtration rate). The Cox proportional hazards model was used to identify factors predicting loss of RRF.

RESULTS

The study included 86 patients (age: 61 ± 14 years; men: 51%), 23 of whom had PAD at baseline. Mean follow-up was 19 months (median: 18 months; range: 6 - 30 months). In univariate analysis, baseline PAD, peritonitis during follow-up, inflammation (C-reactive protein), serum uric acid, Ca×P, and serum phosphate were all significantly associated with a greater-than-50% decrease in RRF during follow-up. In multivariate analysis, only baseline PAD, Ca×P, and peritonitis were independently associated with a decline in RRF.

CONCLUSIONS

Our study suggests that PAD may be a clinically important marker of CVD predicting the loss of RRF. It remains to be determined whether interventions aimed at decreasing PAD may also improve renal vascular status and thus slow the rate of RRF decline.

Decline in residual renal function in automated compared with continuous ambulatory peritoneal dialysis

BACKGROUND AND OBJECTIVES

We compared the decline of RRF in patients starting dialysis on APD with those starting on CAPD, because a faster decline on APD has been suggested.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

NECOSAD patients starting dialysis on APD or CAPD with RRF at baseline were included and followed for 3 years. Residual GFR (rGFR) was the mean of urea and creatinine clearances. Differences in yearly decline of rGFR were estimated in analyses with linear repeated measures models, whereas the risk of complete loss of RRF was estimated by calculating hazard ratios (HRs) for APD compared with CAPD. As-treated (AT) and intention-to-treat (ITT) designs were used. All of the analyses were adjusted for age, gender, comorbidity, and primary kidney disease and stratified according to follow-up and mean baseline GFR.

RESULTS

The 505 CAPD and 78 APD patients had no major baseline differences. No differences were found in the analyses on yearly decline of rGFR. APD patients did have a higher risk of losing RRF in the first year (ITT crude HR 2.43 [confidence interval 95%, 1.48 to 4.00], adjusted 2.66 [1.60 to 4.44]; AT crude 1.89 [1.04 to 3.45], adjusted 2.15 [1.16 to 3.98]). The higher risk of losing all RRF was most pronounced in patients with the highest rGFR at baseline (ITT; crude 3.91 [1.54 to 9.94], adjusted 1.85 to 14.17).

CONCLUSIONS

The risk of losing RRF is higher for patients starting dialysis on APD compared with those starting on CAPD, especially in the first year.

Relevância do estado de hidratação na interpretação de parâmetros nutricionais em diálise peritoneal

OBJETIVO: Identificar determinantes do estado de hidratação de pacientes em diálise peritoneal crônica, bem como investigar os efeitos da sobrecarga líquida sobre o estado nutricional. MÉTODOS: Foi feito estudo transversal, realizado em 2006, avaliando 27 pacientes em diálise peritoneal crônica, acompanhados no Hospital das Clínicas da Faculdade de Medicina de Botucatu (SP), quanto a parâmetros clínicos, dialíticos, laboratoriais, antropométricos e de bioimpedância elétrica. Para avaliar a influência de parâmetros sobre o estado de hidratação empregou-se modelo de regressão linear múltipla. A amostra foi estratificada quanto ao estado de hidratação pela relação entre água extracelular e água corporal total (0,47 para homens e 0,52 para mulheres), parâmetros obtidos por meio de bioimpedância elétrica. Comparações foram realizadas por análise de covariância, Mann-Whitney, Qui-quadrado ou teste exato de Fisher. Considerou-se significância estatística quando p≤0,05. RESULTADOS: Pacientes com maior volume urinário e em modalidade dialítica automatizada apresentaram melhor estado de hidratação. Pacientes com maior sobrecarga líquida, comparados àqueles com menor sobrecarga, apresentaram menor ângulo de fase (M=4,2, DP=0,9 vs M=5,7, DP=0,7º; p=0,006), menor albumina (M=3,06, DP=0,46 vs M=3,55, DP=0,52g/dL; p=0,05) e maior % prega cutânea tricipital (M=75,3, DP=36,9 vs M=92,1, DP=56,9%; p=0,058), sem outras evidências antropométricas. CONCLUSÃO: Pode-se sugerir que os níveis reduzidos de albumina e ângulo de fase nos pacientes com maior sobrecarga líquida não estiveram relacionados a pior estado nutricional. Para o diagnóstico nutricional em vigência de sobrecarga líquida, deve-se considerar o conjunto de variáveis obtidas por diversos métodos, buscando relacioná-las e interpretá-las de maneira abrangente, possibilitando um diagnóstico nutricional fidedigno.

Loss of residual renal function was not associated with glycemic control in patients on peritoneal dialysis

BACKGROUND

Better glycemic control has been reported to slow the progression of nephropathy in predialysis diabetic patients. However, the relationship between glycemic control and residual renal function (RRF) in patients on peritoneal dialysis (PD) is uncertain.

METHODS

89 incident diabetic patients on PD were recruited from 5 centers. We measured glomerular filtration rate (GFR) and hemoglobin A1c (HbA1c) within 2 months (baseline) after the start of PD and at 6 and 12 months. GFR was calculated as the average of renal creatinine and urea clearances. We analyzed whether mean HbA1c was associated with change in GFR (ΔGFR) over 1 year.

RESULTS

During the first year of PD, ΔGFR was -1.7 ± 3.4 mL/min/1.73 m² and was not affected by mean HbA1c. Acute hemodialysis before starting PD and mean arterial diastolic pressure were related to the decline of GFR in a multivariate analysis.

CONCLUSION

Glycemic control was not associated with change in RRF in diabetic patients during the first year after starting PD.