Association between residual renal function, inflammation and patient survival in new peritoneal dialysis patients

High intraperitoneal interleukin-6 levels predict ultrafiltration (UF) insufficiency in peritoneal dialysis patients: A prospective cohort study

Introduction

UF insufficiency is a major limitation in PD efficiency and sustainability. Our study object to investigate the efficacy of intraperitoneal inflammation marker, IL-6 level as a predictor of UF insufficiency in continuous ambulatory peritoneal dialysis (CAPD) patients.

Methods

Stable prevalent CAPD patients were enrolled in this prospective study. IL-6 concentration in the overnight effluent was determined and expressed as the IL-6 appearance rate (IL-6 AR). Patients were divided into two groups according to the median of IL-6 AR and prospectively followed up until death, transfer to permanent HD, recovery of renal function, kidney transplantation, transfer to other centers, lost to follow-up or to the end of study (January 31, 2021). Factors associated with UF capacity as well as dialysate IL-6 AR were assessed by multivariable linear regression. Cox proportional hazards model was used to examine the association between dialysate IL-6 AR and UF insufficiency.

Results

A total of 291 PD patients were enrolled, including 148 males (51%) with a mean age of 56.6 ± 14.1 years and a median PD duration of 33.4 (12.7–57.5) months. No correlation was found between dialysate IL-6 AR and UF capacity at baseline. PD duration was found positively correlated with baseline dialysate IL-6 AR, while 24h urine volume was negatively correlated with baseline dialysate IL-6 AR (P < 0.05). By the end of study, UF insufficiency was observed in 56 (19.2%) patients. Patients in the high IL-6 AR group showed a significantly inferior UF insufficiency-free survival when compared with their counterparts in the low IL-6 AR group (P = 0.001). In the multivariate Cox regression analysis, after adjusting for DM, previous peritonitis episode and 24h urine volume, higher baseline dialysate IL-6 AR (HR 3.639, 95% CI 1.776–7.456, P = 0.002) were associated with an increased risk of UF insufficiency. The area under the ROC curve (AUC) for baseline IL-6 AR to predict UF insufficiency was 0.663 (95% CI, 0.580–0.746; P < 0.001).

Conclusion

Our study suggested that the dialysate IL-6 AR could be a potential predictor of UF insufficiency in patients undergoing PD.

Prognostic Significance of the Albumin to Fibrinogen Ratio in Peritoneal Dialysis Patients

Background

Albumin to fibrinogen ratio (AFR) is a demonstrated predictor of mortality in various diseases. The aim of this study was to evaluate the prognostic value of AFR to predict mortality in peritoneal dialysis (PD) patients.

Methods

We retrospectively analyzed 212 incident PD patients from January 2010 to December 2017 and followed them until December 2019. We used receiver operating curve (ROC) analysis to determine the optimal cut-off point for AFR at baseline to predict overall and cardiovascular mortality during the follow-up period. Kaplan-Meier curve and Cox regression analysis were applied to evaluate the association between AFR and all-cause and cardiovascular mortality.

Results

The optimal threshold for AFR to predict mortality was 8.48. A low AFR was strongly correlated with worse all-cause and cardiovascular mortality in PD patients. Multivariate analysis revealed that elevated AFR was an independent marker predicting reduced all-cause and cardiovascular mortality (HR 2.41, 95% CI 1.11–5.22, P = 0.026; and HR 2.18, 95% CI 1.21–3.95, P = 0.010, respectively).

Conclusions

Patients with a high AFR had reduced all-cause and cardiovascular mortality. AFR is a potential prognostic biomarker in PD patients.

Normalized Protein Catabolic Rate Is a Superior Nutritional Marker Associated With Dialysis Adequacy in Continuous Ambulatory Peritoneal Dialysis Patients

Introduction: Current knowledge of the relationship between normalized protein catabolic rate (nPCR) and dialysis adequacy is limited. Our study aimed to explore the potential relationship between nPCR and dialysis adequacy.

Methods: In this cross-sectional study, we analyzed the association of nPCR with peritoneal dialysis adequacy in 266 continuous ambulatory peritoneal dialysis (CAPD) patients (mean age 48.6 ± 13.1 years; 50.8% male). The patients were divided into two groups: a dialysis inadequacy group (total weekly Kt/V urea < 1.70) and a dialysis adequacy group (total weekly Kt/V urea≥1.70). We then analyzed the correlation between dialysis adequacy and the patients' primary cause of end-stage renal disease, nutritional and inflammatory markers, and biochemical parameters. Multivariable logistic regression analysis was also used to identify risk factors for inadequate dialysis.

Results: We observed a significantly higher level of nPCR (0.98 ± 0.22 vs. 0.79 ± 0.18 g/kg/day, p < 0.001) in the dialysis adequacy group, whereas we observed no significant differences among other nutritional markers such as albumin, prealbumin, and transferrin. Correlation analyses revealed that dialysis adequacy was positively associated with residual glomerular filtration rate (rGFR), hemoglobin, serum calcium, and body mass index (BMI), while dialysis adequacy was negatively associated with leak-protein, uric acid, high-sensitivity C-reactive protein, interleukin-6, and serum phosphorus. Furthermore, a logistic regression analysis revealed that gender (male), nPCR <0.815 g/kg/day, higher weight, and rGFR <2.43 mL/min/1.73 m² were independent risk factors for inadequate dialysis.

Conclusion: Nutritional status is closely associated with dialysis adequacy. Among common nutritional markers, nPCR may be superior for predicting CAPD dialysis adequacy. Gender (male), nPCR <0.815 g/kg/day, higher weight, and rGFR <2.43 mL/min/1.73 m² are independent risk factors for dialysis inadequacy in CAPD patients.

Oncogenic mechanisms in renal insufficiency

The prevalence of both cancer and end-stage renal disease is increasing. In addition, medical advances have meant increased survival rates for both diseases. Many chemotherapeutics are renally excreted, and conversely, renal insufficiency promotes a pro-neoplastic state, including genitourinary and other cancers. Dialysis prolongs life while increasing cancer risk. Proposed oncogenic mechanisms include immune dysfunction, chronic inflammation, changes in gut microbiota and stimulation of the renin-angiotensin system. This review summarizes current concepts in the relationship between cancer and renal insufficiency.

Outcomes after transfer from hemodialysis to peritoneal dialysis vs peritoneal dialysis as initial therapy: A systematic review and meta-analysis

Outcomes of patients who are transferred to peritoneal dialysis (PD) after an initial phase of hemodialysis (HD) compared to patients initiating dialysis with PD is controversial. We performed a systematic literature to assess evidence. Primary outcome was overall survival (OS), while secondary outcomes were technique failure, mortality and peritonitis. Meta-analysis indicated that PD initial group had significantly better OS as compared to HD to PD group. Pooled analysis demonstrated a significantly higher probability of technique failure in the HD to PD group as compared to PD initial group. Mortality rate in HD to PD group was significantly higher but there was no statistically significant difference in peritonitis rates between the two groups. On meta-regression analysis, transfer from HD to PD due to vascular access problems was associated with significantly reduced probability of OS. Our study indicates that patients transferred from HD to PD after at least 3 months of HD therapy may have reduced OS as compared to patients initiating dialysis with PD. Our findings lend some support to PD first policy and the need for heightened vigilance among the switched patients to monitor for adverse events.

Superior Patient Survival for Continuous Ambulatory Peritoneal Dialysis Patients Treated with a Peritoneal Dialysis Fluid with Neutral pH and Low Glucose Degradation Product Concentration (Balance)

Background

In recent years, laboratory and clinical research has suggested the need for peritoneal dialysis fluids (PDFs) that are more biocompatible than the conventional PDFs commonly used today. Bioincompatibility of PDF has been attributed to low pH, lactate, glucose, glucose degradation products (GDPs), and osmolality. PDFs with neutral pH and low GDPs are now available commercially. In vitro and early clinical studies suggest that these solutions are indeed more biocompatible but, as of now, there is no evidence that their use improves patient outcome.

Methods

Using a dedicated database of over 2000 patients treated with PD in Korea, we were able to conduct a retrospective observational study comparing outcomes for incident continuous ambulatory PD patients treated with a standard, conventional, heat-sterilized PDF to the outcomes for patients treated with a novel, low GDP, neutral-pH PDF prepared in a dual-compartment, double-bag PD system (Balance; Fresenius Medical Care, St. Wendel, Germany). In an intention-to-treat analysis, patient and technique survival, peritonitis-free survival, and peritonitis rates were compared in 611 patients treated with Balance for up to 30 months and 551 patients with a standard PDF (stay·safe; Fresenius Medical Care) treated in the same era and with equivalent follow-up.

Results

The patients were well matched for most relevant characteristics except older age distribution for the patients treated with the standard PDF. Patients treated with Balance had significantly superior survival compared to those treated with the standard PDF (74% vs 62% at 28 months, p = 0.0032). In a multivariate Cox regression model including age, diabetes, and gender, the survival advantage persisted (relative risk of death for Balance 0.75, 95% confidence interval 0.56 – 0.99, p = 0.0465). Modality technique survival was similar in Kaplan–Meier analysis for both PDFs. No differences were detected in peritonitis-free survival or in peritonitis rates between the two solutions.

Conclusion

This study, for the first time, suggests that treatment with a novel biocompatible PDF with low GDP concentration and neutral pH confers a significant survival advantage. The exact mechanisms for such a survival advantage cannot be determined from this study. The usual criticisms of observational studies apply and the results reported here strongly warrant the undertaking of appropriately designed, randomized, controlled clinical trials.

Chronic Inflammation in Peritoneal Dialysis: The Search for the Holy Grail?

Mortality and morbidity in chronic kidney disease (CKD) patients are unacceptably high. The annual mortality rate due to cardiovascular disease (CVD) is approximately 9%, which, for the middle-aged person, is at least 10- to 20-fold higher than for the general population. Classic risk factors for CVD are highly prevalent in CKD patients, but they cannot fully account for the excessive rate of CVD in this population. Instead, it has become increasingly clear that nontraditional risk factors, such as systemic inflammation, may play a key role in the development of atherosclerosis. It is well established that inflammatory markers are very powerful predictors of high CVD morbidity and mortality not only in the general population, but particularly in CKD patients. Signs of a sustained low-grade inflammation, such as increased levels of C-reactive protein (CRP), are present in the majority of stage 5 CKD patients, even in patients in clinically stable condition, and they are also commonly observed after the initiation of dialysis therapy. Dialysis therapy — hemodialysis as well as peritoneal dialysis (PD) — may itself contribute to systemic inflammation. Local intraperitoneal inflammation can also occur in patients treated with PD. These local effects may result in a low-grade inflammation, caused by the bioincompatibility of conventional glucose-based dialysis fluids, to intense inflammation associated with peritonitis. Given these circumstances, it is reasonable to hypothesize that strategies aiming to reduce inflammation are potentially important and novel, and could serve to reduce CVD, thereby lowering morbidity and mortality in patients with CKD. In this review we provide information supporting the hypothesis that systemic inflammation is tightly linked to the most common complications of CKD patients, in particular those on PD, and that local inflammation in PD may contribute to various related complications. The aims of this review are to discuss the reasons that make inflammation an attractive target for intervention in CKD, the particular aspects of the inflammation–CVD axis during PD treatment that are likely involved, and possible means for the detection and management of chronic inflammation in PD patients.

Short-Term Effects of a New Bicarbonate/Lactate-Buffered and Conventional Peritoneal Dialysis Fluid on Peritoneal and Systemic Inflammation in CAPD Patients: A Randomized Controlled Study

Objectives

This study was designed to compare the local peritoneal and systemic inflammatory effects of a conventional lactate-based (Lac) peritoneal dialysis (PD) solution and a new biocompatible bicarbonate/lactate-based (Bic/ Lac) solution having low concentration of glucose degradation products.

Methods

26 stable, prevalent PD patients were enrolled in this prospective study. They sequentially underwent 3 months of therapy with the Lac solution and 3 months with the Bic/Lac solution in a randomized order. Flow cytometry was used to measure the expression of inflammatory molecules on peritoneal cells in overnight effluent collected at the end of each study period.

Results

21 patients successfully completed the study. Mean fluorescence intensity of human leukocyte antigen (HLA)-DR and CD14 expression by macrophages were not different between Lac and Bic/Lac. The peritoneal appearance rate of cancer antigen 125 (kU/minute) was 68 ± 37 with Lac and 133 ± 66 with Bic/Lac ( p < 0.001), and of interleukin (IL)-6 (ng/minute), 0.28 ± 0.2 with Lac and 0.18 ± 0.16 with Bic/Lac ( p = 0.014). HLA-DR macrophage expression and IL-6 peritoneal appearance rates did not correlate. Serum concentrations with Lac and Bic/Lac were, for IL-6, 3.49 ± 2.28 and 3.72 ± 2.46 ng/L ( p = 0.17), and for high-sensitivity C-reactive protein, 2.31 ± 2.98 and 2.71 ± 3.31 mg/L ( p = 0.32) respectively. The concentration of effluent macrophages (x106/L) with Lac was 1.6 ± 1.6 and with Bic/Lac 2.6 ± 3.3 ( p = 0.07).

Conclusions

We conclude that, although there was a significant reduction in peritoneal IL-6 in patients using Bic/ Lac solution, systemic levels of inflammatory markers did not differ between the two solutions and no changes were present in macrophage surface activation markers, suggesting perhaps a less important role of peritoneal macrophages in the intraperitoneal chronic inflammatory process. The number of effluent macrophages tended to be higher in patients using the Bic/Lac solution, possibly contributing to improved intraperitoneal defense.

Anti-Inflammatory Effects of 3-Hydroxy-3-Methylglutaryl Coenzyme a Reductase Inhibitors (Statins) in Peritoneal Dialysis Patients

Objective

Elevated C-reactive protein (CRP) level is an independent predictor of all-cause and cardiovascular mortality in peritoneal dialysis (PD) patients. Statins have been demonstrated to have anti-inflammatory properties by virtue of their CRP lowering effects in hemodialysis patients. However, whether statins have an anti-inflammatory effect in PD patients is unknown.

Design

All prevalent PD patients at our center were reviewed. Eligible (257) patients were categorized into 2 groups: those on statin therapy ( n = 137) and those not on statins ( n = 120). Data were abstracted for hemoglobin, albumin, phosphates, cholesterol, CRP, Kt/V, and erythropoietin dose, along with relevant clinical data.

Results

The two groups had similar concentrations of hemoglobin, albumin, and phosphates. They were also matched for dialysis adequacy and duration of dialysis but the statin group patients were older (57 ± 13 vs 52 ± 17 years, p = 0.01). Serum cholesterol was lower in the statin group (4.74 ± 1.05 vs 5.02 ± 1.17 mmol/L, p < 0.05). Single-point (14 ± 13 vs 19 ± 18 mg/L, p < 0.02) and serially measured CRP (9 ± 7.4 vs 12 ± 10 mg/L, p < 0.02) levels were significantly lower in the statin group despite increased comorbidity (0.84 vs 0.54, p < 0.02) and greater incidence of diabetes mellitus (52% vs 25%, p < 0.01).

Conclusion

Statin therapy is associated with low single-point and serially measured CRP levels in PD patients, thereby suggesting that their anti-inflammatory properties persist in PD. These data have implications for considering statin therapy in PD patients as an anti-inflammatory agent in addition to a cholesterol lowering drug.

Inflammation and Extracellular Volume Expansion are Related to Sodium and Water Removal in Patients on Peritoneal Dialysis

Background

Inflammation is an important risk for mortality in dialysis patients. Extracellular fluid volume (ECFv) expansion, a condition commonly seen in peritoneal dialysis (PD) patients, may be associated with inflammation. However, published support for this relationship is scarce.

Objectives

To quantify the proportion of patients on PD with inflammation and to analyze the role of ECFv expansion and the factors related to these conditions.

Design

A prospective, multicenter cross-sectional study in six hospitals with a PD program.

Patients and Methods

Adult patients on PD were studied. Clinical data, body composition, and sodium and fluid intake were recorded. Biochemical analysis, C-reactive protein (CRP), and peritoneal and urinary fluid and sodium removal were also measured.

Results

CRP values positive (≥ 3.0 mg/L) for inflammation were found in 147 (80.3%) and negative in 36 patients. Patients with positive CRP had higher ECFv/total body water (TBW) ratio (women 47.69 ± 0.69 vs 47.36 ± 0.65, men 43.15 ± 1.14 vs 42.84 ± 0.65; p < 0.05), higher serum glucose (125.09 ± 81.90 vs 103.28 ± 43.30 mg/dL, p < 0.03), and lower serum albumin (2.86 ± 0.54 vs 3.17 ± 0.38 g/dL, p < 0.001) levels. They also had lower ultrafiltration (1003 ± 645 vs 1323 ± 413 mL/day, p < 0.005) and total fluid removal (1260 ± 648 vs 1648 ± 496 mL/day, p < 0.001), and less peritoneal (15.59 ± 162.14 vs 78.11 ± 110.70 mEq/day, p < 0.01) and total sodium removal (42.06 ± 142.49 vs 118.60 ± 69.73 mEq/day, p < 0.001). In the multivariate analysis, only ECFv/TBW was significantly ( p < 0.04) and independently associated with inflammation. ECFv/TBW was correlated with fluid removal ( r = 0.16, p < 0.03) and renal sodium removal ( r = 0.2, p < 0.01).

Conclusion

The data suggest that ECFv expansion may have a significant role as an inflammatory stimulus. The results disclose a relationship between the two variables, ECFv expansion and inflammation, identified as independent risk factors for mortality in PD patients.

Analysis of the Prevalence and Causes of Ultrafiltration Failure during Long-Term Peritoneal Dialysis: A Cross-Sectional Study

Background

Ultrafiltration failure (UFF) is a major complication of peritoneal dialysis (PD). It can occur at any stage of PD, but develops in time and is, therefore, especially important in long-term treatment. To investigate its prevalence and to identify possible causes, we performed a multicenter study in The Netherlands, where patients treated with PD for more than 4 years were studied using a peritoneal function test (standard peritoneal permeability analysis) with 3.86% glucose. UFF was defined as net UF < 400 mL after a 4-hour dwell.

Results

55 patients unselected for the presence or absence of UFF were analyzed. Mean age was 48 years (range 18 – 74 years); duration of PD ranged from 48 to 144 months (median 61 months); UFF was present in 20 patients (36%). Patients with and without UFF did not differ in age or duration of PD. Median values for patients with normal UF compared to patients with UFF were, for net UF 659 mL versus 120 mL ( p < 0.01), transcapillary UF rate 3.8 versus 2.1 mL/minute ( p < 0.01), effective lymphatic absorption 1.0 versus 1.6 mL/min ( p < 0.05), mass transfer area coefficient (MTAC) for creatinine 9.0 versus 12.9 mL/min ( p < 0.01), dialysate-to-plasma ratio (D/P) for creatinine 0.71 versus 0.86 ( p < 0.01), glucose absorption 60% versus 73% ( p < 0.01), maximum dip in D/P sodium (as a measure of free water transport) 0.109 versus 0.032 ( p < 0.01), and osmotic conductance to glucose 3.0 versus 2.1 μL/min/mmHg ( p < 0.05). As causes for UFF, high MTAC creatinine, defined as > 12.5 mL/min, or a glucose absorption > 72%, both reflecting a large vascular surface, a lymphatic absorption rate (LAR) of > 2.14 mL/min, and a decreased dip in D/P sodium of < 0.046 were identified. Most patients had a combination of causes (12 patients), whereas there was only a decreased dip in D/P sodium in 3 patients, only high MTAC creatinine in 1 patient, and only high LAR in 2 patients. We could not identify a cause in 2 patients. Both groups had similar clearances of serum proteins and peritoneal restriction coefficients. However, dialysate cancer antigen 125 concentrations, reflecting mesothelial cell mass, were lower in the UFF patients (2.79 vs 5.38 U/L).

Conclusion

The prevalence of UFF is high in long-term PD. It is caused mainly by a large vascular surface area and by impaired channel-mediated water transport. In addition, these patients also had signs of a reduced mesothelial cell mass, indicating damage of the peritoneum on both vascular and mesothelial sites.

Improving Outcome of Capd: Twenty-Five Years’ Experience in a Single Korean Center

Background

Continuous ambulatory peritoneal dialysis (CAPD) is an established treatment for end-stage renal disease (ESRD). We investigated the outcome of CAPD over a period of 25 years at our institution.

Methods

CAPD has been performed in 2301 patients in 25 years. After excluding patients with less than 3 months of follow-up and missing data, we evaluated 1656 patients who started peritoneal dialysis between November 1981 and December 2005. Data for sex, age, primary disease, co-morbidities, follow-up duration, cause of death, and cause of technique failure were collected. We also examined data for urea kinetic modeling (UKM), beginning in 1990, and peritonitis episodes, including causative organisms, starting in 1992.

Results

Compared to incident patients from 1981 – 1992, mean age and incidence of ESRD caused by diabetic nephropathy increased in patients from 1993 to 2005. Technique survival after 5 and 10 years was 71.9% and 48.1% respectively. Technique survival was significantly higher in patients who started CAPD after 1992 than in those who started before 1992. Peritonitis was the main reason for technique failure. Overall peritonitis rate was 0.38 episodes per patient-year, with a significant downward trend to 0.29 per patient-year over 10 years, corresponding to a decrease in gram-positive peritonitis. Patient survival after 5 and 10 years was 69.8% and 51.8% respectively. Patient survival improved significantly during 1992 – 2005 compared to 1981 – 1992 after adjustment for age, gender, diabetes, and cardiovascular comorbidities [hazard ratio (HR) 0.68, p < 0.01]. Subgroup analysis based on UKM revealed that dialysis adequacy did not affect patient survival. However, diabetes (HR 2.78, p < 0.001), older age (per 1 year: HR 1.06; p < 0.001), serum albumin level (per 1 g/dL: increase, HR 0.52; p < 0.05), and cardiovascular comorbidities (HR 2.32, p < 0.01) were identified as significant risk factors.

Conclusion

Technique survival has improved due partly to a decrease in peritonitis, which was attributed to a decrease in gram-positive peritonitis. Patient survival has also improved considering increases in aged patients and ESRD caused by diabetes. The mortality rate of CAPD is still high in older, diabetic, malnourished, and cardiovascular diseased patients. A more careful management of higher risk groups will be needed to improve the outcome of CAPD patients in the future.

Optimization of Dialysis Modality Transitions for Improved Patient Care

Purpose of review:

Initial and subsequent modality decisions are important, impacting both clinical outcomes and quality of life. Transition from chronic kidney disease to dialysis and between dialysis modalities are periods were patients may be especially vulnerable. Reviewing our current knowledge surrounding these critical periods and identifying areas for future research may allow us to develop dialysis strategies beneficial to patients.

Sources of information:

We searched the electronic database PubMed and queried Google Scholar for English peer-reviewed articles using appropriate keywords (non-exhaustive list): dialysis transitions, peritoneal dialysis, home hemodialysis, integrated care pathway, and health-related quality of life. Primary sources were accessed whenever possible.

Methods:

In this narrative review, we aim to expose the controversies surrounding home-dialysis first strategies and examine the evidence underpinning home-dialysis first strategies as well as home-to-home and home-to-in-center transitions.

Key findings:

Diverse factors must be taken into consideration when choosing initial and subsequent dialysis modalities. Given the limitations of available data (and lack of convincing benefit or detriment of one modality over the other), patient-centered considerations may prime over suspected mortality benefits of one modality or another.

Limitations:

Available data stem almost exclusively from retrospective and observational studies, often using large national and international databases, susceptible to bias. Furthermore, this is a narrative review which takes into account the views and opinions of the authors, especially as it pertains to optimal dialysis pathways.

Implications:

Emphasis must be placed on individual patient goals and preferences during modality selection while planning ahead to achieve timely and appropriate transitions limiting discomfort and anxiety for patients. Further research is required to ascertain specific interventions which may be beneficial to patients.

High rates of protein intake are associated with an accelerated rate of decline of residual kidney function in incident peritoneal dialysis patients

BACKGROUND

Preservation of residual kidney function (RKF) is a relevant objective in peritoneal dialysis (PD) patients. The influence of dietary protein intake (PI) on this variable has not been adequately investigated.

METHODS

Following an observational design, we studied 336 patients incident on PD, with a minimum follow-up of 6 months. The main study variable was the mean PI [normalized rate of protein nitrogen appearance (nPNA)] during the first 4 months on PD. The main outcome variables were the absolute rate of decline of RKF and the proportion of patients presenting a >50% decay of their RKF during the first year of follow-up. We applied univariate and multivariate strategies of analysis, taking into consideration the main control variables bearing a correlation with nPNA and/or RKF.

RESULTS

Mean nPNA (first 4 months) was 1.23 ± 0.33 g/kg/day, while the overall rate of decline of RKF was -0.13 ± 0.29 mL/min/month; 69 patients (25.1%) had lost >50% of their initial RKF by the end of the first year. Univariate analysis disclosed consistent associations between the main study variable on one hand and baseline RKF (r = 0.32, P < 0.0005) and its rate of decline (r = -0.23, P < 0.0005) on the other. The latter two variables were also significantly correlated (r = -0.36, P < 0.0005). Multivariate analysis identified mean nPNA as an independent predictor of the rate of decline of RKF [odds ratio 1.09 per 0.10 g/kg/day, 95% confidence interval (CI) 0.99-1.19, P = 0.058] and, in particular, of the probability of losing >50% of the baseline RKF during the first year of treatment (odds ratio 1.15 per 0.10 g/kg/day, 95% CI 1.04-1.27, P = 0.006).

CONCLUSION

Higher rates of PI during the first months of therapy are associated with a faster decline of RKF among patients incident on PD. Our results underline the convenience of keeping an adequate balance between sufficient protein ingestion, to prevent malnutrition and wasting, and sensible restriction in stable, adequately nourished individuals with rates of intake in the higher range or above-recommended allowances.

Association of Lower Serum Bilirubin With Loss of Residual Kidney Function in Peritoneal Dialysis Patients

Bilirubin is recognized as an endogenous antioxidant, and low serum bilirubin is reported to be associated with the progression of kidney disease. However, it is unclear whether serum bilirubin levels are associated with the loss of residual kidney function (RKF) in peritoneal dialysis (PD) patients. This study investigated the relationship between serum total bilirubin and loss of RKF. We prospectively followed 94 PD patients who started PD in our hospital between June 2006 and May 2016. Ten patients who had chronic liver disease or cirrhosis were excluded. Patients were divided into three groups based on serum total bilirubin concentration tertiles: tertile 1 (T1) < 0.3, T2 = 0.3, and T3 ≥ 0.4 mg/dL. We estimated the relationship between serum bilirubin and loss of RKF, defined as daily urine volume (<100 mL) within 3 years after starting PD, using a Cox proportional hazards model. During the 3-year observation period, 22 patients lost RKF. The incidence rate of loss of RKF increased linearly with the decrease in serum total bilirubin levels (P for trend < 0.05). After adjusting for confounding factors, low serum total bilirubin level was shown to be an independent predictor of loss of RKF (hazard ratio [HR] for every 0.1 mg/dL decrease, 1.50; 95% confidence interval [CI], 1.01-2.51; HR [95%CI] for T2 and T1 [vs. T3] 2.03 [0.65-7.88] and 3.70 [1.00-15.9]). This study suggests that low serum total bilirubin levels are associated with the loss of RKF in PD patients.

Patient-reported advantages and disadvantages of peritoneal dialysis: results from the PDOPPS

BACKGROUND

Patient-reported measures are increasingly recognized as important predictors of clinical outcomes in peritoneal dialysis (PD). We sought to understand associations between patient-reported perceptions of the advantages and disadvantages of PD and clinical outcomes.

METHODS

In this cohort study, 2760 PD patients in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) completed a questionnaire on their PD experience, between 2014 and 2017. In this questionnaire, PDOPPS patients rated 17 aspects of their PD experience on a 5-category ordinal scale, with responses scored from - 2 (major disadvantage) to + 2 (major advantage). An advantage/disadvantage score (ADS) was computed for each patient by averaging their response scores. The ADS, along with each of these 17 aspects, were used as exposures. Outcomes included mortality, transition to hemodialysis (HD), patient-reported quality of life (QOL), and depression. Cox regression was used to estimate associations between ADS and mortality, transition to HD, and a composite of the two. Logistic regression with generalized estimating equations was used to estimate cross-sectional associations of ADS with QOL and depression.

RESULTS

While 7% of PD patients had an ADS < 0 (negative perception of PD), 59% had an ADS between 0 and < 1 (positive perception), and 34% had an ADS ≥1 (very positive perception). Minimal association was observed between mortality and the ADS. Compared with a very positive perception, patients with a negative perception had a higher transition rate to HD (hazard ratio [HR] = 1.67; 95% confidence interval [CI]: 1.21, 2.30). Among individual items, "space taken up by PD supplies" was commonly rated as a disadvantage and had the strongest association with transition to HD (HR = 1.28; 95% CI 1.07, 1.53). Lower ADS was strongly associated with worse QOL rating and greater depressive symptoms.

CONCLUSIONS

Although patients reported a generally favorable perception of PD, patient-reported disadvantages were associated with transition to HD, lower QOL, and depression. Strategies addressing these disadvantages, in particular reducing solution storage space, may improve patient outcomes and the experience of PD.

Development of a risk prediction model for infection-related mortality in patients undergoing peritoneal dialysis

Background

Assessment of infection-related mortality remains inadequate in patients undergoing peritoneal dialysis. This study was performed to develop a risk model for predicting the 2-year infection-related mortality risk in patients undergoing peritoneal dialysis.

Methods

The study cohort comprised 606 patients who started and continued peritoneal dialysis for 90 at least days and was drawn from the Fukuoka Peritoneal Dialysis Database Registry Study in Japan. The patients were registered from 1 January 2006 to 31 December 2016 and followed up until 31 December 2017. To generate a prediction rule, the score for each variable was weighted by the regression coefficients calculated using a Cox proportional hazard model adjusted by risk factors for infection-related mortality, including patient characteristics, comorbidities, and laboratory data.

Results

During the follow-up period (median, 2.2 years), 138 patients died; 58 of them of infectious disease. The final model for infection-related mortality comprises six factors: age, sex, serum albumin, serum creatinine, total cholesterol, and weekly renal Kt/V. The incidence of infection-related mortality increased linearly with increasing total risk score (P for trend <0.001). Furthermore, the prediction model showed adequate discrimination (c-statistic = 0.79 [0.72–0.86]) and calibration (Hosmer–Lemeshow test, P = 0.47).

Conclusion

In this study, we developed a new model using clinical measures for predicting infection-related mortality in patients undergoing peritoneal dialysis.

A Fast Decline of Residual Renal Function in the First Year is a Predictor for Early Withdrawal from Peritoneal Dialysis in Non-Diabetic Patients

BACKGROUND/AIMS

Little is known about the relationship between residual renal function (RRF) decline in early period and survival in non-diabetic peritoneal dialysis (PD) patients.

METHODS

A total of 567 non-diabetic patients who began PD from January 1, 2005 to June 30, 2013 was investigated. The rate of RRF decline was determined by the "slope of the trend equation" of serial RRFs. A composite end-point of all-cause mortality and conversion to hemodialysis (HD) was used, survival status was censored on June 30, 2016.

RESULTS

The median of "the slope of RRF decline equation" was 0.308 (0.001-2.111) ml/min/1.73 m2/ month. In the median follow-up period of 43 months (range 12 to 120 months), 65 (11.5%) patients died, 90 (15.9%) patients converted to HD and 171 (30.2%) patients received kidney transplantation. Multivariate linear regression showed male, high baseline RRF, high baseline peritoneal Kt/V urea, low serum albumin and low uric acid were independently associated with the rate of RRF decline in the first year of PD. Multivariate Cox models revealed that RRF decline in the first year remained a predictor for composite end-point (HR, 2.74, 95% CI, 1.53 to 4.90, P=0.001). The patients were divided into high RRF decline group (> 0.308ml/ min/1.73m2/month) and low RRF decline group (≤0.308 ml/min/1.73m2/month). In the first three years of PD, the rate of end-point events was higher in high RRF decline group (23.2%) than that in low RRF decline group (11.0%) (P< 0.001). There were 189 patients in low RRF decline group and 171 patients in high RRF decline group maintaining PD for more than 3 years, in a median follow-up of 54 months (range 37 to 120 months), the survival rate was 30.9% in high RRF decline group and 46.4% in low RRF decline group (P=0.883). In high RRF decline group, there were 92 patients reaching composited end-point and 112 patients maintaining PD; multivariate Cox model showed high peritoneal Kt/V urea after 1 year of PD and high albumin level were protective factors (HR, 0.29, 95% CI, 0.13 to 0.61, P= 0.001; HR, 0.94, 95% CI, 0.90-0.99, P=0.022, respectively), while fast RRF decline remained risk factor for composite end-point (HR, 3.28, 95% CI,1.48-7.31, P=0.004).

CONCLUSION

A faster RRF decline in the first year was a predictor for all-cause mortality and conversion to HD in non-diabetic PD patients, mainly in the first three year. For patients with faster RRF decline, increasing PD dose was effective to improve survival.

Clinical Studies of Interventions to Mitigate Cardiovascular Risk in Peritoneal Dialysis Patients

Cardiovascular disease (CVD) is highly prevalent in the peritoneal dialysis (PD) population, affecting up to 60% of cohorts. CVD is the primary cause of death in up to 40% of PD patients in Australia, New Zealand, and the United States. Cardiovascular mortality rates are reported to be approximately 14 per 100 patient-years, which are 10- to 20-fold greater than those of age- and sex-matched controls. The excess risk of CVD is related to a combination of traditional risk factors (such as hypertension, dyslipidemia, obesity, smoking, sedentary lifestyle, and insulin resistance), nontraditional (kidney disease-related) risk factors (such as anemia, chronic volume overload, inflammation, malnutrition, hyperuricemia, and mineral and bone disorder), and PD-specific risk factors (such as dialysis solutions, glycation end products, hypokalemia, residual kidney function, and ultrafiltration failure). Interventions targeting these factors may mitigate cardiovascular risk, although high-level clinical evidence is lacking. This review summarizes the evidence relating to cardiovascular interventions targeting modifiable CVD risk factors in PD patients, as well as highlighting the key recommendations of the International Society for Peritoneal Dialysis Cardiovascular and Metabolic Guidelines.

Prescribing Hemodialysis or Hemodiafiltration: When One Size Does Not Fit All the Proposal of a Personalized Approach Based on Comorbidity and Nutritional Status

There is no simple way to prescribe hemodialysis. Changes in the dialysis population, improvements in dialysis techniques, and different attitudes towards the initiation of dialysis have influenced treatment goals and, consequently, dialysis prescription. However, in clinical practice prescription of dialysis still often follows a "one size fits all" rule, and there is no agreed distinction between treatment goals for the younger, lower-risk population, and for older, high comorbidity patients. In the younger dialysis population, efficiency is our main goal, as assessed by the demonstrated close relationship between depuration (tested by kinetic adequacy) and survival. In the ageing dialysis population, tolerance is probably a better objective: "good dialysis" should allow the patient to attain a stable metabolic balance with minimal dialysis-related morbidity. We would like therefore to open the discussion on a personalized approach to dialysis prescription, focused on efficiency in younger patients and on tolerance in older ones, based on life expectancy, comorbidity, residual kidney function, and nutritional status, with particular attention placed on elderly, high-comorbidity populations, such as the ones presently treated in most European centers. Prescription of dialysis includes reaching decisions on the following elements: dialysis modality (hemodialysis (HD) or hemodiafiltration (HDF)); type of membrane (permeability, surface); and the frequency and duration of sessions. Blood and dialysate flow, anticoagulation, and reinfusion (in HDF) are also briefly discussed. The approach described in this concept paper was developed considering the following items: nutritional markers and integrated scores (albumin, pre-albumin, cholesterol; body size, Body Mass Index (BMI), Malnutrition Inflammation Score (MIS), and Subjective Global Assessment (SGA)); life expectancy (age, comorbidity (Charlson Index), and dialysis vintage); kinetic goals (Kt/V, normalized protein catabolic rate (n-PCR), calcium phosphate, parathyroid hormone (PTH), beta-2 microglobulin); technical aspects including vascular access (fistula versus catheter, degree of functionality); residual kidney function and weight gain; and dialysis tolerance (intradialytic hypotension, post-dialysis fatigue, and subjective evaluation of the effect of dialysis on quality of life). In the era of personalized medicine, we hope the approach described in this concept paper, which requires validation but has the merit of providing innovation, may be a first step towards raising attention on this issue and will be of help in guiding dialysis choices that exploit the extraordinary potential of the present dialysis "menu".

Does Residual Renal Function Have a Beneficial Effect on Patient and Technique Survival in Peritoneal Dialysis Patients?

Objectives:

Residual renal function (RRF) at the initiation of peritoneal dialysis (PD) therapy can be a predictor of survival in stable PD patients. The aim of the present study was to investigate PD patients regarding the effect of baseline RRF on patient and technique survival.

Methods:

Urine output at the beginning of PD therapy was evaluated retrospectively in 202 PD patients. Patients were divided into two groups: patients with anuria (urine output ≤100 ml/day) and patients without anuria (urine output >100 ml/day).

Results:

The number of patients with anuria was 58 in which 38 patients were females. The mean age of the patients was 42.8±14.9 years. The mean follow-up period was 44.2±35 months. Twelve percent of patients with anuria had history of hemodialysis (HD).

One hundred forty-four had no anuria (68 females, mean age 43.7±14.5 years, mean follow-up period 39.6±26.1 months, mean urine volume 592±442 ml). Twenty-three patients had received HD therapy before. Sixty-five had anuria in the following 22.5±19.6 months.

At the beginning of therapy, systolic and diastolic blood pressures were lower in patients with oliguria than in patients without oliguria (p<0.001), but C-reactive protein (p=0.004) and ferritin (p<0.001) levels were higher. There was no difference between two groups regarding the other parameters (age, follow-up periods, presence of diabetes, ultrafiltration volumes, albumin, hemoglobin, calcium phosphorus product, parathormone, and Kt/V levels) (p>0.05).

The peritonitis rate was one episode per 28.2 versus 30 patient-months for the anuric and non-anuric groups, respectively (p>0.05).

For Kaplan–Meier survival analysis, the mean technique survival rates at 1 and 3 years were 97% and 86.6% in patients without anuria and 94% and 85.3% in patients with anuria, respectively. The 5-year technique survival rates according to residual volume states were not statistically significant with log-rank test (p>0.05).

The 1-, 3-, and 5-year survival rates were 96.9%, 89.6%, and 86.5% in patients without anuria, respectively, whereas they were 87.3%, 77.3%, and 53.7% in patients with anuria, respectively. The 5-year survival rates according to residual volume states were statistically significant (p<0.05).

Conclusion:

RRF at the beginning of PD has an important and positive impact on patient survival in PD patients. Peritonitis rates and technique survival were not different for patients with anuria and without anuria.

Maintenance of Residual Renal Function 10 Years after the Start of Hemodialysis: The Advantage of Tailored Schedules?

Maintenance of residual renal clearance is a clinical advantage, protecting against the long-term effects of uremia: although demonstrated in peritoneal dialysis, the strategies in hemodialysis are less clear. This case suggests that dialysis schedules individualized on the basis of renal clearances may help preserve residual function.

SB is a 58 year-old male who started dialysis in emergency (creatinine 30.7 mg/dL) in 1993. He had a history of gout, small shrunken kidneys and moderate hypertension. The clinical diagnosis was vasculointerstitial nephropathy. Eighteen months after starting hemodialysis on a conventional thrice weekly schedule, the patient was switched to 2 sessions/week (creatinine clearance increased to 6 ml/min). Thereafter, clearances were checked in alternate months and treatment was tailored to an equivalent renal clearance 12 ml/min (1–2 sessions, 2-3.30 hours/week). Ten years after beginning dialysis, he is on a twice weekly schedule (3.30 hours), is normotensive, works full-time and does not want to go on a transplant waiting list.

Oral Bicarbonate Slows Decline of Residual Renal Function in Peritoneal Dialysis Patients

BACKGROUND/AIMS

Metabolic acidosis is a common consequence of end-stage renal disease (ESRD) which may result in a substantial adverse outcome. The effect of oral bicarbonate on the preservation of residual renal function (RRF) in peritoneal dialysis (PD) patients has been rarely reported.

METHODS

We randomly assigned 40 continuous ambulatory peritoneal dialysis (CAPD) patients to the oral bicarbonate group or placebo group at a 1: 1 ratio. All enrollments were followed for a duration of 104 weeks. We took residual creatinine clearance (CCr), a measure of residual renal function (RRF), as the primary outcome. Residual CCr was calculated as the average of urea and creatinine clearance from a 24-hour urine collection.

RESULTS

Thirteen patients in the placebo group and 15 patients in the treatment group completed the 104 weeks of follow-up with a comparable dropout rate (placebo group: 35% vs treatment group: 25%). Compared with the placebo group, serum bicarbonate in treatment group was significantly increased at each time point, and oral bicarbonate resulted in a slower declining rate of residual CCr (F=5.113, p=0.031). Baseline residual CCr at enrollment also had a significant effect on residual CCr (F=168.779, P<0.001). Charlson Comorbidity Index which was adopted to calculate a comorbidity score had no significant effect on residual CCr loss (F=0.168, P=0.685).

CONCLUSION

Oral bicarbonate may have a RRF preserving effect in CAPD patients, and a normal to high level of serum bicarbonate (≥24mmol/L) may be appropriate for RRF preservation.

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.

Overhydration Is a Strong Predictor of Mortality in Peritoneal Dialysis Patients - Independently of Cardiac Failure

Background

Overhydration is a common problem in peritoneal dialysis patients and has been shown to be associated with mortality. However, it still remains unclear whether overhydration per se is predictive of mortality or whether it is mainly a reflection of underlying comorbidities. The purpose of our study was to assess overhydration in peritoneal dialysis patients using bioimpedance spectroscopy and to investigate whether overhydration is an independent predictor of mortality.

Methods

We analyzed and followed 54 peritoneal dialysis patients between June 2008 and December 2014. All patients underwent bioimpedance spectroscopy measurement once and were allocated to normohydrated and overhydrated groups. Overhydration was defined as an absolute overhydration/extracellular volume ratio > 15%. Simultaneously, clinical, echocardiographic and laboratory data were assessed. Heart failure was defined either on echocardiography, as a reduced left ventricular ejection fraction, or clinically according to the New York Heart Association functional classification. Patient survival was documented up until December 31^st 2014. Factors associated with mortality were identified and a multivariable Cox regression model was used to identify independent predictors of mortality.

Results

Apart from higher daily peritoneal ultrafiltration rate and cumulative diuretic dose in overhydrated patients, there were no significant differences between the 2 groups, in particular with respect to gender, body mass index, comorbidity and cardiac medication. Mortality was higher in overhydrated than in euvolemic patients. In the univariate analysis, increased age, overhydration, low diastolic blood pressure, raised troponin and NTproBNP, hypoalbuminemia, heart failure but not CRP were predictive of mortality. After adjustment, only overhydration, increased age and low diastolic blood pressure remained statistically significant in the multivariate analysis.

Conclusions

Overhydration remains an independent predictor of mortality even after adjustment for heart failure in peritoneal dialysis patients and should therefore be actively sought and managed in order to improve survival in this population.

Comparison of Long-Term Outcomes between Peritoneal Dialysis Patients with Diabetes as a Primary Renal Disease or as a Comorbid Condition

Objective

To investigate the long-term outcomes of peritoneal dialysis (PD) patients with diabetes as primary renal disease and patients with diabetes as a comorbid condition.

Methods

All diabetic patients who commenced PD between January 1, 1995 and June 30, 2012 at Ren Ji Hospital, China were included. Patients were divided into diabetic nephropathy group (DN group) and non-diabetic nephropathy group (NDN group) according to their diagnosis of primary renal disease at the initiation of PD. They were followed until death, cessation of PD, transferred to other centers or to the end of study (June 30, 2013). Outcomes were analyzed by Kaplan-Meier method and Cox regression models.

Results

A total of 163 diabetic patients were enrolled in the study, including 121 (74.2%) in DN group and 42 (25.8%) in NDN group. The 1-, 2-, 3- and 5-year patient survival rates were 89%, 78%, 66% and 51% for DN group, and 85%, 63%, 53% and 25% for NDN group, respectively. Kaplan-Meier analysis showed that patients in NDN group had a worse patient survival compared with DN group (log rank 4.830, P=0.028). Patients in NDN group had a marginally shorter peritonitis-free period (log rank 3.297, P=0.069), however, there was no significant difference in technique survival (log rank 0.040, P=0.841). Multivariate Cox regression analysis showed that older age (HR 1.047, 95% CI 1.022-1.073, p<0.001), cardiovascular disease comorbidity (HR 2.200, 95% CI 0.1.269-3.814, P=0.005) and diabetes as a comorbidity condition (HR 1.806, 95% CI 1.003-3.158, P=0.038) were the independent predictors of increased mortality.

Conclusions

PD patients with diabetes as a comorbidity had an inferior patient survival compared to those with diabetic nephropathy, and closer monitoring and extra attention in the former subgroup of patients are therefore warranted.

Strategies for preserving residual renal function in peritoneal dialysis patients

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.

Increased dialysate MCP-1 is associated with cardiovascular mortality in peritoneal dialysis patients: a prospective observational study

BACKGROUND

The aim of this study was to investigate the association between the dialysate MCP-1 (dMCP-1) and systemic inflammatory and nutritional markers in peritoneal dialysis (PD) patients. In addition, we examined the prognostic value of dMCP-1 on all-cause or cardiovascular mortality in these patients.

METHODS

We prospectively followed 169 prevalent PD patients from April 1st 2008 to December 31st 2012. At baseline, dMCP-1 and serum biochemical parameters including high sensitivity CRP (hs-CRP) and albumin were checked. All-cause mortality and cause of death were evaluated during the follow-up period. Based on the median level of dMCP-1, patients were classified as either low or high dMCP-1 groups.

RESULTS

Mean age, hs-CRP, and D/Pcr ratio at 4 h were significantly higher, while serum albumin levels and %lean body mass (LBM) were significantly lower in the high dMCP-1 group. During the mean follow-up period of 47.7 months, all-cause mortality and cardiovascular mortality rate were significantly higher in the high dMCP-1 group (9.6 and 6.3 per 100 person-years, respectively) compared to the low dMCP-1 group (5.1 and 3.1 per 100 person-years, respectively; p = 0.021, 0.038). In multivariate Cox analysis, high dMCP-1 was a significant independent predictor of all-cause mortality (hazard ratio: 1.83, 95% confidence interval: 1.03-3.24, p = 0.039).

CONCLUSIONS

dMCP-1 levels are closely correlated with nutritional and systemic inflammatory markers in PD patients. In addition, increased dMCP-1 is significantly associated with higher all-cause and cardiovascular mortality. These findings suggest that local peritoneal inflammation could contribute to poor clinical outcomes in PD patients.

The association between dialysis modality and the risk for dialysis technique and non-dialysis technique-related infections

BACKGROUND

Infections are a major cause of morbidity and mortality among dialysis patients. Dialysis modality has been hypothesized to be a potential immunomodulatory factor. The objective of this study was to determine the influence of the first dialysis modality on the risk for infections on dialysis.

METHODS

Our study was conducted utilizing the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD) cohort of incident dialysis patients. Medical records of all patients from two tertiary care university hospitals and three regional hospitals were reviewed using pre-specified criteria. Information about infections was collected from the start of dialysis until death, modality switch, study withdrawal, kidney transplantation or at the end of the study. Age-standardized incidence rates for infections were calculated. Poisson regression analysis was used to calculate adjusted incidence rate ratios (IRRs).

RESULTS

In total, 452 patients, of whom 285 started with haemodialysis (HD) and 167 with peritoneal dialysis (PD), were included. The median follow-up time on the first dialysis modality was similar for HD and PD, 1.8 and 2.0 dialysis years, respectively. During the first 6 months, the age-standardized infection incidence rate was higher on HD compared with PD patients (P = 0.02). Overall, PD patients had a higher infection risk [adjusted IRR: 1.65, 95% confidence interval (CI): 1.34-2.03], which could be attributed to a 4-fold increased risk for dialysis technique-related infections. The risk for non-dialysis technique-related infections was lower in PD patients (adjusted IRR: 0.56, 95% CI: 0.40-0.79).

CONCLUSIONS

Overall, PD patients carry a higher risk for infections. Interestingly, the risk for non-dialysis technique-related infections was higher in HD patients. The links between dialysis modality and the immune system are expected to explain this difference, but future studies are needed to test these assumptions.

Intraperitoneal interleukin-6 levels predict peritoneal solute transport rate: a prospective cohort study

BACKGROUND

To evaluate the association of dialysate interleukin-6 (IL-6), a marker of ongoing peritoneal inflammation, with the alteration of peritoneal solute transport rate (PSTR) in continuous ambulatory peritoneal dialysis (CAPD) patients.

METHODS

Stable CAPD patients were enrolled in the present study. A total of 128 patients were analyzed in this prospective study. IL-6 concentration in the overnight effluent was determined and expressed as the IL-6 appearance rate (IL-6AR). Mass transfer area coefficients of creatinine (MTACcr) were measured at enrollment and 12 months later. Logistic regression was used to examine the association between IL-6AR and change in MTACcr.

RESULTS

Multivariable linear regression showed that historical glucose exposure was significantly associated with dialysate IL-6AR level [β = 0.008 (0.001-0.015), p = 0.021]. After 12 months, MTACcr was significantly increased [6.40 (4.70-8.75) vs. 7.14 (5.69-8.73) ml/min, p = 0.004], while ultrafiltration capacity decreased [4 h UF 340 (220-400) vs. 280 (180-380) ml, p = 0.006]. Compared to the patients with stable PSTR, the dialysate IL-6AR in patients with increasing PSTR was significantly higher [277.08 (247.45-349.53) vs. 263.18 (69.94-286.72) pg/min, p = 0.015]. Patients with increasing PSTR had lower residual renal function [0.79 (0-2.12) vs. 1.70 (0.39-3.38) ml/min, p = 0.006] and less urine output [225 (0-600) vs. 500 (125-900) ml/24 h, p = 0.014]. Logistic analysis showed that both high dialysate IL-6AR [OR 1.333 and 95% CI (1.024-1.735), p = 0.033] and low RRF [OR 0.831 and 95% CI (0.699-0.988), p = 0.036] were independent risk factors for increasing PSTR.

CONCLUSIONS

This prospective study suggests that intraperitoneal IL-6 is a predictor of increasing PSTR in peritoneal dialysis patients.

High-sensitivity C-reactive protein predicts mortality and technique failure in peritoneal dialysis patients

Introduction

An elevated level of serum C-reactive protein (CRP) is widely considered an indicator of an underlying inflammatory disease and a long-term prognostic predictor for dialysis patients. This cross-sectional cohort study was designed to assess the correlation between the level of high-sensitivity CRP (HS-CRP) and the outcome of peritoneal dialysis (PD) patients.

Methods

A total of 402 patients were stratified into 3 tertiles (lower, middle, upper) according to serum HS-CRP level and and followed up from October 2009 to September 2011. During follow-up, cardiovascular events, infection episodes, technique failure, and mortality rate were recorded.

Results

During the 24-month follow-up, 119 of 402 patients (29.6%) dropped out from PD, including 28 patients (7.0%) who died, 81 patients (20.1%) who switched to hemodialysis, and 10 patients (2.5%) who underwent kidney transplantation. The results of Kaplan–Meier analysis and log-rank test demonstrated a significant difference in the cumulative patient survival rate across the 3 tertiles (the lowest rate in upper tertile). On multivariate Cox regression analysis, only higher HS-CRP level, older age, the presence of diabetes mellitus (DM), lower serum albumin level, and the occurrence of cardiovascular events during follow-up were identified as independent predictors of mortality. Every 1 mg/L increase in HS-CRP level was independently predictive of a 1.4% increase in mortality. Multivariate Cox regression analysis also showed that higher HS-CRP level, the presence of DM, lower hemoglobin level, lower serum albumin level, higher dialysate/plasma creatinine ratio, and the occurrence of infective episodes and cardiovascular events during follow-up were independent predictors of technique failure.

Conclusions

The present study shows the importance of HS-CRP in the prediction of 2-year mortality and technique survival in PD patients independent of age, diabetes, hypoalbuminemia, and the occurrence of cardiovascular events.

High glucose concentrations in peritoneal dialysate are associated with all-cause and cardiovascular disease mortality in continuous ambulatory peritoneal dialysis patients

BACKGROUND

The effect of high peritoneal dialysate glucose concentration (PDGC) on all-cause and cardiovascular disease (CVD) mortality in peritoneal dialysis (PD) patients is unclear.

OBJECTIVE

Our study aimed to investigate the effect of high PDGC on all-cause and CVD mortality in continuous ambulatory PD (CAPD) patients.

METHODS

The study enrolled 716 patients newly initiated on CAPD therapy between January 2006 and December 2010. We allocated the patients to low (< 1.56%), medium (≥ 1.56% to < 1.74%), and high (≥ 1.74%) average PDGC groups according to the tertile of average PDGC in the first 6 months after PD initiation. Cox regression and ordinal logistic regression were used to analyze determinants of mortality and of PDGC use respectively.

RESULTS

Mean follow-up in the study cohort was 31 ± 15 months. The all-cause mortality was 4.7 events per 100 patient-years, and the leading cause of death was CVD. Patients with a higher PDGC had significantly higher cumulative rates of all-cause (log-rank p < 0.001) and CVD mortality (log-rank p < 0.001). In Cox regression analysis, high PDGC independently predicted higher all-cause (hazard ratio: 2.63; p = 0.004) and CVD mortality (hazard ratio: 2.78; p = 0.01). Compared with a lower PDGC, a higher PDGC was significantly associated with older age [odds ratio (OR): 1.02; p < 0.001], low residual renal function (OR: 0.91; p < 0.001), and high dialysate-to-plasma ratio of creatinine (OR: 28.61; p < 0.001) in ordinal logistic regression.

CONCLUSIONS

Higher PDGC is associated with higher allcause and CVD mortality in CAPD patients.

Independent effects of systemic and peritoneal inflammation on peritoneal dialysis survival

Systemic inflammation, as evidenced by elevated inflammatory cytokines, is a feature of advanced renal failure and predicts worse survival. Dialysate IL-6 concentrations associate with variability in peritoneal small solute transport rate (PSTR), which has also been linked to patient survival. Here, we determined the link between systemic and intraperitoneal inflammation with regards to peritoneal membrane function and patient survival as part of the Global Fluid Study, a multinational, multicenter, prospective, combined incident and prevalent cohort study (n=959 patients) with up to 8 years of follow-up. Data collected included patient demographic characteristics, comorbidity, modality, dialysis prescription, and peritoneal membrane function. Dialysate and plasma cytokines were measured by electrochemiluminescence. A total of 426 survival endpoints occurred in 559 incident and 358 prevalent patients from 10 centers in Korea, Canada, and the United Kingdom. On patient entry to the study, systemic and intraperitoneal cytokine networks were dissociated, with evidence of local cytokine production within the peritoneum. After adjustment for multiple covariates, systemic inflammation was associated with age and comorbidity and independently predicted patient survival in both incident and prevalent cohorts. In contrast, intraperitoneal inflammation was the most important determinant of PSTR but did not affect survival. In prevalent patients, the relationship between local inflammation and membrane function persisted but did not account for an increased mortality associated with faster PSTR. These data suggest that systemic and local intraperitoneal inflammation reflect distinct processes and consequences in patients treated with peritoneal dialysis, so their prevention may require different therapeutic approaches; the significance of intraperitoneal inflammation requires further elucidation.

Nutrition and the kidney: recommendations for peritoneal dialysis

Protein energy wasting (PEW) is highly prevalent in peritoneal dialysis (PD) and is associated with poor outcomes, including hospitalization and mortality. Recognizing and diagnosing PEW in PD is important; although studies are limited, there are interventions that may be associated with improved outcomes. In this review of nutritional aspects of PD, we highlight some of the important causes of PEW and explore the current diagnostic tools that are used to assess PEW. Finally, we discuss the established and experimental therapies for PEW in PD.

Clinical outcomes of peritoneal dialysis patients transferred from hemodialysis: a matched case-control study

OBJECTIVE

Our study aimed to evaluate clinical outcomes of patients transferred to peritoneal dialysis (PD) because of complications related to hemodialysis (HD). ♢

METHODS

In a 1:2 matched case-control study, we compared patient and technique survival between patients initially treated with HD for at least 3 months and then transferred to PD (transfer group) and patients started on and continuing with PD (no-transfer group). ♢

RESULTS

All baseline characteristics except for initial residual urinary output were comparable between the groups. Compared with patients in the transfer group, patients in the no-transfer group had a higher initial daily residual urinary output [850 mL (range: 600 - 1250 mL) vs 0 mL (range: 0 - 775 mL/d), p = 0.000]. The main reasons for transfer to PD were vascular access problems and cardiovascular disease. Patient survival and technique failure rates did not significantly differ between the groups (p > 0.05). The 1-, 3-, and 5-year patient survival rates were 80.0%, 53.7%, and 27.6% in the transfer group and 89.7%, 60.2%, and 43.1% in the no-transfer group. Age (per 10 years) and serum albumin were independent risk factors for long-term survival in PD patients. Relative risk of either death or technique failure was not significantly increased in patients transferred from HD. ♢

CONCLUSIONS

Patients who transferred to PD after failing HD had outcomes on PD similar to those for patients who started with and were maintained on PD. Age (per 10 years) and serum albumin were independent risk factors for long-term survival in PD patients.

Definition and risk factors of rapidly declining residual renal function in peritoneal dialysis: an observational study

BACKGROUND

It is critical to preserve residual renal function (RRF) in peritoneal dialysis (PD), as RRF is associated with lower morbidity and mortality. There is no uniform definition of RRF, and rapidly declining RRF has rarely been studied and predominately limited to single factor analysis and not corrected for lead-time bias.

METHODS

An observational study in 71 incident PD patients. RRF was defined as urine output (UO) ≥500 ml/day and renal glomerular filtration rate (rGFR) ≥2 ml/min/1.73 m(2), rapid declining RRF as UO <500 ml/day and rGFR <2 ml/min/1.73 m(2) occurring within 6 months which were separately evaluated. Independent risk factors associated with rapid RRF decline were identified while correcting for lead-time bias.

RESULTS

RRF declined rapidly by both definitions in 65% patients 2.5 years after PD start. Both definitions of RRF decline were consistent in 96%. Nephrotoxic drugs, renal transplant failure and absent angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II receptor blockers (ARB) were independent risk factors associated with rapidly declining RRF defined both by definitions, intravascular radiocontrast additionally for UO decline.

CONCLUSIONS

Most PD patients demonstrated rapid RRF decline, independent of its definition. Both definitions are highly consistent and interchangeable. Nephrotoxic drugs and radiocontrast were identified as risk factors of acute, absent ACEI or ARB, and renal transplant failure of chronic renal injury.

Cardiovascular mortality and C-reactive protein in elderly patients beginning dialysis: reverse epidemiology?

BACKGROUND AND AIMS

Cardiovascular disease is a major cause of mortality in end-stage renal disease patients (ESRD). The rate of elderly and polypathologic patients in ESRD is increasing. Elevated levels of C-reactive protein (CRP) have been shown to be associated with increased mortality in ESRD patients. The aim of this study was to examine whether, in elderly ESRD patients, the conventional relationship between elevated CRP and cardiovascular mortality is maintained.

METHODS

This prospective European cohort study included 150 ESRD patients. Data obtained at baseline included demographics, comorbidity, late referral to a nephrologist, high-sensitivity CRP, and serum albumin and hemoglobin levels. Cardiovascular events were analysed as a combined end-point.

RESULTS

The mean age of the cohort was 61 years (22-90), with 33.3% of patients over 70 years (75 yrs, 70-83 yrs). Forty-two patients (28.2%) experienced at least one cardiovascular event. Interaction between age over 70 years and CRP exceeding 3 mg/L was a protective factor. Patients over 70 years beginning dialysis with a CRP value <3 mg/L had a higher cardiovascular risk than those with a CRP value >3 mg/L. Multivariate analysis showed that the independent risk factors for cardiovascular events were, in the whole cohort, age over 70 years, previous cardiovascular comorbidity, and interaction between age and CRP.

CONCLUSIONS

This trial shows a reverse relation between cardiovascular risk in dialysis patients over 70 and CRP level. This may be a useful element in evaluating older patients before long-term dialysis.

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.

Association between depression and malnutrition-inflammation complex syndrome in patients with continuous ambulatory peritoneal dialysis

OBJECTIVE

Depression, the most common psychological disorder among patients with end-stage renal disease (ESRD), is associated with poor survival. The prevalence of depression and its relation with the malnutrition-inflammation complex syndrome (MICS) have not yet been clearly defined in Chinese continuous ambulatory peritoneal dialysis (CAPD) patients.

PATIENTS AND METHODS

A total of 142 patients on CAPD were enrolled in the First Affiliated Hospital of Sun Yat-Sen University. The Hamilton Depression Scale (HAMD) and the malnutrition-inflammation score (MIS) were used for depression and MICS evaluation, respectively. Clinical, socioeconomic, and malnutrition-inflammation factors were compared among patients with and without depression. Binary regression analysis was performed to investigate the independent association between depression and MICS.

RESULTS

The mean HAMD and MIS scores were 7.12 ± 5.28 and 4.45 ± 3.56, respectively. According to HAMD, 37 patients (26.1%) had depression and 70 patients (49.3%) had potential depression. Older age, longer dialysis vintage, worse residual renal function, lower employment and reimbursement status, and higher comorbidity index were positively correlated with depression. Compared to non-depressed patients, the depressed ones also showed lower levels of serum albumin and higher levels of C-reactive protein (CRP). Correlation results showed that the HAMD scores were significantly and positively correlated with MIS (r = 0.46, P < 0.01). Moreover, the incidence of peritonitis was significantly higher in depressed compared to non-depressed patients. Binary regression analysis showed that MIS was the only independent risk factor for depression.

CONCLUSION

Depression is commonly encountered in Chinese CAPD patients. A close relationship exists between depression and MICS.

High peritoneal transport status is not an independent risk factor for high mortality in patients treated with automated peritoneal dialysis

We undertook this study to elucidate whether baseline peritoneal membrane transport characteristics are associated with high mortality in incident automated peritoneal dialysis (APD) patients. This retrospective study includes 117 patients who started APD at Yonsei University Health System from 1996 to 2008 and had a PET within 3 months of APD initiation. High transporters were significantly older and had a higher incidence of cardiovascular disease. Patient survival for years 1, 3, and 5 were 85%, 64%, and 35% for high transporter and 94%, 81%, and 68% for non-high transporter group (P<0.01). Multivariate analysis revealed that age, diabetes, cardiovascular disease, serum albumin level, and residual renal function were independently associated with high mortality in APD patients. In contrast, high transport status was not a significant predictor for mortality in this population when the other covariates were included. Even though high transport was significantly associated with mortality in the univariate analysis, its role seemed to be influenced by other comorbid conditions. These findings suggest that the proper management of these comorbid conditions, as well as appropriate ultrafiltration by use of APD and/or icodextrin, must be considered as protective strategies to improve survival in peritoneal dialysis patients with high transport.