Clearing the air: a review of the effects of air pollution on dialysis outcomes

PURPOSE OF REVIEW

An evolving body of literature indicates exposure to air pollutants is associated with adverse health outcomes in dialysis patients. As the prevalence of kidney disease increases, understanding the role of environmental agents on the health of dialysis patients is critical to reducing global morbidity and mortality.

RECENT FINDINGS

We identified 16 publications that investigated associations between pollutants including particulate matter (PM 2.5 and PM 10 ), carbon monoxide (CO), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), and ozone (O 3 ) and health outcomes among dialysis patients. Eight studies examined the effects of particulate matter (PM) and four studies examined the effects CO exposure on dialysis patients. Exposure to PM was consistently associated with outcomes including all-cause mortality and a smaller body of literature suggested relationships with subclinical outcomes. Exposure to CO was associated with all-cause mortality, generalized inflammation, and uremic pruritus. An additional four studies examined multiple pollutant exposures including NO 2 , SO 2 , and O 3 and reported associations with all-cause mortality in dialysis patients.

SUMMARY

This review emphasized the nascent literature that demonstrates consistent relationships between air pollutant exposure and adverse outcomes among dialysis patients. Further research is needed to assess the impact of air pollutants, including how co-exposures will impact dialysis patient health.

Association of serum globulin with all-cause mortality in incident hemodialysis patients

BACKGROUND

Serum globulin is a major component of total protein and can be elevated in inflammatory disease states. While inflammation is common in hemodialysis patients and associated with mortality and morbidity, the association between serum globulin and mortality have never been examined in hemodialysis patients.

METHODS

In a retrospective cohort of 104,164 incident hemodialysis patients treated by a large dialysis organization from 2007 to 2011, we explored the association between baseline serum globulin, A/G ratio and serum protein levels and all-cause, cardiovascular and infection-related mortality with adjustments for demographic variables and laboratory markers of malnutrition and inflammation using Cox proportional hazard models.

RESULTS

Patients with globulin concentration >3.8 g/dL had higher all-cause and infection-related mortality risk (Hazard Ratio [HR] 1.11, 95% Confidence Interval [95%CI]: 1.06, 1.16 and HR 1.28, 95%CI: 1.09, 1.51; respectively) in the fully adjusted model when compared to the reference group of 3.0-<3.2 g/dL. In addition, patients with A/G ratio <0.75 had a 45% higher all-cause mortality hazard (HR 1.45, 95%CI: 1.38, 1.52) and patients with total serum protein <5.5 g/dL had a 34% higher risk of death (HR: 1.34, 95%CI: 1.27, 1.42) when compared to the reference (A/G ratio 1.05-<1.15 and total serum protein 6.5-<7 g/dL, respectively).

CONCLUSIONS

Among incident hemodialysis patients, higher globulin level was associated with higher mortality risk independent of other markers of malnutrition and inflammation, including albumin. Lower A/G ratio and serum protein was also associated with higher mortality hazard. The mechanisms that contribute to elevated serum globulin should be further explored.

Neutrophil-to-Lymphocyte Ratio and Treatment Failure in Peritoneal Dialysis-Associated Peritonitis

Objective: We sought to explore if there is an association between neutrophil-to-lymphocyte ratio (NLR) and treatment failure in patients with peritoneal dialysis-associated peritonitis (PDAP).

Methods: Our cohort involved 337 episodes of PDAP experienced by 202 patients who were undergoing continuous ambulatory peritoneal dialysis at a single center from 1 July 2013 to 30 June 2018. The exposures were log-transformed NLR and a categorical variable grouped by the tertiles of NLR levels (T1, <3.75; T2, 3.75–6.53; and T3, >6.53) at baseline. Generalized estimating equation (GEE) and restricted cubic spline (RCS) analyses were done to determine the association between NLR and treatment failure, defined as catheter removal or all-cause mortality during therapy.

Results: After adjusting for other potential predictors, the log-transformed NLR exhibited an incremental relationship with the risk of treatment failure (odds ratio, 1.82; 95% confidence interval, 1.05–3.15). RCS analyses showed that the relationship was positively and linearly correlated (P for nonlinearity = 0.104). As a three-level categorical variable, in reference to T1, the T3 of NLR showed a 3.41-fold increased venture of treatment failure in fully adjusted model. Subgroup analyses suggested that the prognostic relevance of NLR in PDAP was particularly significant in gram-negative peritonitis.

Conclusions: A greater level of NLR at baseline was remarkably associated with a higher incidence of treatment failure among PDAP episodes regardless of other potential risk factors.

Peritoneal Dialysis Guidelines 2019 Part 1 (Position paper of the Japanese Society for Dialysis Therapy)

Approximately 10 years have passed since the Peritoneal Dialysis Guidelines were formulated in 2009. Much evidence has been reported during the succeeding years, which were not taken into consideration in the previous guidelines, e.g., the next peritoneal dialysis PD trial of encapsulating peritoneal sclerosis (EPS) in Japan, the significance of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), the effects of icodextrin solution, new developments in peritoneal pathology, and a new international recommendation on a proposal for exit-site management. It is essential to incorporate these new developments into the new clinical practice guidelines. Meanwhile, the process of creating such guidelines has changed dramatically worldwide and differs from the process of creating what were “clinical practice guides.” For this revision, we not only conducted systematic reviews using global standard methods but also decided to adopt a two-part structure to create a reference tool, which could be used widely by the society’s members attending a variety of patients. Through a working group consensus, it was decided that Part 1 would present conventional descriptions and Part 2 would pose clinical questions (CQs) in a systematic review format. Thus, Part 1 vastly covers PD that would satisfy the requirements of the members of the Japanese Society for Dialysis Therapy (JSDT). This article is the duplicated publication from the Japanese version of the guidelines and has been reproduced with permission from the JSDT.

Predicting Prolonged Length of Hospital Stay for Peritoneal Dialysis-Treated Patients Using Stacked Generalization: Model Development and Validation Study

Background

The increasing number of patients treated with peritoneal dialysis (PD) and their consistently high rate of hospital admissions have placed a large burden on the health care system. Early clinical interventions and optimal management of patients at a high risk of prolonged length of stay (pLOS) may help improve the medical efficiency and prognosis of PD-treated patients. If timely clinical interventions are not provided, patients at a high risk of pLOS may face a poor prognosis and high medical expenses, which will also be a burden on hospitals. Therefore, physicians need an effective pLOS prediction model for PD-treated patients.

Objective

This study aimed to develop an optimal data-driven model for predicting the pLOS risk of PD-treated patients using basic admission data.

Methods

Patient data collected using the Hospital Quality Monitoring System (HQMS) in China were used to develop pLOS prediction models. A stacking model was constructed with support vector machine, random forest (RF), and K-nearest neighbor algorithms as its base models and traditional logistic regression (LR) as its meta-model. The meta-model used the outputs of all 3 base models as input and generated the output of the stacking model. Another LR-based pLOS prediction model was built as the benchmark model. The prediction performance of the stacking model was compared with that of its base models and the benchmark model. Five-fold cross-validation was employed to develop and validate the models. Performance measures included the Brier score, area under the receiver operating characteristic curve (AUROC), estimated calibration index (ECI), accuracy, sensitivity, specificity, and geometric mean (Gm). In addition, a calibration plot was employed to visually demonstrate the calibration power of each model.

Results

The final cohort extracted from the HQMS database consisted of 23,992 eligible PD-treated patients, among whom 30.3% had a pLOS (ie, longer than the average LOS, which was 16 days in our study). Among the models, the stacking model achieved the best calibration (ECI 8.691), balanced accuracy (Gm 0.690), accuracy (0.695), and specificity (0.701). Meanwhile, the stacking and RF models had the best overall performance (Brier score 0.174 for both) and discrimination (AUROC 0.757 for the stacking model and 0.756 for the RF model). Compared with the benchmark LR model, the stacking model was superior in all performance measures except sensitivity, but there was no significant difference in sensitivity between the 2 models. The 2-sided t tests revealed significant performance differences between the stacking and LR models in overall performance, discrimination, calibration, balanced accuracy, and accuracy.

Conclusions

This study is the first to develop data-driven pLOS prediction models for PD-treated patients using basic admission data from a national database. The results indicate the feasibility of utilizing a stacking-based pLOS prediction model for PD-treated patients. The pLOS prediction tools developed in this study have the potential to assist clinicians in identifying patients at a high risk of pLOS and to allocate resources optimally for PD-treated patients.

Controlling Inflammation in Peritoneal Dialysis: The Role of PD-Related Factors as Potential Intervention Targets

Cardiovascular (CV) disease is the main cause of death in peritoneal dialysis (PD) patients, but the mechanisms mediating the increased CV risk observed in this group of patients are still largely unknown, which limits the perspective on effective therapeutic strategies. Patients on PD are already exposed to a number of traditional risk factors from the start of their chronic kidney disease (CKD), because many of those risk factors are common to CV disease and CKD alike. As renal dysfunction progresses, CKD-related risk factors are introduced, changing the profile of both the CV disease and the markers of risk. In this phase, which usually starts when glomerular filtration rate falls below 60 mL/min, the list of risk factors is expanded to include disturbances of mineral metabolism, anemia, fluid overload, uremic toxicity, and increased signs of oxidative stress and inflammation. Although many of the risk factors linked to CV burden are not related to the dialytic procedure, additional harm is introduced after the initiation of PD—with, for example, the presence of chronic infections and factors related to PD fluids, particularly reabsorption of glucose. In the present article, we review the impact of the novel risk factors introduced with the initiation of PD therapy, and we propose potential therapeutic strategies (which remain to be tested) for reducing CV mortality in this group of patients.

Current Status of Peritoneal Dialysis in Korea: Efforts to Achieve Optimal Outcome

Since its introduction in 1981, peritoneal dialysis (PD) has become firmly established as an effective mode of renal replacement therapy and serves an increasing patient population in Korea. The latest registry data indicate that about 3700 end-stage renal disease patients are maintained on chronic PD, representing 24.1% of the country's dialysis population. The majority (93.3%) of these patients are on continuous ambulatory peritoneal dialysis (CAPD) using the two-bag disconnect system, while only 3.3% are on automated PD. Under current renal reimbursement policies, most dialysis patients have to pay 20% of dialysis fees. Thus CAPD patients on 4 x 2-L daily exchanges pay about US$200 per month, not including medication and travel costs.

Traditionally, most PD centers in Korea have used the “standard” prescription of 4 exchanges of 2 L of solution for most of their patients. A recent survey of 1467 patients who commenced CAPD in 1997 revealed that 84% of these patients were initially prescribed 4 x 2-L exchanges, while 12% were given a daily volume of 6 L. With this standard prescription, the percentages of Korean CAPD patients initially achieving the adequacy target of Kt/V urea ≥ 2.0 and standardized creatinine clearance (SCCr) ≥ 60 L/week/ 1.73 m2, were 74.4% and 82.1%, respectively. It is likely that, among current Korean CAPD patients, a much lower percentage will achieve the clearance targets compared to this initial outcome, but the precise data are not available. However, it is not clear whether the levels of small-solute clearance recommended for optimal PD outcomes, and proposed by the NKF-DOQI guidelines, will bring the expected benefits to Korean patients.

Overall survival of Korean PD patients appears to be as good as, or even better than, that in most other countries. Recently, a single large PD center reported patient survival of 92.1%, 85.6%, 81.4%, and 67.6% at 1, 2, 3, and 5 years respectively. Other centers also reported similar outcomes. As in other countries, cardiovascular deaths predominate among Korean patients: death was due to cardiac causes in 29%, to vascular causes in 21%, and to infectious causes in 24%.

Peritonitis is the most important barrier to prolonged use of CAPD in Korea, and more PD patients transfer to hemodialysis because of peritonitis than in other countries. To further reduce the morbidity and mortality of Korean PD patients, various control measures need to be implemented that can reduce or prevent peritonitis and other infectious complications. Also, to further improve long-term patient outcome, Korean nephrologists need to establish and practice optimal clearance targets in the chronic care of these patients.

The Ratio of Extracellular Fluid to Total Body Water and Technique Survival in Peritoneal Dialysis Patients

Background

Patients receiving peritoneal dialysis experience a high technique failure rate and are often overhydrated. We examined whether an increased extracellular fluid volume (VECF) as a proportion of the total body water (VTBW) predicted technique survival (TS) in a prevalent patient cohort.

Methods

The VECFand VTBWwere estimated by multiple-frequency bioelectric impedance in 59 prevalent peritoneal dialysis patients (median time on dialysis 14 months). Demographic, biochemical (albumin, C-reactive protein, and ferritin), and anthropometric data, forearm muscle strength, nutritional score by three-point Subjective Global Assessment, residual renal function, dialysate-to-plasma (D/P) creatinine ratio, total weekly Kt/V urea, total creatinine clearance, normalized protein equivalent of nitrogen appearance, and midarm muscle circumference were also assessed. Technique survival was determined at 3 years, and significant predictors of TS were sought.

Results

In patient groups defined by falling above or below the median value for each parameter, only residual renal function ( p = 0.002), 24-hour ultrafiltrate volume ( p = 0.02), and VECF/ VTBWratio ( p = 0.05) were significant predictors of TS. Subjects with a higher than median VECF/ VTBWratio had a 3-year TS of 46%, compared to 78% in subjects with a lower than median value. In multivariate analysis, systolic blood pressure and VECF/ VTBWratio (both p < 0.05) were significant predictors of TS. C-reactive protein approached significance.

Conclusion

Increased ratio of extracellular fluid volume to total body water is associated with decreased TS in peritoneal dialysis.

Nutritional Problems of Asian Peritoneal Dialysis Patients

Clear evidence links malnutrition with poor outcome in peritoneal dialysis (PD) patients; however, most studies have evaluated Western populations, which may have clinical and demographic characteristics different from those of Asian populations. Although Asian PD patients are generally regarded to have survival superior to that of Western patients, whether that better survival is related to better nutrition in Asian patients is not clear. Past studies suggest that the overall prevalence of protein–calorie malnutrition as assessed by subjective global assessment (SGA)—especially cases of severe malnutrition—seems to be lower in Asian PD patients than in Western patients. Less activation of systemic inflammatory reaction, less comorbidity, lower prevalence of metabolic acidosis, or better compliance may be responsible for better nutritional status in Asian PD patients. Dietary protein and calorie intake, dialysis dose, and membrane transport characteristics appear not to differ significantly between Asian and non Asian PD patients. Mechanisms that explain the lower prevalence of systemic inflammatory reaction in Asian PD patients need to be investigated, along with their possible impacts on nutrition and cardiovascular morbidity and mortality. Large-scale, prospective studies are also necessary to ascertain the exact correlation between dialysis dose and nutritional status, and to determine the dietary protein and calorie intakes that maintain a positive nitrogen balance and better outcome in Asian PD patients.

Peritonitis-Related Mortality in Patients Undergoing Chronic Peritoneal Dialysis

Peritonitis is a well-known cause of mortality in peritoneal dialysis (PD) patients. We carried out a retrospective study to disclose the clinical spectrum and risk profile of peritonitis-related mortality. We analyzed 693 episodes of infectious peritonitis suffered by 565 patients (follow-up 1149 patient-years). Death was the final outcome in 41 cases (5.9% of episodes), peritonitis being directly implicated in 15.2% of the global mortality and 68.5% of the infectious mortality observed. In 41.5% of patients with peritonitis-related mortality, the immediate cause of death was a cardiovascular event. Highest mortality rates corresponded to fungal (27.5%), enteric (19.3%), and Staphylococcus aureus (15.2%) peritonitis. Multivariate analysis disclosed that the baseline risk of peritonitis-related mortality was significantly higher in female [relative risk (RR) 2.13, 95% confidence interval (CI) 1.24 – 4.09, p = 0.02], older (RR 1.10/year, CI 1.06 – 1.14, p < 0.0005), and malnourished patients (RR 2.51, CI 1.21 – 5.23, p = 0.01) with high serum C-reactive protein (s-CRP) levels (RR 4.04, CI 1.45 – 11.32, p = 0.008) and a low glomerular filtration rate (RR 0.75 per mL/minute, CI 0.64 – 0.87, p < 0.0005). Analysis of risk after a single episode of peritonitis and/or subanalysis restricted to peritonitis caused by more aggressive micro-organisms disclosed that overall comorbidity [odds ratio (OR) 1.21, CI 1.05 – 1.71, p = 0.005], depression (OR 2.35, CI 1.14 – 4.84, p = 0.02), and time on PD at the time of the event (OR 1.02/month, CI 1.00 – 1.03, p = 0.02) were other predictors of mortality.

In summary, the etiologic agent is a definite marker of peritonitis-related mortality but gender, age, residual renal function, inflammation (s-CRP), malnutrition, and depression are other significant correlates of this outcome. Most of these risk factors are common to cardiovascular and peritonitis-related mortality, which may explain the high incidence of cardiovascular event as the immediate cause of death in patients with peritonitis-related mortality.

Biocompatibility of New Peritoneal Dialysis Solutions: What Can We Hope to Achieve?

Despite the bioincompatibility of the “old”, standard, high glucose, lactate-buffered peritoneal dialysis (PD) solutions, PD is itself a highly successful dialysis modality with patient survival equivalent to that of hemodialysis (HD) during the initial 3 – 5 years of dialysis therapy. Nevertheless, PD technique survival is often limited by infectious complications and alterations in the structure and function of the peritoneal membrane. These local changes also have a negative impact on patient survival owing to systemic effects such as those often seen in patients with high peritoneal transport rate and loss of ultrafiltration (UF) capacity.

Patient mortality remains unacceptably high in both HD and PD patients, with most premature deaths being associated with signs of malnutrition, inflammation, and atherosclerotic cardiovascular disease (MIA syndrome). These systemic signs are likely to be influenced by PD solutions both directly and indirectly (via changes in the peritoneal membrane). New, biocompatible PD solutions may have favorable local effects (viability and function of the peritoneal membrane) and systemic effects (for example, on MIA syndrome). Amino acid–based solution [Nutrineal (N): Baxter Healthcare Corporation, Deerfield, IL, U.S.A.] may improve nutritional status as well as peritoneal membrane viability. Bicarbonate/lactate–buffered solution [Physioneal (P): Baxter Healthcare Corporation] may ameliorate local and systemic effects of low pH, high lactate, and high glucose degradation products. Icodextrin-based solution [Extraneal (E): Baxter Healthcare SA, Castlebar, Ireland] may improve hypertension and cardiovascular problems associated with fluid overload and may extend time on therapy in patients with loss of UF capacity.

The positive effects of each of these new, biocompatible solutions have been demonstrated in several studies. It is likely that the combined use of N, P, and E solutions will produce favorable synergies in regard to both local effects (peritoneal viability) and systemic effects (less malnutrition, inflammation, and fluid overload). Solution combination is an exciting area for clinical study in the coming years. Furthermore, dialysis fluid additives such as hyaluronan, which protects and improves the function of the peritoneal membrane, may further improve PD solutions. The new, biocompatible PD solutions represent an entirely new era in the evolution of the PD therapy; they are likely to have markedly positive effects on both PD technique and PD patient survival in coming years.

Influence of Peritoneal Transport Rate, Inflammation, and Fluid Removal on Nutritional Status and Clinical Outcome in Prevalent Peritoneal Dialysis Patients

Objective

To evaluate the possible associations between peritoneal transport rate (PTR), fluid removal, inflammation, and nutritional status in patients treated with peritoneal dialysis (PD) for more than 6 months, and the impact of these factors on subsequent patient survival.

Design and Patients

A prospective study of 82 PD patients (48 males) that had been treated with PD more than 6 months. Based on the dialysate-to-plasma creatinine ratio at 4 hours of dwell (D/PCr; mean ± 1 SD), the patients were classified as having a high (H), high-average (HA), low-average (LA), or low (L) PTR.

Setting

Single PD unit in a university hospital.

Main Outcome Measures

The PTR, evaluation of adequacy of dialysis and nutritional status, and biochemical analyses were assessed at 10.8 ± 2.8 months after the start of PD.

Results

Compared to L and LA (L/LA) transporters, H and HA (H/HA) transporters had increased dialysate protein loss, glucose absorption from dialysate, and peritoneal creatinine clearance (CCr), and decreased night ultrafiltration volume and total Kt/V urea. However, nutritional variables, 24-hour total fluid removal (TFR), total CCr, and residual renal function were not significantly different between the two groups. The 24-hour TFR correlated significantly with D/PCr (rho = –0.25), mean arterial pressure (rho = –0.23), serum albumin (rho = 0.25), normalized protein equivalent of total nitrogen appearance (rho = 0.34), lean body mass (LBM) calculated from creatinine kinetics (rho = 0.41), total Kt/V urea (rho = 0.42), and total CCr (rho = 0.30). The group with serum C-reactive protein (sCRP) ⊕ 10 mg/L had a higher proportion of patients with reduced (< 1000 mL) TFR compared to the group with sCRP < 10 mg/(38% vs 16%, p = 0.04). Two-year patient survival rates from the time of the assessment were not different between the different transport groups (78% vs 73% for H/HA and L/LA, p = 0.99). Upon Cox proportional hazards multivariate analysis, age and high sCRP were independent predictors of mortality.

Conclusions

This study shows that, in a selected group of prevalent PD patients assessed after more than 6 months of PD therapy, ( 1 ) inflammation was an independent predictor for mortality; ( 2 ) reduced TFR was associated with impaired nutritional status, decreased small solute clearance, and inflammation; and ( 3 ) peritoneal transport status was not significantly associated with nutritional status and was not associated with subsequent patient survival. These results indicate that a high peritoneal solute transport rate, as such, should not be regarded as a relative contraindication for PD. Instead, the results suggest that more attention should be given to inflammation and inadequate fluid removal as predictors of mortality in PD patients.

The Time Course of Serum C-Reactive Protein is More Predictive of Mortality than its Baseline Level in Peritoneal Dialysis Patients

Background

Several recent studies reported that a high baseline serum C-reactive protein (CRP) is a powerful predictor of mortality in dialysis patients. However, the acute-phase response is intermittent and not a continuous feature in an individual patient. The aim of this prospective study was to determine whether serial analysis of serum CRP during follow-up allows better prediction of mortality and echocardiographic cardiac disease than a single baseline measurement in peritoneal dialysis (PD) patients.

Methods

97 PD patients were monitored for 3 years from the beginning of the treatment. We evaluated the effect of demographic features, comorbidity, blood pressure, blood biochemistry, including CRP, residual renal function, and indices of dialysis adequacy, on mortality and left ventricular hypertrophy (LVH). Cox regression analysis using both the baseline and the averaged values of the study parameters was carried out to determine factors predicting mortality. Logistic regression analysis was performed to determine which factors were independently predictive for LVH and the type of time course of serum CRP.

Results

Baseline serum CRP was elevated in 29 patients (29.9%). While serum CRP exhibited a stable course (normal or high) in 55 patients (56.7%), it varied considerably over time in 42 patients (43.2%). In the Cox models, both the averaged serum CRP and the type of variability of CRP were predictors of mortality. On the contrary, baseline CRP did not affect adjusted survival. The averaged CRP was also an independent factor affecting LVH, but baseline CRP was not. Age, comorbidity index, instilled dialysate glucose concentration, and Kt/V urea were independently associated with the type of time course of serum CRP.

Conclusion

The averaged value of serum CRP is more predictive of prognosis compared to the baseline value in PD patients. Determining serum CRP on a regular basis may be helpful to detect early signs of tissue damage or asymptomatic inflammation.

The Use of Nocturnal Home Hemodialysis as Salvage Therapy for Patients Experiencing Peritoneal Dialysis Failure

Background

Failure of peritoneal dialysis (PD) results in poor quality of life and worsening morbidity in patients with end-stage renal disease (ESRD). Traditionally, hospital-based conventional hemodialysis has been the only option for this patient population. We hypothesized that nocturnal home hemodialysis (NHD), 3 – 6 sessions per week, 6 – 8 hours per session, is a suitable alternative salvage therapy for this vulnerable patient group.

Methods

This is a descriptive cohort study of all consecutive ESRD patients failing PD that were converted to NHD at the University Health Network and Humber River Regional Hospital from 2003 to 2005. Our primary objective was to describe the changes in clinical and biochemical indices before and after conversion from PD to NHD.

Results

69 patients required transfer from PD to another form of renal replacement therapy during the period of interest. Our pilot cohort included 8 ESRD patients (5 males, 3 females; age 53 ± 7 years). Mean duration on PD was 4.8 ± 4.6 years. NHD delivered a higher dose of dialysis, as reflected by lower plasma creatinine concentration 1 year after beginning NHD (from 1107 ± 312 μmol/L with PD to 649 ± 309 μmol/L, p = 0.01) and a rise in standardized Kt/V (from 2.21 ± 0.73 with PD to 4.49 ± 1.92 after 6 months of NHD, to 4.51 ± 1.77 after 1 year of NHD; p < 0.001). There was a progressive and sustained rise in plasma albumin after conversion to NHD (from 31 ± 4 g/L with PD to 36 ± 4 g/L after 6 months of NHD, to 39 ± 2 g/L after 1 year of NHD; p = 0.001). Hemoglobin concentrations increased (from 102 ± 13 to 125 ± 7 g/L, p = 0.03), while erythropoietin requirement tended to fall (from 17500 ± 8669 to 9197 ± 7573 U/week). Plasma phosphate fell (from 2.1 ± 0.6 to 1.1 ± 0.3 mmol/L, p = 0.01) despite a decrease in phosphate binder requirement. Blood pressure profile also tended to improve after conversion to NHD.

Conclusion

Nocturnal HD represents a promising, viable, alternative renal replacement therapy for patients experiencing PD failure. The clinical impact of transferring ESRD patients failing PD to NHD deserves further investigation.

Inflammation in Peritoneal Dialysis: A Latin-American Perspective

Peritoneal dialysis (PD) patients present an extremely high mortality rate, but the mechanisms mediating the increased risk of mortality observed in this group of patients are still largely unknown, which limits the perspective of effective therapeutic strategies. The leading hypothesis that tries to explain this high mortality risk is that PD patients are exposed to a number of traditional risk factors for cardiovascular disease (CVD) already at the onset of their chronic kidney disease (CKD), since many of these risk factors are common to both CVD and CKD. Of particular importance, chronic inflammation recently emerged as an important novel risk factor related to multiple complications of CKD. There are many stimuli of the inflammatory response in CKD patients, such as fluid overload, decreased cytokine clearance, presence of uremia-modified proteins, presence of chronic infections, metabolic disturbances (including hyperglycemia), obesity. Many of these factors are related to PD. Latin America has made some progress in economic issues; however, a large portion of the population is still living in poverty, in poor sanitary conditions, and with many health-related issues, such as an increasing elderly population, low birth weights, and increasingly high energy intake in the adult population, which, in combination with changes in lifestyle, has provoked an increase in the prevalence of obesity, diabetes, and CVD. Therefore, in Latin America, there seems to be a peculiar situation combining high prevalence of low education level, poor sanitary conditions, and poverty with increases in obesity, diabetes, and sedentary lifestyle. Since inflammation and mortality risk are intimately related to both sides of those health issues, in this review we aim to analyze the peculiarities of inflammation and mortality risk in the Latin-American PD population.

Does inflammation affect outcomes in dialysis patients?

Chronic, low-grade inflammation is a common comorbid condition in chronic kidney disease (CKD), and particularly in chronic dialysis patients. In this review, we consider the question of whether inflammation affects outcomes in dialysis patients. Levels of proinflammatory cytokines, as well as C-reactive protein, are elevated in chronic dialysis patients. Multiple factors likely contribute to chronic inflammatory activation in kidney disease patients including the uremic milieu, lifestyle and epigenetic influences, infectious and thrombotic events, the dialysis process, and dysbiosis. Increased inflammatory markers in both CKD and chronic dialysis patients are associated with adverse clinical outcomes including all-cause mortality, cardiovascular events, kidney disease progression, protein energy wasting and diminished motor function, cognitive impairment, as well as other adverse consequences including CKD-mineral and bone disorder, anemia, and insulin resistance. Strategies that have been shown to reduce chronic systemic inflammation in CKD and chronic dialysis patients include both pharmacological and nonpharmacological interventions. However, despite evidence that systemic inflammatory markers can be lowered in kidney disease patients treated with various strategies, evidence that this improves clinical outcomes is largely unavailable and represents an important future research direction. Overall, there is strong observational evidence that inflammation is high in chronic dialysis patients and that this is independently associated with numerous adverse clinical outcomes. Targeting inflammation represents a potentially novel and attractive strategy if it can indeed improve adverse outcomes common in this population.

High-Sensitivity Troponin T and C-Reactive Protein Have Different Prognostic Values in Hemo- and Peritoneal Dialysis Populations: A Cohort Study

Background

Dialysis patients have an exceedingly high mortality rate. Biomarkers may be useful tools in risk stratification of this population. We evaluated the prognostic value of high‐sensitivity cardiac troponin T (hs‐cTnT) and CRP (C‐reactive protein) in predicting adverse outcomes in stable hemodialysis and peritoneal dialysis (PD) patients. Variability in hs‐cTnT was also examined.

Methods and Results

A retrospective cohort study included 574 dialysis patients (hemodialysis 347, PD 227). Outcomes examined included mortality and major adverse cardiovascular events, with median follow‐up of 3.5 years. hs‐cTnT was an independent predictor of both outcomes in hemodialysis and PD patients. Increased risk only became significant when hs‐cTnT reached quintile 3 (>49 ng/L). Area under the receiver operating curve analysis showed that the addition of hs‐cTnT to clinical parameters significantly improved its prognostic performance for mortality in PD patients (P=0.002). CRP was an independent predictor of both outcomes in PD patients only. Only CRP in the highest quintile (>16.8 mg/L) was associated with increased risk. hs‐cTnT remained relatively stable for the whole follow‐up period for hemodialysis patients, whereas for PD patients, hs‐cTnT increased by 23.63% in year 2 and 29.13% in year 3 compared with baseline (P<0.001).

Conclusions

hs‐cTnT and CRP are useful tools in predicting mortality and major adverse cardiovascular events in hemodialysis and PD patients. Given that hs‐cTnT levels increase over time in PD patients, interval monitoring may be valuable for risk assessment. In contrast, hs‐cTnT in hemodialysis patients has little interval change and progress monitoring is not indicated.

The 24-Month Changes in Body Fat Mass and Adipokines in Patients Starting Peritoneal Dialysis

♦ BACKGROUND: Peritoneal dialysis (PD) is characterized by a gain in fat mass. The fat tissue is a complex endocrine organ that releases various adipokines. In this study, we prospectively examined serial changes of fat composition and adipokines in patients undergoing PD. ♦ METHODS: Body composition was assessed by computed tomography (CT). Nutrition status and adipokines (leptin, adiponectin, interleukin [IL]-6, and tumor necrosis factor [TNF]-α) were assessed on the 7th day and 6 months, 12 months, and 24 months after the start of PD. ♦ RESULTS: Fifty-four patients (28 men), with a mean age of 53.2 ± 13.2 years, were enrolled. Baseline fat mass, especially subcutaneous fat mass, was correlated with baseline leptin (ρ = 0.612), adiponetin (ρ = -0.477), and interleukin-6 (IL-6) (ρ = 0.391). Visceral fat mass was correlated with leptin (ρ = 0.545) and adiponectin (ρ = -0.514). Baseline adiponectin was negatively correlated with baseline leptin (ρ = -0.363). While body weight and leptin increased during the 24 months, serum adiponectin decreased in that period. The changes in visceral and subcutaneous fat mass were greater in the first 12 months and 6 months, respectively. There was no difference in IL-6 and TNF-α. Eight patients died during the follow-up period (mean 47.4 months). Twenty-seven patients continued PD. Increased baseline and serial change of IL-6 level were risk factors for mortality. After adjusting for age, sex, diabetes mellitus (DM), and coronary vascular disease (CVD), the significance of the IL-6 level disappeared. ♦ CONCLUSIONS: Baseline subcutaneous fat in patients starting PD is correlated with baseline adipokine levels rather than visceral fat. The increase in subcutaneous fat was greatest in the first 6 months. While leptin and adiponectin increased and decreased respectively, IL-6 did not change in the first 24 months.

Low prealbumin levels are independently associated with higher mortality in patients on peritoneal dialysis

Background

Prealbumin, a sensitive marker for protein–energy status, is also known as an independent risk factor for mortality in hemodialysis patients. We investigated the impact of prealbumin on survival in incident peritoneal dialysis (PD) patients.

Methods

In total, 136 incident PD patients (mean age, 53.0 ± 15.8 years) between 2002 and 2007 were enrolled in the study. Laboratory data, dialysis adequacy, and nutritional parameters were assessed 3 months after PD initiation. Patients were classified into 2 groups according to prealbumin level: high prealbumin (≥ 40 mg/dL) and low prealbumin (< 40 mg/dL).

Results

The patients in the low-prealbumin group were older and had more comorbidities such as diabetes and cardiovascular diseases compared with the patients in the high-prealbumin group. Mean subjective global assessment scores were lower, and the high-sensitivity C-reactive protein levels were higher in the low-prealbumin group. Serum creatinine, albumin, and transferrin levels; percent lean body mass; and normalized protein catabolic rate were positively associated, whereas subjective global assessment scores and high-sensitivity C-reactive protein levels were negatively associated with prealbumin concentration. During the median follow-up of 49 months, patients in the lower prealbumin group had a higher mortality rate. Multivariate analysis revealed that prealbumin < 40 mg/dL (hazard ratio, 2.30; 95% confidence interval, 1.14–4.64) was an independent risk factor for mortality. In receiver operating characteristic curves, the area under the curve of prealbumin for mortality was the largest among the parameters.

Conclusion

Prealbumin levels were an independent and sensitive predictor for mortality in incident PD patients, showing a good correlation with nutritional and inflammatory markers.

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.

The usefulness of neutrophil CD64 expression for diagnosing infection after orthopaedic surgery in dialysis patients

BACKGROUND

Dialysis patients undergoing orthopaedic surgery are at high risk for postoperative infection. Diagnosis of postoperative infection is difficult in dialysis patients due to presentation of signs and symptoms similar to infection, such as fever and elevated inflammatory marker levels. Neutrophil CD64 expression (CD64), a marker of infection, is upregulated by microbial wall components and several cytokines (interferon-γ and tumor necrosis factor-α). The purpose of this study is to evaluate the usefulness of CD64 for diagnosing postoperative infection in dialysis patients post orthopaedic surgery.

PATIENTS AND METHODS

Between 2013 and 2014, we prospectively studied 36 dialysis patients (18 men, 18 women; mean age 65.9 years; 49 to 83) who underwent orthopaedic surgery. Dialysis patients were classified into three groups according to their postoperative course as follows; non-infected patients, infection suspected patients, and infected patients. Inflammatory markers such as white blood cell count (WBC), C-reactive protein (CRP) and CD64 were measured before operation and one week after surgery. Using the receiver-operating characteristic (ROC) curve and Akaike's Information Criterion (AIC), the cutoff value of CD64 and CRP was calculated leading to a determination of which inflammatory marker is best accurate for detecting postoperative infection.

RESULTS

We found that postoperative CD64 and CRP levels presented a statistically significant difference between infected patients and non-infected patients (p < 0.05). Furthermore, comparison of the ROC curve and AIC value between postoperative CD64 and CRP levels exhibited that CD64 was more accurate infectious marker than CRP.

CONCLUSION

CD64 is a useful marker for detecting postoperative infection after orthopaedic surgery in dialysis patients.

Evaluation of continuous ambulatory peritoneal dialysis fluid C-reactive protein in patients with peritonitis

Severe peritonitis causing death is one of the most devastating complications of peritoneal dialysis (PD). Since the predictive value of C-reactive protein (CRP) in PD fluid has not been assessed, the objective of the present study is to evaluate its predictive value and clinical correlation in patients on PD with peritonitis. One hundred and twenty patients on continuous ambulatory PD (CAPD) were enrolled and their serum and fluid CRP (Fl. CRP) were evaluated at the start of CAPD. All patients who developed peritonitis were further evaluated for serum and fluid CRP. The patients were categorized into four groups, namely: normal patients (control group), patients with peritonitis, patients with peritonitis leading to catheter removal, and death due to peritonitis. Sixty-five patients developed peritonitis of whom, catheter removal was performed in eight patients. Five patients died due to peritonitis-related complications. Fl. CRP showed a significant difference among the three groups, unlike S. CRP. Estimation of CRP in the peritoneal fluid may be a useful marker to monitor the onset of peritonitis.

Association of C-reactive protein, tumor necrosis factor-alpha, and interleukin-6 with chronic kidney disease

BACKGROUND

We studied the association of inflammatory biomarkers including C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) with chronic kidney disease (CKD).

METHODS

We conducted a case-control study among 201 CKD patients and 201 community-based controls in the greater New Orleans area. CKD was defined as estimated-glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) or albuminuria ≥30 mg/24-h. Serum CRP, TNF-α, and IL-6 were measured using standard methods. Multivariable regression models were used to examine associations between the inflammatory biomarkers and CKD adjusting for important CKD risk factors, history of cardiovascular disease, and use of antihypertensive, antidiabetic, and lipid-lowering agents and aspirin.

RESULTS

The multivariable-adjusted medians (interquartile-range) were 2.91 (1.47, 5.24) mg/L in patients with CKD vs. 1.91 (0.99, 3.79) mg/L in controls without CKD (p = 0.39 for group difference) for CRP; 1.86 (1.51, 2.63) pg/mL vs. 1.26 (1.01, 1.98) pg/mL (p < 0.0001) for TNF-α; and 2.53 (1.49, 4.42) pg/mL vs. 1.39 (0.95, 2.15) pg/mL (p = 0.04) for IL-6, respectively. Compared to the lowest tertile, the highest tertile of TNF-α (OR 7.1, 95% CI 3.2 to 15.5) and IL-6 (OR 2.5, 95% CI 1.1 to 5.5) were significantly associated with higher odds of CKD in multivariable-adjusted models. Additionally, higher TNF-α and IL-6 were independently and significantly associated with lower eGFR and higher albuminuria.

CONCLUSIONS

Our data suggest that TNF-α and IL-6, but not CRP, are associated with the prevalence and severity of CKD, independent from established CKD risk factors, history of cardiovascular disease, and use of antihypertensive, antidiabetic, and lipid-lowering agents and aspirin.

Environmental carbon monoxide level is associated with the level of high-sensitivity C-reactive protein in peritoneal dialysis patients

Inflammation is highly prevalent among peritoneal dialysis (PD) patients. High-sensitivity C-reactive protein (hs-CRP) is the most widely used inflammatory marker in clinical medicine and is correlated with mortality in PD patients. Air pollution is associated with systemic inflammation. The aim of this cross-sectional study was to assess the role of air pollutants and other clinical variables on hs-CRP values in PD patients.We recruited a total of 175 patients who had been undergoing continuous ambulatory PD or automated PD for at least 4 months and regularly followed up. Air pollution levels were recorded by a network of 27 monitoring stations near or in the patients' living areas throughout Taiwan. The 12-month average concentrations of particulate matter (PM) with an aerodynamic diameter of <10 and <2.5 μm (PM10 and PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3) were included.In stepwise linear regression, after adjustment for related factors, white blood cell count (β: 0.27, 95% confidence interval [CI] [0.71, 2.11]) and CO level (β: 0.17, 95% CI [2.5, 21.32]) were positively associated with hs-CRP and serum albumin levels (β: -0.25, 95% CI [-13.69, -3.96]) and normalized protein nitrogen appearance (β: -0.18, 95% CI [-17.7, -2.51]) was negatively associated with hs-CRP. However, serum indoxyl sulfate and p-cresyl sulfate levels were not significantly associated with hs-CRP (P > 0.05).In PD patients, the environmental CO level was positively correlated with hs-CRP level.

Peritoneal transport rate, systemic inflammation, and residual renal function determine peritoneal protein clearance in continuous ambulatory peritoneal dialysis patients

BACKGROUND

Peritoneal protein clearance (Pcl) is related to the mortality of patients on continuous ambulatory peritoneal dialysis (CAPD) as well as technique failure. In this prospective observational study, we aimed to investigate factors associated with the level of Pcl.

METHODS

We prospectively enrolled 344 prevalent CAPD patients. A standard peritoneal equilibrium test was conducted for each patient. Baseline demographics, biochemistry, and Pcl were recorded.

RESULTS

The average Pcl of the patients was 97.40 ± 54.14 mL/day. Peritoneal transport level, serum high-sensitivity C-reactive protein (hsCRP), and residual glomerular filtration rate (rGFR) were independently related to Pcl. The standard β values were 0.53, 0.17, and -0.10, respectively. Moreover, compared with non-diabetic patients, diabetic patients had a non-significantly higher level of Pcl (104.90 ± 48.65 vs. 96.15 ± 54.97 mL/day; P = 0.06).

CONCLUSION

Continuous ambulatory peritoneal dialysis patients lose a high amount of protein through the peritoneum each day. The Pcl value is positively related to the level of peritoneal transport and hsCRP and negatively related to the rGFR.

Delta-He: a novel marker of inflammation predicting mortality and ESA response in peritoneal dialysis patients

BACKGROUND

Inflammation impairs erythropoiesis, iron availability and is associated with a higher mortality risk in patients with end-stage renal disease. We studied the associations between Delta-He [the difference between the reticulocyte haemoglobin content (Ret-He) and erythrocyte haemoglobin content], a suggested marker of iron availability, and markers of inflammation, iron status, response to erythropoiesis-stimulating agents (ESAs) and mortality in prevalent peritoneal dialysis (PD) patients.

METHODS

Eighty-two PD patients were followed weekly for 12 weeks with an additional follow-up of 36 months. Delta-He, Ret-He and high-sensitivity C-reactive protein (hs-CRP) were measured weekly and interleukin-6 (IL-6) and iron markers every fourth week. Mortality risk was assessed by Cox proportional hazards model adjusting for potential confounding factors. The relationships between ESA response, inflammatory markers, iron markers and Delta-He were evaluated in the PD patients. The relationship between Delta-He and iron markers was analysed in 87 healthy subjects.

RESULTS

Delta-He correlated with IL-6 (rho = 0.48, P < 0.001), hs-CRP (rho = 0.36, P < 0.001) and ESA hyporesponsivess index (EHRI; rho = -0.44, P < 0.001) in the PD patients. Delta-He did not correlate with iron markers in PD patients nor in healthy subjects. The mean Delta-He levels were significantly different between the tertiles of EHRI (P < 0.01). Delta-He was associated with all-cause mortality risk in PD patients after adjusting for age, gender, hs-CRP, comorbidity and nutritional status [OR 0.70 (0.51-0.96), P < 0.05].

CONCLUSIONS

Delta-He independently predicts all-cause mortality in PD patients after adjusting for potential confounders and is a predictor of ESA response in PD 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.

rHuEPO hyporesponsiveness and related high dosages are associated with hyperviscosity in maintenance hemodialysis patients

Objective. Increased viscosity may increase the risk of thrombosis or thromboembolic events. Recombinant human erythropoietin (rHuEPO) is the key stone treatment in anemic ESRD patients with the thrombotic limiting side effect. We evaluated the influence of clinical and laboratory findings on plasma viscosity in MHD patients in the present study. Method. After applying exclusion criteria 84 eligible MHD patients were included (30 female, age: 54.7 ± 13.7 years). Results. Patients with high viscosity had longer MHD history, calcium × phosphorus product, and higher rHuEPO requirement (356.4 versus 204.2 U/kg/week, P: 0.006). rHuEPO hyporesponsiveness was also more common in hyperviscosity group. According to HD duration, no rHuEPO group had the longest and the low rHuEPO dosage group had the shortest duration. Despite similar Hb levels, 68% of patients in high rHuEPO dosage group; and 38.7% of patients in low rHuEPO dosage group had higher plasma viscosity (P: 0.001). Patients with hyperviscosity had higher rHuEPO/Hb levels (P: 0.021). Binary logistic regression analyses revealed that rHuEPO hyporesponsiveness was the major determinant of hyperviscosity. Conclusion. We suggest that the hyperviscous state of the hemodialysis patients may arise from the inflammatory situation of long term HD, the calcium-phosphorus mineral abnormalities, rHuEPO hyporesponsiveness, and related high dosage requirements.

Effect of statins on chronic inflammation and nutrition status in renal dialysis patients: a systematic review and meta-analysis

AIM

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) may have an adjunctive effect on chronic inflammation and nutrition status in renal dialysis patients. Therefore, we performed a systematic review of randomized controlled trials to assess the effect of statins on chronic inflammation and nutrition status in dialysis patients.

METHODS

The randomized controlled trials (RCTs) of statins versus placebo or no treatment for renal dialysis patients were searched from PubMed, EMbase and Cochran Central Register of Controlled Trials. We screened relevant studies according to predefined inclusion and exclusion criteria, evaluated the quality of the included studies, and performed meta-analyses by using the Cochrane Collaboration's Revman 5.1 software.

RESULTS

We identified nine trials including 3098 patients. Meta-analysis showed statins can significantly decrease the serum C-reactive protein (CRP) (SMD, -0.54; 95% confidence interval (CI), -1.04 to -0.05; P = 0.03) and high sensitivity CRP (hs-CRP) level (SMD, -0.72; 95% CI, -1.14 to -0.31; P = 0.0007) of dialysis patients compared with that of the control group. However, statins did not differ significantly from the control group in increasing the serum Alb level (SMD, -0.13; 95% CI, -0.42 to 0.15; P = 0.37).

CONCLUSIONS

Statins can improve the chronic inflammation status reflected by the decreasing of serum CRP and hs-CRP levels, whereas there is no conclusive evidence that it can improve the nutrition status. However, this result needs to be further confirmed in more high-quality randomized clinical trials.

Nutrition in patients on peritoneal dialysis

Protein-energy wasting (PEW) is prevalent among patients on dialysis and has emerged as an important risk factor for morbidity and mortality in these patients. Numerous factors, including inflammation, inadequate dialysis, insufficient nutrient intake, loss of protein during dialysis, chronic acidosis, hypercatabolic illness and comorbid conditions, are involved in the development of PEW. The causes and clinical features of PEW in patients on peritoneal dialysis and hemodialysis are comparable; assessment of the factors that lead to PEW in patients receiving peritoneal dialysis is important to ensure that PEW is managed correctly in these patients. For the past 20 years, much progress has been made in the prevention and treatment of PEW. However, the results of most nutritional intervention studies are inconclusive. In addition, the multifactorial and complicated pathogenesis of PEW makes it difficult to assess and treat. This Review summarizes the nutritional issues regarding the causes, assessment and treatment of PEW, with a focus on patients receiving peritoneal dialysis. In addition, an in-depth overview of the results of nutritional intervention studies is provided.

Serum resistin as a novel marker of erythropoietin resistance in nondiabetic patients on hemodialysis

The use of higher erythropoietin (EPO) doses is associated with an increased risk of an adverse outcome and increased mortality in patients with renal failure. Resistin is related to heart disease, and may contribute to an increased atherosclerotic risk. We hypothesized that a link between resistin and EPO responsiveness may exist. We therefore investigated the relationship between resistin and the EPO resistance index (ERI) in nondiabetic hemodialysis (HD) patients. Fifty-seven patients enrolled in the study underwent HD for ≥ 3 months and intravenous EPO therapy to maintain a target hemoglobin (Hb) level of 11.0 g/dl. The ERI was defined as the weekly EPO dose per unit Hb per body weight. The mean patient age was 52.6 ± 11.9 years and the mean time on dialysis was 4.9 ± 4.4 years. Serum Hb and ERI were 10.4 ± 0.7 g/dl, and 13.3 ± 7.0 (IU/kg/week/g/dl), respectively. Serum resistin levels were 23.6 ± 9.3 µg/L. EPO resistance is associated with low body mass index (BMI) (coefficient β =-0.393, p = 0.002) and with high serum resistin levels (coefficient β = 0.332, p = 0.018). According to a multiple regression analysis, the serum resistin level was a significant independent factor related to EPO resistance (p = 0.017). The results suggest that serum resistin levels reflect EPO responsiveness in nondiabetic HD patients. Resistin may therefore be considered as a new marker of EPO responsiveness in HD patients.

Low-grade endotoxemia contributes to chronic inflammation in hemodialysis patients: examination with a novel lipopolysaccharide detection method

Chronic inflammation has recently been proposed to play a major role in the development of cardiovascular disease and mortality among advanced chronic kidney disease (CKD) patients; however, why advanced CKD promotes chronic inflammation is still unclear. We hypothesized that a very low level of plasma endotoxin (lipopolysaccharide [LPS]) contributes to chronic inflammation in advanced CKD patients. We measured the plasma LPS levels using a novel LPS detection method (ESP method, a method for endotoxin detection using laser scattering photometry) concurrently with serum C-reactive protein (CRP) levels and various blood tests in 17 stable hemodialysis (HD) patients. As a result, the median LPS levels measured by the ESP method was 0.23 pg/mL (range, 0.01-3.89) (inflow, start of HD), 0.22 pg/mL (<0.01-9.97) (outflow, start of HD), 0.37 pg/mL (<0.01-7.42) (inflow, end of HD), and 1.07 pg/mL (<0.01-10.66) (dialysate), respectively; statistically significant differences were not detected between them. The predialysis median CRP level was 0.19 mg/dL (0.04-3.02). The logarithm of plasma LPS independently correlated with serum CRP (R = 0.595, P = 0.0103). In multiple (forward stepwise) regression analysis, in which CRP was determined to be the criterion variable, LPS (log), albumin, and the white blood cell count were adopted as independent explanatory variables (R = 0.401, -0.397 and 0.387, respectively). In conclusion, the present study revealed a significant relationship between LPS and CRP using the novel ESP method, and suggested that very low-grade endotoxemia is contributing to systemic inflammation in HD patients.

2009 Japanese Society for Dialysis Therapy guidelines for peritoneal dialysis

The guidelines for peritoneal dialysis (PD) of the Japanese Society for Dialysis Treatment were prepared at 2009. Upon presenting a concrete frame of PD practiced in Japan, it aims to promote PD as a standardized therapy in Japan. Notably, the guidelines recommended combination therapy of PD and hemodialysis as a part of integrated renal replacement therapy for end-stage renal disease, as well as timely PD withdrawal by peritoneal degeneration in order to prevent progression of encapsulating peritoneal sclerosis.

Proinflammatory cytokines, hepatocyte growth factor and adipokines in peritoneal dialysis patients

Chronic inflammation is a well-recognized complication in dialysis patients and a potential role of the adipose tissue as an important tissue of origin contributing to inflammation has been proposed. Stable peritoneal dialysis (PD) patients were enrolled to investigate the relationship between serum levels of proinflammatory cytokines and adipokines. Our results revealed that there was a strong association between high sensitivity C-reactive protein and interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-alpha) but not with IL-10 and IL-18. IL-6 correlated with TNF-alpha, IL-10, and IL-18. No association was found between IL-10 and IL-18. Adiponectin was positively correlated with all proinflammatory cytokines, except IL-10. No significant association was found between resistin and proinflammatory cytokines. Hepatocyte growth factor (HGF) was directly related to proinflammatory cytokines but not with adipokines. The presence of residual kidney function (RKF) affected IL-6, TNF-alpha, and HGF levels. The peritoneal transport property did not influence inflammatory cytokine and adipokine levels. In conclusion, there was a close relationship between proinflammatory cytokines and adipokines. HGF correlated with proinflammatory cytokines but not with adipokines. The PD-related factors such as RKF, peritoneal property and dialysis glucose load affected levels of proinflammatory cytokines. Body mass index was an important determinant of leptin and adiponectin in PD patients.

Changes in body fat mass in patients after starting peritoneal dialysis

BACKGROUND

Peritoneal dialysis (PD) is characterized by gain in fat mass. Visceral fat mass is associated with metabolic syndrome and atherosclerosis rather than subcutaneous fat mass. In addition, the change in visceral fat mass is a more reliable predictor of survival in PD patients. In this study, we prospectively examined serial changes in fat composition and nutritional status and analyzed factors associated with gain in fat mass in patients undergoing PD.

METHODS

Body composition was assessed by bioelectric impedance analysis (BIA) and computed tomogram (CT). Nutrition status was assessed by Subjective Global Assessment (SGA), protein equivalent of nitrogen appearance (nPNA), serum albumin, C-reactive protein (CRP), and lipid profile. All measurements except BIA were performed on the seventh day and at 6 and 12 months after the start of PD.

RESULTS

60 patients (30 men; mean age 55.0 ± 12.5 years) were enrolled. Increase in body weight continued during the 12 months but visceral and subcutaneous fat mass increased during the first 6 months and decreased during the second 6 months. While hematocrit and serum albumin decreased during the first 6 months, they did not change during the second 6 months. Serum creatinine, total cholesterol, and triglyceride increased similarly to the weight pattern. While nPNA decreased during the 12 months, Kt/V, SGA, and CRP did not change. Patients that had more visceral fat mass at the start of PD had less gain of visceral fat mass during the first 6 months (r = -0.821, p = 0.002). Patients that had more subcutaneous fat mass at the start of PD had less gain of subcutaneous fat mass (r = -0.709, p = 0.015). The change in weight was not associated with the change in visceral or subcutaneous fat during the first 6 months.

CONCLUSION

Patients starting PD experience weight gain, including visceral and subcutaneous fat, during the first 6 months of PD. Patients with high baseline fat mass had less increase in fat mass than those with low baseline fat mass, regardless of visceral or subcutaneous fat mass.

Short-term effect of simvastatin treatment on inflammatory parameters in peritoneal dialysis patients

OBJECTIVE

Increased serum pro-inflammatory cytokine levels are associated with an increased mortality rate in end-stage renal disease (ESRD) patients. Statins decrease cardiovascular mortality and serum C-reactive protein (CRP) levels in hemodialysis patients. As the anti-inflammatory effect of statins has not previously been studied in peritoneal dialysis (PD) patients with a non-inflammatory status, we wanted to investigate the anti-inflammatory effect of simvastatin in these patients.

MATERIAL AND METHODS

Forty-eight PD patients were randomly allocated to either simvastatin treatment (n=25) or placebo (n=23). Patients in the active-treatment group received simvastatin 20 mg/day for 1 month. At baseline and after 1 month of treatment, blood samples were drawn and high-sensitivity CRP, interleukin-6, tumor necrosis factor (TNF)-alpha and plasma lipid profiles were determined. These parameters were compared between the groups at baseline and at the end of the study period.

RESULTS

Twenty-five subjects in the treatment group and 20 in the placebo group completed the study. Three patients in the placebo group were excluded from the study due to the occurrence of bacterial peritonitis during the study period. Clinical characteristics and baseline parameters were similar in both groups. Serum total and low-density lipoprotein cholesterol levels, and triglyceride and serum TNF-alpha levels decreased significantly compared to baseline in the treatment group; there were no corresponding differences in the placebo group.

CONCLUSIONS

Simvastatin decreased the serum TNF-alpha level in PD patients with a non-inflammatory status. A decrease in the TNF-alpha level could be one of the possible mechanisms of the anti-atherogeneic effect of simvastatin. We suggest that different treatment strategies aimed at decreasing serum cytokine levels could be evaluated to decrease cardiovascular morbidity and mortality in the dialysis population.

Early Prognostic Factors in Patients with Acute Renal Failure Requiring Dialysis

PURPOSE

Despite improvements in renal therapy and technology, the mortality rate of patients with acute renal failure (ARF) remains high. Because ARF is a heterogeneous syndrome, occurring in patients with diverse etiologies and comorbid conditions, predicting its outcome is difficult. This study aims to identify early clinical and laboratory prognostic factors, including acute-phase reactants such as C-reactive protein (CRP), fibrinogen, and albumin, in ARF patients requiring dialysis.

MATERIAL AND METHODS

From June 2002 to March 2004, 61 patients with ARF requiring dialysis at Chang Gung Memorial Hospital, Chiayi, were prospectively analyzed. For each patient, the worst values of prognostic variables 24 hr before starting dialysis were prospectively assessed.

RESULTS

Oliguria, low plasma fibrinogen levels, hypotension, cardiac disease, and neoplastic disease were statistically significant in predicting hospital mortality. Using Youden's index, the best cut-off value for plasma fibrinogen in predicting mortality was 300 mg/dL with a sensitivity and specificity of 61% and 96%, respectively. Serum CRP and serum albumin were not predictive of hospital mortality.

CONCLUSION

Early prognostic factors in predicting mortality for patients with ARF requiring dialysis identified by multivariate logistic regression were oliguria, low plasma fibrinogen, hypotension, cardiac disease, and neoplastic disease. Serum CRP and albumin were not predictive of hospital mortality, whereas a plasma fibrinogen level < or =300 mg/dL had 61% sensitivity and 96% specificity in predicting mortality.

Malnutrition–Inflammation–Atherosclerosis (MIA) Syndrome Components in Hemodialysis and Peritoneal Dialysis Patients

BACKGROUND

Malnutrition, inflammation, and atherosclerosis (MIA syndrome) are common in end-stage renal disease (ESRD) patients. Each component of MIA syndrome is the predictor of outcomes in ESRD patients. In this cross-sectional study, we aimed to compare both dialysis modalities for MIA syndrome components.

MATERIAL AND METHODS

Thirty hemodialysis (HD) (mean age 44 +/- 11 years, 14 male and 16 female, mean time on dialysis: 31.0 +/- 19.0 months) and 30 continuous ambulatory peritoneal dialysis (CAPD) patients (41 +/- 9 years, 12 male and 18 female, mean time on dialysis: 25.5 +/- 21.5 months) were included. In order to determine malnutrition in ESRD patients, serum albumin level and anthropometric measurements were used. For inflammation, serum C-reactive protein level, erythrocyte sedimentation rate, and fibrinogen levels were measured. Mean-carotid artery intima media thickness (m-CIMT), presence of carotid plaque and serum homocysteine level were used to determine atherosclerosis.

RESULTS

Five CAPD patients (16%) and one HD patient (3%) was hypoalbuminemic. HD and CAPD groups were similar for inflammation. Mean-CIMT and serum homocysteine level were higher in HD patients than CAPD patients. There was a positive correlation between homocysteine and m-CIMT.

CONCLUSION

Before choosing renal replacement therapy, malnutrition, inflammation, and atherosclerosis parameters must be investigated in ESRD patients. Hemodialysis seems to be more advantageous for malnutrition components than CAPD. Both dialysis modalities seem to be similar for inflammation, and CAPD modality has superiority for atherosclerosis. Before choosing the type of renal replacement therapy, assessment of MIA syndrome components could be useful for individualization of the decision on which dialytic modality is appropriate in ESRD patients.