Nutritional evaluation of patients receiving dialysis for the management of protein-energy wasting: what is old and what is new?

Advances in the nutritional support of hospitalized patients in the early 1970s led to the recognition that tools were needed to evaluate the nutritional status of patients. The observation that malnutrition in patients receiving dialysis was associated with increased morbidity and mortality prompted many expert groups to develop nutritional scoring systems to be applied in these patients. Given the diverse and confusing terminologies that emerged from these publications, the International Society of Renal Nutritional and Metabolism convened an expert panel to recommend a new nomenclature and preferred methods to evaluate the nutritional status of patients with chronic kidney disease (CKD). The new and inclusive term protein-energy wasting (PEW) refers to a systematically defined condition based on certain criteria and reflects malnutrition and wasting caused not only by inadequate nutrient intake but also by depletion resulting from the inflammatory and noninflammatory conditions that prevail in this population. Serial assessment of nutritional status for detection and management of PEW is recommended using old and new scoring tools, including the Subjective Global Assessment (SGA), malnutrition inflammation score (MIS), Geriatric Nutritional Risk Index (GNRI), and PEW definition criteria. These tools, which are reliable methods and predictors of outcomes, are reviewed in this article.

Similar outcomes of catheters implanted by nephrologists and surgeons: analysis of the Brazilian peritoneal dialysis multicentric study.

A good catheter implantation technique is important to allow for effective peritoneal access function and long-term technique survival. Studies regarding results obtained by nephrologists in comparison with surgeons have been limited to small single-center experiences. Thus, the objective of this study was to explore the impact of the peritoneal dialysis (PD) catheter insertion operator on early catheter complications and on technique survival in a large national multicentric cohort study (Brazilian Peritoneal Dialysis Multicentric Study, BRAZPD). Adult incident patients recruited in the BRAZPD from December 2004 to October 2007 having undergone first PD catheter implantation were included in the analysis. Mechanical and infectious early complication rates were defined as time to the first event occurring up to 3 months after catheter insertion and adjusted for comorbidities. Valid data of 736 patients (mean age of 59 ± 16 years old, 52% women, 61% white) were analyzed. Mechanical (HR 0.99 [CI 0.56-1.76]; p = 0.98) and infectious (HR 0.63 [CI 0.32-1.23]; p = 0.17) early complication rates were similar between groups. Long-term catheter survival was also similar between groups. Early complications rates and catheter survival were similar between groups defined by operator profile (nephrologist or surgeon), supporting the role of interventional nephrology in the placement of PD catheters.

Safety and efficacy of arteriovenous fistula angioplasties performed by nephrologists: report from a Brazilian interventional nephrology center.

INTRODUCTION: Arteriovenous fistulas (AVF) are the first choice vascular access for hemodialysis. However, they present a high incidence of venous stenosis leading to thrombosis. Although training in interventional nephrology may improve accessibility for treatment of venous stenosis, there is limited data on the safety and efficacy of this approach performed by trained nephrologists in low-income and developing countries. METHODS: This study presents the retrospective results of AVF angioplasties performed by trained nephrologists in a Brazilian outpatient interventional nephrology center. The primary outcome was technical success rate (completion of the procedure with angioplasty of all stenoses) and secondary outcomes were complication rates and overall AVF patency. FINDINGS: Two hundred fifty-six angioplasties were performed in 160 AVF. The technical success rate was 88.77% and the main cause of technical failure was venous occlusion (10%). The incidence of complications was 13.67%, with only one patient needing hospitalization and four accesses lost due to the presence of hematomas and/or thrombosis. Grade 1 hematomas were the most frequent complication (8.2%). The overall patency found was 88.2 and 80.9% at 180 and 360 days after the procedure, respectively. CONCLUSION: Our findings suggest that AVF angioplasty performed by trained nephrologists has acceptable success rates and patency, with a low incidence of major complications as well as a low need for hospitalization.

Effects of hemodialysis on the cardiovascular system: quantitative analysis using wave intensity wall analysis and tissue velocity imaging.

Cardiovascular disease is the leading cause of death in patients with end-stage renal disease (ESRD). The aim of this study was to investigate the changes in cardiovascular function induced by a single session of hemodialysis (HD) by the analysis of cardiovascular dynamics using wave intensity wall analysis (WIWA) and of systolic and diastolic myocardial function using tissue velocity imaging (TVI). Gray-scale cine loops of the left common carotid artery, conventional echocardiography, and TVI images of the left ventricle were acquired before and after HD in 45 patients (17 women, mean age 54 years) with ESRD. The WIWA indexes, W(1) and preload-adjusted W(1), W(2) and preload-adjusted W(2), and the TVI variables, isovolumic contraction velocity (IVCV), isovolumic contraction time (IVCT), peak systolic velocity (PSV), displacement, isovolumic relaxation velocity (IVRV), isovolumic relaxation time (IVRT), peak early diastolic velocity (E'), and peak late diastolic velocity (A'), were compared before and after HD. The WIWA measurements showed significant increases in W(1) (P < 0.05) and preload-adjusted W(1) (P < 0.01) after HD. W(2) was significantly decreased (P < 0.05) after HD, whereas the change in preload-adjusted W(2) was not significant. Systolic velocities, IVCV (P < 0.001) and PSV (P < 0.01), were increased after HD, whereas the AV-plane displacement was decreased (P < 0.01). For the measured diastolic variables, E' was significantly decreased (P < 0.01) and IVRT was significantly prolonged (P < 0.05), after HD. A few correlations were found between WIWA and TVI variables. The WIWA and TVI measurements indicate that a single session of HD improves systolic function. The load dependency of the diastolic variables seems to be more pronounced than for the systolic variables. Preload-adjusted wave intensity indexes may contribute in the assessment of true LV contractility and relaxation.

Association between malnutrition, integrin expression and impaired granulocyte adhesion in chronically hemodialyzed patients.

BACKGROUND: The relationship between malnutrition in hemodialysis (HD) patients with a chronic inflammatory condition and the expression levels of leukocyte integrins and their adhesiveness to fibronectin was investigated. METHODS: Subjective global assessment, albumin and body mass index were used as nutritional markers to group malnourished (MP) and eutrophic (EP) patients. C-reactive protein was used as an inflammation marker. LFA-1, VLA-4 and VLA-5 expression levels on circulating leukocytes before and after HD were flow cytometrically measured; and their adhesiveness, through immobilized fibronectin. RESULTS: MPs showed significantly higher VLA-5 expression on granulocytes, when compared with healthy individuals (HPs) as controls (13.7% +/- 2.3% vs. 5.0% +/- 1.1%; p=0.005), particularly after HD (25.8% +/- 4.1%; p<0.001). They also presented a significantly lower ability to adhere to fibronectin when compared with EPs, before HD (48.8% +/- 1.5% vs. 62.3% +/- 0.7%; p<0.001) and after HD (50.6% +/- 1.2% vs. 65.7% +/- 1.4%; p<0.0001). Increased numbers of circulating immature neutrophils were observed only in MPs. CONCLUSIONS: Although presenting higher VLA-5 expression, malnutrition in HD patients is associated with impairment of the adhesive capacity of circulating leukocytes, particularly younger neutrophils, which may contribute to the chronic inflammatory status of these patients.

Immune mechanisms involved in cardiovascular complications of chronic kidney disease.

A sustained status of chronic inflammation is closely linked to several complications of chronic kidney disease (CKD), such as vascular degeneration, myocardial fibrosis, loss of appetite, insulin resistance, increased muscle catabolism and anemia. These consequences of a chronically activated immune system impact on the acceleration of atherosclerosis, vascular calcification and development of heart dysfunction. Recent evidence suggests that these immune-mediated consequences of uremic toxicity are not only important to stratify the risk and understand the mechanisms of disease, but also represent an important area for intervention. Thus, the aim of this brief review is to discuss the immune mechanisms behind atherosclerosis and myocardiopathy in CKD. We also display the emerging evidence that strategies focusing on modulating the immune response or reducing the generation of triggers of inflammation may represent an important tool to reduce mortality in this group of patients. Ongoing studies may generate the evidence that will translate these strategies to definitive changes in clinical practice.

Peritoneal dialysis in Brazil: twenty-five years of experience in a single center.

OBJECTIVES: To evaluate patient and technique survival and to provide an analysis of peritoneal dialysis (PD)-related peritonitis in 25 years of experience in a single center. STUDY DESIGN: Retrospective study of incident patients on PD from July 1980 to July 2005. SETTING: Single, university based, Brazilian dialysis program. PATIENTS: 680 patients were analyzed in our study from July 1980 to July 2005, with a cumulative experience of 15 303 patient-months. All patients over 15 years of age entering the dialysis program were included in the study. Patients with less than 30 days of follow-up were excluded. Biochemical and demographic variables, peritonitis episodes, and patient and technique survival were analyzed. RESULTS: Mean age at start of PD was 53 +/- 16 years; diabetic nephropathy was the main cause of chronic kidney disease. Cardiovascular disease was the main cause of death (44%); peritonitis was responsible for 16% of fatal events. The predictors of death in our study were diabetes [relative risk (RR) 1.23, p < 0.01], advanced age (RR 1.58, p < 0.001), low serum albumin level (RR 1.25, p < 0.01), and low serum phosphate level (RR 1.39, p < 0.001) upon starting PD. There were 1048 cases of peritonitis over the 25-year period, with a significant reduction in incidence after the introduction of the double-bag system. The number of incident PD patients originating from hemodialysis increased threefold over the observation period (p < 0.001), with a similar increase in comorbidities over time. CONCLUSION: In the largest single-center report of PD experience in Latin America, we describe the overall rate and trends over time of peritonitis as well as patient and technique survival, which are similar to previous reports. Significant changes in peritonitis rates and causative organisms as well as a significant time-dependent increase in high-risk patients starting PD were observed.

APOL1-Associated Kidney Disease in Brazil.

INTRODUCTION: Coding variants in apolipoprotein L-1 (APOL1) are associated with an increased risk of end-stage kidney disease (ESRD) in African American individuals under a recessive model of inheritance. The effect of the APOL1 risk alleles on kidney disease has been observed in studies in African American and African populations. Despite the 130 million individuals of recent African ancestry in South America, the impact of APOL1 has not been explored. METHODS: In this case-control study, we tested APOL1 genotype in 106 Brazilian HD (hemodialysis) patients with African ancestry and compared risk allele frequency with 106 healthy first-degree relatives. The association of risk alleles and ESRD was calculated with a linear mixed model and was adjusted for relatedness and additional confounders. In a broader survey, the age of dialysis initiation and APOL1 variants were analyzed in 274 HD patients. RESULTS: Two APOL1 risk alleles were 10 times more common in patients with ESRD than in controls (9.4% vs. 0.9%; odds ratio [OR]: 10.95, SE = 1.49, P = 0.0017). Carriers of 2 risk alleles initiated dialysis 12 years earlier than patients with zero risk alleles. CONCLUSION: The APOL1 risk variants were less frequent in dialysis patients of African ancestry in Brazil than in the United States. Nonetheless, carriers of 2 risk variants had 10-fold higher odds of ESRD. Age of dialysis initiation was markedly lower in 2-risk allele carriers, suggesting a more aggressive disease phenotype. The Brazilian population represents an opportunity to identify different sets of genetic modifiers or environmental triggers that might be present in more extensively studied populations.

Reimbursement and economic factors influencing dialysis modality choice around the world.

The worldwide incidence of kidney failure is on the rise and treatment is costly; thus, the global burden of illness is growing. Kidney failure patients require either a kidney transplant or dialysis to maintain life. This review focuses on the economics of dialysis. Alternative dialysis modalities are haemodialysis (HD) and peritoneal dialysis (PD). Important economic factors influencing dialysis modality selection include financing, reimbursement and resource availability. In general, where there is little or no facility or physician reimbursement or payment for PD, the share of PD is very low. Regarding resource availability, when centre HD capacity is high, there is an incentive to use that capacity rather than place patients on home dialysis. In certain countries, there is interest in revising the reimbursement structure to favour home-based therapies, including PD and home HD. Modality selection is influenced by employment status, with an association between being employed and PD as the modality choice. Cost drivers differ for PD and HD. PD is driven mainly by variable costs such as solutions and tubing, while HD is driven mainly by fixed costs of facility space and staff. Many cost comparisons of dialysis modalities have been conducted. A key factor to consider in reviewing cost comparisons is the perspective of the analysis because different costs are relevant for different perspectives. In developed countries, HD is generally more expensive than PD to the payer. Additional research is needed in the developing world before conclusive statements may be made regarding the relative costs of HD and PD.

Interleukin-6 is a better predictor of mortality as compared to C-reactive protein, homocysteine, pentosidine and advanced oxidation protein products in hemodialysis patients.

Inflammatory markers predict mortality in hemodialysis (HD) patients, whereas a possible association between oxidative stress (OS) markers and survival is less clear. We assessed the impact on all-cause mortality of baseline inflammatory [high-sensitivity C-reactive protein and interleukin-6 (IL-6)] and OS markers (advanced oxidation protein products, pentosidine, homocysteine) in 112 HD patients. We found no significant correlations between inflammatory and OS markers. During the 5.5 years of follow-up, 51 patients died. In a Kaplan-Meier analysis, the survival rate was reduced in patients with IL-6 higher than the median (IL-6 >4.2 pg/ml) (log- rank = 6.47; p = 0.01), in diabetics (log-rank = 12.26; p = 0.0005) and in older patients (log-rank = 11.22; p = 0.0008). Moreover, in Cox analysis only IL-6 and age were independently associated with mortality. We conclude that in this group of prevalent Brazilian HD patients, IL-6 was a better predictor of survival than other inflammatory and OS markers.

International Society of Nephrology's 0by25 initiative (zero preventable deaths from acute kidney injury by 2025): focus on diagnosis of acute kidney injury in low-income countries.

In developing countries with limited medical infrastructure, preservation and recovery of renal function following acute kidney injury (AKI) is difficult. In conjunction with clinical presentation, rapid measurement of renal function is essential for early diagnosis and management. Especially in low- and middle-income countries, simple interventions such as hydration and avoidance of toxins have the highest probability of recovery. In such contexts, measurement of urine volume and osmolality and serum creatinine with point-of-care devices and saliva urea nitrogen dipsticks can be valuable. This review aims to identify currently available methodologies to assist in reaching the ambitious goal of the 0by25 initiative to eliminate all preventable deaths from AKI by 2025.

Associations between the CYBA 242C/T and the MPO -463G/A polymorphisms, oxidative stress and cardiovascular disease in chronic kidney disease patients.

Genetic variations in the NADPH/MPO system in chronic kidney disease (CKD) patients might lead to altered activity of these enzymes, and thus to altered risk for oxidative stress (OS) and cardiovascular disease (CVD). We evaluated the impact of 242C/T CYBA and -463G/A MPO polymorphisms on OS and CVD mortality in stage 5 CKD patients starting dialysis. Two hundred and fifty-seven patients were genotyped using Pyrosequencing. Plasmalogen [dimethylacetal (DMA) 16/C16:0] was used as OS marker. CVD was assessed from patient history and clinical symptoms. Prevalence of CVD was higher (35%) in GG patients (MPO) compared to AG (26%) and AA (0%) patients (p < 0.01). Patients with CC genotype (CYBA) had lower levels of DMA 16/C16:0 (ratio 0.071 +/- 0.003) compared to TT patients (0.089 +/- 0.006; p < 0.05). These patients also had increased CVD mortality compared to CT and TT patients (chi(2) 2.19; p < 0.05). We conclude that genetic variations in the NADPH/MPO system are associated with OS, presence of CVD and CVD-related mortality in CKD patients.

History of peritoneal dialysis in Latin America.

Latin America is a region formed by a number of countries of Latin heritage in which the common languages spoken are Spanish and Portuguese. Latin America was not isolated from the evolution of peritoneal dialysis (PD) throughout the rest of the world, as evidenced by the fact that, between the 1940s and the 1960s, PD was used to treat acute renal failure patients and later for the intermittent treatment of end-stage renal failure patients. The true development of PD took place toward the end of the 1970s and beginning of the 1980s with the introduction of continuous ambulatory peritoneal dialysis (CAPD). It is evident that the introduction of CAPD in most countries was a result of the personal effort and interest of individuals or groups of nephrologists. Initially, PD was not always implemented under ideal circumstances; locally manufactured, improvised supplies were associated with poor results. The arrival of companies with appropriate equipment and supplies led to widespread dissemination of this new modality. Furthermore, regulations and reimbursement by health authorities were additional obstacles. It is clear that PD in Latin America is still largely utilized to treat acute renal failure patients, particularly in countries where hemodialysis is not readily available. It is still employed intermittently to manage end-stage renal failure patients when hemodialysis is not available. With the exception of Colombia and Mexico, CAPD penetration is below 10%. While CAPD is nonexistent in certain countries, such as Cuba, due to lack of supplies, in other countries, such as Chile, it is restricted to patients that cannot be placed or continued on hemodialysis, those for example who lack vascular access, or those from remote rural areas. In addition, automated PD is relatively more costly and is therefore restricted in some countries.

Safety and efficacy of arteriovenous fistula angioplasties performed by nephrologists: report from a Brazilian interventional nephrology center / Segurança e eficácia de angioplastias de fístulas arteriovenosas realizadas por nefrologistas: relato de um centro de nefrologia intervencionista brasileiro

ABSTRACT Introduction: Arteriovenous fistulas (AVF) are the first choice vascular access for hemodialysis. However, they present a high incidence of venous stenosis leading to thrombosis. Although training in interventional nephrology may improve accessibility for treatment of venous stenosis, there is limited data on the safety and efficacy of this approach performed by trained nephrologists in low-income and developing countries. Methods: This study presents the retrospective results of AVF angioplasties performed by trained nephrologists in a Brazilian outpatient interventional nephrology center. The primary outcome was technical success rate (completion of the procedure with angioplasty of all stenoses) and secondary outcomes were complication rates and overall AVF patency. Findings: Two hundred fifty-six angioplasties were performed in 160 AVF. The technical success rate was 88.77% and the main cause of technical failure was venous occlusion (10%). The incidence of complications was 13.67%, with only one patient needing hospitalization and four accesses lost due to the presence of hematomas and/or thrombosis. Grade 1 hematomas were the most frequent complication (8.2%). The overall patency found was 88.2 and 80.9% at 180 and 360 days after the procedure, respectively. Conclusion: Our findings suggest that AVF angioplasty performed by trained nephrologists has acceptable success rates and patency, with a low incidence of major complications as well as a low need for hospitalization.

RESUMO Introdução: As fístulas arteriovenosas (FAV) são a primeira escolha de acesso vascular para hemodiálise. No entanto, elas apresentam uma alta incidência de estenoses venosas levando à trombose. Embora o treinamento em nefrologia intervencionista possa melhorar a acessibilidade para o tratamento das estenoses venosas, há dados limitados sobre a segurança e a eficácia desta abordagem realizada por nefrologistas treinados em países em desenvolvimento e de baixa renda. Métodos: Este estudo apresenta os resultados retrospectivos de angioplastias de FAV realizadas por nefrologistas treinados em um centro ambulatorial brasileiro de nefrologia intervencionista. O desfecho primário foi a taxa de sucesso técnico (conclusão do procedimento com angioplastia de todas as estenoses) e os desfechos secundários foram taxas de complicação e a patência geral das FAV. Achados: Duzentas e cinquenta e seis angioplastias foram realizadas em 160 FAV. A taxa de sucesso técnico foi de 88,77% e a principal causa de falha técnica foi a oclusão venosa (10%). A incidência de complicações foi de 13,67%, com apenas um paciente necessitando de internação e quatro acessos perdidos devido à presença de hematomas e/ou trombose. Hematomas de grau 1 foram a complicação mais frequente (8,2%). A patência geral encontrada foi de 88,2 e 80,9% a 180 e 360 dias após o procedimento, respectivamente. Conclusão: Nossos achados sugerem que a angioplastia de FAV realizada por nefrologistas treinados tem taxas de sucesso e patência aceitáveis, com uma baixa incidência de complicações maiores, bem como uma baixa necessidade de hospitalização.