Inflammation and Overweight in Peritoneal Dialysis: Is There an Association?

Evolving Concepts on Inflammatory Biomarkers and Malnutrition in Chronic Kidney Disease

While patient care, kidney replacement therapy, and transplantation techniques for chronic kidney disease (CKD) have continued to progress, the incidence of malnutrition disorders in CKD appears to have remained unchanged over time. However, there is now a better understanding of the underlying pathophysiology according to the disease background, disease stage, and the treatment received. In CKD patients, the increased production of proinflammatory cytokines and oxidative stress lead to a proinflammatory milieu that is at least partially responsible for the increased morbidity and mortality in this patient population. New insights into the pathogenic role of innate immunity and the proinflammatory cytokine profile, characterized, for instance, by higher levels of IL-6 and TNF-α, explain some of the clinical and laboratory abnormalities observed in these patients. In this article, we will explore currently available nutritional-inflammatory biomarkers in distinct CKD populations (hemodialysis, peritoneal dialysis, transplantation) with a view to evaluating their efficacy as predictors of malnutrition and their involvement in the common proinflammatory process. Although there is a direct relationship between inflammatory-nutritional status, signs and symptoms [e.g., protein-energy wasting (PEW), anorexia], and comorbidities (e.g., atheromatosis, atherosclerosis), we are in need of clearly standardized markers for nutritional-inflammatory assessment to improve their performance and design appropriate bidirectional interventions.

KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for nutrition in kidney diseases since 1999. Since the publication of the first KDOQI nutrition guideline, there has been a great accumulation of new evidence regarding the management of nutritional aspects of kidney disease and sophistication in the guidelines process. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD was developed as a joint effort with the Academy of Nutrition and Dietetics (Academy). It provides comprehensive up-to-date information on the understanding and care of patients with chronic kidney disease (CKD), especially in terms of their metabolic and nutritional milieu for the practicing clinician and allied health care workers. The guideline was expanded to include not only patients with end-stage kidney disease or advanced CKD, but also patients with stages 1-5 CKD who are not receiving dialysis and patients with a functional kidney transplant. The updated guideline statements focus on 6 primary areas: nutritional assessment, medical nutrition therapy (MNT), dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines primarily cover dietary management rather than all possible nutritional interventions. The evidence data and guideline statements were evaluated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Ischemia-modified albumin, a predictive marker of major adverse cardiovascular events in continuous ambulatory peritoneal dialysis patients

OBJECTIVES

The aim of this study was to evaluate the efficiency of ischemia-modified albumin (IMA) for predicting major adverse cardiovascular events (MACE) in continuous ambulatory peritoneal dialysis (CAPD) patients.

DESIGN AND METHODS

A prospective observational study was conducted with 120 CAPD patients and 37 healthy volunteers. Demographic and clinical data were collected. The primary end point is the occurrence of MACE.

RESULTS

A total of 157 participants with a mean age of 43.64 years finally completed this study. The CAPD patients had a significantly high rate of MACE (P=0.001) and high levels of IMA than healthy controls (P<0.001). Compared with CAPD patients with normal levels of IMA, the CAPD patients with high levels of IMA (>85 kU/L) had lower non-MACE survival rate (P<0.001), which indicated that the high IMA CAPD patients may suffer a high rate of MACE. In addition, the high IMA CAPD patients also had a low level of serum albumin (P<0.001) and hemoglobin (P=0.018). The correlation analysis showed that the serum albumin level was the most effective factor influencing IMA (B=-0.967, P<0.001).

CONCLUSIONS

CAPD patients with high levels of IMA had a high incidence rate of MACE. IMA was a good predictive marker of MACE and might be important in cardiovascular risk stratification of CAPD patients.

Body size and longitudinal body weight changes do not increase mortality in incident peritoneal dialysis patients of the Brazilian peritoneal dialysis multicenter study

OBJECTIVES

To determine the roles of body size and longitudinal body weight changes in the survival of incident peritoneal dialysis patients.

PATIENTS AND METHODS

Patients (n = 1911) older than 18 years of age recruited from 114 dialysis centers (Dec/ 2004-Oct/2007) and participating in the Brazilian Peritoneal Dialysis Multicenter Cohort Study were included. Clinical and laboratory data were collected monthly (except if the patient received a transplant, recovered renal function, was transferred to hemodialysis, or died).

RESULTS

Survival analyses were performed using Kaplan-Meier survival curves and Cox proportional hazards. Total follow-up was 34 months. The mean age was 59 years (54% female). The weight category percentages were as follows: underweight: 8%; normal: 51%; overweight: 29%; and obese 12%. The multivariate model showed a higher risk of death for a body mass index <18.5 kg/m², a neutral risk between 25 and 29.9 kg/m² and a protective effect for an index >30 kg/m². Patients were divided into five categories according to quintiles of body weight changes during the first year of dialysis: <-3.1%, -3.1 to+0.12%, +0.12 to <+3.1% (reference category), +3.1 to +7.1% and >+7.1%. Patients in the lowest quintile had significantly higher mortality, whereas no negative impact was observed in the other quintiles.

CONCLUSION

These findings suggest that overweight/obesity and a positive body weight variation during the first year of peritoneal dialysis therapy do not increase mortality in incident dialysis patients in Brazil.

Survival advantage of normal weight in peritoneal dialysis patients

INTRODUCTION

A high body mass index (BMI) is a positive predictor of outcome in hemodialysis. But reports for peritoneal dialysis (PD) have been less numerous. The aim of the present investigation was to study the association between BMI and survival among PD patients and to discuss the main risk factors affecting survival.

MATERIALS AND METHODS

A total of 159 patients who received PD from 1 January 2006 to 31 December 2010 at the Department of Nephrology in the Third Affiliated Hospital of Soochow University were enrolled in the study. Blood samples and baseline characteristics of the study cohort were obtained at the start of PD. Patient survival status was recorded through 31 December 2010.

RESULTS

Patients were stratified into two groups as normal weight (BMI, 18.5-24.9) and overweight (BMI, 25.0-29.9). Kaplan-Meier survival curve revealed that the normal weight patients had survival advantage over overweight patients (p < 0.01, by log-rank test). Cox proportional hazard models revealed that BMI, age, diabetes mellitus, coronary vascular disease, congestive heart failure and lipoprotein(a) (Lp(a)) were significant risk factors associated with all-cause mortality (p < 0.05). After adjustment for these covariates, survival was consistently higher for normal weight patients (p < 0.01). Furthermore, the study demonstrated that normal weight patients had lower serum Lp(a) (p < 0.05), C-reactive protein (CRP) (p < 0.05), and peritonitis rate (p < 0.05) compared with overweight patients.

CONCLUSION

The results indicated that normal BMI at the commencement of PD had significant survival advantage in our study. The mechanisms for this might be related to lower cardiovascular risk, less chronic inflammation, and peritonitis prevalence.

Peritoneal Dialysis Penetration and Peritonitis Rate at a Single Centre during Last Decade

Peritoneal dialysis (PD) has been intensively offered at our centre to patients (pts) with end-stage renal disease (ESRD) from 2000, and the number of PD pts was noticed to raise. We aimed to analyse the PD population from the aspect of penetration and peritonitis rate during eleven years. Cumulative number of new RRT pts was 378 during the study period. We found high PD penetration rate: 53% (range 32–72%). The rate of peritonitis was as high as 9.8 during first study years, but it has declined progressively last year being 29.1 by September 2010 and 21.7 by December 2010. Most cases of peritonitis were due to gram-positive pathogens. We have demonstrated steady high single-centre PD penetration rate and improvement of management of patients during last decade probably because of the result of better pts education and a continued dedication of the staff.

Increased expression of pro-inflammatory genes in abdominal subcutaneous fat in advanced chronic kidney disease patients

OBJECTIVES

Low-grade systemic inflammation, oxidative stress and peripheral insulin resistance are intimately associated and contribute to the increased risk of cardiovascular complications in advanced chronic kidney disease (CKD). Because altered adipose tissue activities have previously been linked to pathophysiological processes in various inflammatory and metabolic diseases we hypothesized that the uraemic milieu in patients with CKD may interact with the adipose tissue, provoking an unfavourable shift in its transcriptional output.

DESIGN

Twenty-one adipokine mRNAs were quantified in abdominal subcutaneous adipose tissue (SAT) biopsies and serum/plasma concentrations of inflammatory markers and related protein products were measured.

SETTING

The study was conducted at the Karolinska University Hospital, Huddinge, and Karolinska Institutet, Stockholm, Sweden.

SUBJECTS

Thirty-seven patients with CKD [15 women, median 58 (interquartile range 49-65) years] and nine nonuraemic individuals [four women, age 62 (45-64) years] were recruited prior to initiation of peritoneal dialysis catheter insertion or elective hernia repair/laparoscopic cholecystectomy, respectively.

RESULTS

Even after correction for body mass index, SAT from patients showed a significant upregulation of inflammatory pathway genes interleukin 6 (3.0-fold, P=0.0002) and suppressor of cytokine signalling 3 (2.5-fold, P=0.01), as well as downregulation of leptin (2.0-fold, P=0.03) and the oxidative stress genes uncoupling protein 2 (1.5-fold, P=0.03) and cytochrome b-245, alpha polypeptide (1.5-fold, P=0.005), in relation to controls.

CONCLUSIONS

These gene expression differences suggest that inflammatory and oxidative stress activities may be important features of the intrinsic properties of uraemic adipose tissue, which may have significant effects on the uraemic phenotype.

Profiles of inflammatory markers and lipoprotein subclasses in patients undergoing continuous ambulatory peritoneal dialysis

BACKGROUND

Patients undergoing continuous ambulatory peritoneal dialysis (CAPD) often have inflammation and dyslipidemia that accelerate to atherosclerosis. This study aimed to evaluate chronic inflammation and dyslipidemia in CAPD patients.

METHODS

We measured inflammatory markers and lipoprotein subclasses in 20 CAPD patients (12 men and 8 women, aged 59.5 ± 9.9 y) and 20 gender-matched controls. Lipoproteins were separated by high-performance liquid chromatography (HPLC) using an anion-exchange column.

RESULTS

High-sensitivity C-reactive protein and serum amyloid A protein (SAA) were higher among CAPD patients vs. controls (1.6 ± 2.2 vs. 0.8 ± 1.2 mg/l, p<0.05; 11.9 ± 12.8 vs. 4.5 ± 2.4 mg/l). HPLC analysis revealed that chylomicron, VLDL, and IDL cholesterol levels were higher among CAPD vs. controls. In contrast, HDL cholesterol was lower among CAPD patients vs. controls. In the subgroup analysis, SAA levels were significantly lower among patients receiving CAPD for >3 y than among controls. However, IDL cholesterol was consistently higher among CAPD patients vs. controls.

CONCLUSIONS

CAPD patients have chronic inflammation and dyslipidemia. IDL cholesterol is the only lipoprotein subclass that is consistently elevated regardless of CAPD duration. More attention should be paid to dyslipidemia in the management of the CAPD patients.