The effect of body mass index on mortality, peritonitis, technique proficiency and residual renal function in peritoneal dialysis patients

BACKGROUND

The prevalence of obesity is increasing worldwide. Obesity is also increasing in the chronic kidney disease (CKD) population. There are conflicting data on complications such as mortality, peritonitis, and technique proficiency of peritoneal dialysis (PD) in underweight and obese patients according to body mass index (BMI). We aimed to present the data in our region to the literature by comparing the residual renal function (RRF), peritonitis, technique proficiency, and mortality rates of the patients we grouped according to BMI.

METHODS

The data of 404 patients who were started and followed up in our clinic between March 2005 and November 2021 were evaluated retrospectively. They were grouped as underweight, normal weight, overweight, and obese according to BMI. RRF, mortality, technique proficiency and peritonitis data of the groups were compared.

RESULTS

Of the 404 patients, 44 were underweight, 199 were normal weight, 110 were overweight, and 55 were obese. No difference was found between the groups in the technique survey and in the time to first peritonitis with Kaplan-Meier analysis (respectively; p = 0.610, p = 0.445). Multivariate Cox regression analysis showed that BMI did not affect mortality (HR 1.196 [95% CI 0.722-1.981] (p = 0.488)).

CONCLUSION

In conclusion, we report that BMI has no effect on RRF, peritonitis, technique proficiency, and mortality in patients undergoing PD, and that mortality may depend on additional factors such as mean albumin, time to first peritonitis, and loss of RRF.

Relationship between intraperitoneal pressure and the development of hernias in peritoneal dialysis: confirmation for the first time of a widely accepted concept

BACKGROUND

Intraperitoneal pressure (IPP) in peritoneal dialysis (PD) is an individual characteristic that can be modified by posture and intraperitoneal volume (IPV). It is considered one of the predisposing factors for complications in the abdominal wall, such as the appearance of hernias. No studies to date have confirmed this. The main aim of this study was to assess the relationship between the development of hernia in incident PD patients and IPP measured at PD onset.

METHODS

A prospective observational study of incident patients in a PD programme between 2010 and 2020. IPP was measured using the Durand's method.

RESULTS

One hundred and twenty-four incident patients on PD, 68% male, mean age 62.1 ± 15.23 years, body mass index (BMI) 27.7 ± 4.82 kg/m2, 44% were diabetic. IPP in supine was 16.6 ± 4.60 cm H2O for a mean IPV of 2047.1 ± 359.19 mL. Hernias were reported in 18.5% of patients during PD follow-up: 57% were inguinal hernias, 33% umbilical, and a further 10% presented in a combined form. PD hernias correlated positively with IPP in supine position (p = 0.037), patient age (p = 0.008), BMI (p = 0.043), a history of prior hernia (0.016), laparoscopic catheter placement (p = 0.026), and technique failure (p = 0.012). In the multivariate analysis, a higher IPP was independently related to the development of hernias (p = 0.028).

CONCLUSIONS

The development of hernias in PD was related to a higher IPP at PD onset, older age, higher BMI, history of prior hernia, catheter placement by laparoscopy, and technique failure.

Pathophysiological concepts and screening of cardiovascular disease in dialysis patients

Dialysis patients experience 10-20 times higher cardiovascular mortality than the general population. The high burden of both conventional and nontraditional risk factors attributable to loss of renal function can explain higher rates of cardiovascular disease (CVD) morbidity and death among dialysis patients. As renal function declines, uremic toxins accumulate in the blood and disrupt cell function, causing cardiovascular damage. Hemodialysis patients have many cardiovascular complications, including sudden cardiac death. Peritoneal dialysis puts dialysis patients with end-stage renal disease at increased risk of CVD complications and emergency hospitalization. The current standard of care in this population is based on observational data, which has a high potential for bias due to the paucity of dedicated randomized clinical trials. Furthermore, guidelines lack specific guidelines for these patients, often inferring them from non-dialysis patient trials. A crucial step in the prevention and treatment of CVD would be to gain better knowledge of the influence of these predisposing risk factors. This review highlights the current evidence regarding the influence of advanced chronic disease on the cardiovascular system in patients undergoing renal dialysis.

Elevated Ferritin Levels Associated with High Body Fat Mass Affect Mortality in Peritoneal Dialysis Patients

Obesity is a common health problem in peritoneal dialysis (PD) patients and causes high serum ferritin levels. However, mixed results have been reported on whether serum ferritin levels affect the prognosis of PD patients. We investigated the effect of increased adiposity on ferritin levels and its association with mortality in 350 well-nourished PD patients. Body composition was measured using a portable whole-body bioimpedance spectroscope, and clinical determinants of high ferritin levels were evaluated. High ferritin levels (≥600 ng/mL) were observed in 63 (18.0%) patients. Patients with high ferritin levels had a significantly higher body fat percentage and a lower lean tissue index than patients with low or normal ferritin levels. During a median follow-up of 30 months, there were 65 deaths. Ferritin ≥ 600 ng/mL was associated with significantly higher all-cause mortality compared with 200-600 ng/mL of ferritin. Multivariate analysis showed that high ferritin levels were significantly associated with a higher percentage of body fat after adjustment for lean tissue index and volume status. High ferritin increased all-cause mortality in PD patients, and increased fat mass was an important determinant of the high ferritin. Our results support that adiposity may lead to an adverse clinical outcome in PD patients.

Association between obesity and 1-year mortality in septic patients: a retrospective cohort study

OBJECTIVE

Sepsis is a major contributor of intensive care units (ICUs) patient mortality. Prior investigations claimed that obesity enhances overall survival (OS) of septic patients. However, the reported results were inconsistent. This study examined the association between obesity and the 1-year mortality of septic patients.

DESIGN

A retrospective cohort study.

SETTING

The Medical Information Mart for Intensive Care III database.

PARTICIPANTS

3145 septic patients were separated into three distinct cohorts, based on their WHO body mass index (BMI) status.

OUTCOMES

Our primary endpoint was the 1-year mortality from the date of ICU hospitalization.

RESULT

1334 (42.4%) died within 1 year. The 1-year mortality rate was low in obese patients (38.8%), compared with normal (46.9%) and overweight (42.1%) patients. Crude assessment revealed that obese patients experienced reduced 1-year mortality, relative to normal weight patients (HR 0.79, 95% CI 0.69 to 0.9, p<0.001). However, once adjusted for baseline variables and comorbidities, no correlation was found between obesity and the 1-year mortality (HR 0.93, 95% CI 0.81 to 1.06, p=0.28) of septic patients. There was an association among diabetic (HR 0.72, 95% CI 0.56 to 0.93, p=0.012) and hypertensive (HR 0.73, 95% CI 0.58 to 0.92, p=0.008) patients, and among males (HR 0.71, 95% CI 0.59 to 0.86, p<0.001), with obese individuals experiencing the lowest mortality rate. Given these evidences, the interactions between BMI and mortality in diabetic (p=0.031) and hypertensive (p=0.035) patients were significant.

CONCLUSION

In our study, obese diabetic and hypertensive patients associated to less sepsis-related mortality risk, compared with normal weight patients. Further researches were need to validated.

Obesity, Weight Gain, and Fluid Overload in Peritoneal Dialysis

Obesity is a global epidemic that has a complicated pathogenesis as well as impact on the outcome of peritoneal dialysis (PD) patients. In this review, the prevalence of obesity in incident PD patients as well as the phenomenon of new-onset glucose intolerance after PD will be reviewed. Published literature on the effect of obesity on the survival and incidence of cardiovascular disease in PD patients will be discussed. Particular emphasis would be put on literature that compared the impact of obesity on the outcome of hemodialysis and PD, and the confounding effect of dialysis adequacy. Next, the complex concept of obesity and its relevance for PD will be explored. The focus would be put on the methods of assessment and clinical relevance of central versus general obesity, as well as visceral versus subcutaneous adipose tissue. The relation between obesity and systemic inflammation, as well as the biological role of several selected adipokines will be reviewed. The confounding effects of metabolic syndrome and insulin resistance will be discussed, followed by the prevalence and prognostic impact of weight gain during the first few years of PD. The differences between weight gain due to fluid overload and accumulation of adipose tissue will be discussed, followed by the current literature on the change in body composition after patients are put on chronic PD. The methods of body composition will be reviewed, and the clinical relevance of individual body component (fluid, fat, muscle, and bone) will be discussed. The review will conclude by highlighting current gaps of knowledge and further research directions in this area.

Dialysis of the Obese Patient: Meeting Needs for a Growing Epidemic

Increasing population obesity and associated metabolic consequences has led to increased number of obese patients with chronic kidney disease and end-stage renal disease. While obesity is associated with increased cardiovascular morbidity and mortality, obese dialysis patients present a seeming paradox for survival benefit, given other acute intervening illnesses for those on dialysis with loss of lean body mass overtime. Challenges remain in providing adequate renal replacement options and therapy for this growing segment of obese patients on dialysis which are discussed in this article.

What is the Optimal Fat Mass in Peritoneal Dialysis Patients?

The prevalence of obesity in peritoneal dialysis (PD) populations has risen dramatically since the mid-1980s. This epidemic has been driven by the increased prevalence of obesity in the general population, the increased risk of progression of chronic kidney disease to end-stage renal failure (ESRF) in obese subjects, the reduced probability of listing obese dialysis patients for renal transplantation, a paradoxical enhanced survival in at least some obese populations on dialysis as compared with non-obese ESRF patients, and a possible adipogenic effect of excessive peritoneal glucose absorption in PD. Although obesity has consistently been associated with improved outcomes in hemodialysis, conflicting results have been seen in PD. In general, an elevated body mass index (BMI) has been associated with a neutral or deleterious impact on PD outcomes, and the relationship appears to be explained predominantly by fat mass. Risk is also elevated in patients with a low BMI, such that the “optimal BMI” appears to lie between 20 kg/m2 and 25 kg/m2. The mechanisms underpinning the harmful effect of obesity appear to include increased peritonitis rate, proinflammatory effects, and a more rapid decline of residual renal function in obese patients. No proof exists that weight reduction engenders an improvement in outcome in PD patients, but the available studies suggest that cautious weight reduction is advisable. A few studies have demonstrated that clinically important and sustained weight reduction can be successfully achieved through a combination of individual meal plans, regular exercise, and substitution of icodextrin for dextrose in the once-daily long dwell.

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.

The Fate of Older Diabetic Patients on Peritoneal Dialysis: Myths and Mysteries and Suggestions for Further Research

The outcome of older and especially of female diabetic patients appears to be worse on peritoneal dialysis (PD) than on hemodialysis (HD). This opinion is based mostly on data coming from the USA, whereas data from other regions seem to give a more balanced picture. The questions arise whether indeed outcome is worse in this patient group, and what might be the underlying reasons for this; further research to unravel this phenomenon is warranted. This review proposes several suggestions for further exploration. The observed differences in outcome might be attributable to differences in treatment practices and experience with PD versus HD. As cardiovascular mortality is a major killer in end-stage renal disease patients, differences in fluid homeostasis and how it is achieved are potential explanations. Fluid balance is potentially more difficult to obtain in PD patients, especially as in the past it was spuriously suggested that fluid restriction was less important in PD patients. PD and HD might also have different impacts on factors related to inflammation, insulin resistance, and hormone balance. The adipocytokine network is of special interest in this respect. It is also possible that bias introduced by the way we measure body composition might have a more negative impact on PD than on HD patients. Finally, it still is not fully established that if diabetic patients are treated appropriately, their outcome on PD is worse than that on HD; further observational trials in this respect are needed. All these topics require further clarification and investigation.

The Influence of Glucose Exposure Load and Peritoneal Membrane Transport on Body Composition and Nutritional Status Changes after 1 Year on Peritoneal Dialysis

Background

The characteristics of peritoneal membrane transport differ among patients, affecting the prescription of peritoneal dialysis (PD) modality and glucose exposure in order to achieve an effective dialysis. This study aims to verify the influence of glucose exposure load and peritoneal membrane transport on body composition and nutritional status changes after the first year of PD.

Methods

We examined a cohort of 85 incident PD patients during the first year of treatment. We established a cut-off of 5% to define changes in dry weight (DW), lean tissue mass (LTM), and fat mass (FM).

Results

In total, 50.6% of the patients presented DW gain, 41.2% showed LTM loss, and 65.9% presented FM gain. Over the time (T0 – T12), we found significant differences in DW, body mass index (BMI), adipose tissue mass (ATM), FM and fat tissue index (FTI). Patients with lower dialysate-to-plasma creatinine ratio showed DW and FM gain. We observed a higher percentage of nonfast transporters in DW gain when comparing with DW no gain. As for glucose exposure load, no body composition changes were seen.

Conclusions

Most patients presented DW gain, FM gain, and LTM loss. The characteristics of peritoneal membrane transport affected DW during the first year, changes being greater in nonfast than in fast transporters.

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

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

Obesity Paradox in Advanced Kidney Disease: From Bedside to the Bench

While obesity is associated with a variety of complications including diabetes, hypertension, cardiovascular disease and premature death, observational studies have also found that obesity and increasing body mass index (BMI) can be linked with improved survival in certain patient populations, including those with conditions marked by protein-energy wasting and dysmetabolism that ultimately lead to cachexia. The latter observations have been reported in various clinical settings including end-stage renal disease (ESRD) and have been described as the "obesity paradox" or "reverse epidemiology", engendering controversy. While some have attributed the obesity paradox to residual confounding in an effort to "debunk" these observations, recent experimental discoveries provide biologically plausible mechanisms in which higher BMI can be linked to longevity in certain groups of patients. In addition, sophisticated epidemiologic methods that extensively adjusted for confounding have found that the obesity paradox remains robust in ESRD. Furthermore, novel hypotheses suggest that weight loss and cachexia can be linked to adverse outcomes including cardiomyopathy, arrhythmias, sudden death and poor outcomes. Therefore, the survival benefit observed in obese ESRD patients can at least partly be derived from mechanisms that protect against inefficient energy utilization, cachexia and protein-energy wasting. Given that in ESRD patients, treatment of traditional risk factors has failed to alter outcomes, detailed translational studies of the obesity paradox may help identify innovative pathways that can be targeted to improve survival. We have reviewed recent clinical evidence detailing the association of BMI with outcomes in patients with chronic kidney disease, including ESRD, and discuss potential mechanisms underlying the obesity paradox with potential for clinical applicability.

Diagnosis and prevalence of protein-energy wasting and its association with mortality in Japanese haemodialysis patients

AIM

The International Society of Renal Nutrition and Metabolism (ISRNM) has proposed the diagnostic criteria for protein-energy wasting (PEW). We studied Japanese haemodialysis (HD) patients to verify the diagnostic method, especially with respect to the body mass index (BMI) criterion, as well as the prevalence of PEW and its association with mortality.

METHODS

Japanese patients receiving maintenance HD at three outpatient clinics in Tokyo (n = 210) were enrolled, and prospectively followed-up for 3 years. PEW was diagnosed at baseline, according to the four categories (serum chemistry, body mass, muscle mass and dietary intake) recommended by the ISRNM. For the category of body mass, we select a body mass index (BMI) and set up three thresholds, <18.5, <20.0 and <23.0 kg/m² , as the diagnostic criterion. The patients who satisfied at least three out of the four categories were diagnosed as PEW.

RESULTS

Protein-energy wasting, when the threshold of a BMI among the diagnostic criteria was defined as <18.5 kg/m² , was recognized as an independent risk factor for mortality. However, PEW was not recognized as a risk factor when the BMI diagnostic criterion was set at <20.0 or <23.0 kg/m² . Overall, 14.8% of the patients had PEW. The survival rate of PEW patients was significantly lower than that of non-PEW patients (log rank, P < 0.001).

CONCLUSIONS

The diagnosis algorithm of PEW proposed by an expert panel of the ISRNM strongly associates with mortality. However, given differences in body size in Japan, we suggest to revise the BMI criterion from <23.0 kg/m² to <18.5 kg/m² .

Survival predictors in anuric patients on peritoneal dialysis: A prospective, multicenter, propensity score-matched cohort study

Prevalent anuric peritoneal dialysis (PD) patients usually have higher mortality than PD patients with residual urine volume. We aimed to evaluate the predictors of survival in anuric PD patients. Anuric PD patients (n = 505, <100 mL of daily urine) enrolled in Korean nationwide prospective cohort were analyzed. Survived and non-survived anuric PD patients were compared by propensity score matching analysis with a ratio of two to one. The propensity method was used to adjust for patient age, dialysis duration, and presence of diabetes. Among the total anuric PD patients, non-survived patients showed a significantly older age, higher incidence of diabetes, coronary artery disease, and arrhythmia, and lower serum creatinine and albumin. After propensity score matching, multivariate Cox regression analysis for patient survival showed a decreasing risk as serum albumin increased (HR = 0.347, p = 0.0094). Analysis using the receiver-operating-characteristic (ROC) curve showed that survival could be predicted with a sensitivity of 59.4% and a specificity of 63.2% using a cutoff value of 3.6 g/dL of serum albumin in unmatched total PD patients. The beneficial impact of high albumin level on death was significantly greater for patients with older age (≥50 years), no diabetes, low ultrafiltration (UF) volume (<1000 mL/day), and low levels of serum creatinine (<10 mg/dL), total cholesterol (<177.5 mg/dL), ferritin (<100 ng/mL), and high-sensitivity C-reactive protein (hs-CRP) (<0.1 mg/dL). Survival in anuric PD patients was associated with age, comorbidities, and nutritional factors such as creatinine and albumin. After adjustment by propensity score matching, serum albumin level was an independent predictor for survival in anuric PD patients.

The association between body mass index and mortality among Asian peritoneal dialysis patients: A meta-analysis

BACKGROUND

Previous studies have revealed that increased body mass index (BMI) is associated with decreased mortality among hemodialysis patients. However, few studies have dealt with the association between BMI and mortality among patients undergoing peritoneal dialysis (PD) and even fewer studies have focused on the Asian PD patients. The reported studies were often non-conclusive and some even yielded contradictory results. This paper, to our best knowledge, registers the first attempt to systematically review the current literature and summarize new results on the association between BMI and mortality among the Asian PD population.

METHOD

A systematic literature review was performed in Medline and EMBASE to identify relevant cohort studies on all-cause and cardiovascular disease (CVD) mortality stratified by BMI categories tailored to Asians among the Asian PD population. We meta-analyzed individual results based on a random effect model, strictly complying with Preferred Reporting Items for Systematic Reviews and Meta-analysis.

RESULTS

The paper reviews seven cohort studies with a total of 3,610 Asian PD patients. Obese group (BMI = 25-29.9 kg/m2) was associated with higher risk of all-cause mortality (HR = 1.46, 95%CI [1.07-1.98]; p = 0.02) and CVD mortality (HR = 2.01, 95%CI [1.14-3.54]; p = 0.02), compared to the normal group (BMI = 18.5-22.9 kg/m2). The underweight group (BMI<18.5kg/m2) was also associated with an elevated risk of all-cause mortality (HR = 2.11, 95%CI [1.46-3.07]; p<0.001). No significant associations between BMI with all-cause mortality were found among the overweight group (23-24.9 kg/m2) (HR = 1.00, 95%CI [0.76-1.32]; p = 0.9). The association between BMI and CVD mortality risk among the underweight and overweight groups was found nonsignificant (p = 0.5 and 0.6 respectively).

CONCLUSION

Obesity is associated with increased mortality in Asian PD patients. The study indicates a "V-shaped" trend in the association between BMI and mortality in these patients.

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.

Obese and diabetic patients with end-stage renal disease: Peritoneal dialysis or hemodialysis?

Obesity is a chronic disease that is increasingly prevalent around the world and is a well-recognized risk factor for type 2 diabetes and hypertension, leading causes of end-stage renal disease (ESRD). The obese diabetic patient with ESRD is a challenge for the nephrologist with regard to the type of renal replacement therapy that should be suggested and offered to the patient. There is no evidence that either peritoneal dialysis or hemodialysis is contraindicated in obese ESRD patients. In the literature, we can find a discrepancy in the impact of obesity on mortality among hemodialysis vs. peritoneal dialysis patients. Several studies in hemodialysis patients suggest that a higher BMI confers a survival advantage - the so-called "reverse epidemiology". In contrast, the literature among obese peritoneal dialysis patients is inconsistent, with various studies reporting an increased risk of death, no difference, or a decreased risk of death. Many of these studies only spanned across a few years, and this is probably too short of a time frame for a realistic assessment of obesity's impact on mortality in ESRD patients. The decision for dialysis modality in an obese diabetic patient with ESRD should be individualized. According to the results of published studies, we cannot suggest PD or HD as a better solution for all obese diabetic patients. The obese patient should be educated about all their dialysis options, including home dialysis therapies. In this review, the available literature related to the dialysis modality in obese patients with diabetes and ESRD was reviewed.

Shortage of Appendicular Skeletal Muscle Is an Independent Risk Factor for Mortality in Peritoneal Dialysis Patients

♦ BACKGROUND: Limited data are available on clinical outcomes among peritoneal dialysis patients with shortage of appendicular skeletal muscle (ASM). In this study, we tested the hypothesis that the shortage of ASM is an independent risk factor for mortality in continuous ambulatory peritoneal dialysis (CAPD) patients. ♦ METHODS: Adult patients undergoing CAPD between March and August 2007 in a single center in China were recruited in this prospective cohort study. Body composition, protein/energy intake, clinical, and biochemical data were collected at baseline, 6 months, and 12 months. End points were all-cause mortality by 12 September 2014. The mean follow-up time was 60.21 (± 24.45) months (11.00 - 89.00). ♦ RESULTS: Compared with the baseline, the mean value of ASM in CAPD patients decreased at 12 months (19.40 ± 5.60 vs 21.85 ± 6.14, p < 0.001). According to the estimation of patient survival by Kaplan-Meier, patients with a shortage of ASM had a worse survival rate than those with normal ASM (χ² = 16.588, p < 0.001). In the Cox's proportional hazards model, patients' survival was independently associated with a shortage of ASM (hazard ratio [HR] = 2.318, p = 0.024, 95% confidence interval [CI] = 1.116 - 4.812). Standard daily protein intake (stDPI) and standard daily energy intake (stDEI) in patients with a shortage of ASM were significantly lower than those in patients with normal ASM in the first follow-up year (t = 2.067, p = 0.041; t = 3.673, p = 0.001). ♦ CONCLUSIONS: A shortage of ASM is an independent risk factor for mortality in CAPD patients. Further studies are needed to demonstrate that nutritional intervention helps with improving muscle mass and, consequently, the survival of CAPD patients.

Metabolic syndrome and obesity in peritoneal dialysis

Metabolic syndrome (MS) refers to clustering of features related to increased risk of cardiovascular disease, which include obesity or central obesity, dyslipidemia, diabetes mellitus or insulin resistance, together with hypertension. The prevalence of MS in end-stage renal failure patients on peritoneal dialysis is quite common, ranging from 40% to 60%, depending on the population studied and the definition used. However, there are controversies about the clinical outcome of patients with MS, particularly in the area of obesity. Whether peritoneal dialysis predisposes patients to MS is another unsolved issue. Despite these controversies, preventing patients from developing MS is important, at least from a theoretical point of view.

Association of Body Mass Index With Mortality in Peritoneal Dialysis Patients: A Systematic Review and Meta-Analysis

♦

BACKGROUND

Although higher body mass index (BMI) is associated with better outcomes in hemodialysis patients, the relationship in peritoneal dialysis (PD) patients is less clear. We aimed to synthesize the results from all large and high-quality studies to examine whether underweight, overweight, or obesity is associated with any significantly different risk of death in peritoneal dialysis patients. ♦

METHODS

We searched MEDLINE, EMBASE, Web of Science, CINAHL, and Cochrane CENTRAL, and screened 7,123 retrieved studies for inclusion. Two investigators independently selected the studies using predefined criteria and assessed each study's quality using the Newcastle-Ottawa Quality Assessment Scale. We meta-analyzed the results of the largest studies with no overlap in their data sources. ♦

RESULTS

We included 9 studies (n = 156,562) in the systematic review and 4 studies in the meta-analyses. When examined without stratifying studies by follow-up duration, the results of the studies were inconsistent. Hence, we pooled the study results stratified based upon their follow-up durations, as suggested by a large study, and observed that being underweight was associated with higher 1-year mortality but had no significant association with 2- and 3- to 5-year mortalities. In contrast, being overweight or obese was associated with lower 1-year mortality but it had no significant association with 2-, and 3- to 5-year mortalities. ♦

CONCLUSION

Over the short-term, being underweight was associated with higher mortality and being overweight or obese was associated with lower mortality. The associations of body mass with mortality were not significant over the long-term.

Excessive Weight Gain during the First Year of Peritoneal Dialysis Is Associated with Inflammation, Diabetes Mellitus, and a Rapid Decrease in Residual Renal Function

OBJECTIVES

Significant weight gain is a potential problem in most patients starting peritoneal dialysis (PD); however, few studies have explored the clinical effects of increased body weight (BW) in these patients. We evaluated the effect of excess weight gain during the first year after PD on residual renal function (RRF).

METHODS

A total of 148 incident PD patients were analyzed in a longitudinal observational study. The mean duration of follow-up was 23.8 months. RRF was measured at baseline (within 1 month of starting PD) and thereafter at 6-month intervals for 2-3 years or until loss of RRF. BW was measured at the time of RRF measurement, and excess weight gain was defined as a BW increase over the median value (3.0%).

RESULTS

The median 1-year increase in BW was 2.3kg (IQR, 1.01-4.58) or 3.0% (IQR, 1.13-5.31). The mean slope of RRF decline was -0.068 ± 0.053 mL/min/month/1.73m2, and RRF loss developed in 48 patients at a mean follow-up time of 19.4 ± 6.8 months. Patients with BW increases > 3.0% showed significantly increased RRF decline rate compared to those without excess weight gain (p<0.001), and the BW increase (%/year) correlated significantly with higher hs-CRP levels and RRF decline rate. High systolic blood pressure, diabetes, large amount of proteinuria and excess BW gain significantly influenced the RRF decline rate. Also, it increased the risk of RRF loss by 4.17-fold (95% confidence intervals, 1.87-9.28; p<0.001).

CONCLUSIONS

Excess weight gain during the first year of PD was closely linked to systemic inflammation, diabetes and rapid decline in RRF.

Dietary restriction and exercise for diabetic patients with chronic kidney disease: a systematic review

BACKGROUND

Obesity and sedentary lifestyle are major health problems and key features to develop cardiovascular disease. Data on the effects of lifestyle interventions in diabetics with chronic kidney disease (CKD) have been conflicting.

STUDY DESIGN

Systematic review.

POPULATION

Diabetes patients with CKD stage 3 to 5. SEARCH STRATEGY AND SOURCES: Medline, Embase and Central were searched to identify papers.

INTERVENTION

Effect of a negative energy balance on hard outcomes in diabetics with CKD.

OUTCOMES

Death, cardiovascular events, glycaemic control, kidney function, metabolic parameters and body composition.

RESULTS

We retained 11 studies. There are insufficient data to evaluate the effect on mortality to promote negative energy balance. None of the studies reported a difference in incidence of Major Adverse Cardiovascular Events. Reduction of energy intake does not alter creatinine clearance but significantly reduces proteinuria (mean difference from -0.66 to -1.77 g/24 h). Interventions with combined exercise and diet resulted in a slower decline of eGFR (-9.2 vs. -20.7 mL/min over two year observation; p<0.001). Aerobic and resistance exercise reduced HbA1c (-0.51 (-0.87 to -0.14); p = 0.007 and -0.38 (-0.72 to -0.22); p = 0.038, respectively). Exercise interventions improve the overall functional status and quality of life in this subgroup. Aerobic exercise reduces BMI (-0.74% (-1.29 to -0.18); p = 0.009) and body weight (-2.2 kg (-3.9 to -0.6); p = 0.008). Resistance exercise reduces trunk fat mass (-0,7±0,1 vs. +0,8 kg ±0,1 kg; p = 0,001-0,005). In none of the studies did the intervention cause an increase in adverse events.

LIMITATIONS

All studies used a different intervention type and mixed patient groups.

CONCLUSIONS

There is insufficient evidence to evaluate the effect of negative energy balance interventions on mortality in diabetic patients with advanced CKD. Overall, these interventions have beneficial effects on glycaemic control, BMI and body composition, functional status and quality of life, and no harmful effects were observed.

Anabolic Effect of Exercise Training in People with End-Stage Renal Disease on Hemodialysis: A Systematic Review with Meta-analysis

PURPOSE

The primary purpose of this systematic review was to evaluate the anabolic effect of exercise intervention in adults with end-stage renal disease on hemodialysis (HD). The secondary objectives were to evaluate the influences of participant characteristics and exercise parameters on changes in muscle size.

METHODS

Electronic databases (Cochrane, CINAHL, EMBASE, PEDro, PubMed and SCOPUS) were searched from inception to November 2012. Randomized clinical trials published in English that included adults on HD undergoing an exercise intervention where muscle mass was measured as an outcome were included in this review. Two reviewers independently selected the studies, extracted data, and assessed risk of bias within the included studies. RESULTS were then combined by meta-analysis. The effect of exercises was determined using a standardized mean difference (SMD), expressed as Hedges' g, computed using a random effects model.

RESULTS

Seven SMDs extracted from five studies were included for final analysis. Strength training was used in all studies; one study used aerobic and mixed strength and aerobic training with two subgroups of participants. The overall effect of exercise on muscle mass was statistically significant (SMD: 0.272; 95% CI, 0.020-0.525).

CONCLUSIONS

Our results confirm a small but significant effect of strengthening exercise as an anabolic intervention to increase muscle mass. Exercise training should be included in routine management of people on maintenance HD. Although current results indicate that one in nine people on HD is likely to benefit from exercise intervention, parameters influencing these results require further research.

The association between body mass index and mortality on peritoneal dialysis: a prospective cohort study

BACKGROUND

Previous studies have demonstrated that increased body mass index (BMI) is associated with decreased mortality in hemodialysis (HD) patients. However, the association between BMI and survival has not been well established in patients undergoing peritoneal dialysis (PD). The aim of the study was to determine the association between BMI and mortality in the PD population using the Clinical Research Center (CRC) registry for end-stage renal disease (ESRD) cohort in Korea.

METHODS

Prevalent patients with PD were selected from the CRC registry for ESRD, a prospective cohort study on dialysis patients in Korea. Patients were categorized into four groups by quartiles of BMI. Cox regression analysis was used to calculate the adjusted hazard ratio (HR) of mortality with a BMI of quartile 2 (21.4 - 23.5 kg/m(2)) as the reference.

RESULTS

A total of 900 prevalent patients undergoing PD were included. The median follow-up period was 24 months. The multivariate Cox proportional hazard model showed that the lowest quartile of BMI was associated with higher mortality (HR 3.00, 95% confidence interval (CI), 1.26 - 7.15). However, the higher quartiles of BMI were not associated with mortality compared with the reference category of BMI quartile 2 (Quartile 3: HR 1.11, 95% CI, 0.43 - 2.85, Quartile 4: HR 1.64, 95% CI, 0.66 - 4.06) after adjustment for clinical variables.

CONCLUSIONS

Lower BMI was a significant risk factor for death, but increased BMI was not associated with mortality in Korean PD patients.

Effect of body mass index on outcomes of peritoneal dialysis patients in India

OBJECTIVES

We studied the effect of body mass index (BMI) at peritoneal dialysis (PD) initiation on patient and technique survival and on peritonitis during follow-up.

METHODS

We followed 328 incident patients on PD (176 with diabetes; 242 men; mean age: 52.6 ± 12.6 years; mean BMI: 21.9 ± 3.8 kg/m(2)) for 20.0 ± 14.3 months. Patients were categorized into four BMI groups: obese, ≥ 25 kg/m(2); overweight, 23 - 24.9 kg/m(2); normal, 18.5 - 22.9 kg/m(2) (reference category); and underweight, <18.5 kg/m(2). The outcomes of interest were compared between the groups.

RESULTS

Of the 328 patients, 47 (14.3%) were underweight, 171 (52.1%) were normal weight, 53 (16.2%) were overweight, and 57 (17.4%) were obese at commencement of PD therapy. The crude hazard ratio (HR) for mortality (p = 0.004) and the HR adjusted for age, subjective global assessment, comorbidities, albumin, diabetes, and residual glomerular filtration rate (p = 0.02) were both significantly greater in the underweight group than in the normal-weight group. In comparison with the reference category, the HR for mortality was significantly greater for underweight PD patients with diabetes [2.7; 95% confidence interval (CI): 1.5 to 5.0; p = 0.002], but similar for all BMI categories of nondiabetic PD patients. Median patient survival was statistically inferior in underweight patients than in patients having a normal BMI. Median patient survival in underweight, normal, overweight, and obese patients was, respectively, 26 patient-months (95% CI: 20.9 to 31.0 patient-months), 50 patient-months (95% CI: 33.6 to 66.4 patient-months), 57.7 patient-months (95% CI: 33.2 to 82.2 patient-months), and 49 patient-months (95% CI: 18.4 to 79.6 patient-months; p = 0.015). Death-censored technique survival was statistically similar in all BMI categories. In comparison with the reference category, the odds ratio for peritonitis occurrence was 1.8 (95% CI: 0.9 to 3.4; p = 0.086) for underweight patients; 1.7 (95% CI: 0.9 to 3.2; p = 0.091) for overweight patients; and 3.4 (95% CI: 1.8 to 6.4; p < 0.001) for obese patients.

CONCLUSIONS

In our PD patients, mean BMI was within the normal range. The HR for mortality was significantly greater for underweight diabetic PD patients than for patients in the reference category. Death-censored technique survival was similar in all BMI categories. Obese patients had a greater risk of peritonitis.

Body mass index and mortality risk in Asian peritoneal dialysis patients in Hong Kong-impact of diabetes and cardiovascular disease status

BACKGROUND

Obesity increases mortality in the general population, but improves survival in hemodialysis patients. In peritoneal dialysis (PD) patients, the reported effect is controversial. We investigated the effect of body mass index (BMI) on patient survival in Asian PD patients.

METHODS

The survival of incident Asian PD patients from 2001 to 2008 in a single center in Hong Kong was analyzed retrospectively. Baseline demographic and clinical data were collected from patient records. Patients who had a total Kt/V below 1.7 or who died within 6 months were excluded. The BMI was categorized using the World Health Organization recommendation for Asian populations.

RESULTS

In the 274 study patients [154 men (56%); 138 with diabetes (50.4%); mean age: 63.4 ± 14.6 years; mean BMI: 21.97 ± 3.23 kg/m(2); 37 underweight (13.5%); 35 obese (12.8%)], the relative risk (RR) for mortality [adjusted for age, diabetes status, and cardiovascular disease (CVD)] was similar for the normal and overweight groups, but higher for the underweight (RR: 1.909; p = 0.028) and obese groups (RR: 1.799; p = 0.048). The increased mortality in obese patients was more prominent in patients with diabetes (RR: 1.9 vs 1.19 in patients without diabetes; p = 0.074 and 0.76 respectively), and in patients with CVD (RR: 8.895 vs 1.642 in patients without CVD; p = 0.012 and 0.122 respectively).

CONCLUSIONS

In Asian PD patients, the relationship between BMI and mortality was U-shaped, with higher mortality in the underweight and obese patients. The negative impact of obesity was more prominent in patients with diabetes and CVD.

Urine creatinine excretion and clinical outcomes in CKD

BACKGROUND AND OBJECTIVES

Twenty-four-hour urine creatinine excretion is a reliable approximation of muscle mass. Whether changes in urine creatinine predict clinical outcomes in persons with CKD is unknown. This work studied the relationship between urine creatinine and patient and renal survival in people with CKD not requiring renal replacement therapy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This longitudinal cohort study included incident stages 3-5 CKD patients referred to the renal clinic at the University Federico II in Naples between January of 1995 and December of 2005. Clinical data and urine creatinine were updated at each visit. Main outcomes were all-cause mortality and kidney failure requiring dialysis.

RESULTS

This study enrolled 525 individuals and followed them for a median of 6 years (range of 4 months to 15 years). Urine creatinine excretion declined by 16 mg/d per year (95% confidence interval, 14 to 19) in participants with CKD stages 3a, 3b, and 4, and it remained stable in participants with stage 5 CKD. Per each 20 mg/d decline in urine creatinine, mortality increased by 3% (adjusted hazard ratio, 1.03; 95% confidence interval, 1.01 to 1.05), and the risk of initiating dialysis increased by 2% (adjusted hazard ratio, 1.02; 95% confidence interval, 1.01 to 1.03). These associations were independent of body mass index and GFR.

CONCLUSIONS

In persons with CKD stages 3 and 4, urine creatinine declines at a rate of 16 mg/d per year. Lower urine creatinine excretion predicts greater risk of kidney failure and patient mortality.

Obesity paradox in end-stage kidney disease patients

In the general population, obesity is associated with increased cardiovascular risk and decreased survival. In patients with end-stage renal disease (ESRD), however, an "obesity paradox" or "reverse epidemiology" (to include lipid and hypertension paradoxes) has been consistently reported, i.e. a higher body mass index (BMI) is paradoxically associated with better survival. This survival advantage of large body size is relatively consistent for hemodialysis patients across racial and regional differences, although published results are mixed for peritoneal dialysis patients. Recent data indicate that both higher skeletal muscle mass and increased total body fat are protective, although there are mixed data on visceral (intra-abdominal) fat. The obesity paradox in ESRD is unlikely to be due to residual confounding alone and has biologic plausibility. Possible causes of the obesity paradox include protein-energy wasting and inflammation, time discrepancy among competitive risk factors (undernutrition versus overnutrition), hemodynamic stability, alteration of circulatory cytokines, sequestration of uremic toxin in adipose tissue, and endotoxin-lipoprotein interaction. The obesity paradox may have significant clinical implications in the management of ESRD patients especially if obese dialysis patients are forced to lose weight upon transplant wait-listing. Well-designed studies exploring the causes and consequences of the reverse epidemiology of cardiovascular risk factors, including the obesity paradox, among ESRD patients could provide more information on mechanisms. These could include controlled trials of nutritional and pharmacologic interventions to examine whether gain in lean body mass or even body fat can improve survival and quality of life in these patients.

Peritoneal dialysis outcomes in a modern cohort of overweight patients

BACKGROUND

The incidence of obesity is increasing both in the general population and in incident dialysis patients. While there is evidence that being overweight is associated with good outcomes in hemodialysis, the evidence in peritoneal dialysis (PD) patients is not very clear. We studied a modern cohort of PD patients to examine outcomes in large patients.

METHODS

Forty-three patients who started PD, who weighed more than 90 kg at dialysis initiation, between January/2000 and June/2010 were matched with 43 control patients who weighed less than 90 kg. Detailed review of the charts was undertaken.

RESULTS

The mean weight and body mass index of the wt < 90 kg group were 69.3 ± 11.3 kg and 25.0 ± 3.9 kg/m(2). The number of peritonitis episodes per year was 0.33 ± 0.6 (wt < 90 kg) and 0.82 ± 1.7 (wt ≥ 90 kg) (p = 0.26). The median time to first peritonitis showed a trend toward earlier peritonitis in larger patients [9.5 (4.3, 27) months in wt ≥ 90 kg, 19.1(7.9, 30.8) months in wt < 90 kg] but did not reach statistical significance (p = 0.12). Surprisingly, hernias and leaks were more common in the weight <90 kg group (44 vs. 18.6 % p = 0.02). There was no difference in total number of hospitalizations or the number of days hospitalized. Kaplan-Meier analysis of survival on PD showed no differences between the two groups (logrank p = 0.99). Cox regression analysis using age, race, cause of ESRD due to diabetes and Charlson comorbidity index as the covariates did not show weight to be associated with survival on PD.

CONCLUSIONS

Large patients tend to do just as well on PD, with survival on PD being no different compared to individuals with lower weight and body mass index.

Does body fat mass define survival in patients starting peritoneal dialysis?

BACKGROUND AND AIMS

Peritoneal dialysis (PD) is characterized by a gain in fat mass. Unlike subcutaneous fat, visceral fat is associated with metabolic syndrome and survival. We prospectively examined whether visceral or subcutaneous fat could predict outcome in patients undergoing PD.

METHODS

We studied 117 new patients (57 men) undergoing PD between February 2006 and November 2011. Baseline body composition was measured on computed tomograms. Visceral obesity was defined as a visceral fat area exceeding 100 cm(2), and subcutaneous obesity, as a subcutaneous fat area exceeding 130 cm(2).

RESULTS

Among the 117 patients, 37 and 29 were diagnosed with visceral and subcutaneous obesity respectively. Visceral and subcutaneous obesity were both present in 21 patients. In the study population, the 1-year and 5-year survival rates were 94% and 59%. The rates of peritonitis and exit-infection were 0.31 and 0.14 episodes per patient-year. Mortality was greater in patients with visceral obesity than in those without visceral obesity (p = 0.005). Visceral obesity had no influence on peritonitis and exit-infection rates. Subcutaneous obesity was associated neither with survival nor with peritonitis or exit-site infection. In a multivariate Cox regression analysis, visceral obesity was not a risk factor for poor outcome.

CONCLUSIONS

Increased visceral fat at PD initiation is not an independent predictor of poor survival. Any impact of visceral or subcutaneous fat mass on outcomes in patients undergoing PD would be better defined by larger, long-term studies.

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.

Frailty and protein-energy wasting in elderly patients with end stage kidney disease

Older people constitute an increasingly greater proportion of patients with advanced CKD, including those patients undergoing maintenance dialysis treatment. Frailty is a biologic syndrome of decreased reserve and resistance to stressors that results from cumulative declines across multiple physiologic systems and causes vulnerability to adverse outcomes. Frailty is common in elderly CKD patients, and it may be associated with protein-energy wasting (PEW), sarcopenia, dynapenia, and other complications of CKD. Causes of frailty with or without PEW in the elderly with CKD can be classified into three categories: causes primarily caused by aging per se, advanced CKD per se, or a combination of both conditions. Frailty and PEW in elderly CKD patients are associated with impaired physical performance, disability, poorer quality of life, and reduced survival. Prevention and treatment of these conditions in the elderly CKD patients often require a multifaceted approach. Here, we examine the causes and consequences of these conditions and examine the interplay between frailty and PEW in elderly CKD patients.

Visceral fat thickness is associated with carotid atherosclerosis in peritoneal dialysis patients

Visceral fat has been known to associate with atherosclerosis, inflammation, and insulin resistance. However, the influence of visceral fat on cardiovascular disease (CVD) in peritoneal dialysis (PD) patients has never been elucidated. We investigated whether visceral fat thickness (VFT) has a predictive role in carotid atherosclerosis determined by carotid intima-media thickness (cIMT) in PD patients. A cross-sectional study was undertaken in 88 prevalent PD patients. BMI and waist circumference (WC) were measured as anthropometric indexes of obesity. VFT and subcutaneous fat thickness (SFT) were determined by sonographic measurement of abdominal fat. Carotid atherosclerosis was defined as increased cIMT (>1.0 mm) or presence of plaque. Thirty-two (36.3%) patients had carotid atherosclerosis. Patients with carotid atherosclerosis showed significantly higher VFT, BMI, and WC. In univariate logistic analysis, BMI, WC, and VFT except SFT were significant risk factors of carotid atherosclerosis. However, multivariate analysis revealed VFT was an independent factor associated with carotid atherosclerosis after adjusting for demographic, biochemical parameters, and anthropometric indexes (per 1 mm increase, odds ratio (OR) = 2.294, 95% confidence interval: 1.048-5.021, P = 0.038). When the patients were divided into three groups according to VFT, log high sensitivity C-reactive protein (hs-CRP), and homeostasis model assessment-insulin resistance (HOMA(IR)) were both higher in the third tertile compared to other tertiles. In conclusion, VFT, not SFT, is independently associated with carotid atherosclerosis in PD patients. Therefore sonographic measurement of VFT could be useful to stratify the risk of cardiovascular disease in PD patients.

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.

Influence of megestrol acetate on nutrition, inflammation and quality of life in dialysis patients

AIM

Malnutrition is a common clinical problem in dialysis patients. The objective of this study was to evaluate the efficacy and safety of megestrol acetate in malnourished dialysis patients. Thirty-two hypoalbuminemic dialysis patients took 160 mg of megestrol acetate daily for up to 6 months.

METHODS

We measured height, dry weight, BMI, modified Subjective Global Assessment (SGA) score, and serum albumin, triglycerides, total cholesterol, hsCRP, IL-1β and IL-6 concentrations. We used validated questionnaires to evaluate selected dimensions of the quality of life.

RESULTS

Only 12 patients completed the study. All patients reported improved appetite, and there were concurrent statistically significant increases in weight, BMI, SGA and albumin concentration (P < 0.05). For the 12 patients who completed 6 months of treatment the increase in these parameters was from 63.26 ± 13.04 to 65.58 ± 12.53 kg, from 23.5 ± 3.8 to 24.66 ± 4.23 kg/m(2), from 5.16 ± 0.94 to 6.16 ± 0.72 points, and from 36.45 ± 1.82 to 40.33 ± 2.71 g/l, respectively. However, there were no significant changes in the levels of inflammatory markers and in quality of life. Side effects included overhydration, excessive weight gain and hyperglycaemia.

CONCLUSION

Megestrol acetate may be effective in reversing poor appetite in carefully selected maintenance dialysis patients, but it might not reduce inflammation or improve the quality of life. Because of the potential side effects, close monitoring is essential.

When to initiate dialysis--is early start always better?

The question when to initiate dialysis is attracting increasing attention. In recent years, there has been a tendency to initiate dialysis earlier in terms of estimated glomerular filtration rate (eGFR) in an attempt to achieve better patient outcomes. However, several observational studies and one randomized controlled trial have found no benefit for early dialysis initiation. On the contrary, they have found that starting dialysis with a higher eGFR is associated with increased mortality. These studies need to be carefully interpreted in light of their reliance on eGFR to estimate kidney function at dialysis initiation. The decision to start dialysis should not be based solely on a predefined eGFR value, but more importantly on a careful clinical assessment of the individual patient.

Protein-energy wasting and mortality in chronic kidney disease

Protein-energy wasting (PEW) is common in patients with chronic kidney disease (CKD) and is associated with an increased death risk from cardiovascular diseases. However, while even minor renal dysfunction is an independent predictor of adverse cardiovascular prognosis, PEW becomes clinically manifest at an advanced stage, early before or during the dialytic stage. Mechanisms causing loss of muscle protein and fat are complex and not always associated with anorexia, but are linked to several abnormalities that stimulate protein degradation and/or decrease protein synthesis. In addition, data from experimental CKD indicate that uremia specifically blunts the regenerative potential in skeletal muscle, by acting on muscle stem cells. In this discussion recent findings regarding the mechanisms responsible for malnutrition and the increase in cardiovascular risk in CKD patients are discussed. During the course of CKD, the loss of kidney excretory and metabolic functions proceed together with the activation of pathways of endothelial damage, inflammation, acidosis, alterations in insulin signaling and anorexia which are likely to orchestrate net protein catabolism and the PEW syndrome.

Predictive value of malnutrition markers for mortality in peritoneal dialysis patients

INTRODUCTION

Alterations in nutritional status have been described as important predictors of mortality in patients with chronic kidney disease (CKD). However, the association between multiple markers for nutritional status and the mortality rates of patients with CKD on peritoneal dialysis (PD) has not yet been illustrated in previously published data, particularly by using the new definition of protein energy wasting (PEW).

OBJECTIVE

To evaluate the predictive value of malnutrition markers for mortality rates, on the basis of the PEW definition, of PD patients.

MATERIALS AND METHODS

At the start of PD treatment, the nutritional status of 199 patients (mean age, 56 ± 13.3 years; 53% females) was evaluated. Body mass index (BMI), arm circumference, mid-arm muscle circumference, protein and caloric intake (by using a 3-day food record), and serum albumin were all recorded, as well as a subjective global assessment (SGA) and presence of PEW. Cut-off points were defined on the basis of the consensus of the International Society for Renal Nutrition and Metabolism (albumin, <3.8 g/dL; BMI, <23 kg/m(2); mid-arm muscle circumference, >10% in comparison with the 50th percentile for the reference population; protein intake, <0.8 g/kg/daily; caloric intake, <25 kcal/kg/daily). The data were obtained retrospectively between the years 2001 and 2008 on the basis of routine nutritional evaluation. Patients were monitored for fatal events from all possible causes.

RESULT

The mean BMI for the population was 26.6 ± 5.0 kg/m(2). A median protein intake of 0.94 (0.18 to 4.57) g/kg/daily was reported and 60.3% of the patients reported a protein intake of <0.8 g/kg/daily. With respect to caloric intake, 38.7% of the patients consumed <25 kcal/kg/daily. A median of 3.5 (1.4 to 5.3) g/dL for serum albumin was observed and 29.3% of the patients presented values of <3.8 g/dL. PEW was diagnosed in 17.5% of patients. In the univariate model, being of age >65 years (P = .002), cardiovascular disease (P < .001), diabetes mellitus (P = .02), SGA (P = .02), and albumin (P = .002), were all significant markers for mortality. The presence of patients aged >65 years (P = .02), with diabetes mellitus (P = .057), cardiovascular disease (P = .005), and albumin were considered as independent factors for mortality in this study.

CONCLUSION

SGA, albumin, and PEW were the only nutritional markers found to be associated with mortality in this cohort of PD patients. In the multivariate analysis, after adjusting for classic mortality risk factors, only patients with hypoalbuminemia were found to be at a high risk for mortality at follow-up. These results may be limited by the number of observations and a necessity for confirmation in larger prospective studies.

Assessing creatinine clearance from modification of diet in renal disease study equations in the ADEMEX cohort: limitations and potential applications

BACKGROUND AND OBJECTIVES

Twenty-four-hour urine and dialysate collections provide accepted means to assess adequacy in peritoneal dialysis (PD). Recent publications suggest that creatinine clearance (CrCl) estimated from the Modification of Diet in Renal Disease (MDRD) equations (eCrCl) accurately approximates measured CrCl (mCrCl) derived from 24-hour collections of urine and dialysate and might serve as an alternative means to assess small-solute clearance and adequacy in PD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Post hoc analysis of data from patients enrolled in ADEMEX was used to assess agreement between mCrCl and eCrCl derived by four- and six-variable MDRD equations (4V-MDRDE and 6V-MDRDE, respectively). Additionally, associations among mCrCl, eCrCl, and survival were determined.

RESULTS

Acceptable precision was observed between mCrCl and 4V-MDRDE-eCrCl and 6V-MDRDE-eCrCl for the entire cohort. Precision was markedly diminished when analysis was limited to functionally anuric patients with mCrCl < 12 ml/min per 1.73 m². Although there was no association between survival and mCrCl, for every 1-ml/min per 1.73 m² increase in 4V- and 6V-MDRDE-eCrCl, there was a 6% and 4% increase in risk of death, respectively. There was a negative association between MDRDE-eCrCl and creatinine appearance rates, suggesting MDRDE-eCrCl is significantly confounded by individual differences in muscle mass.

CONCLUSIONS

MDRDE-eCrCl provides demographically comparable values to 24-hour urine and dialysate collections across the ADEMEX cohort. However, MDRDEs should not be used to assess small-solute removal or adequacy in individual PD patients or to predict outcome in any cohort of patients over narrow ranges of limited clearance.

Survival predictability of lean and fat mass in men and women undergoing maintenance hemodialysis

BACKGROUND

Larger body size is associated with greater survival in maintenance hemodialysis (MHD) patients. It is not clear how lean body mass (LBM) and fat mass (FM) compare in their associations with survival across sex in these patients.

OBJECTIVE

We examined the hypothesis that higher FM and LBM are associated with greater survival in MHD patents irrespective of sex.

DESIGN

In 742 MHD patients, including 31% African Americans with a mean (± SD) age of 54 ± 15 y, we categorized men (n = 391) and women (n = 351) separately into 4 quartiles of near-infrared interactance-measured LBM and FM. Cox proportional hazards models estimated death hazard ratios (HRs) (and 95% CIs), and cubic spline models were used to examine associations with mortality over 5 y (2001-2006).

RESULTS

After adjustment for case-mix and inflammatory markers, the highest quartiles of FM and LBM were associated with greater survival in women: HRs of 0.38 (95% CI: 0.20, 0.71) and 0.34 (95% CI: 0.17, 0.67), respectively (reference: first quartile). In men, the highest quartiles of FM and percentage FM (FM%) but not of LBM were associated with greater survival: HRs of 0.51 (95% CI: 0.27, 0.96), 0.45 (95% CI: 0.23, 0.88), and 1.17 (95% CI: 0.60, 2.27), respectively. Cubic spline analyses showed greater survival with higher FM% and higher "FM minus LBM percentiles" in both sexes, whereas a higher LBM was protective in women.

CONCLUSIONS

In MHD patients, higher FM in both sexes and higher LBM in women appear to be protective. The survival advantage of FM appears to be superior to that of LBM. Clinical trials to examine the outcomes of interventions that modify body composition in MHD patients are indicated.

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.

Risk factors for high dialysate glucose use in PD patients--a retrospective 5-year cohort study

BACKGROUND

Use of high concentrations of glucose for peritoneal dialysis (PD) may produce unfavorable results. Our previous study showed that high initial glucose load is associated with poor PD technique survival.

OBJECTIVE

This retrospective cohort study at a medical center in Taiwan aimed to understand the factors associated with high glucose load in long-term PD patients.

PATIENTS AND METHODS

We reviewed 90 newly started PD patients over 5 years. We determined glucose load by calculating annual glucose weight and dialysate volume administered. Multiple linear regression analyses with time-dependent covariates were used to determine factors that influence the annual average dialysate glucose concentration.

RESULTS

The study group included 47 men and 43 women with a mean age of 53.4 +/- 13.9 years. Technique survival rates were 91.0%, 84.1%, and 77.6% at the beginning of the second, third, and fourth year of PD therapy respectively. The presence of diabetes mellitus (DM), high body mass index (BMI), and low weekly renal Kt/V were significantly correlated with high average dialysate glucose concentration during the first, second, and third years. For patients undergoing PD for more than 3 years, residual renal function (RRF) deteriorated, and only DM significantly affected higher dialysate glucose concentration in the fourth year.

CONCLUSIONS

Patients with DM, high BMI, and low RRF were more likely to require a high glucose load for PD therapy, especially during the first 3 years. After those 3 years of PD, DM was the only significant factor in the need for higher glucose load. To reduce the glucose load in chronic PD patients, alternative osmotic agents such as icodextrin or amino acids should be considered in the daily PD regimen.