Associations of body fat and its changes over time with quality of life and prospective mortality in hemodialysis patients

Sagittal abdominal diameter is an independent predictor of all-cause and cardiovascular mortality in incident peritoneal dialysis patients

Backgrounds and Aims

Visceral fat has a crucial role in the development and progression of cardiovascular disease, the major cause of death in end-stage renal disease (ESRD). Although sagittal abdominal diameter (SAD), as an index of visceral fat, significantly correlated with mortality in the general population, the impact of SAD on clinical outcomes has never been explored in ESRD patients. Therefore, we sought to elucidate the prognostic value of SAD in incident peritoneal dialysis (PD) patients.

Methods

We prospectively determined SAD by lateral abdominal X-ray at PD initiation, and evaluated the association of SAD with all-cause and cardiovascular mortality in 418 incident PD patients.

Results

The mean SAD was 24.5±4.3 cm, and during a mean follow-up of 39.4 months, 97 patients (23.2%) died, and 49.4% of them died due to cardiovascular disease. SAD was a significant independent predictor of all-cause [3rd versus 1st tertile, HR (hazard ratio): 3.333, 95% CI (confidence interval): 1.514–7.388, P = 0.01; per 1 cm increase, HR: 1.071, 95% CI: 1.005–1.141, P = 0.03] and cardiovascular mortality (3rd versus 1st tertile, HR: 8.021, 95% CI: 1.994–32.273, P = 0.01; per 1 cm increase, HR: 1.106, 95% CI: 1.007–1.214, P = 0.03). Multivariate fractional polynomial analysis also showed that all-cause and cardiovascular mortality risk increased steadily with higher SAD values. In addition, SAD provided higher predictive value for all-cause (AUC: 0.691 vs. 0.547, P<0.001) and cardiovascular mortality (AUC: 0.644 vs. 0.483, P<0.001) than body mass index (BMI). Subgroup analysis revealed higher SAD (≥24.2 cm) was significantly associated with all-cause mortality in men, women, younger patients (<65 years), and patients with lower BMI (<22.3 kg/m²).

Conclusions

SAD determined by lateral abdominal X-ray at PD initiation was a significant independent predictor of all-cause and cardiovascular mortality in incident PD patients. Estimating visceral fat by SAD could be useful to stratify mortality risk in these patients.

Effect of age and dialysis vintage on obesity paradox in long-term hemodialysis patients

BACKGROUND

In contrast to the general population, higher body mass index (BMI) is associated with greater survival in patients receiving hemodialysis (HD; "obesity paradox"). We hypothesized that this paradoxical association between BMI and death may be modified by age and dialysis vintage.

STUDY DESIGN

Retrospective observational study using a large HD patient cohort.

SETTING & PARTICIPANTS

123,383 maintenance HD patients treated in DaVita dialysis clinics between July 1, 2001, and June 30, 2006, with follow-up through September 30, 2009.

PREDICTORS

Age, dialysis vintage, and time-averaged BMI. Time-averaged BMI was divided into 6 subgroups; <18.5, 18.5-<23.0, 23.0-<25.0, 25.0-<30.0, 30.0-<35.0, and ≥35.0kg/m(2). BMI category of 23-<25kg/m(2) was used as the reference category.

OUTCOMES

All-cause, cardiovascular, and infection-related mortality.

RESULTS

Mean BMI of study participants was 27±7kg/m(2). Time-averaged BMI was <18.5 and ≥35kg/m(2) in 5% and 11% of patients, respectively. With progressively higher time-averaged BMI, there was progressively lower all-cause, cardiovascular, and infection-related mortality in patients younger than 65 years. In those 65 years or older, even though overweight/obese patients had lower mortality compared with underweight/normal-weight patients, sequential increases in time-averaged BMI > 25kg/m(2) added no additional benefit. Based on dialysis vintage, incident HD patients had greater all-cause and cardiovascular survival benefit with a higher time-averaged BMI compared with the longer term HD patients.

LIMITATIONS

Causality cannot be determined, and residual confounding cannot be excluded given the observational study design.

CONCLUSIONS

Higher BMI is associated with lower death risk across all age and dialysis vintage groups. This benefit is more pronounced in incident HD patients and those younger than 65 years. Given the robustness of the survival advantage of higher BMI, examining interventions to maintain or even increase dry weight in HD patients irrespective of age and vintage are warranted.

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.

Obesity as an effect modifier of the risk of death in chronic kidney disease

In the general population, obesity is associated with increased risk of end-stage renal disease (ESRD), especially if obesity occurs during young adulthood. Obesity is also associated with increased cardiovascular risk and mortality in the general population. However, observational studies which focused on populations with ESRD have demonstrated a more indirect association between body mass index and mortality, and this association has been termed paradoxical. Some have questioned whether the association between obesity and mortality is modified by ESRD. In this review, we discuss effect modification and interaction and factors that may lead to an assumption of effect modification when we observe decreased mortality among obese adults with ESRD. We show that assumptions of the existence of effect modification may be incorrect when the analysis is conditioned on a particular disease state that is influenced by obesity.

Influence of body mass index on the association of weight changes with mortality in hemodialysis patients

BACKGROUND AND OBJECTIVES

A high body mass index (BMI) is associated with lower mortality in patients undergoing hemodialysis. Short-term weight gains and losses are also related to lower and higher mortality risk, respectively. The implications of weight gain or loss may, however, differ between obese individuals and their nonobese counterparts.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Current Management of Secondary Hyperparathyroidism: A Multicenter Observational Study (COSMOS) is an observational study including 6797 European hemodialysis patients recruited between February 2005 and July 2007, with prospective data collection every 6 months for 3 years. Time-dependent Cox proportional hazard regressions assessed the effect of BMI and weight changes on mortality. Analyses were performed after patient stratification according to their starting BMI.

RESULTS

Among 6296 patients with complete data, 1643 died. At study entry, 42% of patients had a normal weight (BMI, 20-25 kg/m(2)), 11% were underweight, 31% were overweight, and 16% were obese (BMI ≥ 30 kg/m(2)). Weight loss or gain (<1% or >1% of body weight) was strongly associated with higher rates of mortality or survival, respectively. After stratification by BMI categories, this was true in nonobese categories and especially in underweight patients. In obese patients, however, the association between weight loss and mortality was attenuated (hazard ratio, 1.28 [95% confidence interval (CI), 0.74 to 2.14]), and no survival benefit of gaining weight was seen (hazard ratio, 0.98 [95% CI, 0.59 to 1.62]).

CONCLUSIONS

Assuming that these weight changes were unintentional, our study brings attention to rapid weight variations as a clinical sign of health monitoring in hemodialysis patients. In addition, a patient's BMI modifies the strength of the association between weight changes with mortality.

Is there any interaction of resistin and adiponectin levels with protein-energy wasting among patients with chronic kidney disease

The aim of this study was to evaluate the effects of adipocytokines including adiponectin, leptin, resistin, neuropeptide Y and ghrelin in chronic kidney disease (CKD) patients on appearance of protein-energy wasting (PEW). One hundred fifty patients with mean age of 45.4 ± 15.9 years, without active infections or chronic inflammatory conditions were recruited into the study. Study groups were control group (consisting of 30 healthy volunteers with normal kidney functions), hemodialysis group, predialysis group, peritoneal dialysis group and kidney transplant group. Fasting morning serum leptin, ghrelin, acylated ghrelin, neuropeptide Y, adiponectin, resistin levels of all of the groups were measured. Anthropometric and nutritional assessments of all patients were obtained. Diagnosis of PEW was made according to definition recommended by the International Society of Renal Nutrition and Metabolism. Presence of PEW in hemodialysis (23.3%) and peritoneal dialysis (26.7%) groups were significantly higher than those of predialysis (3.3%), and transplantation (0%) groups. Adiponectin and resistin levels in predialysis, peritoneal dialysis and hemodialysis patients were significantly higher than control group (p: 0.0001). This study had given significant positive correlations between presence of PEW and serum resistin (r: 0.267, p: 0.001), and serum adiponectin levels (r: 0.349, p: 0.0001). There were no relationship between presence of PEW and ghrelin, acylated-ghrelin, neuropeptide Y, and leptin levels of the groups. CKD patients except transplant patients had higher adiponectin and resistin levels than control group. PEW was found to be linearly correlated with resistin and adiponectin. High serum resistin and adiponectin levels might have a role in development of PEW among dialysis patients.

Save life and improve quality: report from the 5th Congress of International Society for Hemodialysis

The 5th congress of International Society for Hemodialysis took place last August 3-5, 2012 at the Grand Hotel in Taipei and focused on "Save Life and Improve Quality." It attracted a total of 927 participants from 18 countries. The full spectrum of hemodialysis was covered with plenary lectures and symposiums delivered by experts from different subspecialties in nephrology starting from the history of hemodialysis, mineral bone disease, microinflammation and advanced techniques in hemodialysis. It was followed by critical care in nephrology, anemia, and nutrition in dialysis. Last but not the least, natural disasters and medical economics in hemodialysis were also discussed extensively. This special article will highlight the authentic contributions and innovative clinical presentations from the meeting.

Obesity and kidney transplantation

Obesity confers increased risk for graft loss and death among renal transplant recipients. However the relationship of changes in body weight and composition to outcome on the transplant waitlist and post-transplantation is not straightforward. Strategies to manage weight in the waitlisted patient and after kidney transplantation must be performed in the context of a multidisciplinary approach and individualized based on risk factors in particular patients. Although retrospective studies offer considerable insights into the relationship between obesity and kidney transplant outcome, causal inferences must be made with great caution.

Obesity and kidney disease: potential mechanisms

Assessment of adiposity should include measurements of both body mass index and waist circumference. The prevalence of obesity, based on a body mass index of 30 kg/m(2) or greater, has increased substantially over the past 2 decades in Western societies. Obesity remains the number one preventable risk factor for chronic kidney disease because obesity largely mediates diabetes and hypertension, the 2 most common etiologies for end-stage kidney disease. However, obesity itself likely has independent effects on renal hemodynamics and individuals with a low number of nephrons are likely to be the most susceptible to these changes. Multiple mechanisms have been postulated whereby obesity directly impacts kidney disease including hyperfiltration, increased glomerular capillary wall tension, and podocyte stress. Weight loss reduces glomerular filtration rate and effective renal plasma flow along with proteinuria, but these changes are most notable after bariatric surgery in adults with morbid obesity. Aside from adiposity itself, the high caloric intake that leads to obesity also may heighten chronic kidney disease risk via the circuitous loop between Sirt1 and adiponectin and podocyte effacement. Sirt1 is a nicotinamide adenine dinucleotide+dependent deacteylase that is up-regulated in the setting of caloric restriction. Sirt1 expression modulates adiponectin levels that in turn appear to influence podocyte effacement. Clinical trials are needed to assess the benefits and risks of intentional weight loss on kidney disease measures and progression.

Changes in anthropometry and mortality in maintenance hemodialysis patients in the HEMO Study

BACKGROUND

Poor nutritional status has been associated with worse patient survival in maintenance hemodialysis patients. Anthropometric values are important nutritional measures, incorporating muscle and fat mass. However, the association of changes in anthropometry, including midarm circumference (MAC) and skinfold measurements, with mortality in hemodialysis patients remains unknown. Accordingly, we explored this association in the Hemodialysis (HEMO) Study.

STUDY DESIGN

Post hoc analysis of cohort data from a clinical trial.

SETTING & PARTICIPANTS

1,846 hemodialysis patients enrolled in the HEMO Study.

PREDICTORS

MAC and skinfold measurements.

OUTCOMES

Longitudinal changes in MAC and skinfolds were jointly modeled using repeated measures and survival modeling. Time-to-event outcomes were all-cause mortality, cardiac death and hospitalization, and infection-related death.

RESULTS

Mean MAC was 30.1 cm, and mean baseline sum of subscapular, biceps, and triceps skinfolds was 42.4 mm. During a median follow-up of 2.5 years, there were 845 deaths. During follow-up, MAC and the skinfold measurement declined 0.26 cm and 1.1 mm per year, respectively. Declines in MAC (per cm) and skinfold (per mm) measurements were associated with higher all-cause mortality (HRs of 1.58 [95% CI, 1.29-1.94; P < 0.001] and 1.06 [95% CI, 0.99-1.13; P = 0.09], respectively), poorer cardiac outcomes (HRs of 1.49 [95% CI, 1.23-1.81; P < 0.001] and 1.05 [95% CI, 0.99-1.10; P = 0.09], respectively), and higher infection-related hospitalization (HRs of 2.45 [95% CI, 1.55-3.88; P < 0.001] and 1.16 [95% CI, 0.98-1.37; P = 0.08], respectively). The association between declining MAC and skinfold with patient survival was most notable for those with body mass index (BMI) ≤25 kg/m2 (HRs of 2.41 [95% CI, 1.81-3.19; P < 0.001] and 1.22 [95% CI, 1.10-1.35; P < 0.001], respectively).

LIMITATIONS

Prevalent dialysis patients only, excluding individuals weighing >85 kg.

CONCLUSIONS

Declines in skinfold thickness were not associated significantly with outcomes except for participants with BMI ≤25 kg/m2. Declines in MAC are associated significantly with all-cause mortality and cardiac outcomes in hemodialysis patients, most notably in those with BMI ≤25 kg/m2.

Natural history of skeletal muscle mass changes in chronic kidney disease stage 4 and 5 patients: an observational study

Cross-sectional studies in dialysis demonstrate muscle wasting associated with loss of function, increased morbidity and mortality. The relative drivers are poorly understood. There is a paucity of data regarding interval change in muscle in pre-dialysis and dialysis-dependant patients. This study aimed to examine muscle and fat mass change and elucidate associations with muscle wasting in advanced CKD.

134 patients were studied (60 HD, 28 PD, 46 CKD 4–5) and followed up for two years. Groups were similar in age, sex and diabetes prevalence. Soft tissue cross-sectional area (CSA) was measured annually on 3 occasions by a standardised multi-slice CT thigh. Potential determinants of muscle and fat CSA were assessed. Functional ability was assessed by sit-to-stand testing.

88 patients completed follow-up (40 HD, 16 PD, 32 CKD). There was a significant difference in percentage change in muscle CSA (MCSA) over year 1, dependant on treatment modality (χ² = 6.46; p = 0.039). Muscle loss was most pronounced in pre-dialysis patients. Muscle loss during year 1 was partially reversed in year 2 in 39%. Incident dialysis patients significantly lost MCSA during the year which they commenced dialysis, but not the subsequent year. Baseline MCSA, change in MCSA during year 1 and dialysis modality predicted year 2 change in MCSA (adjusted R² = 0.77, p<0.001). There was no correlation between muscle or fat CSA change and any other factors. MCSA correlated with functional testing, although MCSA change correlated poorly with change in functional ability.

These data demonstrate marked variability in MCSA over 2 years. Loss of MCSA in both pre-dialysis and established dialysis patients is reversible. Factors previously cross-sectionally shown to correlate with MCSA did not correlate with wasting progression. The higher rate of muscle loss in undialysed CKD patients, and its reversal after dialysis commencement, suggests that conventional indicators may not result in optimal timing of dialysis initiation.

Prevention and treatment of protein energy wasting in chronic kidney disease patients: a consensus statement by the International Society of Renal Nutrition and Metabolism

Protein energy wasting (PEW) is common in patients with chronic kidney disease (CKD) and is associated with adverse clinical outcomes, especially in individuals receiving maintenance dialysis therapy. A multitude of factors can affect the nutritional and metabolic status of CKD patients requiring a combination of therapeutic maneuvers to prevent or reverse protein and energy depletion. These include optimizing dietary nutrient intake, appropriate treatment of metabolic disturbances such as metabolic acidosis, systemic inflammation, and hormonal deficiencies, and prescribing optimized dialytic regimens. In patients where oral dietary intake from regular meals cannot maintain adequate nutritional status, nutritional supplementation, administered orally, enterally, or parenterally, is shown to be effective in replenishing protein and energy stores. In clinical practice, the advantages of oral nutritional supplements include proven efficacy, safety, and compliance. Anabolic strategies such as anabolic steroids, growth hormone, and exercise, in combination with nutritional supplementation or alone, have been shown to improve protein stores and represent potential additional approaches for the treatment of PEW. Appetite stimulants, anti-inflammatory interventions, and newer anabolic agents are emerging as novel therapies. While numerous epidemiological data suggest that an improvement in biomarkers of nutritional status is associated with improved survival, there are no large randomized clinical trials that have tested the effectiveness of nutritional interventions on mortality and morbidity.

Mortality predictability of body size and muscle mass surrogates in Asian vs white and African American hemodialysis patients

OBJECTIVE

To determine whether the association of body size and muscle mass with survival among patients undergoing long-term hemodialysis (HD) is consistent across race, especially in East Asian vs white and African American patients.

PATIENTS AND METHODS

Using data from 20,818 patients from South Korea who underwent HD from February 1, 2001, to June 30, 2009, and 20,000 matched patients from the United States (10,000 whites and 10,000 African Americans) who underwent HD from July 1, 2001, to June 30, 2006, we compared mortality associations of baseline body mass index (BMI) and serum creatinine level as likely surrogates of obesity and muscle mass across the 3 races.

RESULTS

In Korean HD patients, higher BMI together with higher serum creatinine levels were associated with greater survival, as previously reported from US and European studies. In the matched cohort (10,000 patients from each of the 3 races), mortality risks were lower across higher BMI and serum creatinine levels, and these associations were similar in all 3 races (reference groups: patients with BMI >25.0 kg/m(2) or serum creatinine >12 mg/dL in each race). White, African American, and Korean patients with BMI levels of 18.5 kg/m(2) or less (underweight) had 78%, 79%, and 57% higher mortality risk, respectively, and white, African American, and Korean patients with serum creatinine levels of 6.0 mg/dL or less had 108%, 87%, and 78% higher mortality, respectively.

CONCLUSION

This study shows that race does not modify the association of higher body size and muscle mass with greater survival in HD patients. Given the consistency of the obesity paradox, which may be related to a mitigated effect of protein-energy wasting on mortality irrespective of racial disparities, nutritional support to improve survival should be tested in HD patients of all races.

Optimal nutrition in hemodialysis patients

Protein-energy wasting (PEW) is highly prevalent in patients undergoing maintenance hemodialysis (MHD). It is important to note that there is a robust association between the extent of PEW and the risk of hospitalization and death in these patients, regardless of the nutritional marker used. The multiple etiologies of PEW in advanced kidney disease are still being elucidated. Apart from the multiple mechanisms that might lead to PEW, it appears that the common pathway for all of the derangements is related to exaggerated protein degradation along with decreased protein synthesis. The hemodialysis procedure per se is an important contributor to this process. Metabolic and hormonal derangements such as acidosis, inflammation, and resistance to anabolic properties of insulin resistance and growth hormone are all implicated for the development of PEW in MHD patients. Appropriate management of MHD patients at risk for PEW requires a comprehensive combination of strategies to diminish protein and energy depletion and to institute therapies that will avoid further losses. The mainstay of nutritional treatment in MHD patients is provision of an adequate amount of protein and energy, using oral supplementation as needed. Intradialytic parenteral nutrition should be attempted in patients who cannot efficiently use the gastrointestinal tract. Other anabolic strategies such as exercise, anabolic hormones, anti-inflammatory therapies, and appetite stimulants can be considered as complementary therapies in suitable patients.

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.

Association between helicobacter pylori infection and body mass index, before and after eradication of infection in hemodialysis batients

BACKGROUND

In dialysis patients, chronic infections have been associated with cachexia and anorexia.

OBJECTIVES

This study was carried out to determine the association between Helicobacter pylori (HP) infection and body mass index (BMI) in hemodialysis (HD) patients.

PATIENTS AND METHODS

Ninety eight patients were divided into two groups of negative (group 1) and positive (group 2), for HP. BMI of all patients was measured at the beginning and in group2 after six months following eradication of HP. Before dialysis, various paraclinical parameters were checked at the same intervals.

RESULTS

Fifty-nine patients were enrolled in group 1 and 39 patients in group 2. The means of BMI in groups 1 and 2 were 23.4±3.7 and 25.8±4.4kg/m², respectively. Prior to the study, there was no significant difference for BMI, duration of HD and paraclinic data between two groups. Group 2 took anti HP therapy and eradication occurred in 30 of them. In this group six months after eradication of HP, the BMI was significantly decreased from 25.02±4.4 to 24.4±4.0 kg/m² (P = 0.001). Also six months following the eradication of HP, the mean of serum albumin level was significantly declined from 4.2 to 3.7 g/L (P<0.001). There was also significant decrease in cholesterol (P=0.001), blood urea nitrogen (P=0.005) and calcium (P=0.02). However, significant increase in hemoglobin level was also seen (P=0.03).

CONCLUSIONS

The results of this study show that eradication of HP has an impact on BMI. The results need to be investigated with larger cases.

Uncovering the FUTREX-6100XL prediction equation for the percentage body fat

Based on the near infra-red (NIR) interactance method, the FUTREX company has developed a series of instruments, for the estimation of the body fat percentage (%BF). %BF is estimated through prediction equations incorporated in the instruments, which for the newest models (FUTREX-6100XL and FUTREX-6100A/ZL) are proprietary and they are not published anywhere. This missing knowledge may lead to several misunderstandings and confusion and degrades those instruments to 'black boxes'. The present work uncovers and presents the prediction equation of FUTREX-6100/XL and discusses the contribution of each term of that equation to the %BF. Furthermore, this study presents the method used, which can be used to uncover equations incorporated in other instruments. This method is based on the idea of firstly uncovering the dependence of the equation on each parameter separately and then combining those dependencies to uncover the unknown equation.

Combined values of serum albumin, C-reactive protein and body mass index at dialysis initiation accurately predicts long-term mortality

BACKGROUND

Protein-energy wasting and chronic inflammation are prevalent in patients with end-stage renal disease (ESRD). We investigated the combination of serum albumin, C-reactive protein (CRP) and body mass index (BMI) at initiation of hemodialysis therapy as a predictor of all-cause and cardiovascular disease (CVD) mortality in Japanese ESRD patients.

METHODS

A total of 1,228 consecutive Japanese ESRD patients on hemodialysis therapy were enrolled and followed for up to 10 years. Patients were divided into quartiles according to levels of albumin, CRP and BMI. Furthermore, to clarify the joint role of these factors, albumin <3.5 g/dl, CRP >4.0 mg/l and BMI <19.6 were defined as risk factors using receiver operating characteristic analysis; thereafter, patients were divided into groups according to the positive number of these factors.

RESULTS

Adjusted hazard ratios (HRs) for lower serum albumin, elevated CRP and lower BMI for 10-year all-cause mortality were 1.97, 3.13 and 2.61, respectively. Regarding the combination of these variables, adjusted HRs for mortality were 2.31, 4.28 and 8.07, respectively, in patients having any one factor, any two factors and all three factors. The C-index for an established risk model with these three positive markers was the most accurate for predicting mortality (0.768), as compared to other models with one or two markers. Similar results were seen for CVD mortality.

CONCLUSIONS

Serum albumin, CRP and BMI at the start of hemodialysis therapy were able to individually stratify the risk of long-term mortality in ESRD patients. Furthermore, a combination of these variables could more accurately predict mortality.

Accuracy and limitations of the diagnosis of malnutrition in dialysis patients

Uremic malnutrition, also known as protein-energy wasting (PEW), is a common phenomenon in maintenance dialysis patients and a risk factor for poor clinical outcomes including worse quality of life and increased hospitalization and mortality. The paradoxical association between traditional cardiovascular risk factors and better outcomes in dialysis patients also referred to as "reverse epidemiology," is a good example of the powerful effect-modifying impact of the nutritional status in this population. Measures of food intake, body composition tools, nutritional scoring systems, and laboratory values such as serum albumin are used to diagnose PEW and to assess the degree of severity of PEW without clearly validated diagnostic criteria. Some observational studies suggest that inflammation is a missing link between the PEW and poor clinical outcomes in dialysis patients, although PEW per se may also predispose to illness and inflammation. Ongoing debate as to whether such surrogates as serum albumin or prealbumin concentrations are markers of nutritional status, inflammation, comorbidity, or other conditions has led to confusion and diagnostic and therapeutic nihilism. Irrespective of the cause of hypoalbuminemia in dialysis patients, evidence suggests that nutritional interventions can increase serum albumin in dialysis patients. Hence, we should continue assessing serum albumin and other surrogates of nutritional status to risk-stratify patients and to allocate nutritional therapy, while well-designed, large-scale, randomized, controlled trials of the effects of nutritional intake on clinical outcomes are awaited.

Obesity, health status, and 7-year mortality in percutaneous coronary intervention: in search of an explanation for the obesity paradox

BACKGROUND

Obesity is a growing health problem and is associated with adverse outcomes in coronary artery disease (CAD). However, recent studies have shown better survival in cardiovascular patients with overweight or obesity, which has been referred to as the "obesity paradox". As there is no clear understanding of the phenomenon, we examined the association between body mass index (BMI) and all-cause mortality in patients treated with percutaneous coronary intervention (PCI) at 7-year follow-up, and the potential role of health status in explaining the obesity paradox.

METHODS

Consecutive PCI patients (72.5% men; mean age 62.0 ± 11.2 years, range [27-90]years) from the Rapamycin-Eluting Stent Evaluated at Rotterdam Cardiology Hospital (RESEARCH) registry completed the 36-item short-form health survey (SF-36) to assess health status at baseline. Patients were classified into a normal weight, overweight or obesity group.

RESULTS

The prevalence of normal weight was 34.7% (354/1019), overweight was seen in 45.9% (468/1019) of patients, and 19.3% (197/1019) was obese. After a median follow-up of 7.0 ± 1.7 years, 163 deaths (16.0%) from any cause were recorded. Cumulative hazard functions differed significantly for the obese and overweight group when compared to the normal weight group (log-rank X(2)=6.59, p<0.05). In multivariable analysis, overweight, but not obesity, remained associated with a lower risk for all-cause mortality (HR=0.60, 95%CI [0.42-0.86], p=0.005). Additionally, after adding the 8 health status SF-36 domains to the multivariate model, the association between overweight and mortality remained unchanged.

CONCLUSION

In our study population overweight, but not obesity, was associated with a lower risk for 7-year mortality in PCI patients. Health status as measured with the SF-36 did not seem to play a role in explaining the obesity paradox.

Relationships between appetite and quality of life in hemodialysis patients

The aim of this paper was to investigate the association between appetite and kidney-disease specific quality of life in maintenance hemodialysis patients. Quality of life (QoL) was measured using the kidney disease quality of life survey. Appetite was measured using self-reported categories and a visual analog scale. Other nutritional parameters included Patient-Generated Subjective Global Assessment (PGSGA), dietary intake, body mass index and biochemical markers C-reactive protein and albumin. Even in this well nourished sample (n=62) of hemodialysis patients, PGSGA score (r=-0.629), subjective hunger sensations (r=0.420) and body mass index (r=-0.409) were all significantly associated with the physical health domain of QoL. As self-reported appetite declined, QoL was significantly lower in nine domains which were mostly in the SF36 component and covered social functioning and physical domains. Appetite and other nutritional parameters were not as strongly associated with the Mental Health domain and Kidney Disease Component Summary Domains. Nutritional parameters, especially PGSGA score and appetite, appear to be important components of the physical health domain of QoL. As even small reductions in nutritional status were associated with significantly lower QoL scores, monitoring appetite and nutritional status is an important component of care for hemodialysis patients.

Conventional but not High-Purity Dialysis Fluid Induces Apoptosis and Insulin Resistance in Adipocytes in Vitro

Purpose:

Previous study has shown an independent association of low body fat percentage and fat loss over time with higher mortality in hemodialysis (HD) patients. High-purity dialysis fluid (HPDF) used in place of conventional dialysis fluid (CDF) may decrease inflammation and improve nutritional status. Its effect on adipocytes and therefore fat storage is unclear. The purpose of this study was to assess the effects of these dialysates on apoptosis and insulin resistance in cultured adipocytes to determine a basis for the superiority of HPDF.

Methods:

Flow cytometry and fluorescence staining were used to evaluate apoptosis in adipocytes. Insulin receptor substrate-1 (IRS-1) and −2 and serine phosphorylation of IRS-1 levels were assayed by Western blot. Tumor necrosis factor α (TNFα) levels were measured by enzyme-linked immunosorbent assay (ELISA).

Results:

Although CDF contained more bacteria (66 ± 6 CFU/mL) than HPDF (7 ± 3 CFU/mL) and higher levels of bacterial DNA, endotoxin levels were similar. Combined with uremic serum (containing high TNFα levels), CDF (vs. HPDF) induced more apoptosis in adipocytes. Exposure to CDF also decreased expression of IRS-1 protein, increased expression of IRS-2 protein and insulin-stimulated serine phosphorylation of IRS-1, and decreased glucose consumption. Additionally, the culture supernatant from adipocytes exposed to CDF plus uremic serum for 48 hours contained significantly higher levels of TNFα (15.17 ± 2.89 vs. 8.12 ± 0.54 pg/mL [HPD plus uremic serum], p<0.0001).

Conclusion:

The advantage of HPDF over CDF may be due to lower levels of dialysis fluid impurities.

Quality of life and protein-energy wasting in kidney transplant recipients

PURPOSE

Chronic kidney disease has profound effects on the health-related quality of life (HRQoL) of patients, with serious physiological, psychological and socio-economic implications. The co-occurrence of protein-energy wasting and inflammation in end-stage renal disease patients is associated with worse HRQoL and increased mortality. We designed this study to examine the relationship between nutritional and inflammatory status and HRQoL in kidney transplant recipients.

METHODS

Data from 100 randomly selected kidney transplant patients were analyzed in a cross-sectional survey. Socio-demographic parameters, laboratory results, transplantation-related data, comorbidities, medication and malnutrition-inflammation score (MIS) (Kalantar Score) were tabulated at baseline. Patients completed the Kidney Disease Quality of Life-SF (KDQoL-SF™) self-administered questionnaire.

RESULTS

Mean age was 51 ± 13 years, median (interquartile range, IQR) time since transplantation 66 (83) months, 57% were men, and 19% had diabetes. The median (IQR) MIS was 3 (3). The MIS significantly and negatively correlated with almost all HRQoL domains analyzed, and this association remained significant in multivariate linear regression analysis for the log-transformed scores on energy/fatigue (β = -0.059 P < 0.001), bodily pain (β = -0.056 P = 0.004), physical functioning (β = -0.029, P = 0.022) and symptoms/problems (β = -0.023 P = 0.005) domains after statistical correction for age, gender, eGFR, dialysis vintage, Charlson Comorbidity Index and occupational status. Additionally, cubic spline analyses revealed linearly increasing, "dose-response" relationship between almost all domains of KDQoL-SF™ and the MIS.

CONCLUSIONS

Malnutrition-inflammation score is independently associated with different dimensions of HRQoL in kidney transplant recipients.

The clinical impact of plasma leptin levels in a cohort of chronic kidney disease patients

Background

Recent research has clarified the relationship between adipokines, metabolic syndrome (MS) and cardiovascular disease (CVD). The results of animal and clinical studies have revealed a positive relationship between leptin and vascular smooth muscle cell counts and calcification, arterial rigidity, carotid thickness and the incidence of CVD. However, despite leptin fulfilling the definition of a uremic toxin, its exact role in chronic kidney disease (CKD) has yet to be determined.

Methods

One hundred and forty-two CKD patients (stages 2–5D) participated in this study, and were followed for a minimum of 20 months at Amiens University Medical Center.

Results

Leptin was negatively correlated with the glomerular filtration rate (GFR), total adiponectin (TAdip) and high-molecular weight adiponectin and positively correlated with age, waist circumference, body mass index (BMI), aortic calcification score (ACS), C-reactive protein (CRP), triglycerides, insulin and parathormone (PTH). Leptin and insulin were significantly correlated with the MS score. The BMI, insulin, MS score and PTH were independent predictors of leptin levels (P = 0.002, 0.016, 0.028 and 0.017, respectively). Leptin, insulin and TAdip were independent predictors of the presence of MS (P = 0.05, 0.04 and 0.04). However, leptin levels were not significantly predictive of the clinical outcomes.

Conclusions

Our study was the first to demonstrate a significant, independent link between leptin and MS (but not clinical outcomes) and PTH in patients at different CKD stages. Future studies will have to assess the involvement of leptin in MS and clinical outcomes in CKD, and the potential modulation of leptin by PTH.

Charlson comorbidity score is a strong predictor of mortality in hemodialysis patients

PURPOSE

The Charlson comorbidity index (CCI) is a commonly used scale for assessing morbidity, but its role in assessing mortality in hemodialysis patients is not clear. Age, a component of CCI, is a strong risk factor for morbidity and mortality in chronic diseases and correlates with comorbidities. We hypothesized that the Charlson comorbidity index without age is a strong predictor of mortality in hemodialysis patients.

METHODS

A 6-year cohort of 893 hemodialysis patients was examined for an association between a modified CCI (without age and kidney disease) (mCCI) and mortality.

RESULTS

Patients were 53±15 years old (mean±SD), had a median mCCI score of 2, and included 47% women, 31% African Americans and 55% diabetics. After adjusting for case-mix and nutritional and inflammatory markers including C-reactive protein and interleukin-6, 2nd (mCCI: 1-2), 3rd (mCCI=3), and 4th (mCCI: 4-9) quartiles compared to 1st (mCCI=0) quartiles showed death hazard ratios (95% confidence intervals) of 1.43 (0.92-2.23), 1.70 (1.06-2.72), and 2.33 (1.43-3.78), respectively. The mCCI-death association was robust in non-African Americans. The CCI-death association linearity was verified in cubic splines. Each 1 unit higher mCCI score was associated with a death hazard ratio of 1.16 (1.07-1.27).

CONCLUSIONS

CCI independent of age is a robust and linear predictor of mortality in hemodialysis patients, in particular in non-African Americans.

Ghrelin and its analogues, BIM-28131 and BIM-28125, improve body weight and regulate the expression of MuRF-1 and MAFbx in a rat heart failure model

Cardiac cachexia is a serious complication of chronic heart failure with a prevalence of 10–16% and poor prognosis. There are no current therapy options for cardiac cachexia. Ghrelin is the natural ligand for the GHS-1a-receptor and a potential target for conditions associated with cachexia. Ghrelin has been shown to increase weight in several species. The GHS-1a-receptor is not only found in the brain, but also in other tissues, including the myocardium. Human clinical trials with native ghrelin in cardiac cachexia demonstrated increases in appetite, weight and cardiac output.

Longitudinal body composition changes due to dialysis

BACKGROUND AND OBJECTIVES

Nutritional status remains a powerful predictor of outcome in the dialysis population. High body mass index (BMI) seems protective, but which body compartment (fat or lean mass) confers this protection remains unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a longitudinal study (n = 60; n = 46 completed) examining changes in body composition in incident peritoneal dialysis (PD) and hemodialysis (HD) patients over 12 months. We measured total body protein (TBP) by in vivo neutron activation, expressed as nitrogen index (NI), and lean body mass (LBM) and total body fat (TBF) by dual-energy x-ray absorptiometry. Visceral and subcutaneous fat areas (SFAs) were determined from computed tomography. Comparisons were made between different BMI groups and dialysis modalities.

RESULTS

No significant change was found in TBP, NI, or TBF. The obese group (BMI >30) had an increase in all mean LBM parameters with a significant increase in NI compared with normal-weight and the overweight group. This increase in NI remained significant after multivariate analysis β coefficient (0.08). PD patients had the greatest increase in TBF, with a significant increase in visceral fat (VFA:SFA ratio β coefficient = 0.23).

CONCLUSIONS

Obese patients showed preservation of TBP compared with normal- and overweight patients, suggesting that energy storage as fat mass is of value in the dialysis population.

Racial and ethnic differences in the association of body mass index and survival in maintenance hemodialysis patients

BACKGROUND

In maintenance hemodialysis (HD) patients, overweight and obesity are associated with survival advantages. Given the greater survival of maintenance HD patients who are minorities, we hypothesized that increased body mass index (BMI) is associated more strongly with lower mortality in blacks and Hispanics relative to non-Hispanic whites.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

We examined a 6-year (2001-2007) cohort of 109,605 maintenance HD patients including 39,090 blacks, 17,417 Hispanics, and 53,098 non-Hispanic white maintenance HD outpatients from DaVita dialysis clinics. Cox proportional hazards models examined the association between BMI and survival.

PREDICTORS

Race and BMI.

OUTCOMES

All-cause mortality.

RESULTS

Patients had a mean age of 62 ± 15 (standard deviation) years and included 45% women and 45% patients with diabetes. Across 10 a priori-selected BMI categories (<18-≥40 kg/m(2)), higher BMI was associated with greater survival in all 3 racial/ethnic groups. However, Hispanic and black patients experienced higher survival gains compared with non-Hispanic whites across higher BMI categories. Hispanics and blacks in the ≥40-kg/m(2) category had the largest adjusted decrease in death HR with increasing BMI (0.57 [95% CI, 0.49-0.68] and 0.63 [95% CI, 0.58-0.70], respectively) compared with non-Hispanic whites in the 23- to 25-kg/m(2) group (reference category). In linear models, although the inverse BMI-mortality association was observed for all subgroups, overall black maintenance HD patients showed the largest consistent decrease in death HR with increasing BMI.

LIMITATIONS

Race and ethnicity categories were based on self-identified data.

CONCLUSIONS

Whereas the survival advantage of high BMI is consistent across all racial/ethnic groups, black maintenance HD patients had the strongest and most consistent association of higher BMI with improved survival.

Examining associations of circulating endotoxin with nutritional status, inflammation, and mortality in hemodialysis patients

OBJECTIVE

Lipopolysaccharide or endotoxin constitutes most part of the outer portion of the cell wall in the gram-negative bacteria. Subclinical endotoxemia could contribute to increased inflammation and mortality in hemodialysis (HD) patients. Endotoxin level and clinical effect are determined by its soluble receptor sCD14 and high-density lipoprotein. We examine the hypothesis that endotoxin level correlates with mortality.

METHODS

In this cohort study, endotoxin levels were measured in 306 long-term HD patients who were then followed up for a maximum of 42 months. Soluble CD14 and cytokines levels were also measured.

RESULTS

The mean (±SD) endotoxin level was 2.31 ± 3.10 EU/mL (minimum: 0.26 EU/mL, maximum: 22.94 EU/mL, interquartile range: 1.33 EU/mL, median: 1.27 EU/mL). Endotoxin correlated with C-reactive protein (r = 0.11, P < .04). On multivariate logistic regression analysis, high body mass index and low high-density lipoprotein (HDL) cholesterol levels were associated with higher endotoxemia (endotoxin below or above of median). In multivariate Cox regression analysis adjusted for case-mix and nutritional/inflammatory confounders, endotoxin levels in the third quartile versus first quartile were associated with a trend toward increased hazard ratio for death (hazard ratio: 1.83, 95% confidence interval: 0.93 to 3.6, P = .08).

CONCLUSIONS

In this HD cohort, we found associations between endotoxemia and C-reactive protein, body composition, and HDL. Moderately high endotoxin levels tended to correlate with increased mortality than the highest circulating endotoxin level. Additional studies are required to assess the effect of endotoxemia on mortality in dialysis population.

Association of waist circumference and body mass index with all-cause mortality in CKD: The REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study

BACKGROUND

Obesity management requires understanding the mortality risks associated with different adiposity measures.

STUDY DESIGN

Prospective cohort.

SETTING & PARTICIPANTS

5,805 adults with body mass index (BMI) ≥18.5 kg/m(2) and stages 1-4 chronic kidney disease, defined as a spot urine albumin-creatinine ratio ≥30 mg/g and/or estimated glomerular filtration rate <60 mL/min/1.73 m(2), enrolled in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

PREDICTOR

BMI categorized as 18.5-24.9, 25.0-29.9, 30.0-34.9, 35.0-39.9, and ≥40 kg/m(2) and waist circumference categorized as <80, 80-87.9, 88-97.9, 98-107.9, and ≥108 cm in women and <94, 94-101.9, 102-111.9, 112-121.9, and ≥122 cm in men.

OUTCOMES

All-cause mortality.

MEASUREMENTS

BMI and waist circumference were measured using a standardized protocol during the home visit.

RESULTS

686 (11.8%) deaths occurred during a median follow-up of 4 years. Compared with the referent BMI category of 25-29.9 kg/m(2), HRs for mortality were 1.27 (95% CI, 0.96-1.69) for BMI <25 kg/m(2) and 0.84 (95% CI, 0.62-1.13), 0.81 (95% CI, 0.52-1.26), and 0.95 (95% CI, 0.54-1.65) for BMI categories 30-34.9, 35-39.9, and ≥40 kg/m(2) after adjustment for covariates including waist circumference, respectively. In contrast, after adjustment for covariates including BMI, higher mortality rates were noted for all waist circumference categories compared with the referent (<80 cm in women and <94 cm in men), with HRs of 1.04 (95% CI, 0.77-1.41) for waist circumference of 80-87.9 cm in women and 94-101.9 cm in men, 1.29 (95% CI, 0.92-1.81) for waist circumference of 88-97.9 cm in women and 102-111.9 cm in men, 1.72 (95% CI, 1.12-2.62) for waist circumference of 98-107.9 cm in women and 112-121.9 cm in men, and 2.09 (95% CI, 1.26-3.46) for waist circumference ≥108 cm in women and ≥122 cm in men.

LIMITATIONS

BMI and waist circumference measured at baseline only.

CONCLUSIONS

Waist circumference should be considered in conjunction with BMI when assessing mortality risk associated with obesity in adults with chronic kidney disease.

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.

The cachexia score (CASCO): a new tool for staging cachectic cancer patients

BACKGROUND: According to a recent consensus, the cachectic syndrome is defined as: "… a complex metabolic syndrome associated with underlying illness and characterized by loss of muscle with or without loss of fat mass. The prominent clinical feature of cachexia is weight loss in adults (corrected for fluid retention) or growth failure in children (excluding endocrine disorders). Anorexia, inflammation, insulin resistance, and increased muscle protein breakdown are frequently associated with cachexia." Although this definition is accompanied by diagnostic criteria, it does not consider the problem of staging. Stratification of patients is important when considering therapy. The very first stage of the wasting syndrome does not necessarily involve body weight loss-a state known as pre-cachexia. METHODS AND RESULTS: The aim of the present score was to overcome the problem of patient staging in cancer. This score considers five main different factors: body weight and lean body mass loss; anorexia; inflammatory, immunological, and metabolic disturbances; physical performance; and quality of life. The scoring scale goes from 0 to 100: mild cachexia (less than 25), moderate (more than 26 and less than 50), severe (more than 51 and less than 75), and terminal phase (more than 76 and up to 100). The score also takes into consideration the condition known as pre-cachexia. CONCLUSION: The present score will facilitate cachexia staging and will therefore allow for a more adequate therapy. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13539-011-0027-5) contains supplementary material, which is available to authorized users.

Diets and enteral supplements for improving outcomes in chronic kidney disease

Protein-energy wasting (PEW), which is manifested by low serum levels of albumin or prealbumin, sarcopenia and weight loss, is one of the strongest predictors of mortality in patients with chronic kidney disease (CKD). Although PEW might be engendered by non-nutritional conditions, such as inflammation or other comorbidities, the question of causality does not refute the effectiveness of dietary interventions and nutritional support in improving outcomes in patients with CKD. The literature indicates that PEW can be mitigated or corrected with an appropriate diet and enteral nutritional support that targets dietary protein intake. In-center meals or oral supplements provided during dialysis therapy are feasible and inexpensive interventions that might improve survival and quality of life in patients with CKD. Dietary requirements and enteral nutritional support must also be considered in patients with CKD and diabetes mellitus, in patients undergoing peritoneal dialysis, renal transplant recipients, and in children with CKD. Adjunctive pharmacological therapies, such as appetite stimulants, anabolic hormones, and antioxidative or anti-inflammatory agents, might augment dietary interventions. Intraperitoneal or intradialytic parenteral nutrition should be considered for patients with PEW whenever enteral interventions are not possible or are ineffective. Controlled trials are needed to better assess the effectiveness of in-center meals and oral supplements.

Survival disparities within American and Israeli dialysis populations: learning from similarities and distinctions across race and ethnicity

There are counterintuitive but consistent observations that African American maintenance dialysis patients have greater survival despite their less favorable socioeconomic status, high burden of cardiovascular risks including hypertension and diabetes, and excessively high chronic kidney disease prevalence. The fact that such individuals have a number of risk factors for lower survival and yet live longer when undergoing dialysis treatment is puzzling. Similar findings have been made among Israeli maintenance dialysis patients, in that those who are ethnically Arab have higher end-stage renal disease but exhibit greater survival than Jewish Israelis. The juxtaposition of these two situations may provide valuable insights into racial/ethnic-based mechanisms of survival in chronic diseases. Survival advantages of African American dialysis patients may be explained by differences in nutritional status, inflammatory profile, dietary intake habits, body composition, bone and mineral disorders, mental health and coping status, dialysis treatment differences, and genetic differences among other factors. Prospective studies are needed to examine similar models in other countries and to investigate the potential causes of these paradoxes in these societies. Better understanding the roots of racial/ethnic survival differences may help improve outcomes in both patients with chronic kidney disease and other individuals with chronic disease states.

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.

Quality-of-life and mortality in hemodialysis patients: roles of race and nutritional status

BACKGROUND AND OBJECTIVES

Maintenance hemodialysis (MHD) patients often have protein-energy wasting, poor health-related quality of life (QoL), and high premature death rates, whereas African-American MHD patients have greater survival than non-African-American patients. We hypothesized that poor QoL scores and their nutritional correlates have a bearing on racial survival disparities of MHD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined associations between baseline self-administered SF36 questionnaire-derived QoL scores with nutritional markers by multivariate linear regression and with survival by Cox models and cubic splines in the 6-year cohort of 705 MHD patients, including 223 African Americans.

RESULTS

Worse SF36 mental and physical health scores were associated with lower serum albumin and creatinine levels but higher total body fat percentage. Spline analyses confirmed mortality predictability of worse QoL, with an almost strictly linear association for mental health score in African Americans, although the race-QoL interaction was not statistically significant. In fully adjusted analyses, the mental health score showed a more robust and linear association with mortality than the physical health score in all MHD patients and both races: death hazard ratios for (95% confidence interval) each 10 unit lower mental health score were 1.12 (1.05-1.19) and 1.10 (1.03-1.18) for all and African American patients, respectively.

CONCLUSIONS

MHD patients with higher percentage body fat or lower serum albumin or creatinine concentration perceive a poorer QoL. Poor mental health in all and poor physical health in non-African American patients correlate with mortality. Improving QoL by interventions that can improve the nutritional status without increasing body fat warrants clinical trials.

Associations of body mass index and weight loss with mortality in transplant-waitlisted maintenance hemodialysis patients

A body mass index (BMI) below morbid obesity range is often a requirement for kidney transplant wait-listing, but data linking BMI changes to mortality during the waitlist period are lacking. By linking the 6-year (7/2001-6/2007) national databases of a large dialysis organization and the Scientific Registry of Transplant Recipients, we identified 14 632 waitlisted hemodialysis patients without kidney transplantation. Time-dependent survival models examined the mortality predictability of 13-week-averaged BMI, pretransplant serum creatinine as a muscle mass surrogate and their changes over time. The patients were on average 52 ± 13 years old, 40% women and had a BMI of 26.9 ± 6.3 kg/m². Each kg/m² increase of BMI was associated with a death hazard ratio (HR) of 0.96 (95%CI: 0.95-0.97). Compared to the lowest creatinine quintile, the 4th and 5th quintiles had death HRs of 0.75 (0.66-0.86) and 0.57 (0.49-0.66), respectively. Compared to minimal (< ± 1 kg) weight change over 6 months, those with 3 kg- < 5 kg and ≥ 5 kg weight loss had death HRs of 1.31 (1.14-1.52) and 1.51 (1.30-1.75), respectively. Similar associations were observed with creatinine changes over time. Transplant-waitlisted hemodialysis patients with lower BMI or muscle mass and/or unintentional weight or muscle loss have higher mortality in this observational study. Impact of intentional weight change remains unclear.

Associations of pretransplant weight and muscle mass with mortality in renal transplant recipients

BACKGROUND AND OBJECTIVES

The association between pretransplant body composition and posttransplant outcomes in renal transplant recipients is unclear. It was hypothesized that in hemodialysis patients higher muscle mass (represented by higher pretransplant serum creatinine level) and larger body size (represented by higher pretransplant body mass index [BMI]) are associated with better posttransplant outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Linking 5-year patient data of a large dialysis organization (DaVita) to the Scientific Registry of Transplant Recipients, 10,090 hemodialysis patients were identified who underwent kidney transplantation from July 2001 to June 2007. Cox regression hazard ratios and 95% confidence intervals of death and/or graft failure were estimated.

RESULTS

Patients were 49 ± 13 years old and included 49% women, 45% diabetics, and 27% African Americans. In Cox models adjusted for case-mix, nutrition-inflammation complex, and transplant-related covariates, the 3-month-averaged postdialysis weight-based pretransplant BMI of 20 to <22 and < 20 kg/m(2), compared with 22 to <25 kg/m(2), showed a nonsignificant trend toward higher combined posttransplant mortality or graft failure, and even weaker associations existed for BMI ≥ 25 kg/m(2). Compared with pretransplant 3-month- averaged serum creatinine of 8 to <10 mg/dl, there was 2.2-fold higher risk of combined death or graft failure with serum creatinine <4 mg/dl, whereas creatinine ≥14 mg/dl exhibited 22% better graft and patient survival.

CONCLUSIONS

Pretransplant obesity does not appear to be associated with poor posttransplant outcomes. Larger pretransplant muscle mass, reflected by higher pretransplant serum creatinine level, is associated with greater posttransplant graft and patient survival.

Wasting in chronic kidney disease

Wasting/cachexia is prevalent among patients with chronic kidney disease (CKD). It is to be distinguished from malnutrition, which is defined as the consequence of insufficient food intake or an improper diet. Malnutrition is characterized by hunger, which is an adaptive response, whereas anorexia is prevalent in patients with wasting/cachexia. Energy expenditure decreases as a protective mechanism in malnutrition whereas it remains inappropriately high in cachexia/wasting. In malnutrition, fat mass is preferentially lost and lean body mass and muscle mass is preserved. In cachexia/wasting, muscle is wasted and fat is relatively underutilized. Restoring adequate food intake or altering the composition of the diet reverses malnutrition. Nutrition supplementation does not totally reverse cachexia/wasting. The diagnostic criteria of cachexia/protein-energy wasting in CKD are considered. The association of wasting surrogates, such as serum albumin and prealbumin, with mortality is strong making them robust outcome predictors. At the patient level, longevity has consistently been observed in patients with CKD who have more muscle and/or fat, who report better appetite and who eat more. Although inadequate nutritional intake may contribute to wasting or cachexia, recent evidence indicates that other factors, including systemic inflammation, perturbations of appetite-controlling hormones from reduced renal clearance, aberrant neuropeptide signaling, insulin and insulin-like growth factor resistance, and metabolic acidosis, may be important in the pathogenesis of CKD-associated wasting. A number of novel therapeutic approaches, such as ghrelin agonists and melanocortin receptor antagonists are currently at the experimental level and await confirmation by randomized controlled clinical trials in patients with CKD-associated cachexia/wasting syndrome.

Racial and ethnic differences in mortality of hemodialysis patients: role of dietary and nutritional status and inflammation

BACKGROUND

Racial/ethnic disparities prevail among hemodialysis patients. We hypothesized that significant differences exist between Black and non-Hispanic and Hispanic White hemodialysis patients in nutritional status, dietary intake and inflammation, and that they account for racial survival disparities.

METHODS

In a 6-year (2001-2007) cohort of 799 hemodialysis patients, we compared diet and surrogates of nutritional-inflammatory status and their mortality-predictabilities between 279 Blacks and 520 Whites using matched and regression analyses and Cox with cubic splines.

RESULTS

In age-, gender- and diabetes-matched analyses, Blacks had higher lean body mass and serum prealbumin, creatinine and homocysteine levels than Whites. In case-mix-adjusted analyses, dietary intakes in Blacks versus Whites were higher in energy (+293 ± 119 cal/day) and fat (+18 ± 5 g/day), but lower in fiber (-2.9 ± 1.3 g/day) than Whites. In both races, higher serum albumin, prealbumin and creatinine were associated with greater survival, whereas CRP and IL-6, but not TNF-α, were associated with increased mortality. The highest (vs. lowest) quartile of IL-6 was associated with a 2.4-fold (95% CI: 1.3-3.8) and 4.1-fold (2.2-7.2) higher death risk in Blacks and Whites, respectively.

CONCLUSIONS

Significant racial disparities exist in dietary, nutritional and inflammatory measures, which may contribute to hemodialysis outcome disparities. Testing race-specific dietary and/or anti-inflammatory interventions is indicated.

Association of chronic kidney disease with muscle deficits in children

The effect of chronic kidney disease (CKD) on muscle mass in children, independent of poor growth and delayed maturation, is not well understood. We sought to characterize whole body and regional lean mass (LM) and fat mass (FM) in children and adolescents with CKD and to identify correlates of LM deficits in CKD. We estimated LM and FM from dual energy x-ray absorptiometry scans in 143 children with CKD and 958 controls at two pediatric centers. We expressed whole body, trunk, and leg values of LM and FM as Z-scores relative to height, sitting height, and leg length, respectively, using the controls as the reference. We used multivariable regression models to compare Z-scores in CKD and controls, adjusted for age and maturation, and to identify correlates of LM Z-scores in CKD. Greater CKD severity associated with greater leg LM deficits. Compared with controls, leg LM Z-scores were similar in CKD stages 2 to 3 (difference: 0.02 [95% CI: -0.20, 0.24]; P = 0.8), but were lower in CKD stages 4 to 5 (-0.41 [-0.66, -0.15]; P = 0.002) and dialysis (-1.03 [-1.33, -0.74]; P < 0.0001). Among CKD participants, growth hormone therapy associated with greater leg LM Z-score (0.58 [0.03, 1.13]; P = 0.04), adjusted for CKD severity. Serum albumin, bicarbonate, and markers of inflammation did not associate with LM Z-scores. CKD associated with greater trunk LM and FM, variable whole body LM, and normal leg FM, compared with controls. In conclusion, advanced CKD associates with significant deficits in leg lean mass, indicating skeletal muscle wasting. These data call for prospective studies of interventions to improve muscle mass among children with CKD.

Serum creatinine improves body mass index survival prediction in hemodialysis patients: a 1-year prospective cohort analysis from the ARNOS study

OBJECTIVE

This study sought to better characterize the relationships between body mass index (BMI) and lean body mass (LBM) as assessed by serum creatinine (SCr) and mortality.

DESIGN

The data were collected from a prospective prevalent cohort in maintenance hemodialysis patients.

SETTING

The study was carried out in 25 dialysis units in Rhônes Alpes area (France and Switzerland).

PATIENT

A total of 1,205 patients were followed up for 1-year, starting July 1, 2005.

OUTCOME

Mortality as well as clinical and biological routine parameters were recorded. Kaplan-Meier, Cox model, Log rank test were used for the statistical analysis.

RESULTS

We found that SCr was a strong predictor of mortality (P < .001), whereas BMI was not. Additionally, higher BMI lost its protective effect when it was associated with low SCr. Survival was strongly reduced in patients having a predialysis SCr <717 μmol/L in patients with a BMI >23 (P < .001).

CONCLUSION

BMI should not be used by itself but in conjunction with SCr as a surrogate of LBM to improve its morbid-mortality predictive power. LBM should also be taken into account in further survival studies carried out in hemodialysis patients.