Frailty and the Quality of Life in Hemodialysis Patients: The Importance of Waist Circumference.

OBJECTIVE: Frailty among the end-stage renal disease (ESRD) population is highly prevalent and has been associated with mortality. Little is known about the relation of different aspects of body composition, a modifiable risk factor, with the risk of frailty in ESRD population. DESIGN AND METHODS: One hundred and fifty-one patients including 85 men and 66 women, aged ≥18 years with ESRD who had been receiving conventional maintenance hemodialysis (HD) for at least 3 months were included. Body fat and muscle mass from both bioimpedance spectroscopy and skin-fold thickness and waist circumference as a surrogate of abdominal obesity were measured. Frailty was defined based on Fried's criteria. Health-related quality of life was collected using the RAND version of the Kidney Disease Quality of Life (KDQOL-36) Survey. RESULTS: We performed single and multiple predictor logistic regression analyses to determine factors associated with frailty. After adjustment for age, sex, and comorbidities, fat mass (both by bioimpedance spectroscopy and anthropometry) and waist circumference, but not muscle mass remained the main predictors of frailty. The odds ratio of frailty in the third tertile compared with the first was 4.97 (1.70-14.55) and 3.84 (1.39-10.61) for fat mass and waist circumference, respectively (P for trends for both <.05). The scores of physical health and kidney disease effect component of quality of life were lower in frail compared with nonfrail patients (40.7 ± 9.2 vs. 33.7 ± 10.2, P < .01 and 66.8 ± 22.4 vs. 51.6 ± 25.7, P < .05 for physical health and effects of disease, respectively). CONCLUSIONS: Frailty, which is associated with poor outcomes in chronic HD patients, is common and predicted by fat mass and waist circumference but not by body mass index and muscle mass. Interventions to modify abdominal obesity, reflected by waist circumference, could potentially lower the incidence of frailty and hence improve the quality of life in the HD population.

Urinary lithogenic risk profile in recurrent stone formers with hyperoxaluria: a randomized controlled trial comparing DASH (Dietary Approaches to Stop Hypertension)-style and low-oxalate diets.

BACKGROUND: Patients with nephrolithiasis and hyperoxaluria generally are advised to follow a low-oxalate diet. However, most people do not eat isolated nutrients, but meals consisting of a variety of foods with complex combinations of nutrients. A more rational approach to nephrolithiasis prevention would be to base dietary advice on the cumulative effects of foods and different dietary patterns rather than single nutrients. STUDY DESIGN: Randomized controlled trial. SETTING & PARTICIPANTS: Recurrent stone formers with hyperoxaluria (urine oxalate > 40 mg/d). INTERVENTION: The intervention group was asked to follow a calorie-controlled Dietary Approaches to Stop Hypertension (DASH)-style diet (a diet high in fruit, vegetables, whole grains, and low-fat dairy products and low in saturated fat, total fat, cholesterol, refined grains, sweets, and meat), whereas the control group was prescribed a low-oxalate diet. Study length was 8 weeks. OUTCOMES: Primary: change in urinary calcium oxalate supersaturation. SECONDARY: Changes in 24-hour urinary composition. RESULTS: 57 participants were randomly assigned (DASH group, 29; low-oxalate group, 28). 41 participants completed the trial (DASH group, 21; low-oxalate group, 20). As-treated analysis showed a trend for urinary oxalate excretion to increase in the DASH versus the low-oxalate group (point estimate of difference, 9.0mg/d; 95% CI, -1.1 to 19.1mg/d; P=0.08). However, there was a trend for calcium oxalate supersaturation to decrease in the DASH versus the low-oxalate group (point estimate of difference, -1.24; 95% CI, -2.80 to 0.32; P=0.08) in association with an increase in magnesium and citrate excretion and urine pH in the DASH versus low-oxalate group. LIMITATIONS: Limited sample size, as-treated analysis, nonsignificant results. CONCLUSIONS: The DASH diet might be an effective alternative to the low-oxalate diet in reducing calcium oxalate supersaturation and should be studied more.

Effects of combined lipoic acid and pyridoxine on albuminuria, advanced glycation end-products, and blood pressure in diabetic nephropathy.

This study was designed to investigate the effects of combined administration of lipoic acid and pyridoxine on albuminuria, oxidative stress, blood pressure, serum advanced glycation end-products, nitric oxide (NO), and endothelin-1 in patients with diabetic nephropathy. Thirty-four patients were randomly assigned to either a supplement group or a placebo group. The patients in the supplement group received 800 mg lipoic acid and 80 mg pyridoxine daily for 12 weeks, whereas the placebo group received corresponding placebos. Urinary albumin, serum malondialdehyde (MDA), and systolic blood pressure decreased significantly in the supplement group compared to the placebo group (p < 0.05). Serum NO increased in the supplement group compared to the placebo group (p < 0.05). Serum pentosidine and carboxymethyl lysine decreased significantly in the supplement group at the end of week 12 compared to baseline (p < 0.05). No statistically significant differences were observed between the two groups in mean changes of serum endothelin-1, glucose, and diastolic blood pressure. The present study indicates that combined administration of lipoic acid and pyridoxine improves albuminuria in patients with diabetic nephropathy by reducing oxidative stress, advanced glycation end-products, and systolic blood pressure. The reduction in microalbuminuria may be of benefit in retarding the progression of diabetic nephropathy.

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.

Validation of the SMH Equations for the Estimation of the Total Body Water Volume in Hemodialysis Patients.

Background: Online dialysis clearance monitors typically provide an accurate value for Kt. A value for V (total body water [TBW]) is required to calculate Kt/V, the measure of the adequacy of the delivered dialysis in hemodialysis (HD) patients. Using bioimpedance spectroscopy (BIS), we previously developed 2 sex-specific equations for the estimation of the TBW, which we have chosen to name the St Michael's Hospital (SMH) equations. Objective: The objective of this study was to validate the SMH equations in a second distinct population of patients. Design: Cross-sectional study. Setting: Single center hemodialysis unit at St Michael's Hospital, a tertiary care teaching hospital, in Toronto, Canada. Patients: Eighty-one adult HD patients who had been receiving conventional maintenance HD for at least 3 months. Measurements: Anthropometric measurements including weight, height, and waist circumference were collected. TBW was measured by BIS using the Body Composition Monitor (Fresenius Medical Care, Bad Homburg, Germany). Methods: The Bland-Altman method to calculate the bias and limits of agreement and the difference plot analysis were used to evaluate the difference between the BIS-TBW and the TBW derived from our equations (SMH equation) in this validation cohort. Results: The TBW values based on our equations had a high correlation with BIS-TBW (correlation coefficients = 0.93, P values < .01, bias = 1.8 [95% CI: 1-2.6] liter). Application of SMH equations closely predicted Kt/V, based on BIS value, in all categories of waist circumference. Limitations: Small sample size, single-center, not including peritoneal dialysis patients. A larger and more heterogeneous sample with more patients at the extremes of body mass index would allow for more detailed sub-group analyses in different races and different anthropometric categories to better understand the performance of these equations in discrete sub-groups of patients. Conclusions: In maintenance HD patients, our previously derived equations to estimate the TBW using weight and waist circumference appear to be valid in a distinct patient population. Given the centrality of TBW to the calculation of small molecule clearance, the SMH equations may enhance the measurement of dialysis adequacy and inform practice.

Contexte: En général, les versions en ligne des moniteurs de clairance de la dialyse fournissent une valeur de Kt précise. Une valeur de V (ECT = eau corporelle totale) est nécessaire pour calculer le Kt/V, soit la mesure de l'adéquation de la dialyse chez les patients sous hémodialyse (HD). Grâce à la spectroscopie de bio-impédance (BIS), nous avons précédemment développé deux équations spécifiques au sexe qui permettent d'estimer l'ECT, les « équations du St Michael's Hospital ¼ (équations SMH). Objectif: Valider les équations SMH dans une deuxième population distincte de patients. Conception: Étude transversale. Cadre: L'unité d'hémodialyse du St Michael's Hospital, un hôpital universitaire de soins tertiaires de Toronto (Canada). Sujets: 81 patients adultes suivant des traitements d'HD de maintien conventionnelle depuis au moins 3 mois. Mesures: Des mesures anthropométriques, soit le poids, la taille et le tour de taille, ont été recueillies. L'ECT a été mesurée par BIS (ECT-BIS) à l'aide d'un moniteur de composition corporelle, le Body Composition Monitor TM de Fresenius Medical Care (Bad Homburg, Allemagne). Méthodologie: La méthode Bland-Altman a été utilisée pour calculer le biais et les limites d'agrément. L'analyse des courbes de différence a servi à évaluer la différence entre l'ECT-BIS et l'ECT dérivée de nos équations (équations SMH) dans la cohorte de validation. Résultats: Les valeurs d'ECT obtenues par les équations se sont avérées très étroitement corrélées aux valeurs obtenues par bio-impédance (coefficient de corrélation: 0,93; valeurs de p < 0,01; biais = 1,8 litres [IC 95 %: 1-2,6]). L'application des équations SMH a prédit précisément le Kt/V, sur la base de la valeur par BIS, dans toutes les catégories de tour de taille. Limites: Échantillon de petite taille provenant d'un seul centre et n'incluant pas les patients sous dialyse péritonéale. Un échantillon plus vaste et plus hétérogène, avec davantage de patients dont l'IMC se situe aux extrêmes de la courbe, permettrait une analyse plus détaillée de sous-groupes provenant de différentes ethnies et présentant différentes catégories anthropométriques; ceci permettrait de valider la performance des équations SMH dans des sous-groupes distincts de patients. Conclusion: Dans une population de patients sous HD de maintien, nos équations précédemment dérivées, qui permettent d'estimer l'ECT à partir du poids et du tour de taille, semblent valides. Compte tenu de l'importance de l'ECT dans le calcul de la clairance des petites molécules, les équations SMH pourraient améliorer la mesure de l'adéquation de la dialyse et éclairer la pratique.

Novel equations to estimate lean body mass in maintenance hemodialysis patients.

BACKGROUND: Lean body mass (LBM) is an important nutritional measure representing muscle mass and somatic protein in hemodialysis patients, for whom we developed and tested equations to estimate LBM. STUDY DESIGN: A study of diagnostic test accuracy. SETTING & PARTICIPANTS: The development cohort included 118 hemodialysis patients with LBM measured using dual-energy x-ray absorptiometry (DEXA) and near-infrared (NIR) interactance. The validation cohort included 612 additional hemodialysis patients with LBM measured using a portable NIR interactance technique during hemodialysis. INDEX TESTS: 3-month averaged serum concentrations of creatinine, albumin, and prealbumin; normalized protein nitrogen appearance; midarm muscle circumference (MAMC); handgrip strength; and subjective global assessment of nutrition. REFERENCE TEST: LBM measured using DEXA in the development cohort and NIR interactance in validation cohorts. RESULTS: In the development cohort, DEXA and NIR interactance correlated strongly (r = 0.94, P < 0.001). DEXA-measured LBM correlated with serum creatinine level, MAMC, and handgrip strength, but not with other nutritional markers. Three regression equations to estimate DEXA-measured LBM were developed based on each of these 3 surrogates and sex, height, weight, and age (and urea reduction ratio for the serum creatinine regression). In the validation cohort, the validity of the equations was tested against the NIR interactance-measured LBM. The equation estimates correlated well with NIR interactance-measured LBM (R² ≥ 0.88), although in higher LBM ranges, they tended to underestimate it. Median (95% confidence interval) differences and interquartile range for differences between equation estimates and NIR interactance-measured LBM were 3.4 (-3.2 to 12.0) and 3.0 (1.1-5.1) kg for serum creatinine and 4.0 (-2.6 to 13.6) and 3.7 (1.3-6.0) kg for MAMC, respectively. LIMITATIONS: DEXA measurements were obtained on a nondialysis day, whereas NIR interactance was performed during hemodialysis treatment, with the likelihood of confounding by volume status variations. CONCLUSIONS: Compared with reference measures of LBM, equations using serum creatinine level, MAMC, or handgrip strength and demographic variables can estimate LBM accurately in long-term hemodialysis patients.

Dietary omega-3 fatty acid, ratio of omega-6 to omega-3 intake, inflammation, and survival in long-term hemodialysis patients.

BACKGROUND: Mortality in long-term hemodialysis patients is high, mostly attributed to cardiovascular events, and may be related to chronic inflammation. We hypothesized that the anti-inflammatory benefits of higher dietary intake of omega-3 compared with omega-6 polyunsaturated fatty acids may modulate the inflammatory processes and decrease death risk. STUDY DESIGN: Prospective cohort study using linear and Cox proportional regressions. SETTING & PARTICIPANTS: 145 hemodialysis patients from 8 DaVita dialysis clinics in Southern California in 2001-2007. PREDICTORS: Intake of dietary omega-3 and ratio of omega-6 to omega-3 using 3-day food record supplemented by dietary interview. OUTCOMES: 1-year change in serum C-reactive protein (CRP) level and 6-year survival. RESULTS: Patients were aged 53 ± 14 years (mean ± SD) and included 43% women and 42% African Americans. Median dietary omega-3 intake, ratio of omega-6 to omega-3 intake, baseline serum CRP level, and change in CRP level over 1 year were 1.1 (25th-75th percentile, 0.8-1.6) g/d, 9.3 (25th-75th percentile, 7.6-11.3), 3.1 (25th-75th percentile, 0.8-6.8) mg/L, and +0.2 (25th-75th percentile, -0.4 to +0.8) mg/L, respectively. In regression models adjusted for case-mix, dietary calorie and fat intake, body mass index, and history of hypertension, each 1-unit higher ratio of omega-6 to omega-3 intake was associated with a 0.55-mg/L increase in serum CRP level (P = 0.03). In the fully adjusted model, death HRs for the first (1.7-<7.6), second (7.6-<9.3), third (9.3-<11.3), and fourth (11.3-17.4) quartiles of dietary omega-6 to omega-3 ratio were 0.39 (95% CI, 0.14-1.18), 0.30 (95% CI, 0.09-0.99), 0.67 (95% CI, 0.25-1.79), and 1.00 (reference), respectively (P for trend = 0.06). LIMITATIONS: 3-day food record may underestimate actual dietary fat intake at an individual level. CONCLUSIONS: Higher dietary omega-6 to omega-3 ratio appears to be associated with both worsening inflammation over time and a trend toward higher death risk in hemodialysis patients. Additional studies including interventional trials are needed to examine the association of dietary fatty acids with clinical outcomes in these patients.

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.

Design and development of a dialysis food frequency questionnaire.

OBJECTIVES: Periodic assessment of dietary intake across a given dialysis population may help to improve the clinical outcomes related to nutrients such as dietary protein, phosphorus, or potassium. Although dietary recalls and food records are used to assess dietary intake at individual level and over shorter periods, food frequency questionnaires (FFQ) are used to rank subjects of a given population according to their nutrient intake over longer periods. DESIGN: To modify and refine the conventional Block FFQ to develop a specific FFQ for dialysis patients. SETTING: A total of 8 DaVita outpatient dialysis clinics in Los Angeles area, which participated in the "Nutrition and Inflammation in Dialysis Patients" study. PATIENTS: The study included 154 patients undergoing maintenance hemodialysis (MHD). MAIN OUTCOME MEASURE: Dietary intake of participating MHD patients using a 3-day food record, supplemented by a person-to-person dietary interview, to capture food intake over the last hemodialysis treatment day of the week and the 2 subsequent nondialysis days. RESULTS: Analyses of the food records identified the key contributors to the daily nutrient intake in the 154 participating MHD patients. A "Dialysis-FFQ" was developed to include approximately 100 food items representing the total food intake of 90% of the patients of the "Nutrition and Inflammation in Dialysis Patients" study population. Distinctions were made in several food items on the basis of key nutritional issues, such as protein, phosphorus, and potassium, in dialysis patients. CONCLUSIONS: We have developed a "Dialysis FFQ" to compare and rank dialysis patients according to their diverse nutrient intake. Although the Dialysis-FFQ may be a valuable tool to compare dialysis patients and to identify those who ingest higher or lower amounts of a given nutrient, studies are needed to examine the utility of the Dialysis-FFQ for nutritional assessment of dialysis patients.

Dietary potassium intake and mortality in long-term hemodialysis patients.

BACKGROUND: Hyperkalemia has been associated with higher mortality in long-term hemodialysis (HD) patients. There are few data concerning the relationship between dietary potassium intake and outcome. STUDY DESIGN: The mortality predictability of dietary potassium intake from reported food items estimated using the Block Food Frequency Questionnaire (FFQ) at the start of the cohort was examined in a 5-year (2001-2006) cohort of 224 HD patients in Southern California using Cox proportional hazards regression. SETTING & PARTICIPANTS: 224 long-term HD patients from 8 DaVita dialysis clinics. PREDICTORS: Dietary potassium intake ranking using the Block FFQ. OUTCOMES: 5-year survival. RESULTS: HD patients with higher potassium intake had greater dietary energy, protein, and phosphorus intakes and higher predialysis serum potassium and phosphorus levels. Greater dietary potassium intake was associated with significantly increased death HRs in unadjusted models and after incremental adjustments for case-mix, nutritional factors (including 3-month averaged predialysis serum creatinine, potassium, and phosphorus levels; body mass index; normalized protein nitrogen appearance; and energy, protein, and phosphorus intake) and inflammatory marker levels. HRs for death across the 3 higher quartiles of dietary potassium intake in the fully adjusted model (compared with the lowest quartile) were 1.4 (95% CI, 0.6-3.0), 2.2 (95% CI, 0.9-5.4), and 2.4 (95% CI, 1.1-7.5), respectively (P for trend = 0.03). Restricted cubic spline analyses confirmed the incremental mortality predictability of higher potassium intake. LIMITATIONS: FFQs may underestimate individual potassium intake and should be used to rank dietary intake across the population. CONCLUSIONS: Higher dietary potassium intake is associated with increased death risk in long-term HD patients, even after adjustments for serum potassium level; dietary protein; energy, and phosphorus intake; and nutritional and inflammatory marker levels. The potential role of dietary potassium in the high mortality rate of HD patients warrants clinical trials.

Comparing body composition assessment tests in long-term hemodialysis patients.

BACKGROUND: Protein-energy wasting is common in chronic kidney disease and is associated with decreases in body muscle and fat stores and poor outcomes. The accuracy and reliability of field methods to measure body composition is unknown in this population. STUDY DESIGN: Cross-sectional observational study. SETTING & PARTICIPANTS: 118 maintenance hemodialysis patients were seen at the General Clinical Research Center at Harbor-UCLA Medical Center, Torrance, CA. INDEX TESTS: Triceps skinfold, near-infrared interactance, and bioelectrical impedance analysis using the Segal, Kushner, and Lukaski equations. REFERENCE TEST: Dual-energy x-ray absorptiometry (DEXA). RESULTS: Participants (42% women, 52% with diabetes, 40% African Americans, and 38% Hispanics) were aged 49.4 +/- 11.5 (mean +/- SD) years, and had undergone dialysis therapy for 41.1 +/- 32.9 months. Body mass index was 27.0 +/- 6.0 kg/m(2). Using DEXA as the reference test, the bioelectrical impedance analysis-Kushner equation, triceps skinfold, and near-infrared interactance were most accurate of the index tests in estimating total-body fat percentage, whereas bioelectrical impedance analysis-Segal equation and bioelectrical impedance analysis-Lukaski equation overestimated total body fat percentage. Bland-Altman analyses and difference plots showed that bioelectrical impedance analysis-Kushner and near-infrared interactance were most similar to the reference test. Bioelectrical impedance analysis-Kushner, triceps skinfold, and near-infrared interactance had the smallest mean differences from DEXA, especially in women (1.6%, 0.7%, and 1.2%, respectively). Similar results were observed in African American participants (n = 47). LIMITATIONS: Measurements were performed 1 day after a hemodialysis treatment, leading to more fluid retention, which may have affected the reference and index tests differently. CONCLUSIONS: Using DEXA as the reference test, both near-infrared interactance and bioelectrical impedance analysis-Kushner method yield more consistent estimates of total body fat percentage in maintenance hemodialysis patients compared with the other index tests. Near-infrared interactance is not affected by skin color. Field methods with portable devices may provide adequate precision.

Total and individual coronary artery calcium scores as independent predictors of mortality in hemodialysis patients.

Many traditional and nontraditional risk factors contribute to vascular calcification among maintenance hemodialysis (MHD) patients. It is not clear whether coronary artery calcification (CAC) delineates a higher mortality risk independent of known risk factors. We examined 6-year (10/2001-9/2007) survival of 166 MHD patients, aged 53 +/- 13 years, with baseline CAC scores. Patients were grouped into four CAC groups: 0, 1-100, 101-400, and 400+. The 101-400 and 400+ groups were associated with a significantly higher adjusted risk of death than CAC 0 with hazard ratios (HR) 8.5 (95% CI: 1.1-48.1, p = 0.02) and 13.3 (95% CI: 1.3-65.1, p = 0.01), respectively, independent of demographics, comorbidity, lipids and other cardiovascular risks, surrogates of bone disease, nutritional and inflammatory markers and dialysis dose. Total CAC [HR 6.7 (1.1-21.5, p = 0.03)] followed by the presence of CAC in the left main [4.6 (2.2-9.8, p = 0.001)] and left anterior descending artery [4.3 (2.1-14.2, p = 0.001)] were strong independent predictors of mortality even after adjusting for above covariates. Total and vessel-specific CAC predict mortality in MHD patients independent of traditional and nontraditional risk factors.

Effect of diabetes mellitus on protein-energy wasting and protein wasting in end-stage renal disease.

Protein wasting (PW) or protein-energy wasting (PEW) occurs commonly in patients with diabetes mellitus who have end-stage renal disease (ESRD) and are undergoing maintenance dialysis (MD) therapy. Some but not all studies indicate that PW or PEW is more prevalent in diabetic when compared with nondiabetic MD patients and that diabetic patients commencing maintenance hemodialysis (MHD) are more likely to lose fat-free, edema-free weight than are incident nondiabetic MHD patients. The causes of PW and PEW in diabetic MD patients are probably largely similar to those of nondiabetic MD patients. These causes include anorexia, reduced food intake, concurrent illnesses particularly when associated with inflammatory processes, physical or mental debility, removal of nutrients by dialysis procedure, acidemia, possibly physical deconditioning, and oxidant and carbonyl stress. However, diabetic MD patients are also at greater risk for PW or PEW from comorbidities related to diabetes per se. These disorders include ischemic vascular disease, hypertension, gastrointestinal dysfunction, and neuropathy. Metabolic disorders such as insulin deficiency or resistance to the actions of insulin, and elevated levels of counterregulatory hormones may also contribute to PW or PEW in diabetic MD patients. Mechanisms by which these metabolic disorders in diabetic ESRD patients may cause PW or PEW are discussed.

Dietary protein intake in patients with advanced chronic kidney disease and on dialysis.

Many patients with chronic kidney disease (CKD), particularly those with stage 5 CKD, have protein wasting. The degree to which increased morbidity and mortality seen in these patients is due to protein depletion rather than to the often accompanying comorbidity is not clear. High protein diets lead to the accumulation of metabolites of protein that are potentially toxic. The MDRD Study, which investigated the effects of three levels of dietary protein and phosphorus intakes and two blood pressure goals on the progression of CKD, has several limitations. Several meta-analyses have examined the effects of low protein diets (LPD) on the progression of CKD. It is possible that the lower SUN levels or lesser degree of uremic symptoms may have contributed to the positive findings of LPD in the meta-analyses of Fouque and Pedrini et al., when compared with the study of Kasiske et al. A number of published reports indicate that LPD provide adequate protein for almost all clinically stable CKD patients and do not adversely affect body composition. In general, there are no large differences in the protein intake recommended by different expert groups for a given stage of CKD.

Dietary assessment of individuals with chronic kidney disease.

Examining the quality and quantity of food intake by appropriate methods is critical in the management of patients with chronic kidney disease (CKD). The four commonly used dietary assessment methods in CKD patients include short-term dietary recalls, several days of food records with or without dietary interviews, urea kinetic based estimates such as protein nitrogen appearance calculation, and food histories including food screeners and food frequency questionnaires (FFQ). There are a number of strengths and limitations of these dietary assessment methods. Accordingly, none of the four methods is suitable in and of itself to give sufficiently accurate dietary information for all purposes. Food frequency questionnaires, which is the preferred method for epidemiological studies, should be used for dietary comparisons of patients within a given population rather than individual assessment. Food histories including FFQ and dietary recalls may underestimate important nutrients, especially in CKD patients. Given the large and increasing number of dialysis patients and work responsibilities of renal dietitians, routine analysis of dietary records and recalls is becoming less feasible. Ongoing and future studies will ascertain additional strengths and limitations of dietary assessment methods in CKD populations including the assessment of food intake during an actual hemodialysis treatment.

Dietary intakes of fiber and magnesium and incidence of metabolic syndrome in first year after renal transplantation.

OBJECTIVE: Considering the high prevalence of metabolic syndrome (MetS) and the associated cardiovascular disease mortality after renal transplant, and considering that the lack of prospective studies regarding the role of fiber and magnesium in MetS prevention after transplant precludes definitive recommendations, we prospectively evaluated the potential role of fiber and magnesium intake in the incidence of MetS at 1 year after renal transplantation. DESIGN: This was a prospective cohort study. SETTING, PARTICIPANTS, AND MEASUREMENTS: We included 160 recipients of kidney transplant (100 men and 60 women) aged over 18 years who were free of MetS or diabetes at time of transplant, and followed these patients for 1 year. METHODS: The usual dietary intakes were assessed with a Willett-format 168-item food-frequency questionnaire. We defined MetS according to modified Adult Treatment Panel III guidelines. We categorized participants by tertiles of dietary fiber and magnesium. To determine associations of fiber and magnesium intake with MetS incidence 1 year posttransplant, we used multivariable logistic regression. RESULTS: After controlling for potential confounders, including baseline body mass index and energy intake, subjects within the highest tertile of fiber intake had a lower odds ratio for incident MetS (odds ratio, 0.41; 95% confidence interval, 0.08 to 0.99; P < .05 for trend) than those in the lowest tertile. There was no significant overall association between magnesium intake and MetS. CONCLUSIONS: These findings support current dietary recommendations to increase intakes of fiber-rich foods as a primary preventive approach against MetS and cardiovascular disease, which are very prevalent after renal transplant.

Effects of coadministration of DHA and vitamin E on spermatogram, seminal oxidative stress, and sperm phospholipids in asthenozoospermic men: a randomized controlled trial.

BACKGROUND: It is unknown which compounds in spermatozoa or seminal plasma may be involved in the regulation of sperm motility. OBJECTIVES: The aim of this study was to investigate the effects of DHA (22:6n-3), vitamin E, and their probable interactions in men with asthenozoospermia. METHODS: A factorial, randomized, double-blind, placebo-controlled trial was conducted in infertility clinics in Tehran, Iran. The participants were idiopathic asthenozoospermic men aged 20-45 y, with normal endocrine function. Their concentration of spermatozoa and percentage of morphologically normal spermatozoa were equal to or above the lower reference limits, according to the fifth edition of the WHO guideline. Out of 717 men referred to the infertility clinics, 180 asthenozoospermic men were randomly assigned to 1 of 4 groups according to stratified blocked randomization by age and sperm concentration. Participants took daily 465 mg DHA plus 600 IU vitamin E (DE), 465 mg DHA plus placebo (DP), 600 IU vitamin E plus placebo (EP), or both placebo capsules (PP) for 12 wk. Sperm characteristics, oxidative stress of seminal plasma, serum and sperm membrane fatty acids, dietary intakes, anthropometric measurements, and physical activity were measured at baseline and after 12 wk. RESULTS: After the intervention, mean ± SD sperm progressive motility was greater in the DE group (27.9 ± 2.8) than in the DP (25.7 ± 3.4), EP (26.1 ± 2.8), and PP (25.8 ± 2.6) groups (P < 0.05). Sperm count (P = 0.001) and concentration (P = 0.044) increased significantly in the DE group compared with the other 3 groups, whereas other semen parameters were not significantly different between the groups after the intervention. Serum concentrations of n-3 PUFAs were significantly higher in the DE and DP groups than in the EP and PP groups. CONCLUSIONS: Combined DHA and vitamin E supplements led to increased sperm motility; however, no significant changes occurred in sperm morphology and vitality in asthenozoospermic men.This trial was registered at clinicaltrials.gov as NCT01846325.

Mediterranean diets are associated with a lower incidence of metabolic syndrome one year following renal transplantation.

Considering the high prevalence of metabolic syndrome and its association with cardiovascular mortality, we prospectively evaluated the role of diet in the incidence of metabolic syndrome in renal transplant recipients. Our prospective cohort of 160 adult renal allograft recipients was followed for 1 year and had no existing metabolic syndrome or diabetes mellitus. Routine dietary intakes were assessed with food-frequency questionnaires, and metabolic syndrome was defined according to the Adult Treatment Panel III guidelines. We identified 3 major patterns by factor analysis, consisting of those recipients predominantly consuming fats and sugars, those predominantly consuming whole grain, and the Mediterranean diet. When analyzed by multivariable logistic regression and after controlling for potential confounders, subjects in the highest tertile of scores for the Mediterranean diet had a significantly lower odds of metabolic syndrome than those in the lowest tertile. Subjects in the highest tertile of scores for consuming fats and sugars had significantly greater odds of metabolic syndrome compared with those in the lowest tertile. Our study shows that the Mediterranean dietary pattern is associated with a reduced risk of metabolic syndrome in renal transplant recipients.

Comparison of overall obesity and abdominal adiposity in predicting chronic kidney disease incidence among adults.

OBJECTIVE: Epidemiological data on the association between different aspects of adiposity and the risk for chronic kidney disease (CKD) in a cohort are limited. We compared the independent power of waist circumference (WC), waist-to-hip ratio (WHR), and body mass index (BMI) in predicting CKD in a large cohort of adults. DESIGN: This was a population-based cohort study. SETTING, PARTICIPANTS, AND MEASUREMENTS: A representative sample of 3107 subjects (1309 men and 1798 women), aged over 20 years, and free of CKD at baseline, was followed for 7 years. METHODS: We estimated glomerular filtration rate (GFR) by using the abbreviated equation from the Modification of Diet in Renal Disease Study, and defined CKD as an estimated GFR of less than 60 mL/min/1.73 m(2). Adjusted relative hazards of CKD were modeled using Cox proportional hazards regression, including BMI, WC, and WHR as risk factors. RESULTS: During the 7-year follow-up (median of 2183 days), 13.5% of participants (n = 419) developed CKD. The WC was positively related to risk of CKD, after multivariable adjustment for age, sex, smoking, menopause, physical activity, blood pressure, prevalent and incident diabetes, and change in WC during study period: Hazard ratios for CKD incidence were 1.00 (reference), 1.60 (95% CI: 1.06, 2.42), 1.86 (0.95 CI: 1.21, 2.85), and 1.88 (0.95 CI: 1.17, 3.01) for WC categories 1 to 4, respectively (P for trend < .02). The WHR was not independently associated with CKD. The rate of GFR decline (measured in mL/min/1.73 m(2)/year) was associated with baseline waist categories: regression coefficient for 1 SD increase in WC = -0.18 (0.95 CI:-0.28, -0.07). Based on Harrell's measure of concordance statistics, baseline WC was a better predictor of CKD than WHR (P < .05) and BMI (P < .05). CONCLUSIONS: Abdominal adiposity measured with WC, irrespective of general adiposity, is a more important determinant of CKD risk in adults than are WHR and BMI.