Relationship between dietary protein intake and nutritional status in maintenance hemodialysis patients

Objective To assess the influence of protein intake on nutritional status and mineral metabolism in patients with maintenance hemodialysis (MHD). Methods A cross-sectional study and a prospective cohort study were conducted. According to dietary protein intake (DPI), patients were divided into two groups: DPI≥1.2 g?kg-1?d-1 group (HP group) and DPI＜1.2 g?kg-1?d-1 group (NP group). One hundred and twenty-six MHD patients were enrolled in the cross-sectional study and their datum of dietary intake, as well as laboratory examinations were recorded. In the prospective cohort study lasted 2 years, 32 MHD patients were enrolled, with their dietary and laboratory examinations being collected every 3 months, and somatometric measurements being recorded at the beginning and the end of the study. Results In the cross-sectional study, the average DPI of HP group was (1.36±0.14) g?kg-1?d-1 and the average DPI of NP group was (1.04±0.09) g?kg-1?d-1. Compared with patients in NP group, patients in HP group had higher DPI, daily energy intake (DEI), normalized protein equivalent of nitrogen appearance rate (nPNA) and serum phosphate, and lower carbon dioxide combining power (CO2CP) (all P＜0.05) . There was no difference between two groups in hemoglobin, total protein, albumin, total cholestoral, blood calcium and intact parathyroid hormone (iPTH). In the prospective cohort study, the average DPI of HP group was (1.35±0.13) g?kg-1?d-1 and the average DPI of NP group was (1.05±0.11) g?kg-1?d-1. During the follow-up period, there were no significant differences in times comparison (all Ptime＞0.05). There was higher DPI, nPNA and serum phosphate, and lower CO2CP in HP group, than those in NP group (all Pgroup＜0.05). In terms of hemoglobin, total protein, albumin, total cholestoral and somatometric measurements, there was no difference between two groups (all Pgroup＞0.05). Conclusions DPI around 1.05 g?kg-1?d-1 can satisfy the nutritional requirement in MHD patients with good nutrional status, and ameliorate hyperphosphatemia and acidosis.     

Influence of protein intake on phytohemagglutinin skin test in patients undergoing maintenance hemodialysis

We studied the influence of protein intake on the phytohemagglutinin (PHA) skin test and purified protein derivative (PPD) skin test in 45 patients on maintenance hemodialysis. The patients were 23 males and 22 females, the ages ranging from 19 to 80 years, with an average of 53.6 years. All patients were being maintained on long-term hemodialysis (mean 37.3 months). They were divided into three groups according to protein intake: Group A; less than 1.1 g/kg/day, Group B; 1.1-1.5 g/kg/day, Group C; more than 1.5 g/kg/day. There were no significant differences among the three groups with respect to age, causative disease and the period of maintenance hemodialysis. We measured protein intake, PHA skin test and PPD skin test. Significant differences were found between Group B and Group C with respect to the PHA skin test values and PPD skin test values, the values of Group C being very low compared with those of Group B. The PHA skin test values and PPD skin test values were only slightly lower in Group A than in Group B. The negative reaction rate of PPD in Group A and Group C was much higher than in Group B. The results suggest that excess intake of protein impaired cellular immunity in maintenance hemodialysis patients, and that protein deficiency can also have a detrimental effect on cellular immunity. Therefore, adequate protein intake should be maintained for optimizing cellular immunity.     

Effect of energy intake on nutritional status in maintenance hemodialysis patients

Although maintenance hemodialysis (MHD) patients are often wasted, little is known about their dietary energy needs. We studied four men and two women in a clinical research center while they received diets providing 45, 35 and 25 kcal/kg desirable body weight/day; diets were fed, in random order, for 21 to 23 days each. Protein intake, 1.13 +/- 0.02 (SEM) g protein/kg/day, was similar with all three diets. Body weight rose with 45 and 35 kcal/kg/day (P less than 0.05) and fell with 25 kcal/kg/day (P less than 0.05). Nitrogen balance, adjusted for estimated unmeasured losses, was neutral with 45 and 35 kcal/kg/day and negative with 25 kcal/kg/day. Balance was neutral or positive in 6 of 6, 4 of 6, and 0 of 6 patients fed 45, 35, 25 kcal/kg/day, respectively. Nitrogen balance, many plasma amino acids and changes in body weight, mid-arm circumference, mid-arm muscle area and body fat each correlated with energy intake. Resting energy expenditure was normal. The energy intake estimated from regression equations to maintain neutral nitrogen balance was 38.5 kcal/kg desirable weight/day; for body fat and weight, it was 32 kcal/kg/day. These data suggest that MHD patients have normal energy expenditure and approximately normal requirements for maintenance of protein balance, body weight and body fat. An average energy intake of about 38 kcal/kg desirable weight/day may be necessary to maintain nitrogen balance in these patients.     

Effect of sevelamer on dyslipidemia and chronic inflammation in maintenance hemodialysis patients

BACKGROUND: Hemodialysis (HD) patients often experience cardiovascular events, that might be related to altered calcium-phosphate metabolism, dyslipidemia, and chronic inflammation in addition to hypertension. Sevelamer, a non-calcium-containing phosphate binder, may improve the lipid profile of HD patients. However, the influence of sevelamer on chronic inflammation has not been clarified. METHODS: We enrolled 36 maintenance HD patients with a serum calcium (Ca) or phosphate (P) level constantly greater than 9.5 mg/dL and 5.5 mg/dL, respectively. The dose of sevelamer was titrated to achieve a serum Ca and P in the target ranges. The study period was 24 weeks. Patients underwent the following measurements: bone mineral markers, lipids, and a high-sensitivity C-reactive protein (hs-CRP). RESULTS: In the 28 patients who completed the study, sevelamer significantly reduced the mean non-high-density lipoprotein cholesterol (non-HDL-C) level by 15% and 20% (p < 0.0001) after 12 and 24 weeks, respectively, in addition to reducing the serum P level and Ca x P product. Similarly, there was a significant reduction of the serum hs-CRP level after 12 and 24 weeks [median at baseline: 1.03 mg/dL (interquartile range 0.26-3.98 mg/dL) versus 0.57 (0.17-1.47) and 0.38 (0.16-1.03), respectively, p = 0.0259]. The reduction rate of hs-CRP was significantly correlated with those of non-HDL-C (r = 0.451, p < 0.0401) and P (r = 0.453, p < 0.0008) CONCLUSION: Hs-CRP levels were reduced by sevelamer administration, as well as non-HDL-C, P, and the Ca x P product. Sevelamer may have an anti-inflammatory effect, in addition to lowering phosphate and lipid levels in HD patients.     

Age-related decline in serum parathyroid hormone in maintenance hemodialysis patients is independent of inflammation and dietary nutrient intake.

BACKGROUND: There is a direct relationship between age and serum parathyroid hormone (iPTH) in the normal population, but several studies suggest this relationship is reversed in maintenance hemodialysis (MHD) patients. The pathophysiologic basis of this age-related decline in serum iPTH levels remains unclear, although others have proposed that it is related to low dietary phosphorus intakes. METHODS: We conducted a prospective, cross-sectional evaluation of the relationship between age and serum iPTH levels and factors affecting this relationship. All participating subjects were asked to complete a 3-day food diary. The charts were reviewed to obtain routinely measured laboratory values over the preceding 3 months, and serum was collected to measure markers of systemic inflammation. RESULTS: Ninety-two MHD patients (47 men; age, 51.3+/-14.9 [standard deviation] years; median dialysis vintage, 25.8 months) were studied. Age was inversely correlated with both serum phosphorus and iPTH; these relationships remained significant even when the data were adjusted for diabetic status, dialysis vintage, and dietary nutrient intake. However, there were no associations of age, serum phosphorus, or iPTH with dietary intakes of protein, calories, phosphorus, or calcium either on univariate or multivariate analyses. Markers of systemic inflammation (serum C-reactive protein, and alpha1 acid glycoprotein) did not correlate with age, serum phosphorus, and iPTH or dietary nutrient intake. On the other hand, serum albumin, which may reflect long-term effects of inflammation, did correlate inversely with age and positively with serum phosphorus. CONCLUSIONS: Our cross-sectional study confirms that there are age-related lower levels of both serum phosphorus and iPTH in MHD patients. The mechanisms regarding the inverse relationship between serum phosphorus and age are unclear, but may not be caused by low phosphorus intake or systemic inflammation. In elderly MHD patients, the reduced responsiveness of parathyroid glands may be related to age-dependent accumulation of uremic toxins.     

维持性血液透析患者生活质量与蛋白质能量消耗和微炎症状态的相关性研究

目的 探讨维持性血液透析(MHD)患者生活质量(QOL)与蛋白质能量消耗(PEW)和微炎症状态(MIS)的关系.方法 采用病例对照研究,观察2016年5月至2018年6月在桂平市人民医院行血液透析治疗的慢性肾脏病5期患者,按照是否合并PEW分为PEW组和非PEW组,按照是否存在MIS分为MIS组与非MIS组;分析患者的...     

维持性血液透析患者营养不良-炎性反应状态与其住院及死亡风险的临床研究

目的 探讨维持性血液透析(MHD)患者营养和炎性反应状态与其住院和死亡情况的关系,并寻找能够反映MHD患者住院和死亡风险的营养及炎性反应指标.方法 随访观察1年我院血透中心MHD患者的营养和炎性反应状况,比较住院和非住院患者的营养及炎性反应状态的差别;并通过Cox比例风险模型寻找能够反映患者1年内首次住院及死亡风险的营养及炎性反应指标.结果 入组患者118例,轻、中、重度营养不良的住院率分别为32.93％、56.67％和83.33％;病死率分别为3.66％、6.67％和80.00％;存在微炎性反应状态和不存在微炎性反应状态患者的住院率分别为56.45％和46.43％,病死率分别为14.29％和1.61％.住院患者营养不良-炎性反应评分(8.36比5.86,P＜0.05)和改良主观营养评价得分(14.49比12.88,P＜ 0.05)均高于未住院患者,差异有统计学意义.与非住院患者比较,住院患者Scr (886.83 μmol/L比991.76 μmol/L,P＜ 0.05)、白蛋白(38.57g/L比40.27g/L,P＜0.05)较低,差异有统计学意义.住院患者TNF-α高于非住院患者(65.41 μg/L比59.76 μg/L,P＜ 0.05),差异有统计学意义.Cox比例风险模型显示营养不良炎性反应评分(MIS)和TNF-α 与患者首次住院的危险性有关,其值越大,1年内首次住院的危险性越大.结论 MHD患者营养不良与炎性反应状态的程度越重,其住院和死亡的风险越大.营养不良-炎性反应评分和TNF-α水平越高,1年内首次住院的危险性越大.     

维持性血液透析患者胎球蛋白A和炎症水平与心脏瓣膜钙化的相关性

目的 探讨继发性甲状旁腺功能亢进患者行甲状旁腺全切除或次全切除术的预后.方法 入选2009年1月至2014年3月前在青岛大学附属医院血液透析中心的维持性血液透析(maintenance hemodialysis,MHD)患者99例,所有患者均行超声心动检查,根据超声心动结果将患者分为合并心脏瓣膜钙化组和无心脏瓣膜钙化组,另根据心脏瓣膜钙化数量将患者分为无瓣膜钙化(A组)、单个瓣膜钙化(B组)和双瓣膜钙化(C组).采用酶联免疫吸附法(ELISA)检测血胎球蛋白A(Fetuin-A)、白细胞介素6(interleukin-6,IL-6)、超敏C反应蛋白(high sensitivity C-reactive protein,hs-CRP)水平并评价上述指标与心脏瓣膜钙化的相关性.结果 99例患者中合并瓣膜钙化40例(占40.4％),其中二尖瓣瓣膜钙化(mitral valve calcification,MVC)27例(占27.3％),主动脉瓣瓣膜钙化(aortic valve calcification,AVC)30例(占30.3％),二尖瓣瓣膜合并主动脉瓣瓣膜钙化(MVC合并AVC)17例(占17.2％).比较合并瓣膜钙化组和无瓣膜钙化组患者的临床资料发现,合并瓣膜钙化组的年龄、透析时间、血磷、全段甲状旁腺素(intact parathyroid hormone,iPTH)、hs-CRP、IL-6更高,白蛋白、Fetuin-A水平更低.比较A组、B组和C组发现,随着年龄、透析时间的增高,血磷、钙磷乘积、IL-6、hs-CRP水平的增高,瓣膜钙化的数量逐渐增多,而随着血白蛋白、Fetuin-A水平的增高,瓣膜钙化的数量逐渐减少.以Fetuin-A为自变量行相关性分析发现,与年龄(r=-0.246,P=0.014)、透析时间(r=-0.297,P=0.003)、iPTH(r=-0.256,P=0.011)、hs-CRP(r=-0.272,P=0.006)、IL-6(r=-0.492,P=0.000)、心脏瓣膜钙化(r=-0.6,P=0.001)呈负相关,而与血白蛋白(r=0.298,P=0.003)呈正相关.结论 MHD患者心脏瓣膜钙化的发生率较高,以主动脉瓣瓣膜钙化多见.Fetuin-A、炎症水平与心脏瓣膜钙化有着重要的相关性,评估Fetuin-A、炎症水平可能对识别心血管事件特别是心脏瓣膜钙化的发展和恶化有重要价值.     

Urinary matrix calculi consisting of microfibrillar protein in patients on maintenance hemodialysis

In seven patients on maintenance hemodialysis, de novo recurrent renal stone formation was observed. In all patients, the underlying disease was glomerulonephritis, with or without the nephrotic syndrome. All patients had considerable persistent proteinuria. The stones consisted predominantly of protein, as revealed by amino acid analysis, and had a negligible carbohydrate and lipid content. Only in some specimens, X-ray diffraction and scanning electron microscopy revealed the presence of small amounts of whewellit (calcium oxalate monohydrate) and/or uric acid. In semithin sections, the stones had a laminated texture and exhibited structural anisotropy under polarized light. With transmission electron microscopy, they were found to consist of peculair microfibrils. The proteinaceous material differed from fibrin or Tamm-Horsfall-protein, as indicated by ultrastructure, carbohydrate analysis, and amino acid analysis. Symptomatic de novo matrix stone formation constitutes another complication of dialyzed patients which has not been reported so far.     

Calculated nitrogen balance in hemodialysis patients: influence of protein intake

BACKGROUND: Optimal nutrient intake is important in the maintenance of a positive nitrogen balance in hemodialysis (HD) patients. The objectives of this study were (1) to assess the influence of two levels of protein intakes on nitrogen balance in stable adult HD patients, and (2) to identify a minimum level of protein intake that would result in a negative nitrogen balance, so that preliminary recommendations may be made in Indian patients on maintenance HD (MHD). METHODS: Stable, adult, nondiabetic MHD patients were recruited after informed consent into a cross over trial with a high-protein (HP) diet [1.2 g/kg ideal body weight (IBW)/day), followed by a low-protein (LP) diet (0.6 g/kg IBW/day] after appropriate periods of equilibration; for both diets, 50% of protein was of high biological value, and calorie intake was 35 kCal/kg IBW/day. Duplicate meals and residues were weighed, homogenized, and stored at -20 degrees C for analysis of dietary N by the Kjeldahl method, used to check the consistency of the N content of the diet supplied. Pre- and post- (30-minute equilibrated) blood urea samples were drawn, and details of weights and other HD parameters were recorded. Interdialytic urine collections for urea were obtained. N input came from dietary protein calculated as 16% of the weight of biological protein; N output was calculated using blood-side urea measurements and urinary urea excretion and was the sum of urea N (UN) and nonurea N (NUN) losses (assumed to be equal to 0.031 g N/kg/day). RESULTS: Fifteen patients were recruited. Twelve patients completed both limbs of the study. The mean age was 30.3 +/- 12.7 years. The body mass index was 18.9 +/- 2.4. Serum albumin was 3.8 +/- 0.35 g/dL, and Kt/V (equilibrated) was 1.17 +/- 0.3 g/dL. Protein consumed was 1.06 +/- 0.18 g/kg IBW/day in the HP limb versus 0.61 +/- 0.1 g/kg IBW/day in the LP limb (P = 0.000). Energy intake was 33 +/- 6.5 vs. 32.8 +/- 6. 7 kCal/kg IBW/day, respectively (P = 0.8). The normalized protein N appearance (nPNA) was 0.88 +/- 0.2 g/kg/day in the HP limb versus 0. 78 +/- 0.2 g/kg/day in the LP limb (P = 0.02). Dietary N was 73.5 +/- 15.3 g in the HP week and 42.5 +/- 7.5 g in the LP week (P = 0. 000). The difference between this and the sum of (UN + NUN) losses over the week was 29 +/- 13.2 g versus 1.2 +/- 8.1 g, respectively (P = 0.001), showing a strong, uniformly positive nitrogen balance with HP diet and neutral to negative nitrogen balance with LP diet. The ratio of dietary protein intake (DPI) to nPNA was significantly lower (anabolic) in the HP limb (0.7 +/- 0.2 vs. 1.12 +/- 0.3, P = 0. 000). On a scatter plot of nPNA to DPI, a catabolic relationship was demonstrated below a DPI of 0.75 g/kg/day (95% CI, 0.65 to 0.85 g/kg/day). CONCLUSION: A DPI of approximately 1.1 g/kg/day produces a positive nitrogen balance and 0.6 g/kg/day a neutral to negative nitrogen balance, demonstrating protein anabolism as a function of protein intake. It is suggested that a protein intake of 0.85 g/kg/day should be considered unsafe. These conclusions apply in stable nondiabetic adult HD patients in the setting of adequate dialysis and adequate calorie intake.     

Usefulness of artificial neural networks to predict follow-up dietary protein intake in hemodialysis patients

BACKGROUND: Artificial neural networks (ANN) represent a promising alternative to classical statistical and mathematic methods to solve multidimensional nonlinear problems. The aim of the study was to verify, by comparing the performance of ANN with that of experienced nephrologists, whether ANN are useful tools in hemodialysis to predict the follow-up (=1 month after the observation used for the prediction) dietary protein intake (PCR), and whether their performance is influenced by the size of the population and by the data pool used to built the model. METHODS: A combined retrospective and prospective observational study was performed in two Swiss dialysis units (84 chronic hemodialysis patients, 500 monthly clinical observations and biochemical test results). Using mathematical models based on linear regressions to evaluate the variables, ANN were built and then prospectively and interinstitutionally compared with the ability of six experienced nephrologists to predict the follow-up PCR. RESULTS: ANN compared with nephrologists gave a more accurate correlation between estimated and calculated follow-up PCR (P < 0.001). The same superiority of ANN was also seen in the ability to detect a follow-up PCR <1.00 g/kg/day expressed as a percentage of correct predictions, sensitivity, specificity, and predictivity. The interinstitutional performance of the ANN is positively influenced by the size and the variability of the population used to build the mathematical model. CONCLUSION: The use of ANN significantly improves the ability of the experienced nephrologist to estimate and to detect an unsatisfactory (<1.00 g/kg/day) follow-up PCR. The size of the population selected to build the ANN is critical for his performance.     

维持性血液透析患者血红蛋白变异性影响因素分析

目的调查分析湖北省中医院维持性血液透析(maintenance hemodialysis,MHD)患者血红蛋白变异性(hemoglobin variability,Hb-Var)情况,并探讨Hb-Var的影响因素。方法选取湖北省中医院血液净化中心2013年12月至2014年6月期间MHD患者56例,入组时收集患者基本资料,随访6个月内记录患者使用红细胞生成刺激剂(erythropoietin stimulating agents,ESAs)剂量、ESAs调整次数、静脉铁剂总量、血液透析滤过及血液灌流次数,6个月内至少检查3次实验室指标,包括血红蛋白(hemoglobin,Hb)、血钙(calcium,Ca)、血磷(phosphorus,P)、全段甲状旁腺素(immunoreactive parathyroid hormone,iPTH)、血清铁蛋白(serum ferritin,SF)、血清白蛋白(albumin,Alb)。以血红蛋白变异系数(hemoglobin-coefficient of variation,Hb-CV)代表Hb-Var,分析Hb-Var的影响因素。结果①血红蛋白波动组43例,占总例数76.79%;②单因素分析发现,在性别、年龄、透析龄、血管通路、静脉铁剂总量、ESAs调整次数方面,Hb-CV差异有统计学意义(P0.05);③Pearson相关分析显示,Hb-CV与ESAs调整次数、静脉铁剂总量呈正相关(r值分别为0.757、0.264,P0.05),与透析龄、SF、Alb呈负相关(r值分别为-0.323,-0.390,-0.418,P0.05),与年龄、血钙、血磷、iPTH无相关性;④Hb-CV影响因素的多元线性回归分析,性别、血管通路、ESAs调整次数、静脉铁剂总量、SF与Hb-CV独立相关。结论 MHD患者普遍存在Hb-Var,年龄越大血红蛋白波动可能更明显。血红蛋白的波动与性别、血管通路、使用静脉铁剂关系密切。Hb-Var与慢性肾脏病预后的关系尚存争议,需进一步研究证实。     

Interleukin-6 predicts hypoalbuminemia, hypocholesterolemia, and mortality in hemodialysis patients

Low serum albumin and low serum cholesterol levels are among the most consistent predictors of mortality in patients with end-stage renal disease (ESRD) undergoing hemodialysis. Hypoalbuminemia is often interpreted as a marker of poor nutrition, but serum albumin and cholesterol levels can also be low as part of a cytokine-mediated acute-phase reaction to acute or chronic inflammation. Here we report the results from a 900-day prospective study designed to determine whether tumor necrosis factor-alfa (TNF-alpha) and interleukin-6 (IL-6) predict serum albumin and cholesterol levels and mortality in a group of 90 ambulatory, adult hemodialysis patients with no acute infection, hospitalization or surgery, and no known acquired immunodeficiency syndrome (AIDS), malignancy, or liver disease. Measurable levels of TNF-alpha and/or IL-6 were found in 89 of 90 patients. Significant relationships were found between TNF-alpha and IL-6 and the degree of hypoalbuminemia and dyslipoproteinemia. IL-6 was the strongest predictor of mortality in univariate and multivariate analysis, followed by age, albumin level, and body mass index (BMI). Although the cause of hypercytokinemia was not addressed in this study, the data support the view that hypoalbuminemia and hypocholesterolemia are negative acute-phase responses to inflammatory stimuli. These results suggest that efforts to identify the nature of the stimuli for cytokine production and to lower cytokine levels in hemodialysis patients might be effective in improving the survival of patients undergoing hemodialysis.     

Plasma beta-endorphin in patients on maintenance hemodialysis

A sensitive and specific radioimmunoassay for beta-endorphin without gel filtration of plasma extracts has been developed by using newly raised antibody. The minimal detectable quantity was 5 pg, and ED 50 was 23 pg/ml. The crossreactivity of antibody with beta-lipotropin was 3.3%, but not showed crossreaction with other fragments of beta-lipotropin, beta-MSH and ACTH. The inter-assay coefficient of variation was 2.7% to 17.4%, and the intra-assay coefficient of variation was 4.5% to 26.4%, respectively. The mean recovery for unlabeled beta-endorphin added to plasma and extracted was 92.1% to 110.4%. Plasma levels of beta-endorphin in 40 normal subjects was 14.7 +/- 3.1 pg/ml and 14.8 +/- 1.1 pg/ml in 10 patients with chronic glomerulonephritis whose renal function was normal. There was no significant difference between the two groups. On the other hand, plasma levels of beta-endorphin in 16 patients on maintenance hemodialysis was significantly increased of 56.3 +/- 6.3 pg/ml than the other two groups. Physiological role of this high beta-endorphinemia in patients on maintenance hemodialysis still remains to be resolved.