The effect of diet education on the laboratory values and knowledge of hemodialysis patients with hyperphosphatemia.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of 20 to 30 minutes per month of additional diet education on monthly laboratory values (phosphorus, calcium, parathyroid hormone, and calcium/phosphorus product) and knowledge of dietary phosphorus management in hemodialysis patients with hyperphosphatemia. DESIGN: A quasi-experimental design. SETTING: Three outpatient dialysis centers owned by the same corporation in 1 southern state. PATIENTS: Based on a 3-month average serum phosphorus >6.0 mg/dL, 70 patients were selected for participation; 63 dialysis patients completed the study, 32 in the experimental group and 31 in the control group. INTERVENTION: All patients completed a before-and-after knowledge test and had monthly blood samples drawn. Each month, the same registered dietitian provided the routine laboratory results review with control group. The experimental group received the routine laboratory review plus 20 to 30 minutes of additional diet education specifically targeting phosphorus.Main outcome measures Before-and-after knowledge test results and baseline and final serum calcium, phosphorus, parathyroid hormone, and calcium/phosphorus product levels. RESULTS: At baseline, there were no significant differences in any of the laboratory values, but the knowledge level of the experimental group was greater (P <.05) After 6 months, gains in knowledge were significantly higher in the intervention group, and the serum phosphorus and calcium/phosphorus product levels were significantly lower (P <.01) than in the control group. CONCLUSION: Based on this research, those patients who received extra education monthly showed positive changes, which may be beneficial in reducing hyperphosphatemia.     

The impact of Super Bowl parties on nutritional parameters among hemodialysis patients.

BACKGROUND: Little is known about the impact of holiday and other special-event meals on patients with chronic medical conditions. It is possible that patients are less adherent with dietary restrictions during such meals. We sought to determine the impact of Super Bowl parties on nutritional parameters among hemodialysis patients. OBJECTIVE: To determine the relationship between attending a Super Bowl party and subsequent change in serum phosphorus level, serum potassium level, interdialytic weight gain, and blood pressure. DESIGN: Retrospective cohort study. SETTING: Outpatient dialysis unit. PATIENTS: One hundred twenty-two chronic hemodialysis patients. MAIN OUTCOME MEASURES: Patients were asked whether they had attended a Super Bowl party. Serum phosphorus level, serum potassium level, interdialytic weight gain, and predialysis blood pressure at the hemodialysis treatment after the Super Bowl and at the hemodialysis treatment 1 month previously were obtained by chart abstraction. RESULTS: The 15 patients who had attended a party had increased serum phosphorus levels (+0.5 mg/dL) and interdialytic weight gain (+1.1% of dry weight) from baseline. These increases were statistically significant (P values .005 and .02, respectively) compared with patients who did not attend a party. Attendees also had increased systolic blood pressure (+6 mm Hg) from baseline, but this was of marginal statistical significance compared with nonattendees (P = .14). Attending a party was not significantly associated with changes in serum potassium and diastolic blood pressure. CONCLUSIONS: Attending a Super Bowl party is associated with adverse changes in several nutritional parameters. Although patients should not be discouraged from attending holiday and special-event meals, management of hemodialysis patients should include increased dietary counseling before holidays and special events and increased monitoring afterward.     

Adherence to treatment and hospitalization risk in hemodialysis patients

Background: The aim of this study was to evaluate whether adherence to treatment is associated with hospitalization risk in hemodialysis patients. Methods: We completed a cohort analysis of risk factors during 1 census month (November) and 1 year of follow-up during 5 consecutive years (2002-2006) in all end-stage renal disease patients hemodialyzed in the Kaunas region. During the census month, we collected data on noncompliance defined as (i) skipping of a hemodialysis (HD) session, (ii) shortening of 1 or more HD sessions, (iii) presence of hyperkalemia, (iv) presence of hyperphosphatemia, or (v) interdialytic weight gain (IDWG). In addition, data on age, sex, disability status, comorbidities, anemia control, malnutrition and inflammation, calcium-phosphorus metabolism and hospitalization rate were collected. Relative risk of hospitalization was estimated using Cox regression evaluating time to first hospitalization. Results: We analyzed 559 patients for a total of 1,163 patient-years during the 5 years of the study. On multivariate analysis, adjusting for ischemic heart disease, diabetes mellitus, higher number of comorbid conditions, higher systolic blood pressure before dialysis, worse disability status, lower hemoglobin, albumin and urea before dialysis, the relative risk for hospitalization increased by 1.1 for every additional percentage point of IDWG and by 1.19 with each 1 mmol/L rise of serum phosphorus level. Skipping or shortening of hemodialysis sessions and serum potassium level were not associated with hospitalization. Conclusions: Higher IDWG and higher serum levels of phosphorus independently increased the relative risk of hospitalizations in hemodialysis patients. With skipped and shortened dialysis sessions, higher serum potassium level was not associated with hospitalization risk.     

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.     

Nutrition counseling impacts serum albumin levels.

OBJECTIVE: To determine the difference in the rate of change of serum albumin levels between protein-energy malnourished patients who receive intensive dietary counseling and patients who receive a special oral liquid nutritional supplement (Nepro; Ross Products, Division Abbott Laboratories, Columbus, OH). DESIGN: Participants with serum albumin values < or =3.5 g/dL (bromocresol green) or 3.2 g/dL (bromocresol purple) and a Mini Nutrition Assessment (MNA) Malnutrition score < or =23.5 were randomized to the supplement group (Nepro) or the nonsupplement group with intensive dietary counseling. PATIENTS: Forty-one hemodialysis patients 18 years and older who had been on dialysis for at least 6 months. INTERVENTION: Participants were randomly assigned to supplement (26) or nonsupplement (14) groups. MAIN OUTCOME MEASURES: Albumin levels. STATISTICAL ANALYSES PERFORMED: Analysis of variance and chi2 tests, linear regression. RESULTS: After adjustment for demographic and clinical characteristics, the rate of change in serum albumin level was significantly greater among patients randomized to dietary counseling alone than among those who received oral supplements. These preliminary results suggest that intensive nutritional counseling may be of greater benefit than nutritional supplements alone in the management of protein-energy malnutrition in patients on hemodialysis. These preliminary findings should be confirmed by a larger full-scale trial.     

Randomized double-blind trial of oral essential amino acids for dialysis-associated hypoalbuminemia

BACKGROUND: Hypoalbuminemia is associated with substantial morbidity and mortality in dialysis patients. METHODS: Subjects with a mean three-month prestudy serum albumin of 3.8 g/dL or less and who demonstrated >/=90% compliance during a two-week run-in period were randomized to 3.6 g of essential amino acids (EAAs) or placebo three times daily with meals for three months. Randomization was stratified by dialysis modality and by severity of the hypoalbuminemia. The primary study outcome was change in the average of three monthly serum albumin measurements between baseline and follow-up. RESULTS: Fifty-two patients were randomized; 47 patients (29 hemodialysis and 18 peritoneal dialysis) met the predetermined primary analysis criteria. The mean compliance rates averaged 75, 70, and 50% at months 1, 2, and 3, respectively, and were similar for EAAs and placebo. Serum albumin in the hemodialysis patients, EAA versus placebo, improved [(mean +/- SE) 0.22 +/- 0.09 g/dL, P = 0.02]. Changes in peritoneal dialysis patients were not significant (0.01 +/- 0.15 g/dL), but approached significance for the total study group (0.14 +/- 0.08 g/dL, P = 0.08). Patients in the very low albumin strata (<3.5 g/dL) improved more than those in the low albumin strata (3.5 to 3.8 g/dL, P < 0.01). There was a significant correlation (r = 0.83, P = 0.001) within the hemodialysis EAA group between the baseline C-reactive protein level and improvement in serum albumin. Improvements were also seen in grip strength and SF-12 mental health score, but not in serum amino acid levels, SF-12 physical health score, or anthropometric measurements. CONCLUSIONS: Oral EAAs induce a significant improvement in the serum albumin concentration in hemodialysis but not peritoneal dialysis subjects. Further study of their long-term effects on morbidity and mortality is warranted.     

Variation of clinical and laboratory features in chronic dialysis patients treated with high-flux hemodialysis after switching to online hemodiafiltration

Purpose

The study of online hemodiafiltration (HDF) benefits over high-flux hemodialysis (HD) raises great interest. The purpose was to compare clinical and laboratory parameters in patients treated with HD who were switched to HDF.

Methods

Forty-eight HD patients (study group) were switched to HDF, while other 521 patients remained on HD as a control group. During last 6 HD months and during first year of HDF, we determined in both groups the following parameters: monthly–weekly dialysis time, systolic and diastolic blood pressure, body mass index (BMI), interdialytic body weight gain (IBWG), blood flow rate (Qb), weekly erythropoietin-stimulating agents dose (EPO), single-pool Kt/V, calcium, phosphorus (P), hemoglobin and normalized protein catabolic ration (nPCR), plus every 3 months—albumin, parathormone (PTH), ferritin and transferrin saturation (TSAT). In both groups, parameters in the last 6 HD months were compared to those in the first 6 months and, respectively, to those in the first year of HDF.

Results

In the study group, albumin and nPCR were significantly higher in the HD period not only compared to the first 6 months of HDF, but also compared to the first year of HDF. IBWG and P were higher with HD compared to the first year of HDF, but not with the first 6 months. PTH, Kt/V, Qb and EPO were higher in both HDF periods. In the control group, albumin was significantly higher in the first 6 months after the switch, but it was significantly lower in the first year. BMI, ferritin, PTH, Kt/V, Qb, TSAT and weekly dialysis time were higher in both HDF periods, while nPCR, EPO, SBP and DBP were lower. IBWG and Hb rose only during the first year after the switch, while P was lower in the first year, but not in the first 6 months.

Conclusions

Nutrition, assessed by albumin, nPCR and BMI, was not improved by HDF compared to HD. With HDF, Kt/V and phosphorus control were better, similar results were observed in the control group. A larger EPO dose was needed with HDF for maintaining a similar hemoglobin level.     

Length of interdialytic interval influences serum calcium and phosphorus concentrations.

BACKGROUND: Higher levels of serum phosphorus and calcium are associated with increased haemodialysis (HD) patient mortality. Both of these factors act synergistically to promote vascular smooth muscle differentiation to an osteoblast-like phenotype and subsequent vascular calcification. The aim of this study was to investigate the influence of interdialytic interval on serum levels, as well as the influence of oral calcium-based phosphate binder load on the magnitude of the observed differences. METHODS: We studied 100 patients undergoing HD three times per week, over a 2 week period. Haemoglobin, albumin, calcium and phosphate were measured pre-dialysis before each HD session. Oral phosphate binder usage was recorded. All patients were treated with dialysate containing 1.25 mEq/l calcium. RESULTS: Both mean serum phosphate and calcium were higher after the long interdialytic interval (1.59+/-0.05 vs 1.45+/-0.04 mmol/l, P = 0.0005, and 2.46+/-0.03 vs 2.4+/-0.02 mmol/l, P = 0.001, for serum phosphate and uncorrected calcium, respectively). There were no significant differences in haemoglobin or serum albumin, indicating that variable dilution from an increased hydration status in the long interdialytic interval was unlikely to contribute to these observed differences. A total of 74 patients were treated with calcium-containing binders and 26 patients with sevelamer. Patients on sevelamer did not exhibit the observed cyclical increase in serum calcium seen in patients on calcium-containing binders (mean difference in serum calcium 0.09+/-0.01 mmol/l in the calcium-treated group vs 0.01+/-0.01 mmol/l in the sevelamer-treated patients, P = 0.0004). The increase in serum calcium after the long interval as compared with the short interval was proportional to the daily amount of the oral calcium-containing binder load ingested (r = 0.63, P<0.0001). CONCLUSION: Cyclical differences in interdialytic interval and overall exposure to both dietary phosphate and oral calcium load influence serum levels. This may have consequences for registry reporting, therapy modulation and potentially the pathogenesis of accelerated vascular calcification seen in HD patients.     

Daily nutrient intake represents a modifiable determinant of nutritional status in chronic haemodialysis patients.

BACKGROUND: In maintenance haemodialysis patients, daily food intake is changeable; however, its relationship with nutritional status is unexplored. This study aimed to evaluate the isolated, long-term effect of daily nutrient intake on nutritional status in haemodialysis patients. METHODS: We performed a prospective 1-year controlled study in 27 chronic haemodialysis patients, without recognized risk factors for malnutrition. Each day for 1 week, four times in the year, we measured protein nitrogen appearance, and assessed dietary protein (DPI) and energy (DEI) intake from dietary diaries. We compared the nutritional outcome of patients spontaneously reducing nutrient intake below the threshold of 0.8 g/kg body weight/day for DPI and 25 kcal/kg body weight/day for DEI during the week (LOW, n = 8), with controls at adequate nutrient intake (CON, n = 19). An interventional 6-month study was then carried out in LOW to verify the cause-effect relationship. RESULTS: All patients showed a day-by-day reduction of whole nutrient intake during interdialytic period, which was mostly relevant in the third interdialytic day (L3). During the 1-year study, even in the presence of adequate dialysis dose and normal inflammatory indexes, body weight (68.0 +/- 5.5 to 65.8 +/- 5.9 kg), serum albumin (3.96 +/- 0.07 to 3.66 +/- 0.06 g/dl) and creatinine (9.2 +/- 1.1 to 8.1 +/- 0.7 mg/dl) significantly decreased in LOW but not in CON. Diaries evidenced in LOW a reduced number of meals at L3 that was explained by the fear of excessive interdialytic weight gain. During the interventional study, daily DPI and DEI increased at L3; this was associated with a significant increment of body weight, and serum albumin and creatinine levels. CONCLUSIONS: In maintenance haemodialysis patients the persistent, marked reduction of daily nutrient intake, even if limited to a single day of the week, is an independent determinant of reversible impairment of nutritional status.     

药用活性炭有效降低顽固性高磷血症透析患者血磷水平与钙磷乘积

目的 研究口服药用活性炭对未能控制的高磷血症透析患者血磷与钙磷乘积的作用.方法 采用单中心、前瞻性、自身前后对照研究.经含钙的磷结合剂治疗后仍存在高磷血症的血液透析或腹膜透析患者,餐中加服药用活性炭4.5～7.2 g/d治疗3个月.检测治疗前后血磷、钙、钙磷乘积、全段甲状旁腺激素( iPTH)、白蛋白、血红蛋白水平.用配对t检验进行统计学分析.结果 与治疗前比较,治疗3个月后患者血磷水平显著下降[(1.85±0.30)mmol/L比(2.16±0.34) mmol/L,P＜0.01];血钙磷乘积也相应显著下降[(54.12±8.37) mg2/dl2比(63.93±8.83) mg2/dl2,P＜0.01];有更多并发继发性甲状旁腺功能亢进症的患者可以接受维生素D治疗(83.3％比50％);血钙与iPTH水平无显著性变化(P=0.734,0.665).活性碳治疗期间血白蛋白水平较前下降[(40.1±2.2)g/L比(41.7±2.9) g/L,P=0.001].结论 顽固性高磷血症透析患者在继续原有磷结合剂治疗基础上,口服药用活性炭可以有效地降低血磷水平与钙磷乘积,对血钙及iPTH水平没有显著性影响.活性炭治疗可使患者血白蛋白水平轻度下降.     

A randomized trial of intermittent versus continuous oral alfacalcidol treatment of hyperparathyroidism in end-stage renal disease

BACKGROUND: Secondary hyperparathyroidism, a major clinical problem in patients with chronic renal failure, develops in response to phosphate retention and impaired calcitriol [1,25-dihydroxyvitamin D3] synthesis. Vitamin D therapy, particularly alfacalcidol [1 alpha-hydroxyvitamin D3], has been shown to be effective in the treatment of secondary hyperparathyroidism. The aim of this study was to compare the effect of a 12-week course of continuous versus intermittent oral alfacalcidol therapy on parathyroid hormone suppression. PATIENTS AND METHODS: 34 patients were selected and randomly divided into 2 groups to receive either intermittent or continuous oral alfacalcidol. Baseline data were obtained on serum calcium, phosphorus, alkaline phosphatase and PTH. All but the PTH were monitored monthly. PTH levels were measured again until the end of the protocol. The intervention was 2 microg of alfacalcidol given after each dialysis session (intermittent group) or 1 microg given 6 days/week (continuous group). RESULTS: Serum calcium and phosphorus showed a tendency to increase from baseline levels in both groups. Mean PTH levels for both groups showed a progressive reduction over time during the study period. This decrement showed no significant difference with regard to the schedule of alfacalcidol administration when comparing the 2 groups. There also was no difference in the incidence of side effects--hypercalcemia and hyperphosphatemia--between the intermittent and continuous intervention. CONCLUSION: Feedback regulation of PTH with oral alfacalcidol therapy is efficient in the treatment of hyperparathyroidism. However, intermittent and continuous oral administration are equally effective in suppressing an elevated PTH level in hemodialysis patients, with similar safety margins.     

Interdialytic weight gain is less with the Mediterranean type of diet in hemodialysis patients.

OBJECTIVE: Interdialytic weight gain is an important prognostic factor in dialysis patients. Different eating patterns may affect interdialytic weight gain. The goal was to assess the effect of the Mediterranean type of diet on interdialytic weight gain of chronic hemodialysis patients. DESIGN: This study had a cross-sectional design. SETTING: Four hospital-based satellite hemodialysis units in different cities in Turkey. PATIENTS: A total of 702 patients (279 women, 423 men; mean age, 47.8 +/- 15.5 years) were included in the study. They were grouped according to the hemodialysis centers: Alanya-Izmir (group 1, n = 194) and Ankara-Adana (group 2, n = 508). INTERVENTION: Group 1 patients were consuming a Mediterranean type of diet, whereas group 2 patients had a diet rich in protein and carbohydrates. All of the patients were under the same dialysis and treatment protocols. The demographic data, the medications, interdialytic weight gains, and laboratory data such as serum albumin, C-reactive protein, hemoglobin, hematocrit, serum iron binding capacity, ferritin, and parathyroid hormone during the last 3 months for each patient were recorded. MAIN OUTCOME MEASURE: The interdialytic weight gain differences between the groups were compared using the Student t-test and the Mann-Whitney U test. RESULTS: When the two groups were compared according to age, sex, blood pressure, serum albumin, hematocrit, and parathyroid hormone levels, there was no statistically significant difference. Mean interdialytic weight gain for group 1 and group 2 was 2.47 +/- 0.94 kg and 3.08 +/- 0.94 kg, respectively (P < .001). When the two groups were compared according to their iron requirements, group 1 showed an increased requirement for doses of iron and erythropoietin (P < .001 and P < .001, respectively). CONCLUSIONS: A Mediterranean-type diet, rich in seafood and vegetables, was associated with less interdialytic weight gain compared with a diet rich in protein and carbohydrates. Although all of our patients had the same diet education and treatment protocols, the geographic region and culture influenced their compliance to diet and their therapeutic outcomes.     

Long-term use of 1.1% amino acid dialysis solution in hypoalbuminemic continuous ambulatory peritoneal dialysis patients

INTRODUCTION: Malnutrition is a common problem in patients treated with continuous ambulatory peritoneal dialysis (CAPD). Hypoalbuminemia in CAPD patients is an independent risk factor for death and is associated with malnutrition. Previous short-term studies have examined the use of amino acid based PD solutions in terms of albumin levels and anthropometric changes, but not clinical outcome. We report on the extended use of 1.1% amino acid based peritoneal dialysis solution (Nutrineal) and have assessed clinical utility in terms of nutrition, biochemical indices, dialysis adequacy and clinical outcomes. METHODS: The effect of Nutrineal was studied retrospectively in 22 patients during the past 30 months. All patients had an albumin level of < 35 g/l prior to commencing Nutrineal, and had either a protein intake < 1.2 g/kg or weight loss of > 5% in the previous 3 months. 19 of the 22 patients underwent an 8-week trial of oral nutritional supplements with no improvement in serum albumin level. Albumin level, normalized protein catabolic rate, weight, Kt/V and creatinine clearance were assessed for all patients prior to Nutrineal and at the end of the study period. RESULTS: The mean time on Nutrineal therapy was 13.6 months (range 6-26 months). There were no reported side effects of the treatment. There was an average of 1 episode of peritonitis per 23 treatment months, and only 1 patient died (4% annually adjusted mortality cf 8.9% on the peritoneal dialysis program as a whole). There was a significant increase in albumin level from 22.45 +/- 0.97 range 14-33 g/l to 25.68 +/- 1.159 range 16-35 g/l (p = 0.0036). Normalized protein catabolic rate increased significantly, from 0.898 +/- 0.053 to 1.085 +/- 0.056 g/kg/day (p = 0.0057). Weight decreased slightly although this did not reach statistical significance. Kt/V and creatinine clearance both decreased significantly, but remained within the adequate range in > 80% of the patients. There was no significant change in residual renal function (mean residual creatinine clearance 3.8 +/- 0.59 ml/min at the start of the study period, cf 3.4 +/- 0.61 ml/min at the end). CONCLUSION: These data suggest that Nutrineal can be used safely and effectively for an extended period of time. Such use is associated with a low mortality rate and a low peritonitis rate, although dialysis adequacy is compromised to a degree.     

Dominant factors of the phosphorus regulatory network differ under various dietary phosphate loads in healthy individuals

BackgroundThe purpose of this study was to explore the contribution of each factor of the phosphorus metabolism network following phosphorus diet intervention via Granger causality analysis.MethodsIn this study, a total of six healthy male volunteers were enrolled. All participants sequentially received regular, low-, and high-phosphorus diets. Consumption of each diet lasted for five days, with a 5-day washout period between different diets. Blood and urinary samples were collected on the fifth day of consumption of each diet at 9 time points (00:00, 04:00, 08:00, 10:00, 12:00, 14:00, 16:00, 20:00, 24:00) for measurements of serum levels of phosphate, calcium, PTH, FGF23, BALP, α-Klotho, and 1,25 D and urinary phosphorus excretion. Granger causality and the centrality of the above variables in the phosphorus network were analyzed by pairwise panel Granger causality analysis using the time-series data.ResultsThe mean age of the participants was 28.5 ± 2.1 years. By using Granger causality analysis, we found that the α-Klotho level had the strongest connection with and played a key role in influencing the other variables. In addition, urinary phosphorus excretion was frequently regulated by other variables in the network of phosphorus metabolism following a regular phosphorus diet. After low-phosphorus diet intervention, serum phosphate affected the other factors the most, and the 1,25 D level was the main outcome factor, while urinary phosphorus excretion was the most strongly associated variable in the network of phosphorus metabolism. After high-phosphorus diet intervention, FGF23 and 1,25 D played a more critical role in active regulation and passive regulation in the Granger causality analysis.ConclusionsVariations in dietary phosphorus intake led to changes in the central factors involved in phosphorus metabolism.     

Influence of haemodialysis on plasma total homocysteine concentration.

BACKGROUND: The high prevalence of hyperhomocysteinaemia in uraemic patients is of interest because of the cardiovascular risk associated with increased plasma total homocysteine (tHcy) concentration. Treatment with folic acid lowers tHcy in haemodialysis patients, however, in most patients not to normohomocysteinaemic levels. With possible tHcy-lowering modifications in mind, we studied the influence of standard haemodialysis on tHcy. METHODS: In 56 folate-loaded haemodialysis patients, tHcy and parameters of dialysis adequacy were measured. In six patients, interdialytic curves of tHcy and serum creatinine concentrations were obtained and in five patients, the amount of homocysteine (Hcy) in dialysate was determined. RESULTS: tHcy (21.8+/-14.4 micromol/l) correlated significantly with Kt/V (r=0.32, P<0.05), total Kt/V (r=0.29, P<0.05), nPCR (r=0.30, P<0.05) and serum concentrations of albumin (r=0.28, P<0.05) and cobalamines (r=-0.27, P<0.05). In a multiple linear regression analysis, only serum albumin concentrations significantly predicted tHcy (r=0.34, P < 0.05). During dialysis, tHcy decreased by 28% and remained constant for at least 8 h after treatment. The amount of Hcy recovered in dialysate was 63 micromol (12-158 micromol). There was no difference in tHcy between those who had residual renal function and those who had not. CONCLUSIONS: The direct relationship between tHcy and Kt/V seemed to be mediated by the serum albumin concentration. The shape of the interdialytic tHcy curve suggested facilitated Hcy removal for at least 8 h after dialysis possibly due to reduced levels of inhibitory activities against relevant enzyme(s). The dialysed amount of Hcy did not seem to contribute significantly to Hcy removal. Thus, modifications of standard dialytic regimens are not likely to be effective from a tHcy-lowering point of view whereas convective procedures such as haemofiltration or haemodiafiltration might be more effective.