Cystatin C as marker of residual renal function in patients on peritoneal dialysis: relation with parameters of peritoneal function

INTRODUCTION: Cystatin C (CysC) is a nonglycosylated protein of low molecular weight not influenced by age, sex or inflammation. The aim of this paper is to ascertain the usefulness of serum CysC level determination in peritoneal dialysis (PD) patients. MATERIAL AND METHODS: CysC serum levels were determined in 80 PD patients. The mean age of patients was 53.7 +/- 15 years, with 15.3 +/- 25.8 months on PD. Thirty-three percent were on continuous ambulatory peritoneal dialysis (CAPD) and 66.3% on automated peritoneal dialysis (APD). Fourteen patients (17%) had no residual renal function (RRF). RESULTS: Mean CysC levels were 5.8 +/- 1.4 mg/L, without differences between men (5.5 +/- 1.4 mg/L) and women (5.6 +/- 1.5 mg/L, NS). There was no correlation between CysC levels and age, weight, height or time on PD. Anuric patients had CysC levels significantly higher than non-anuric (6.7 +/- 1.4 vs. 5.3 +/- 1.3 mg/L, p<0.001). CysC levels showed an inverse correlation with RRF (r=-0.60, p<0.001) and residual urine volume (r=-0.58, p<0.001). CONCLUSIONS: In conclusion, serum CysC levels had the same statistical significance as plasma creatinine levels, and they are not influenced by peritoneal transport in PD patients. Consequently, both parameters are valid RRF markers.     

小剂量日间非卧床腹膜透析对残肾功能较好的糖尿病终末期肾病患者的疗效

目的　研究小剂量日间非卧床腹膜透析（DAPD）和小剂量持续非卧床腹膜透析（CAPD）对残肾功能较好的糖尿病终末期肾病（ESRD）患者的疗效。 方法 病情稳定、残肾功能较好（rGFR≥5 ml/min,且尿量≥750 ml/d）的40例糖尿病ESRD患者入选。按数字随机法分为小剂量DAPD组20例和小剂量CAPD组20例。DAPD组透析处方为1.5 L或2 L,3次/d,每次留腹3～4 h,夜间干腹。CAPD组透析处方为1.5～2 Ｌ,3次/d,或1.5 L,4次/d,夜间留腹。在研究开始及6个月后,分别计算两组腹膜尿素氮清除率（Kt/V）、残肾Kt/V、每周总Ｋt/V、Ccr、rGFR等指标;测定24 h尿蛋白量、24 h腹透液蛋白、血清白蛋白、空腹血糖、糖化血红蛋白及胰岛素剂量;用改良主观综合性营养评估法（SGA）评估患者营养状况。 结果 共35例患者完成研究。两组患者年龄、性别、体质量指数、透析龄、透析液肌酐/血肌酐（D/Pcr）等基线值差异无统计学意义。6个月后,CAPD组胰岛素剂量和24 h腹透液丢失蛋白明显高于DAPD组,分别为（33.6±10.9） U/d 比（20.6±6.2） U/d（P < 0.05）和（11.13±4.95） g比（5.66±2.88） g（P < 0.01）,而血清白蛋白明显低于DAPD组[（29.7±4.2） 比（36.5±3.9） g/L,P < 0.05]。DAPD组与CAPD组相比,24 h净超滤量为（554±187） ml比（309±177） ml,24 h尿量为（1090±361） ml比（750±258） ml,rGFR为（8.21±2.40） ml/min比（4.88±2.11） ml/min,DAPD组均显著高于CAPD组（均P < 0.05）。 结论 对于残肾功能较好的糖尿病ESRD患者,小剂量DAPD较小剂量CAPD能更好地控制血糖,改善营养状态及保护残肾功能。     

The contribution of residual renal function to overall nutritional status in chronic haemodialysis patients.

BACKGROUND: The benefits of residual renal function (RRF) in peritoneal dialysis patients have been described frequently. However, previous reports have shown that RRF diminished faster in haemodialysis (HD) patients than in peritoneal dialysis patients, and in most of the studies in HD patients, RRF was ignored. In this study, the RRF in chronic HD patients was studied to assess its impact on patients' nutritional status. METHODS: In 41 chronic HD patients with at least a 2-year history of HD treatment, RRF was determined by a urine collection for 7 consecutive days. Nutritional parameters, such as percentage body fat, fat-free mass index, serum albumin concentration and normalized protein catabolic rate, were also measured. RESULTS: In all 41 patients, mean weekly total Kt/V urea was 4.88 and renal Kt/V urea was 0.65. RRF was well correlated with serum albumin concentration, but dialysis Kt/V urea was not. One year after the start of this study, RRF and nutritional indices were re-examined and patients were classified into two groups: with RRF, preserved residual renal diuresis over 200 ml/day (mean, 720 ml; range, 230-1640 ml), N=23; and without RRF, persistent anuria (mean, 51 ml; range, 0-190 ml), N=18. At the start of this study, the mean serum albumin concentration and mean normalized protein catabolic rate in patients with RRF were 3.84 g/dl and 1.16 g/kg/day, respectively, which were significantly higher than those in patients without RRF (P=0.02 and P=0.0002, respectively), despite total (renal+dialysis) Kt/V urea being equal in both groups. During the 1-year study period, there was no significant change in total Kt/V urea in either group. Mean serum albumin concentration increased to 4.05 g/dl in patients with RRF, but did not change significantly (from 3.66 to 3.62 g/dl) in patients without RRF. The same trend was observed in all other parameters. CONCLUSION: Over half of our HD patients had sufficient RRF. RRF itself may have a beneficial effect on nutritional parameters, and it is important to determine RRF over time, even in chronic HD patients.     

The impact of residual renal function and total body water volume on achieving adequate dialysis in CAPD.

AIMS: The objective is to evaluate the impact of residual renal function (RRF) and total body water (TBW) on achieving adequate dialysis. METHODS: Sixty three CAPD patients performing four 2 liter exchanges daily were evaluated for RRF, total weekly Kt/V (TWKt/V), total weekly creatinine clearance (TWCC) and TBW. RESULTS: In patients with residual renal function (N = 41), TWKt/V and TWCC were 2.2 +/- 0.8 and 77.4 +/- 24.5 L, respectively. In patients without RRF (N = 22), TWKt/V was 1.6 +/- 0.4 and TWCC 42.6 +/- 9.2 L. TBW correlated negatively with TWKt/V in the group without RRF (r = -0.75, P<0.001). CONCLUSION: It is not possible for larger patients without RRF treated with CAPD (2L x 4 exchanges) to achieve the acceptable targets for TWKt/V and TWCC due to TBW.     

Benefits of preserving residual renal function in peritoneal dialysis

Residual renal function (RRF) is of paramount importance in patients with end-stage renal disease, with benefits that go beyond contributing to achievement of adequacy targets. Several studies have found that RRF rather than overall adequacy (as estimated from total small solute removal rates) is an essential marker of patient and, to a lesser extent, technique survival during chronic peritoneal dialysis (PD) therapy. In addition, RRF is associated with a reduction in blood pressure and left ventricular hypertrophy, increased sodium removal and improved fluid status, lower serum beta(2)-microglobulin, phosphate and uric acid levels, higher serum hemoglobin and bicarbonate levels, better nutritional status, a more favorable lipid profile, decreased circulating inflammatory markers, and lower risk for peritonitis in PD. As compared with conventional hemodialysis, PD is associated with a slower decrease in RRF. This highlights the usefulness of strategies oriented to preserve both RRF and the long-term viability of the peritoneal membrane. Several factors contributing to the loss of RRF have been identified and should be avoided. Renoprotective drugs and new glucose-sparing, more biocompatible PD regimes may prove useful tools to preserve RRF and peritoneal membrane function in the near future.     

Leptin in CAPD patients: serum concentrations and peritoneal loss.

BACKGROUND: To determine whether serum leptin concentrations in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) are influenced by peritoneal loss of leptin and to compare serum leptin levels of normal subjects with those of patients receiving renal replacement therapy such as haemodialysis (HD), CAPD, or kidney transplantation. SUBJECTS AND METHODS: Eighty-four individuals were investigated: six females and 14 males on standard CAPD; 13 females and 13 males on chronic HD; 10 female and eight male kidney transplant recipients, and 10 female and 10 male subjects as controls. Morning serum, 8-h and 24-h samples of peritoneal fluid concentrated to 6-20-fold by Centricon 3 (cutoff 3000 daltons), and 24-h urinary concentrations of leptin were measured with commercial RIA (Linco Research, Inc., USA). Venous blood and peritoneal fluid samples of albumin, beta2-microglobulin, glucose, urea, and creatinine were determined by standard laboratory techniques. Serum insulin levels were measured by radioimmunoassay. RESULTS: Patients (men and women) on CAPD and after kidney transplantation exhibited significantly higher serum concentrations of leptin and leptin/BMI ratios than control subjects. These increased values did not reach statistical significance in HD patients. Serum leptin concentrations were correlated very significantly with BMI in all cases (r=0.380, P<0.001). Moreover, in CAPD patients (r=0.630, P<0.007) and in HD patients (r=0.668, P<0.005), but not in kidney transplant recipients or control subjects, significant correlations were observed between serum leptin and insulin concentrations. Residual renal function (RRF) in the range 0-12.8 ml/min and serum beta2-microglobulin levels in the range 7.9-47.1 mg/l did not influence serum leptin levels in CAPD and HD patients. As expected, leptin was detected in the peritoneal fluid of CAPD patients. Twenty-four-hour peritoneal loss (30.95+/-21.05 ng/min) and 24-h peritoneal clearance (0.01+/-0.01 ml/kg/min) of leptin account for only 3.9% of estimated whole-body leptin production rate and 0.7% of leptin clearance from plasma respectively. Twenty-four-hour urinary losses of leptin in CAPD patients were negligible, accounting for 5.6+/-1.8% (range 0.3-15.2%) of total (peritoneal and urinary) loss of this hormone. CONCLUSIONS: These findings suggest that serum leptin levels are not affected by continuous peritoneal loss of leptin during CAPD and that insulin resistance and hyperinsulinaemia contribute to elevated serum leptin concentrations in CAPD and HD patients. The aetiology of increased serum leptin levels in kidney transplant recipients is probably different from that in dialysis patients.     

Incremental peritoneal dialysis: effects on the choice of dialysis modality, residual renal function and adequacy

There is still disagreement on whether peritoneal dialysis (PD) should begin with a full dose (Full_Dial) or with incremental doses (Incr_Dial) to compensate for the amount of Kt/V no longer supplied by the residual renal function (RRF). The aim of this study is to assess the effects of an Incr_Dial protocol on the choice of dialysis modality, RRF, and adequacy. The Incr_Dial protocol in our center is as follows: for patients with a glomerular filtration rate (GFR)>5 ml min(-1), PD is initiated with two exchanges per day (continuous ambulatory PD (CAPD)) or four sessions per week (ambulatory PD (APD)); and hemodialysis (HD) is initiated with two sessions per week. The PD dose is then increased in proportion to the reduction in the GFR as follows: GFR< or =5 and >3 ml min(-1)=3 CAPD exchanges or five APD sessions; GFR <3 ml min(-1)=full dialysis dose (Full_Dial). The effects of the Incr_Dial protocol on the choice of dialysis modality were assessed on 87 patients (pts) (age: 69.3+/-13.1 years) who initiated dialysis between 1 January 2004 and 31 May 2007. The effects of Incr_Dial on RRF and dialytic adequacy were assessed in 11 pts treated with two CAPD exchanges per day for a total of 106 months (mean+/-s.d. 9.7+/-6.5), and then treated with three CAPD exchanges per day for an additional 105 months (9.4+/-8.3). The use of Incr_Dial determined the choice of PD in 27 of 44 pts (61.4%) without indications or contraindications to HD or PD. CAPD was chosen by 20 of these pts (74.1%), whereas APD was preferred by 6 of the 8 pts switched from Incr_Dial to Full_Dial. During Incr_Dial, a significant reduction in the loss of GFR of 2.4+/-3.1 ml min(-1) year(-1) was observed when compared to the pre-dialysis period. Incr_Dial allowed for adequate clearance, as confirmed by the Kt/V (2.07+/-0.2), protein nitrogen appearance (1.17+/-0.13), and biochemical parameters. Ultrafiltration (UF) with icodextrin (772+/-166 ml per exchange) provided a daily UF of 517+/-296 ml day(-1) and remained unchanged when the duration of the dwell time increased significantly from 12.3+/-1.4 to 17.5+/-2.6 h.     

Sequential change of asymmetric dimethylarginine levels after initiation of peritoneal dialysis in patients with end-stage renal disease

Background: We hypothesized that the asymmetric dimethylarginine (ADMA) metabolism in end‐stage renal disease may be linked to the rate of protein turnover and to the vast pool of amino acids. In order to determine a correlation between the plasma levels of ADMA and the protein catabolic rate, we measured the ADMA levels as well as nutritional markers such as the normalized protein catabolic rate (nPCR) in patients with newly initiated continuous ambulatory peritoneal dialysis (CAPD). Methods: Twenty‐four patients were recruited for this study. All patients were on the standard CAPD protocol, and followed for at least 1 year. Blood samples were collected at baseline before the initiation of peritoneal dialysis, and every 6 months for 1 year. The blood parameters studied included the serum albumin, total cholesterol, glucose, urea nitrogen, creatinine and ADMA. Peritoneal equilibrium test and measurements of weekly Kt/Vurea and nPCR were performed within 4 weeks of the blood sampling. Results: The change of ADMA levels over 1 year was positively correlated with that of haemoglobin (r = 0.592, P = 0.002) and nPCR during the same period (r = 0.508, P = 0.026). Conclusion: The findings of our study suggest that nPCR might influence the change of ADMA levels after initiation of CAPD.     

Low prevalence of hyperphosphatemia independent of residual renal function in peritoneal dialysis patients.

OBJECTIVE: Our objective was to evaluate serum phosphorus control in patients undergoing continuous ambulatory peritoneal dialysis, with and without residual renal function, by investigating the metabolic balance of phosphorus. METHODS: We assessed serum phosphorus levels in 205 patients undergoing continuous ambulatory peritoneal dialysis (CAPD). The clinical factors related to serum phosphorus were also examined, including dietary phosphate intake, dietary protein intake (DPI), phosphate removal through urine and dialysate, doses of phosphorus binder and vitamin D, and serum intact parathyroid hormone (PTH) levels. Nutritional indexes, including serum albumin (Alb), lean body mass (LBM), hand-grip strength (HGS), and subjective global assessment (SGA), were also assessed. Dialysis adequacy and residual renal function (RRF) were calculated by a standard technique. Patients with RRF <2 mL/min were viewed as having no significant RRF. Hyperphosphatemia was diagnosed in patients with serum phosphorus levels >1.78 mmol/L. RESULTS: The mean serum phosphorus level of all patients was 1.6 +/- 0.5 mmol/L (mean +/- SD). Only 58 of 205 patients (28%) had hyperphosphatemia. The average DPI was 0.8 +/- 0.3 g/kg/d, whereas the average dietary phosphorus intake was 691 +/- 201 mg/d. There were no differences in mean serum phosphorus levels or incidents of hyperphosphatemia between patients with and without RRF (1.6 +/- 0.4 mmol/L vs. 1.7 +/- 0.5 mmol/L, P = .256; 22% vs. 31%, P = .336). Although total phosphorus removal through urine and dialysate was lower in the 115 patients without RRF than in the 90 patients with RRF (270 +/- 106 mg vs. 333 +/- 129 mg, P = .000), they simultaneously had a lower dietary phosphorus intake (656 +/- 191 mg vs. 713 +/- 215 mg, P = .046). In addition, patients without RRF had significantly lower DPI, Alb, LBM, and right HGS levels than patients with RRF (P < .01-.05). In those without RRF, the 79 patients without hyperphosphatemia had significantly lower DPI, LBM, and HGS levels, and a higher prevalence of malnutrition diagnosed by SGA, than the 36 patients with hyperphosphatemia (P < .001-.05). However, in patients with RRF, there was no difference in nutritional index between patients with and without hyperphosphatemia (P > .05). CONCLUSION: A relatively lower prevalence of hyperphosphatemia existed in CAPD patients both with and without RRF, which may be associated with incremental dialysis, the correct administration of phosphorus binder, and a lower protein and phosphorus intake. However, patients without RRF, especially those without hyperphosphatemia, ran the risk of malnutrition, despite a well-controlled phosphorus intake.     

高血脂对腹膜透析患者的残余肾功能影响

目的：观察高血脂对连续性不卧床腹膜透析（CAPD）患者的残余肾功能（RRF）的作用。方法：定期监测共72例CAPD患者血脂成分及残余肾功能,根据血脂的变化将患者分为胆固醇（TC）增高组、三酰甘油（TG）增高组及二者均增高组与TC、TG正常组,比较各组残余肾功能变化。结果：CAPD治疗初期残余肾功能无明显变化（P〉0.05）。第12月时,TC增高组RRF较同组透析初月时下降（P〈0.05）。TG增高组及TC、TG均增高组的RRF分别与透析初月时同组RRF比较显著下降（P〈0.001）。第18月时3个血脂增高组RRF与TC、TG组比较均有下降（P〈0.05）。RRF下降数值与TC（r=0.234,P〈0.05）、TG（r=0.528,P〈0.05）均呈正相关。结论：CAPD患者的RRF随着透析时间的延长而降低。高血脂与RRF改变值有正相关性。     

The outcome for pediatric patients on peritoneal dialysis

BACKGROUND: The adverse effects of peritonitis and of the duration of dialysis on dialysis adequacy and clinical outcome were evaluated in this study. METHODS: The study comprised 24 chronic peritoneal dialysis patients who were followed up at least for 12 months. Casual blood pressure (BP) measurements, echocardiographic evaluation, peritonitis rate, hemoglobin (Hb), serum albumin, normalized protein catabolic rate (nPCR), total Kt/Vurea, weekly creatinine clearance (CCr), residual renal function (RRF), removal of fluid and dose of recombinant human erythropoietin (EPO) were evaluated. RESULTS: Mean age of the patients was 15.3 +/- 3.6 years. Mean follow-up was 50.4 +/- 26.8 months. Peritonitis rate was calculated as 1 episode/32.7 patient-months. Systolic hypertension was detected in 14 patients (58%) and diastolic hypertension in 15 (63%). RRF showed a negative correlation with duration on dialysis (r=-0.623, p=0.006).There was no significant correlation between RRF and nPCR, Hb, hematocrit, albumin and dose of EPO. A negative correlation was found with left ventricular mass index and fluid removal (r=-0.461, p=0.041). Higher doses of Kt/Vurea are associated with higher protein intake (r=0.503, p=0.024). A positive correlation was found between Kt/Vurea and Hb and Hct levels (r=0.460, p=0.009, and r=0.528, p=0.017, respectively). Dialysis adequacy tests were found not to be affected by the frequency of peritonitis. CONCLUSION: The most important factor for the prevention of hypervolemia in chronic peritoneal dialysis patients is RRF. The concept of adequate dialysis should include normal volume homeostasis, control of blood pressure and adequate nutrition.     

Important differentiation of factors that predict outcome in peritoneal dialysis patients with different degrees of residual renal function.

BACKGROUND: Residual renal function (RRF) is an important predictor of outcome in peritoneal dialysis (PD) patients. Whether results from survival studies in dialysis patients with RRF can also be extrapolated to anuric patients remains uncertain. In this observational study, we examined the characteristics of PD patients with a residual glomerular filtration rate (GFR) > or =1 ml/min per 1.73 m2 vs those with complete anuria and differentiated factors that predict outcome in the two groups of patients. METHODS: Two hundred and forty-six continuous ambulatory peritoneal dialysis (CAPD) patients (39% being completely anuric) were recruited from a single regional dialysis centre. Assessments of haemodynamic, echocardiographic, nutritional and biochemical parameters and indices of dialysis adequacy were done at study baseline and were related to outcomes. RESULTS: During the prospective follow-up of 30.8+/-13.8 (mean+/-SD) months, 28.0% of patients with residual GFR > or =1 ml/min per 1.73 m2 vs 50.5% of anuric patients had died (P = 0.005). The overall 2 year patient survival was 89.7 and 65.0% for patients with GFR > or =1 ml/min per 1.73 m2 and anuric patients, respectively (P = 0.0012). Compared with patients with GFR > or =1 ml/min per 1.73 m2, anuric patients were dialysed for longer (P<0.001), were more anaemic (P<0.005), and had higher calcium-phosphorus product (P<0.01), higher C-reactive protein (P<0.001), lower serum albumin (P<0.05), greater prevalence of malnutrition according to subjective global assessment (P<0.05) and more severe cardiac hypertrophy (P<0.001) at baseline. Using multivariable Cox regression analysis, serum albumin, left ventricular mass index and residual GFR were significant factors associated with mortality in patients with GFR > or =1 ml/min per 1.73 m2, while increasing age, atherosclerotic vascular disease and higher C-reactive protein were associated with greater mortality in anuric PD patients. CONCLUSIONS: Our study demonstrates more adverse cardiovascular, inflammatory, nutritional and metabolic profiles as well as higher mortality in anuric PD patients. Furthermore, factors associated with mortality are also not equivalent for PD patients with and without RRF, suggesting that patients with and without RRF are qualitatively different.     

肾衰合剂对维持性腹膜透析患者残余肾功能的影响

目的：观察肾衰舍剂对连续不卧床腹膜透析（CAPD）患者残余肾功能的影响，探讨中药治疗对CAPD患者残余肾功能的保护作用及其机制。方法：将56例脾肾气（阳）虚型的CAPD患者随机分为常规腹膜透析对照组，及加服中药肾衰合剂治疗组。治疗6个月，比较残余肾KT／V、残余肾CCr的变化及下降速率。结果：在维持总体透析效能的前提下，治疗组残余肾KT／V、残余肾CCr下降速度较对照组明显缓慢。结论：肾衰合荆能有效延缓PD患者的RRF的下降。     

Peritoneal solute transport predicts survival on CAPD independently of residual renal function

Background: Loss of residual renal function has a profound effect on the survival of peritoneal dialysis patients. Less is known of the impact of peritoneal function. The purpose of this study was to investigate the influence of solute transport on clinical outcome in CAPD patients. Methods: Two hundred and ten consecutive patients commencing CAPD since 1990 were enrolled into a single centre prospective longitudinal observational study of urea, protein, and peritoneal kinetics. On entry, and at 6-monthly intervals, estimations were made of weight, body mass index (BMI), plasma albumin, Kt/V, residual renal function (RRF), NPCR, low-molecular-weight solute transport (D/Pcreat), and peritoneal protein losses. All patients were censored in 1996, regardless of treatment modality. Results: During the 6-year follow up period (median 22 months) there were 51 deaths, and the actuarial survival was 58% at 5 years. Urea, protein and peritoneal kinetics varied with time on dialysis: as anticipated there was a reduction in Kt/V, attributable to loss of RRF, whereas plasma albumin was stable for the first 2 years of treatment, but subsequently started to decline, a trend that became significant at 42 months. Peritoneal kinetics stabilized within the first 6 months of treatment and then showed a trend of increased solute transfer with time on treatment, which became significant by the end of the study. Comparing survivors with non-survivors Kt/V and RRF were similar at the start of treatment, but loss of RRF occurred significantly earlier in non-survivors than survivors (0.37vs 0.68, P=0.02 at 6 months, 0.19 vs 0.54, P=0.01 at 12 months). D/Pcreat was also identical at commencement of treatment, but subsequently whilst survivors had stable solute transfer non-survivors had consistently higher solute transfer beyond 6 months that reached increasing significance after 18 months, (0.70 vs 0.67, P=0.05 at 18 months, 0.72 vs 0.66, P=0.03 at 24 months). A Cox proportional hazard model constructed for the variables age, sex, BMI, albumin, Kt/V and D/Pcreat at 6 months of treatment indicated that low Kt/V (P=0.0004), high D/Pcreat (P=0.013) and age (P=0.028) were independent predictors of death. Conclusion: There is good reason to believe that high peritoneal solute transport is an independent marker of poor outcome in CAPD patients.     

Behavior of beta 2-microglobulin in patients with chronic renal failure undergoing hemodialysis, hemodiafiltration and continuous ambulatory peritoneal dialysis (CAPD)

beta 2-microglobulin (beta 2-m) is the major component of a new form of amyloid deposit found in carpal tunnel syndrome and dialysis arthropathy of long-term hemodialysis patients. In 52 patients on maintenance hemodialysis, serum beta 2-m concentration was elevated to 37.9 +/- 1.4 (normal 1.2 +/- 0.6) mg/l. It was correlated with the time on hemodialysis (r = 0.43, p less than 0.01) and was inversely correlated with residual renal function (r = 0.87, p less than 0.001). In 20 patients on CAPD, beta 2-m likewise was increased to 31.6 +/- 2.3 mg/l; daily elimination by dialysate was only 34 mg (normal 150 mg). Hemodialysis with a cuprophane membrane caused a rise in serum beta 2-m, whereas hemodiafiltration with a polysulfone membrane performed in 5 patients over 2 1/2 months was accompanied by a decrease in serum beta 2-m from 39.5 +/- 0.7 to 29.7 +/- 1.0 mg/l predialysis (19.1 +/- 1.1 postdialysis). On the other hand, beta 2-m elimination reached only approximately 100 mg per day in spite of markedly elevated serum levels. It is concluded that serum beta 2-m is massively elevated in long-term hemodialysis and CAPD patients; contrary to routine hemodialysis with cuprophane membranes, newer more permeable membranes will permit some elimination of beta 2-m. However, based on quantitative considerations it seems difficult to obtain beta 2-m concentrations in the high normal or moderately elevated range with present day techniques.     

Cefazolin plus netilmicin versus cefazolin plus ceftazidime for treating CAPD peritonitis: effect on residual renal function

BACKGROUND. The International Society for Peritoneal Dialysis (ISPD) treatment guidelines for continuous ambulatory peritoneal dialysis (CAPD) peritonitis 2000 recommended the use of cefazolin plus ceftazidime as the initial empirical therapy in patients with residual renal function (RRF). However, this treatment regimen has not been compared with the conventional regimen of cefazolin plus netilmicin in prospective, randomized controlled trials. METHODS: Stable CAPD patients who developed clinical evidence of peritonitis were randomized to receive intraperitoneal (i.p.) cefazolin plus netilmicin or cefazolin plus ceftazidime once daily in the long dwell for 14 days. For patients with RRF (>1 mL/minute) before entry into the study (N= 50), RRF and 24-hour urine volume were measured at days 1, 14, and 42 after commencement of i.p. antibiotic treatment. RESULTS: One hundred and two patients were recruited into the study. The primary cure rates of i.p. cefazolin plus netilmicin and cefazolin plus ceftazidime were 66.7% and 64.7%, respectively. The overall cure rate for the 2 treatment regimens was 82.3% for both. Seven patients (14%) from each treatment group required removal of the dialysis catheters due to treatment failure. Relapse of peritonitis occurred in 2 patients (4%) in both treatment groups. Thirty-six patients with RRF at baseline achieved primary cure of their peritonitis by the assigned antibiotics. In this subgroup of patients, their RRF and daily urine volume showed significant reduction at day 14 and returned to near baseline values at day 42. The degree of reduction in RRF and urine volume did not differ significantly between the patients treated with cefazolin plus netilmicin and cefazolin plus ceftazidime. CONCLUSION: Intraperitoneal cefazolin plus netilmicin and cefazolin plus ceftazidime have similar efficacy as empirical treatment for CAPD peritonitis. In CAPD patients with RRF, significant but reversible reduction in RRF and 24-hour urine volume could occur after an episode of peritonitis, despite successful treatment by i.p. antibiotics. The effect of i.p. cefazolin plus netilmicin, or i.p. cefazolin plus ceftazidime on RRF in CAPD patients with peritonitis does not appear to be different. Our findings do not support the routine use of cefazolin and ceftazidime as the empirical treatment for CAPD peritonitis.     

Serum erythropoietin levels and hematocrit in end-stage renal disease: influence of the mode of dialysis

Serum erythropoietin (Ep) levels were measured by radioimmunoassay in 70 patients with end-stage renal disease (ESRD) to evaluate the influence of the mode of dialysis on the relationship between serum Ep levels and the severity of anemia. Thirty-five patients were on hemodialysis (HD), seven were on intermittent peritoneal dialysis (IPD), and 28 were on continuous ambulatory peritoneal dialysis (CAPD). Compared to HD, CAPD patients had higher serum Ep (CAPD), 46.1 +/- 13.4 v HD, 16.9 +/- 2.2 mU/mL) and hematocrit (CAPD, 33.9 +/- 2.5 v HD, 24.8 +/- 1.4%; P less than 0.05). The Ep and Hct values for IPD patients were intermediate between the other two groups. Serum Ep levels were higher in CAPD patients in the first 4 weeks of initiation of CAPD (144 +/- 35 mU/mL, n = 6) than later (39 +/- 6.4 mU/mL, n = 24). A significant fluctuation in serum Ep and Hct values was noted in patients on all three modes of dialysis, when multiple samples were obtained at different time intervals. There was a weak correlation between serum Ep and Hct in the three groups of dialysis patients; r = 0.36, P less than 0.005. The data suggest that CAPD provides a better biochemical milieu for Ep production and responsiveness than HD treatment of ESRD.     

Beta 2-microglobulin levels in patients with renal insufficiency

beta 2-microglobulin (beta 2M) has been implicated in the pathogenesis of amyloidosis in long-term dialysis patients. beta 2M levels were measured in patients with chronic renal failure: before and after conventional hemodialysis in 30, before and after high-flux (HF) hemodialysis in 35, and during the first hemodialysis treatment in five patients, as well as in the serum and peritoneal fluid of 13 patients who were receiving continuous ambulatory peritoneal dialysis (CAPD) and in the serum and urine of three patients who had received kidney transplants. Dialysis patients had markedly elevated beta 2M levels; prehemodialysis values were not significantly different for patients receiving conventional v HF hemodialysis. Most of these patients were functionally anephric, and the beta 2M levels did not correlate with age, sex, or time on dialysis. In patients receiving conventional hemodialysis using cellulose acetate membrane, beta 2M levels increased 25.4% after hemodialysis, whereas in patients receiving HF hemodialysis using polysulfone membrane, beta 2M levels decreased significantly (43.0%) after hemodialysis. End-stage renal disease patients dialyzed for the first time had beta 2M values significantly lower than the other two groups because of residual glomerular filtration rate (GFR). CAPD patients also had lower values because they had an estimated loss of 80.4 mg/d of beta 2M in the dialysate fluid. In patients with chronic renal failure, beta 2M levels paralleled the increase in serum creatinine. Patients who received kidney transplants had a dramatic decrease in beta 2M levels that correlated with improvement in GFR. beta 2M correlated with the residual GFR, and its removal was membrane-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)