A novel association between residual renal function and left ventricular hypertrophy in peritoneal dialysis patients

BACKGROUND: Left ventricular hypertrophy (LVH) and dialysis adequacy are both important predictors for mortality in dialysis patients. This study evaluated the association between residual renal function (RRF) and the severity of LVH in endstage renal failure (ESRF) patients undergoing long-term continuous ambulatory peritoneal dialysis (CAPD). METHODS: A cross-section study was performed with left ventricular mass index (LVMi), determined in 158 non-diabetic CAPD patients using echocardiography and its relationship with residual glomerular filtration rate (GFR), peritoneal dialysis (PD) and total weekly urea clearance (Kt/V) and other known risk factors for LVH was evaluated. RESULTS: Twelve patients had no LVH (group I). The remaining 146 patients were stratified [group II (lowest), III and IV (highest)] according to the LVMi (median 207 g/m2; range 103 to 512 g/m2). Across the four groups of patients with increasing LVMi, there was significant decline in GFR (2.27 +/- 1.98 vs. 1.49 +/- 1.58 vs. 1.61 +/- 1.91 vs. 0.80 +/- 1.42 mL/min/1.73 m2; P = 0.011) and total weekly Kt/V (1.98 +/- 0.44 vs. 1.96 +/- 0.38 vs. 1.92 +/- 0.42 vs. 1.71 +/- 0.42; P = 0.037); however, PD Kt/V was similar for all four groups. Patients with better-preserved residual GFR not only had significantly higher total Kt/V, but were less anemic and hypoalbuminemic and had a trend toward lower systolic blood pressure and arterial pulse pressure. Multiple regression analysis showed that other than age, gender, body weight, arterial pulse pressure, hemoglobin and serum albumin, known factors for LVH, residual GFR (estimated mean -7.94; 95% confidence interval -15.13 to -0.74; P = 0.031) was also independently associated with LVMi. CONCLUSIONS: Other than anemia, hypoalbuminemia and arterial pulse pressure, this study demonstrates an important, novel association between the degree of RRF and severity of LVH in ESRF patients undergoing long-term CAPD. Prospective studies are needed to define if indeed there is a cause-effect relationship between this association, to evaluate if a decline in residual GFR is independently associated with an increase in LVMi, and to determine whether treatment directed at preserving RRF will reduce the severity of LVH, improve cardiac performance and hence survival of these patients.     

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。     

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.     

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.     

Clinical outcome of continuous ambulatory peritoneal dialysis predicted by urea and creatinine kinetics.

The effectiveness of urea kinetics (Kt/V, where K is urea clearance, t is treatment time, and V is the volume of distribution for urea) to assess the adequacy of continuous ambulatory peritoneal dialysis (CAPD) and clinical outcome has not been established prospectively, and cross-sectional clinical studies have been inconclusive. A minimum weekly creatinine clearance of 40 to 50 L is recommended, but the adequacy of this dose is unproven. We introduced a simpler approach to creatinine kinetics in the form of an efficacy number (EN) calculated from data obtained in a standardized 4-h dwell exchange. To determine the most effective model for predicting CAPD adequacy, residual renal function, weekly Kt/V urea, weekly creatinine clearance standardized to body surface area, and EN (liters per gram of creatinine per day) were measured in 18 stable CAPD patients followed prospectively for at least 12 months. Patients were divided into three groups, good (G), intermediate (I), and poor (P), on the basis of uremic symptoms, mortality, hospital days, biochemical indices, and the need for transfer to hemodialysis. When comparing groups G (N = 6) and P (N = 8), weekly Kt/V were 2.3 +/- 0.2 versus 1.5 +/- 0.1 (P less than 0.005), weekly creatinine clearances were 71.5 +/- 8.6 versus 35.1 +/- 1.3 L (P less than 0.001), and EN were 7.4 +/- 0.8 versus 3.6 +/- 0.2 L/g of creatinine/day (P less than 0.005). Creatinine kinetics (weekly clearance and EN) but not urea kinetics could differentiate group I (N = 4) from groups G or P. Both urea and creatinine kinetics predict clinical outcome in CAPD.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Impact of Residual Renal Function on Dialysis Adequacy in Paediatric CAPD Patients

This study was designed to determine the impact of residual renal function (RRF) on dialysis adequacy indices and clinical outcome parameters in paediatric CAPD patients. Seventeen children on CAPD were included. Residual renal function was described by residual diuresis (UO: urine output), residual renal solute clearances [RR.KT/V (residual renal KT/V), RR.Ccr (residual renal creatinine clearance) and GFR (glomerular filtration rate)]. Pearson's correlation coefficients and multiple linear regression analysis were used in statistical analysis. Mean W.KT/V (weekly KT/V) vas 1.97±0.6 and mean T.Ccr (total Ccr) was 56±32 L/week/1.73 m². Both of these indices were found to be strongly correlated with RRF (GFR, UO, RR.KT/V and RR.Ccr) (p<0.001), but not with peritoneal solute clearances. W.KT/V was found to be influenced essentially by RR.KT/V (p<0.001) and also dialysate fill volume (DV) (p<0.01). T.Ccr was influenced primarily by RR.Ccr (p<0.001) and serum cr levels (p<0.05). In addition significant positive correlations were detected between serum albumin, haemoglobin (Hb), haematocrit (Htc) levels and residual diuresis (p<0.05) and a significant negative correlation was found between mean blood pressure and residual diuresis (p<0.05). It was concluded that the mean values of W.KT/V and T.Ccr were heavily influenced by RRF. Almost all variations in W.KT/V and T.Ccr represented changes in RRF. In addition, anaemia, hypertension and hypoalbuminaemia, which are known as clinical criteria of inadequate dialysis, were found to be influenced by residual diuresis. Thus one of the goals of paediatric nephrologists must be the preservation of renal reserve. Since the rate of decline in RRF was significantly lower in CAPD, it should be the first choice of long-term maintenance dialytic therapy for children who have residual renal reserve.     

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.     

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。     

Impact of dialysis adequacy on the mortality and morbidity of anuric Chinese patients receiving continuous ambulatory peritoneal dialysis

Dialysis adequacy has a major impact on the outcome of continuous ambulatory peritoneal dialysis (CAPD) patients. However, most studies on peritoneal dialysis adequacy have focused on patients with significant residual renal function. The present study examined the effect of dialysis adequacy on anuric CAPD patients. A single-center prospective observational study on 140 anuric CAPD patients was performed. These patients were followed for 22.0 +/- 11.9 mo. Dialysis adequacy and nutritional indices, including Kt/V, creatinine clearance (CCr), protein equivalent nitrogen appearance, percentage of lean body mass, and serum albumin level were monitored. Clinical outcomes included actuarial patient survival, technique survival, and duration of hospitalization. In the study population, 64 were male, 36 (25.7%) were diabetic, and 59 (42.1%) were treated with 6 L exchanges per day. The body weight was 59.2 +/- 10.2 kg. Average Kt/V was 1.72 +/- 0.31, and CCr was 43.7 +/- 11.5 L/wk per 1.73m(2). Two-yr patient survival was 68.8%, and technique survival was 61.4%. Multivariate analysis showed that DM, duration of dialysis before enrollment, serum albumin, and index of dialysis adequacy (Kt/V or CCr) were independent factors of both patient survival and technique survival. It was estimated that for two patients who differed only in weekly Kt/V, a 0.1 higher value was associated with a 6% decrease in the RR of death (P: < 0.05; 95% confidence interval, 0.92 to 0.99). Serum albumin and CCr were the only independent factors that predicted hospitalization. It was found that even when there is no residual renal function, higher dialysis dosage is associated with better actuarial patient survival, better technique survival, and shorter hospitalization. Dialysis adequacy has a significant impact on the clinical outcome of CAPD patients, and the beneficial effect is preserved in anuric patients as well as in an ethnic group that has a low overall mortality.     

Importance of residual renal function in continuous ambulatory peritoneal dialysis: its influence on different parameters of renal replacement treatment.

OBJECTIVE: To study the influence of residual renal function (RRF) on different parameters of the renal substitutive treatment offered by peritoneal dialysis. METHODS: We analyzed the impact of RRF on dialysis dose, nutrition parameters, anemia and phosphocalcic metabolism in 37 patients with end-stage renal disease (ESRD) treated by continuous ambulatory peritoneal dialysis (CAPD). Analytical controls were done every 6 months after an initial assessment at the end of the first month of treatment. Multiple lineal regression models were used as the statistical method to analyze the influence of RRF on different theoretically dependent factors. RRF was calculated as a mean of creatinine and urea clearances. Three observations per patient were used: one at the end of the first month of treatment; a final one at the end of follow-up (mean time 24.2 +/- 11.4 months), and at a mean time between them (13.4 +/- 6.7 months), with a final number of 111 observations. RESULTS: Dialysis dose: RRF was the most important factor in terms of creatinine clearance (r(2) = 0.94; beta = 0.999), KT/V (r(2) = 0. 68; beta = 0.819) and beta(2)-microglobulin levels (r(2) = 0.46; beta = -0.489). Nutrition parameters: RRF was a determinant factor for normalized protein catabolic rate (r(2) = 0.53; beta = 0.471), percent lean body mass (r(2) = 0.45; beta = 0.446) and albumin levels (r(2) = 0.25; beta = 0.229). Anemia: RRF was the most important factor when studying hemoglobin levels (r(2) = 0.28; beta = 0.407). Phosphocalcic metabolism: Between the analyzed factors, RRF was the only one which reached significance on serum phosphate levels (r(2) = 0.19; beta = -0.594). RRF did not show any relationship with either calcium or PTH levels. CONCLUSIONS: Independent of other factors, RRF in CAPD is positively and directly related to dialysis dose, beta(2)-microglobulin levels, nutrition parameters (albumin, normalized protein catabolic rate and percent lean body mass, hemoglobin and serum phosphate levels.     

Importance of dialysis adequacy in mortality and morbidity of chinese CAPD patients

BACKGROUND: In continuous ambulatory peritoneal dialysis (CAPD), the impact of dialysis adequacy on patient outcome is well established in Caucasian patients but is less clear in Asian patients. Recent evidence suggests that Asian dialysis patients enjoy better overall survival. We hypothesize that dialysis adequacy may be less important in determining outcome for this ethnic group. METHODS: We performed a single-center prospective observational study. From September 1995, we enrolled 150 existing and 120 new CAPD patients. They were followed for up to three years. We monitored dialysis adequacy and nutritional indices, including Kt/V, weekly creatinine clearance (CCr), residual glomerular filtration rate (GFR), normalized protein catabolic rate (NPCR), percentage of lean body mass (%LBM), and plasma albumin level. Clinical outcomes included mortality, technique failure, and duration of hospitalization. RESULTS: The duration of study follow-up was 22.1 +/- 12.3 months. In our study population, 136 were male. Seventy were diabetic (25.9%), and 212 were treated with 6 L exchanges per day (78.5%). The body weight was 59.3 +/- 9.4 kg. Baseline total Kt/V was 1.78 +/- 0.41, peritoneal Kt/V 1.48 +/- 0.36, and median residual GFR 0.98 mL/min (range 0 to 7.45). Two-year patient survival was 83.0%, and technique survival was 72.8%. Multivariate analysis showed that the duration of dialysis, diabetes, %LBM, index of dialysis adequacy (Kt/V or CCr), residual GFR, and requirement of a helper for CAPD exchanges were independent factors of patient survival; serum albumin, adequacy index (Kt/V or CCr), and requirement of a helper were independent factors of technique survival. Duration of dialysis, body weight, requirement of helper, cardiovascular disease, HBsAg carrier, serum albumin, and CCr had independent effects on hospitalization. The peritoneal component of Kt/V or CCr had no independent effect on any outcome parameter. When the prevalent and new CAPD cases were analyzed separately, Kt/V predicted survival only for new CAPD cases. CONCLUSIONS: Our results show that dialysis adequacy has significant impact on outcome of Asian CAPD patients. Although we have excellent medium-term patient and technique survival, this favorable outcome should not prevent health care workers from providing adequate dialysis to Asian patients. The reason of discrepancy in outcome between Asian and Caucasian dialysis patients requires further study.     

Salt and fluid intake in the development of hypertension in peritoneal dialysis patients

BACKGROUND: Although fluid overload contributes to hypertension in CAPD patients, less attention has been paid to the role of excess salt and fluid intake. Therefore, we investigated the role of salt and fluid intake in the development of hypertension in CAPD patients. METHODS: A total of 165 stable CAPD patients were included into this study. Based on the blood pressure in three consecutive months, they were divided into three groups: persistent hypertensive (PH; n = 33), intercurrent hypertensive (IH; n = 58) and persistent normotensive (PN; n = 74). The IH group was further divided into two phases: normotensive and hypertensive. Fluid status was evaluated by clinical assessment and bioimpedance analysis (BIA). RESULTS: There were no differences in age, gender, and duration of dialysis among groups. Patients were more fluid overloaded in the PH group. Extracellular water (ECW), total body water (TBW), and normalized extracellular water by height (NECW) were higher in the PH group than the PN group (16.77 +/- 3.62 L vs. 14.61 +/- 2.92 L for ECW, p < 0.01; 32.22 +/- 8.23 L vs. 28.98 +/- 6.00 L for TBW, p < 0.05; and 10.28 +/- 1.86 L/m vs. 9.08 +/- 1.63 L/m for NECW, p < 0.01). However, patients in the PH group also had more total fluid removal (TFR) and total sodium removal (TSR) compared with the PN group (1346.82 +/- 431.27 mL/d vs. 1139.28 +/- 412.65 mL/d for TFR, p < 0.05; and 141.52 +/- 61.57 mmol/d vs. 102.42 +/- 62.51 mmol/d for TSR, p < 0.01). The same trend was demonstrated when compared values of hypertensive and normotensive phase in IH group; patients had higher ECW, TBW, NECW, TSR, and PNa when they were in hypertensive phase than in the normotensive phase. CONCLUSIONS: This study confirmed that fluid overload was closely associated with the development of hypertension in CAPD patients. It also showed that hypertensive patients were in general more fluid overloaded despite a higher fluid and sodium removal as compared with normotensive patients.     

Reduced residual renal function is a risk of peritonitis in continuous ambulatory peritoneal dialysis patients.

BACKGROUND: Loss of residual renal function (RRF) contributes to anaemia, inflammation and malnutrition and is also a strong predictor of mortality in continuous ambulatory peritoneal dialysis (CAPD) patients. However, the role of RRF on peritonitis is not yet clearly established. This study aimed to evaluate the effect of RRF on the development of peritonitis. METHODS: Study subjects were 204 end-stage renal disease (ESRD) patients who started PD from January 2000 to December 2005. Biochemical and clinical data within 1 month of PD commencement were considered as baseline. To determine risk factors for peritonitis, multivariate Cox regression was performed. Kaplan-Meier analysis and log-rank test were used to examine the difference of peritonitis-free period according to the presence of diabetes and RRF. RESULTS: On univariate analysis based on baseline data in first peritonitis, diabetes was less prevalent and RRF (6.7+/-2.6 vs 4.0+/-2.3 ml/min/1.73 m2, P<0.01), haemoglobin (10.9+/-1.2 vs 10.6+/-1.2 g/dl, P<0.05) and serum albumin level (3.6+/-0.4 vs 3.4+/-0.4 g/dl, P<0.01) were significantly higher in the peritonitis-free group. Kaplan-Meier analysis showed that time to first PD peritonitis episode was significantly longer in the non-diabetic patients (P<0.001) and in patients with higher residual GFR (P<0.001). Multivariate analysis showed that diabetes [hazard ratio(HR) 1.64, P<0.05] and RRF (per 1 ml/min/1.73 m2 increase, HR 0.81, P<0.01) were independent risk factors. CONCLUSION: Our study revealed that RRF and diabetes were risk factors for peritonitis. These results suggest that preservation of RRF should be viewed as a protective strategy to reduce peritonitis.     

Does loss of residual renal function lead to malnutrition in peritoneal dialysis patients?

OBJECTIVES: It is usually believed that loss of residual renal function is associated with anorexia and the development of malnutrition. We conducted a retrospective study in our center to evaluate the effect of declining residual renal function on patients' nutritional status. METHODS: All incident uremic patients (n = 46) who began peritoneal dialysis from January 1, 2003 June 1, 2003 in our center were closely followed for 1 year with focus on maintaining strict volume control with time on dialysis. Patient's residual renal function (RRF) was assessed by the average renal urea and creatinine clearances. Those patients who had more than 50% decrease in GFR were selected for the present analysis. Serum albumin (ALB), dietary protein intake (DPI) and subjective global assessment (SGA) were closely followed. RESULTS: There were 16 patients (9 males and 7 females) included in the present analysis, among whom 31.3% were diabetics. Patients' GFR declined significantly (RRF were 4.32 +/- 2.69, 2.99 +/- 2.21 and 1.24 +/- 0.99 ml/min for Months 1, 6 and 12, respectively, p < 0.05), along with a significant decline in urine volume (985.62 +/- 543.29, 698.13 +/- 463.59 and 425.63 +/- 320.52 ml/d for Months 1, 6 and 12, respectively, p < 0.01). Although weekly peritoneal Kt/V did not increase significantly, peritoneal ultrafiltration increased significantly during this period (428.75 +/- 408.96, 534.38 +/- 296.39, 844.38 +/- 440.35 ml for Months 1, 6 and 12, respectively, p < 0.05). Serum ALB increased significantly (32.34 +/- 5.07, 34.74 +/- 4.89 and 36.21 +/- 3.98 g/l for Months 1, 6 and 12, respectively, p < 0.01). DPI also increased significantly. The prevalence of malnutrition (by SGA) decreased from 62.5% at the start of dialysis to 18.8% at the end of this study (p < 0.05). CONCLUSIONS: Our study suggests that rapid decline of residual renal function in PD patients does not necessarily lead to decreased dietary protein intake and deteriorated nutritional status. Focus on incremental peritoneal fluid removal along with the decline in residual renal function and, thus, maintaining volume control may be one of the critical reasons for the success.     

Middle molecule and small protein removal in children on peritoneal dialysis

BACKGROUND: Dialysis efficiency has a great influence on the outcome of patients. Few data are available on the removal of solutes with molecular weights higher than urea and creatinine. The aim of our study was to assess the transport and the removal of substances with molecular weights up to 15 kD and to evaluate the contribution of residual renal function in peritoneal dialysis (PD) children. METHODS: Seventeen patients of 12 +/- 4 years undergoing automated PD were studied. Ten patients had 563 +/- 355 mL/day of urine output, and 7 were anuric. During a standardized nightly intermittent PD (NIPD) session, a single-injection inulin clearance was performed. Urea, creatinine, inulin (measured by HPLC), cystatin C and beta2-microglobulin (beta2m) were measured in blood, urine and dialysate. Clearances (L/week/1.73 m2) and weekly solute removal index (SRI) were calculated for all the solutes; weekly Kt/V was calculated for urea. RESULTS: In non-anuric versus anuric patients the total clearances were: urea 82.6 +/- 18.3 versus 71.3 +/- 26.4; creatinine 82.7 +/- 28.6 versus 47.8 +/- 18.8; inulin 42.8 +/- 11.3 versus 32.8 +/- 20.4; beta2m 14.2 +/- 13.8 versus 9.2 +/- 8.3; cystatin C 20.2 +/- 9.4 versus 9.7 +/- 4.8. In the patients with residual diuresis, the urea was removed mainly by PD (69.2%), while inulin, beta2m and cystatin C were removed by renal clearance (64.0%, 79.5% and 62.8%, respectively). Total, peritoneal and renal weekly Kt/V values in the subjects with residual renal function, were 2.86 +/- 0.70, 1.99 +/- 0.40 and 0.87 +/- 0.43, respectively. Peritoneal weekly Kt/V in the anuric patients was 2.36 +/- 0.85; total weekly Kt/V in the total group was 2.65 +/- 0.78. Weekly SRIs in non-anuric versus anuric patients were: urea 2.56 +/- 0.58 versus 2.09 +/- 0.74; creatinine 2.66 +/- 0.73 versus 1.46 +/- 0.56; inulin 2.36 +/- 0.92 versus 1.64 +/- 1.60; beta2m 1.26 +/- 1.10 versus 1.20 +/- 1.90; cystatin C 1.72 +/- 0.83 versus 1.58 +/- 1.62. CONCLUSIONS: Solutes removed during PD tend to decrease following an increase in molecular weight of the substance. Since anuric patients are at higher risk of middle molecule and small protein accumulation, more attention should be paid to the removal of middle molecules. Further studies should be undertaken to evaluate whether removing them has a clinical impact and to determine their threshold levels.