Higher Residual Renal Function Research Articles

Comparison of clinical outcome between incremental peritoneal dialysis and conventional peritoneal dialysis: a propensity score matching study

Background Incremental peritoneal dialysis (iPD) can be useful in patients with residual renal function (RRF). RRF was well preserved and similar survival was shown in iPD compared to conventional PD (cPD) in previous study. However, the long-term survival of iPD remains unclear compared to cPD in diabetic patients. This study evaluated whether patient survival, hospitalization and peritonitis, and PD survival in iPD were lower than cPD or not. Methods We conducted a 12-year retrospective observational study of 303 PD patients (232 cPD and 71 iPD) using propensity score matching by age, gender, and diabetes mellitus (DM). Finally, 78 cPD patients and 39 iPD patients were included and 44 patients had DM. Incremental PD was defined as starting PD with two or three manual exchanges per day. Results The median duration of iPD was 24.1 months and iPD had higher RRF than cPD. Compared to cPD, the patient survival, PD survival and hospitalization benefits were not found in iPD but diabetic iPD patients had significantly longer survival and less hospitalization. Cumulative risk for peritonitis was lower iPD and PD duration of iPD was longer than those of cPD. The iPD was an independent factor associated with survival in patients with DM. Conclusions Incremental PD may be a safe PD modality to initiate and maintain PD in less uremic patients with tolerable RRF. Incremental PD would be a benefit for survival in diabetic patients. Further prospective studies are necessary to confirm the effectiveness of iPD in PD patients with similar RRF.

P1507COMPETING RISKS MODELING IN PERITONEAL DIALYSIS: THE URGE FOR A CHANGE IN SURVIVAL ANALYSIS METHODOLOGY

Abstract Background and Aims Survival analysis is a cornerstone in medical research. For this purpose Kaplan-Meier is the most widely used statistical test, but the presence of competing risks violates the fundamental assumption that the censoring mechanism is independent of survival time. This leads to overestimation of the cumulative probability of cause-specific failure. Cumulative incidence estimate and competing risks analysis are preferred. The purpose of this study was to compare different survival analysis methods: Kaplan-Meier and cumulative incidence function estimates in a cohort of Peritoneal Dialysis (PD) patients. Method The survival of 115 incident patients on PD in a university hospital was evaluated after establishing 2 cohorts: patients starting renal replacement therapy with PD (PD first; n=85) and patients switching to PD on the first 6 months of dialysis (PD transfer; n=30). Kaplan-Meier, cumulative incidence function, cause-specific and subdistribution hazards were performed. The event of interest was death and the competing risk events were transfer to hemodialysis and renal transplantation. Results Besides higher residual renal function (RRF) and kt/V in the PD first group, there were no other significant differences between groups. There were 22 deaths. PD first group had a better survival with both Kaplan-Meier (log-rank test, p=0.013) and cumulative incidence function (p=0.021) approaches. The Cox regression model showed, as protecting variables, higher albumin (HR=0.174; CI95% 0.054-0.562), higher RRF (HR=0.785; CI95% 0.666-0.925) and PD first (HR=0.350; CI95% 0.132-0.927). Higher Charlson Index predicted worse outcome (HR=1.459; CI95% 1.159-1.835). PD as first dialysis therapy was associated with 65.0 % lower risk of death comparing with PD transfer. The subdistribution multivariable model found higher Charlson Index (HR=1.389; CI95% 1.118-1.725) and lower RRF (HR=0.798; CI95% 0.680-0.936) were statistically associated with death, but not PD transfer or albumin. This result differs from the obtained using the cause-specific hazard model. Analyzing the competing events, patients submitted to renal transplantation had a lower Charlson Index. Conclusion The probability of death was overestimated by the Kaplan-Meier method. The bias of Kaplan-Meier is especially great when the hazard of the competing risks is large. This study consisted on a statistical critical analysis of a real medical example, broader clinical conclusions related with “PD first initiative” should be cautious in this context. It is primordial to recognize the presence of competing risks in studies with multiple outcomes, as in Peritoneal Dialysis studies, to estimate cumulative incidence and yield more accurate results. This study shows how different conclusions are attained with different statistical methodology and its relevance in clinical context.

A Fast Decline of Residual Renal Function in the First Year is a Predictor for Early Withdrawal from Peritoneal Dialysis in Non-Diabetic Patients

Background/Aims: Little is known about the relationship between residual renal function (RRF) decline in early period and survival in non-diabetic peritoneal dialysis (PD) patients. Methods: A total of 567 non-diabetic patients who began PD from January 1, 2005 to June 30, 2013 was investigated. The rate of RRF decline was determined by the “slope of the trend equation” of serial RRFs. A composite end-point of all-cause mortality and conversion to hemodialysis (HD) was used, survival status was censored on June 30, 2016. Results: The median of “the slope of RRF decline equation” was 0.308 (0.001-2.111) ml/min/1.73 m2/ month. In the median follow-up period of 43 months (range 12 to 120 months), 65 (11.5%) patients died, 90 (15.9%) patients converted to HD and 171 (30.2%) patients received kidney transplantation. Multivariate linear regression showed male, high baseline RRF, high baseline peritoneal Kt/V urea, low serum albumin and low uric acid were independently associated with the rate of RRF decline in the first year of PD. Multivariate Cox models revealed that RRF decline in the first year remained a predictor for composite end-point (HR, 2.74, 95% CI, 1.53 to 4.90, P=0.001). The patients were divided into high RRF decline group (> 0.308ml/ min/1.73m2/month) and low RRF decline group (≤0.308 ml/min/1.73m2/month). In the first three years of PD, the rate of end-point events was higher in high RRF decline group (23.2%) than that in low RRF decline group (11.0%) (P< 0.001). There were 189 patients in low RRF decline group and 171 patients in high RRF decline group maintaining PD for more than 3 years, in a median follow-up of 54 months (range 37 to 120 months), the survival rate was 30.9% in high RRF decline group and 46.4% in low RRF decline group (P=0.883). In high RRF decline group, there were 92 patients reaching composited end-point and 112 patients maintaining PD; multivariate Cox model showed high peritoneal Kt/V urea after 1 year of PD and high albumin level were protective factors (HR, 0.29, 95% CI, 0.13 to 0.61, P= 0.001; HR, 0.94, 95% CI, 0.90-0.99, P=0.022, respectively), while fast RRF decline remained risk factor for composite end-point (HR, 3.28, 95% CI,1.48-7.31, P=0.004). Conclusion: A faster RRF decline in the first year was a predictor for all-cause mortality and conversion to HD in non-diabetic PD patients, mainly in the first three year. For patients with faster RRF decline, increasing PD dose was effective to improve survival.

Allopurinol Effects on Residual Renal Function in End-Stage Renal Disease Patients Undergoing Peritoneal Dialysis: Randomized Controlled Trial.

Objective:There is increasing evidence to show that hyperuricemia may have a pathogenic role in the progression of renal diseases. We performed a prospective, randomized, controlled trial to investigate the renal effects of allopurinol treatment in hyperuricemic patients with end-stage renal disease (ESRD) who undergo peritoneal dialysis.Methods:This was a unicenter, randomized, controlled clinical trial conducted in “Alzahra Hospital, Isfahan, Iran.” Patients were randomly assigned into treatment or control group. Treatment-group patients were administered a starting allopurinol dose of 100 mg/day. The dose was adjusted according to serum uric acid level, aiming to maintain uric acid levels within the normal range. Participants were followed up for 6 months after receiving the medicine. Residual renal function (RRF) was assessed by measuring the renal component of Kt/V urea and estimating the patient's glomerular filtration rate (GFR) by calculating the mean of urea and creatinine clearance. In addition, systolic and diastolic blood pressure and serum level of creatinine were measured every 3 months during the follow-up period.Findings:Eighty patients were enrolled in the study and divided into two groups, including 40 ESRD patients receiving allopurinol and 40 ESRD did not receive allopurinol and considered as the control group. GFR measurements showed that there was not a significant difference between patients’ RRF of two groups. However, allopurinol group had higher RRF than the control group during the follow-up period. Evaluating RRF by Kt/V showed the same results.Conclusion:Our study demonstrated significant effects of allopurinol on decreasing serum levels of uric acid in ESRD patients undergoing peritoneal dialysis. On the other hand, renal residual function of patients under treatment with allopurinol was better than the control group. We recommend that further studies should be conducted on the effects of allopurinol with greater sample size and longer time of follow-up.

Parameters associated with therapeutic response using peritoneal dialysis for therapy refractory heart failure and congestive right ventricular dysfunction.

BackgroundIn patients with refractory heart failure (HF) peritoneal dialysis (PD) is associated with improved functional status and decrease in hospitalization. However, previous studies did not focus on right ventricular dysfunction as an important pathophysiologic component of cardiorenal syndrome.MethodsIn a prospective cohort study PD was started in 40 patients with refractory right HF (with/without left HF). Refractoriness to conservative therapy was defined as persistent right heart congestion/ascites with intensified diuretic treatment and/or ≥2 hospitalizations within 6 months because of cardiac decompensation despite optimal medical treatment, and/or acute renal failure during intensified conservative treatment of cardiac decompensations.ResultsPatient survival was 55.0% at 1 year, 35.0% at 2 years and 27.5% at 3 years. The number of hospitalization days declined after initiation of PD for both cardiac [13 (IQR 1–53) days before vs. 1 (IQR 0–12) days after start of PD, p<0.001] and unplanned reasons [12 (IQR 3–44) days before vs. 1 (IQR 0–33) days after start of PD, p = 0.007]. Using a combined endpoint including survival time of ≥1 year and either improvement in quality of life or decline in hospitalizations we found that patients with extended ascites, higher systolic pulmonary artery pressure, more marked impairment of right ventricular function and tricuspid valve insufficiency, higher residual renal function as well as those who could perform PD without assistance have benefited most from this therapy.ConclusionsPatients with more pronounced backward failure, less marked residual renal functional impairment and those not depending on assistance for therapy are likely to profit most from PD.

Lower serum beta-2 microglobulin levels are associated with worse survival in incident peritoneal dialysis patients.

There is a general consensus that elevated serum beta-2 microglobulin (B2M) levels measured at a single time-point are significantly associated with mortality in patients on maintenance dialysis. To date, the majority of prior studies that have examined B2M-associated mortality have been conducted in prevalent hemodialysis patients with little residual renal function (RRF). However, studies in incident peritoneal dialysis (PD) patients are lacking. Moreover, changes in serum B2M levels over time have not been considered in this population. We examined the association of time-updated and baseline serum B2M levels with mortality in a 10-year cohort of 725 incident PD patients who were maintained on dialysis between January 2006 and December 2011 using Cox proportional hazards regression analyses. Patients were categorized into tertiles according to B2M levels. During a median follow-up of 38 (interquartile range 23-64) months, 258 (35.4%) deaths occurred, including 106 (14.6%) and 86 (11.9%) deaths from cardiovascular and infectious causes, respectively. The lowest B2M tertile was associated with a higher risk of all-cause and infectious mortality compared with the middle tertile: the hazard ratios (95% confidence interval) for all-cause deaths were 2.12 (1.38-3.26) and 2.20 (0.96-5.05) in time-varying analyses and 1.52 (1.07-2.17) and 2.41 (1.19-4.88) in baseline analyses. Subgroup analyses showed that this association was particularly observed in females, older patients, those with comorbidities such as diabetes, a lower body mass index, lower albumin levels or those with higher RRF (all P for interactions <0.05). In incident PD patients, lower B2M levels were independently associated with overall and infectious mortality. These associations can be potentially modified by malnutrition, inflammation and RRF.

Impact of residual renal function on clinical outcome and quality of life in patients on peritoneal dialysis.

We studied the impact of residual renal function (RRF) on clinical outcome and quality of life in 61 patients on peritoneal dialysis (PD). They were assigned to two groups, at the time of initiation of PD, based on their estimated glomerular filtration rate (eGFR). The high RRF group had eGFR ≥5 mL/min/1.73 m[2] and the low RRF group hade GFR <5 mL/min/1.73 m[2]. All patients were followed up at regular intervals for clinical and biochemical variables. Baselines characteristics including age, sex, body mass index and cause of the kidney disease were similar in both groups. The high RRF group had a higher rate of continuous ambulatory peritoneal dialysis discontinuation. The incidence of peritonitis was higher in the low RRF group. Other infections (cellulitis, gastroenteritis, sepsis) were more common in patients with low RRF, compared to the high RRF group. The quality of life as assessed by depression score, restless leg syndrome, and sleep quality were poor in patients with reduced RRF. We found that a high RRF at the time of initiation of PD, significantly decreased the incidence of infections, depression, better nutrition, and lower levels of alkaline phosphatase; providing indirect evidence of better renal clearance of phosphorous, in those with preserved RRF.

Incremental Hemodialysis Schedule in Patients with Higher Residual Renal Function at the Start of Dialysis

We present an observational study to evaluate a progressive schedule of dose of dialysis, starting with 2 HD/week, when the renal clearance of urea was equal to or greater than 2,5 mL/min/1,73 m2and the patient is in a stable clinical situation. From 2006 to 2011, 182 patients started hemodialysis in our center, of which 134 were included in the study. Residual renal function (RRF), Kt/V, eKru, nPCR, hemoglobin, weekly erythropoietin dose, and beta-2-microglobulin were determined at 6, 12, 18, 24, and 30 months after dialysis initiation. Seventy patients (52%) began with the progressive schedule of 2 HD/week and 64 (48%) patients began with the conventional thrice-weekly schedule (3 HD/week). The decline of RRF was lower in the group of 2 HD/week: 0,20 (0,02–0,53) versus 0,50 (0,14–1,08) mL/min/month (median and interquartile range,P=0,009). No relationship was found between the decline rate and the basal RRF. Survival analysis did not show differences between both groups. Our experience demonstrates that patients with higher residual renal function may require less than conventional 3 HD sessions per week at the start of dialysis. Twice-weekly hemodialysis schedule is safe and cost-effective and may have additional benefit in maintaining the residual renal function.

Biocompatible dialysis fluids for peritoneal dialysis

The longevity of peritoneal dialysis (PD) is limited by high rates of technique failure, some of which stem from peritoneal membrane injury. 'Biocompatible' PD solutions have been developed to reduce damage to the peritoneal membrane. This review aimed to look at the benefits and harms of biocompatible PD solutions in comparison to standard PD solutions in patients receiving PD. We searched the Cochrane Renal Group's Specialised Register (28 February 2013), through contact with the Trials Search Co-ordinator using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE and EMBASE, and handsearching conference proceedings. All randomised controlled trials (RCTs) and quasi-RCTs in adults and children comparing the effects of biocompatible PD solutions (neutral pH, lactate-buffered, low glucose degradation product (GDP); neutral pH, bicarbonate (± lactate)-buffered, low GDP; glucose polymer (icodextrin)) in PD were included. Studies of amino acid-based PD solutions were excluded. Two authors extracted data on study quality and outcomes (including adverse effects). The authors contacted investigators to obtain missing information. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for categorical variables, and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous variables. Thirty-six eligible studies (2719 patients) were identified: Neutral pH, lactate-buffered/bicarbonate (± lactate)-buffered, low GDP PD solution (24); icodextrin (12). Allocation methods and concealment were generally incompletely reported, and adequate in only ten studies (27.8%). Patients lost to follow-up ranged from 0% to 83.4%. Neutral pH, low GDP versus conventional glucose PD solutionBased on generally sub-optimal quality evidence, the use of neutral pH, low GDP PD solutions was associated with larger urine volumes at the end of the studies, up to three years of therapy duration (7 studies, 520 patients: MD 126.39 mL/d, 95% CI 26.73 to 226.05). Improved preservation of residual renal function was evident in studies with greater than 12 month follow-up (6 studies, 360 patients: SMD 0.31, 95% CI 0.10 to 0.52). There was no significant effect on peritonitis, technique failure or adverse events with the use of neutral pH, low GDP PD solutions. Glucose polymer (icodextrin) versus conventional glucose PD solutionThere was a significant reduction in episodes of uncontrolled fluid overload (2 studies, 100 patients: RR 0.30, 95% CI 0.15 to 0.59) and improvement in peritoneal ultrafiltration (4 studies, 102 patients, MD 448.54 mL/d, 95% CI 289.28 to 607.80) without compromising residual renal function (4 studies, 114 patients: SMD 0.12, 95% CI -0.26 to 0.49) or urine output (3 studies, 69 patients: MD -88.88 mL/d, 95% CI -356.88 to 179.12) with icodextrin use. A comparable incidence of adverse events with the icodextrin (four studies) was reported. Based on generally sub-optimal quality studies, use of neutral pH, low GDP PD solution led to greater urine output and higher residual renal function after use exceeded 12 months. Icodextrin prescription improved peritoneal ultrafiltration and mitigated uncontrolled fluid overload. There were no significant effects on peritonitis, technique survival, patient survival or harms identified with their use. Based on the best available evidence, the use of these 'biocompatible' PD solutions resulted in clinically relevant benefits without added risks of harm.

Is residual renal function and better phosphate control in peritoneal dialysis an answer for the lower prevalence of valve calcification compared to hemodialysis patients?

Cardiac valve calcification (CVC) has long been regarded as a consequence of abnormal calcium-phosphate metabolism in uremic patient associated with increased cardiovascular mortality in this population. We evaluated the association between residual renal function (RRF), phosphate level and valve calcification in peritoneal dialysis (PD) and hemodialysis (HD) patients. We studied 30 stable PD patients (60 % males; mean age 57 ± 12.36 years) and 34 HD patients (58.8 % males; mean age 50.8 ± 10.4 years) on renal replacement therapy (RRT) from 6 up to 36 months. The presence of CVC was assessed by standard bi-dimensional echocardiography. RRF was calculated by standard technique. Valve calcification was more frequently found in HD compared to PD patients (70.6 vs 29.4 %, p = 0.007). Significantly lower phosphate [1.38 ± 0.41 versus 1.99 ± 0.35 mmol/L (p < 0.0001)], a higher RRF [4.09 ± 2.09 ml/min vs 0.62 ± 0.89 ml/min (p < 0.0001)], and older age [57 ± 12.36 years vs 50.8 ± 10.4 years (p = 0.033)] were observed in PD as compared to HD patients. The logistic regression analysis for the presence of valve calcification when adjusted for age and diabetes, with type of therapy, serum phosphate, RRF, CRP, and serum albumin as variables in the model, revealed significant association between the presence of valve calcification and age and RRF. The correlation between phosphate levels and RRF was even stronger in PD patients than in HD patients (r = -0.704; p = 0.0001) vs (r = -0.502; p = 0.02). Our study shows that the residual renal function in PD patients contributes significantly to the maintenance of phosphate balance and may explain the lower prevalence of valve calcification in PD patients compared with HD patients in the period up to first 3 years under renal replacement therapy.

Safety Issues of Long-Term Glucose Load in Patients on Peritoneal Dialysis—A 7-Year Cohort Study

BackgroundEffects of long-term glucose load on peritoneal dialysis (PD) patient safety and outcomes have seldom been reported. This study demonstrates the influence of long-term glucose load on patient and technique survival.MethodsWe surveyed 173 incident PD patients. Long-term glucose load was evaluated by calculating the average dialysate glucose concentration since initiation of PD. Risk factors were assessed by fitting Cox's models with repeatedly measured time-dependent covariates.ResultsWe noted that older age, higher glucose concentration, and lower residual renal function (RRF) were significantly associated with a worse patient survival. We found that female gender, absence of diabetes, lower glucose concentration, use of icodextrin, higher serum high density lipoprotein cholesterol, and higher RRF were significantly associated with a better technique survival.ConclusionsLong-term glucose load predicted mortality and technique failure in chronic PD patients. These findings emphasize the importance of minimizing glucose load in PD patients.

Risk Factors for Mortality in Stable Peritoneal Dialysis Patients

Background: The mortality rates of end-stage renal disease patients have significantly declined over the past decade. However, there are few reports on the risk factors for mortality in stable peritoneal dialysis (PD) patients who survive for a considerable time. Patients and methods: We reviewed the medical records and identified all adult patients who received PD between April 2001 and March 2009 in our institution. The total cohort was 550 patients. Among these patients, 383 patients were enrolled as stable PD patients. Results: The cumulative survival of the stable PD patients was 91.6% at 3 years and 78.7% at 5 years. On univariate analysis, old age (≥65 years of age), hypoalbuminemia (<35 g/L), log C-reactive protein (CRP) (≥0.84), phosphorus (<1.13 mmol/L), statin, icodextrin, and the Davies index were associated with mortality for all PD patients. Old age, hypoalbuminemia, log CRP, phosphorus, the residual renal function (RRF) (≤4 mL/min/1.73 m2) at 24 months, renin–angiotensin system blockade, icodextrin, and the Davies index were associated with mortality for the stable PD patients. Multivariate analysis showed that, among the variables, age, log CRP, phosphorus, initial RRF, and the Davies index were associated with mortality for all PD patients. In stable PD patients, age, log CRP, phosphorus, RRF at 24 months, and the Davies index were associated with mortality. Conclusion: Initial high RRF combined with the RRF preservation, maintenance of proper phosphorus, control of inflammation, and proper management of comorbidities may help to improve the survival of PD patients including stable PD patients.

Reliability of 51Cr-EDTA plasma and urinary clearance as a measure of residual renal function in dialysis patients

Purpose: In dialysis patients, longer survival is associated with a higher residual renal function. Randomized controlled trials are conducted to clarify how residual renal function can be preserved. However, existing methods for measuring residual renal function are uncertain and there is a need for establishing a standard for measurements of glomerular filtration rate (GFR) in dialysis patients. Methods: 51Cr-EDTA clearances in plasma, urine, and dialysate were evaluated in a sample of 12 hemodialysis and 12 peritoneal dialysis patients. The patients’ condition was generally stable, and all patients were investigated twice within 4–10 days. Results: Plasma clearances of 51Cr-EDTA for all patients ranged between 2.1 and 30.8 mL/min/1.73m2, whereas urinary 51Cr-EDTA clearances ranged from 0.7–20.0 mL/min/1.73m2. This difference was statistically significant (p < 0.001). Week-to-week reproducibility expressed as coefficients of variation were below or equal to 10% for plasma clearances and 13% for urinary clearances in hemodialysis patients and 14% in peritoneal dialysis patients. Conclusions: This study demonstrated a difference between 51Cr-EDTA plasma and urinary clearances in dialysis patients. Plasma clearance of 51Cr-EDTA had the best reproducibility. For repeated measurements as in clinical prospective trials, we recommend 51Cr-EDTA plasma clearance based on blood sampling at 5 + 24 hours with subtraction of 51Cr-EDTA dialysate clearance in peritoneal dialysis patients. Further studies are needed to corroborate our findings.

Asymmetric Dimethylarginine in Hemodialysis, Hemodiafiltration, and Peritoneal Dialysis

Asymmetric dimethylarginine (ADMA) is a mediator of endothelial dysfunction. Production and elimination of ADMA may be affected by the type of renal replacement therapy used and oxidative stress. Plasma ADMA, advanced glycation end products (AGE), and homocysteine were assessed in 59 subjects: 20 hemodialysis (HD) patients, 19 patients undergoing peritoneal dialysis (PD), and 20 controls. Results were compared between the groups. The effect of 8 weeks of HD and high-volume predilution hemodiafiltration (HDF) was compared in a randomized study. HD patients showed higher ADMA (1.20 [0.90-1.39 micromol/L]) compared to controls (0.89 [0.77-0.98], P < 0.01), while ADMA in PD did not differ from controls (0.96 [0.88-1.28]). AGE and homocysteine were highest in HD, lower in PD (P < 0.01 vs. HD), and lowest in controls (P < 0.001 vs. HD and PD). PD patients had higher residual renal function than HD (P < 0.01). The decrease in ADMA at the end of HD (from 1.25 [0.97-1.33] to 0.66 [0.57-0.73], P < 0.001) was comparable to that of HDF. Switching from HD to HDF led to a decrease in predialysis homocysteine level in 8 weeks (P < 0.05), while ADMA and AGE did not change. Increased ADMA levels in patients undergoing HD, as compared to PD, may be caused by higher oxidative stress and lower residual renal function in HD. Other factors, such as diabetes and statin therapy, may also be at play. The decrease in ADMA at the end of HD and HDF is comparable. Switching from HD to HDF decreases in 8 weeks the predialysis levels of homocysteine without affecting ADMA.

Residual renal function and arterial stiffness mediated the blood pressure change during interdialytic weight gain in hemodialysis patients

Volume overload is thought to be the main cause of hypertension in dialysis patients. However, the effect of interdialytic weight gain (IDWG) in hemodialysis (HD) patients, which was considered as an increase in extracellular water (ECW), on blood pressure (BP) change, was controversial. Our aim was to examine the changes in hemodynamics and arterial stiffness during IDWG in HD patients and attempt to explore the possible mechanism of diverse BP change. Thirty prevalent patients on HD were enrolled. The height, weight, BP, blood chemistry, volume status assessed by bioelectrical impedance analysis, hemodynamic parameters obtained by echocardiography, and pulse wave velocity (PWV) were collected within 1 hour postdialysis and again just before the next dialysis session. Meanwhile, blood samples were drawn to analyze vasoactive hormones, including renin, angiotensin II, catecholamine, and endothelin. The patients' weights and ECWs during the next predialysis were significantly higher than those during the postdialysis. The BP showed no difference between postdialysis and the next predialysis. There was an obvious increase in cardiac output and decrease in total peripheral resistance as a whole during the next predialysis than that during postdialysis. When patients were divided into the BP increase group (BPI group, 13 patients) and BP decrease group (BPD group, 11 patients) according to the change in systolic BP higher than 10 mmHg, both groups displayed a significant increase in weight, ECW, cardiac output, and a decrease in total peripheral resistance. As compared with the BPI group, patients in the BPD group had significantly lower IDWG, shorter time on dialysis treatment, and higher residual renal function. A decrease in catecholamine and endothelin in the next predialysis was obvious in the BPD group. There was a significant decrease in PWV at the next predialysis in the BPD group while the PWV did not change significantly in the BPI group. Our results showed that the diverse BP change during IDWG was significantly affected by residual renal function, PWV, and vasoactive substances.

Residual Daily Urine Volume Association with Inflammation and Nutrition Status in Maintenance Hemodialysis Patients

Background. This study determines the clinical significance of residual renal function (RRF), defined as residual daily urine volume (RDUV), in maintenance hemodialysis (MHD) patients. Methods. This multi-center study enrolled 704 MHD patients. Geographic, hematological, biochemical, and dialysis-related data were obtained. Values for nutritional and inflammatory markers were analyzed together with RDUV. Results. In total, 670 of 704 patients (95.2%) with HD duration greater than 1 year had abnormal RDUV (<500 ml). Patients with higher RRF were younger, had shorter HD duration, higher prevalence of hypertension and levels of serum albumin, high density lipoprotein (HDL), and lower mid-week inter-dialysis body weight increase (MIBWI), cardio-thoracic ratio, levels of intact parathyroid hormone, high sensitivity C-reactive protein (Hs CRP), and KT/V (Daugirdes) values than those with low RRF. Stepwise multiple regression analysis demonstrated that RRF was positively correlated with serum albumin, HDL levels, and presence of hypertension, and negatively correlated with age, HD duration, and MIBWI in MHD patients. Moreover, after adjusting factors that were significantly related to serum albumin or Hs CRP, RRF was still positively correlated with serum albumin (0.000137 ± 0.000585, p = 0.0197) and negatively correlated with log Hs CRP (−0.000184 ± 0.000952, p = 0.0533). A one-liter increase in RDUV was associated with a 1.4 g/L increase in serum albumin level in MHD patients. Conclusion. This clinical study first demonstrated that RRF affects nutritional and inflammatory status in MHD patients. Because malnutrition and inflammation can cause high mortality in MHD patients, preserving RRF is important for these patients.

Superior dialytic clearance of β2-microglobulin and p-cresol by high-flux hemodialysis as compared to peritoneal dialysis

Both residual renal and dialytic clearance confer to the total solute clearance in dialysis patients. Dialytic clearances of the middle molecule beta-microglobulin (beta(2)M) and the protein-bound solute p-cresol (pcr) are generally believed to be higher with peritoneal dialysis (PD) as compared to hemodialysis (HD). Supportive data, however, are lacking. We performed a single-center cross-sectional observational study including 70 unselected patients treated with either high-flux HD (n=20) or PD (n=50). Mid-day serum levels (PD) and time-averaged concentrations (HD) of the water-soluble solutes urea nitrogen, creatinine and phosphate, the middle molecule beta(2)M, and the protein-bound solute pcr were determined. Dialytic solute clearances (l/week/1.73 m(2)) were calculated from total dialysate collection during the mid-week session in HD and 24 h dialysate collection in PD. Renal clearances were calculated for each of the respective solutes from a timed urine collection. Total clearances were obtained by summation. HD delivered significantly higher clearances of all retention solutes studied. This superiority was especially pronounced for pcr (30.9+/-62.7 vs 4.4+/-2.3, HD vs PD, P<0.0001) and beta(2)M (28.6+/-6.6 vs 5.8+/-3.1, HD vs PD, P<0.0001). Renal clearances, conversely, were significantly higher in patients on PD. Serum levels of all solutes but pcr were significantly lower in HD than in PD. Both a higher residual renal function and a lower generation rate contribute to the lower pcr levels in PD. In conclusion, superior dialytic clearance of both water-soluble solutes, beta(2)M, and pcr is achieved by high-flux HD as compared to PD.

ASPD: A Prospective Study of Adequacy in Asian Patients on Long Term, Small Volume, Continuous Ambulatory Peritoneal Dialysis

The impact of small solute clearance on patient survival in continuous ambulatory peritoneal dialysis (CAPD) is not yet solidified. Previously, we demonstrated that CAPD using small volume (6 L) daily exchanges provides adequate dialysis for most Asian patients. We conducted a prospective, long-term observational study to determine the optimal dialysis adequacy that may provide better patient survival for Asian patients who receive small-volume CAPD. We recruited 294 patients. The initial CAPD regime was 3 x 2-L exchanges daily. The same regime was maintained unless there was significant loss of ultrafiltration or fluid retention despite the use of hypertonic dialysate. Median study period was 38.9 (range 5 - 76.5) months, with 81% and 27% of patients remaining in the study at 24 and 48 months respectively. The overall survival rates at 2 and 4 years were 94.0% and 74.8% respectively. Our long-term data revealed that survival rate was related to Kt/V values. Survival rates were significantly higher for patients with total Kt/V > 2.0 than for patients with Kt/V < 1.7 (p = 0.02). The former group had lower body mass index and higher residual renal function and peritoneal Kt/V than the Latter group. On analysis using Cox proportional hazards regression models, cardiovascular disease (CVD), lower urine volume, and higher body mass index were independent predictors of mortality. Patients with higher renal Kt/V had a significantly lower risk of mortality (RR = 0.018, p = 0.01) after adjusting for the effects of CVD and diabetes mellitus. Our data recommend that 1.7 be the minimal target for total Kt/V in patients on long-term CAPD. Patients with high body mass index, low residual urine volume, and significant CVD need close monitoring.

Residual Renal Function and Volume Control in Peritoneal Dialysis Patients

Background: Fluid overload is not uncommon in patients on continuous ambulatory peritoneal dialysis (CAPD). Previous studies suggested that residual renal function (RRF) played an important role in maintaining fluid balance. However, good fluid status should be a balance between fluid intake and removal. Therefore, in the present study, we investigated the effect of RRF on patients’ fluid status after focusing on the balance between fluid intake and removal in CAPD patients. Methods: In this cross-sectional study, 195 stable CAPD patients in a single center were included. Patients were divided into three groups according to their urine output: anuric group with urine ≤100 ml/day, oliguric group with urine ≤400 ml/day and UO >400 ml group with urine >400 ml/day. Fluid status was evaluated by bioimpedance analysis and mean arterial pressure (MAP). The sodium removal and plasma sodium concentration were also measured. All the patients were educated to try to achieve good volume control by focusing on salt and fluid intake and their removals. Results: There were 51, 31 and 113 patients in anuric, oliguric and UO >400 ml group, respectively. Anuric patients were older and had been on CAPD longer than that of the oliguric and UO >400 ml patients (p < 0.05). The urine output in the three groups were 9.28 ± 22.68, 236.13 ± 75.43 and 1,013.34 ± 541.54 ml/day, respectively (p < 0.001). Bioimpedance analysis showed that the differences of extracellular water, intracellular water and total body water were not statistically significant among the three groups. However, there was significant difference in MAP among the three groups (MAP in anuric, oliguric and UO >400 ml groups were 93.27 ± 13.35, 96.63 ± 9.94 and 102.36 ± 13.70 mm Hg, p < 0.01), and UO >400 ml group had higher MAP than anuric and oliguric groups (p < 0.05). The total sodium removal (renal + peritoneal) in anuric, oliguric and UO >400 ml groups were 96.44 ± 60.18, 98.95 ± 73.82 and 134.64 ± 72.44 mmol/day, respectively (p < 0.01). The UO >400 ml group also had higher plasma sodium concentration than anuric and oliguric groups (plasma sodium in the three groups were 137.49 ± 3.43, 137.82 ± 2.63 and 139.15 ± 3.30 mmol/l, respectively; p < 0.01). Conclusions: This study showed that extracellular water among anuric, oliguric and UO >400 ml groups was not significantly different, which suggested that RRF may be not so important as expected in maintaining good volume status. The higher blood pressure in patients with higher RRF and higher sodium and fluid removal in the present study suggested restricting salt and fluid intake might be more important for better blood pressure control in CAPD patients.

Residual renal function and blood count in patients on continuous ambulatory peritoneal dialysis

Most of patients with chronic renal failure are affected by normochromic, normocytic anemia caused by different etiological factors. Anemia causes a series of symptoms in chronic renal failure, which can hardly be recognized from the uremic signs. Anemia adds to morbidity and mortality rates in patients affected by advanced chronic renal failure. Blood count partially improves during the first months after starting the chronic renal replacement therapy, in correlation with the quality of depuration program, with extension of erythrocyte lifetime and with hemoconcentration due to reduction of plasma volume. Recent trials found that higher residual renal function (RRF) significantly reduced co-morbidity, the rate and duration of hospitalization and risk of treatment failure. The aim of the study was to follow blood count parameters in 32 patients on chronic continuous ambulatory peritoneal dialysis (CAPD) during the first six months of treatment, to evaluate the influence of demographic and clinical factors on blood count and RRF, and to examine the correlation between RRF and blood count parameters. A total of 32 patients affected by end-stage renal disease of different major cause during the first six months of CADP treatment were studied. RRF and blood count were evaluated as well as their relationship during the follow-up. RESULTS Blood count significantly improved in our patients during the first six months of CAPD treatment even if Hb and HTC failed to reach normal values. Iron serum level slightly decreased because of more abundant erythropoiesis and iron utilization during the first six months of treatment. RRF slightly decreased. After six months of CAPD treatment, the patients with higher RRF had significantly higher Hb, HTC and erythrocyte number and a lot of positive correlations between RRF and anemia markers were observed. After 6-month follow-up period, the patients with higher RRF had significantly higher blood count parameters, and several positive correlations between RRF and blood count markers were confirmed.