Clinical guideline on adequacy and prescription of peritoneal dialysis

In recent years, the meaning of adequacy in peritoneal dialysis has changed. We have witnessed a transition from an exclusive achievement of specific objectives -namely solute clearances and ultrafiltration- to a more holistic approach more focused to on the quality of life of these patients. The purpose of this document is to provide recommendations, updated and oriented to social and health environment, for the adequacy and prescription of peritoneal dialysis. The document has been divided into three main sections: adequacy, residual kidney function and prescription of continuous ambulatory peritoneal dialysis and automated peritoneal dialysis. Recently, a guide on the same topic has been published by a Committee of Experts of the International Society of Peritoneal Dialysis (ISPD 2020). In consideration of the contributions of the group of experts and the quasi-simultaneity of the two projects, references are made to this guide in the relevant sections. We have used a systematic methodology (GRADE), which specifies the level of evidence and the strength of the proposed suggestions and recommendations, facilitating future updates of the document.

Intraperitoneal vancomycin for peritoneal dialysis-associated peritonitis in children: Evaluation of loading dose guidelines

Background:

Current pediatric International Society for Peritoneal Dialysis guidelines for initial treatment of peritoneal dialysis (PD)-associated peritonitis suggest either monotherapy with cefepime or double therapy with first-generation cephalosporin or glycopeptide and ceftazidime or aminoglycoside. When using vancomycin, the intraperitoneal (IP) recommended pediatric loading dosage is 1000 mg/L of dialysate. This is based on adult pharmacokinetic (PK) studies and roughly translates to the adult recommendation where 30 mg/kg in 2 L is approximately 1000 mg/L. However, since the dialysate volume in pediatric patients is normalized to body surface area and not weight, the current recommended dosing can result in high vancomycin exposure in children. Vancomycin can potentially cause adverse effects. We aimed to determine if the IP vancomycin dosing of 1000 mg/L was causing elevated vancomycin levels and to offer possible dosing recommendations based on PK modeling and simulation.

Methods:

Retrospective review of pediatric patients who had been treated with IP vancomycin for PD-associated peritonitis. Vancomycin levels obtained for clinical monitoring were analyzed using NONMEM to generate population and individual (empiric Bayesian) estimates of vancomycin PK parameters and estimated peak levels. Predicted vancomycin peaks were also simulated from virtual pediatrics patients 3–70 kg following various dosing strategies.

Results:

Six episodes of peritonitis in three patients were analyzed. In the two episodes treated with 1000 mg/L, the first vancomycin levels (h post) were 95.6 ug/mL (3) and 49 (33) and following 500 mg/L were 33.2 (11), 30.2 (11), 23.6 (24), and 22.1 (11). All patients were cured of their peritonitis without the need for catheter removal. Based on our population PK model, a 1000 mg/L IP vancomycin loading dose will typically result in peak > 50 mg/L in patients weighing <35 kg and >60 mg/L in patients <15 kg. Vancomycin levels will remain above 20 mg/L for over 2 days without additional vancomycin dosing.

Conclusion:

The data suggest that a loading dose of vancomycin 1000 mg/L leads to higher than desired vancomycin levels and should be lowered. A 500 mg/L loading dosing appears more appropriate and needs further study.

Factors affecting the relationship between ionized and corrected calcium levels in peritoneal dialysis patients: a retrospective cross-sectional study

BACKGROUND

Chronic kidney disease-mineral and bone disorder (CKD-MBD) management in patients with end-stage renal disease is important owing to the risk of cardiovascular diseases. In clinical practice, we manage patients not by monitoring the levels of biologically active ionized calcium (iCa) but by monitoring total serum calcium or corrected calcium (cCa). We previously reported that iCa/cCa ratio was different between patients with hemodialysis and those with peritoneal dialysis (PD). In PD patients, several factors are expected to affect iCa/cCa ratio. Therefore, modifying the strategy to achieve better CKD-MBD management might be necessary; however, no reports have studied this to date. Therefore, we investigated the factors influencing iCa/cCa ratio in PD patients.

METHODS

This retrospective cross-sectional study examined background and laboratory data, including iCa, collected at routine outpatient visits. The patients were divided into the first, second, and third tertile of iCa/cCa ratio groups to compare patient background and laboratory data. Multiple regression analysis was used to investigate the factors influencing iCa/cCa ratio. We used multiple imputation to deal with missing covariate data.

RESULTS

In total, 169 PD patients were enrolled. In PD patients with lower iCa/cCa ratio, PD duration was longer and pH was higher. Urine volume and weekly renal Kt/V were lower in the patients with lower iCa/cCa ratio than in those with higher iCa/cCa ratio. iCa/cCa ratio and weekly renal Kt/V were directly correlated (r = 0.41, p < 0.01), and weekly renal Kt/V and pH were independent factors affecting iCa/cCa ratio (t = 2.86, p < 0.01 and t = - 5.42, p < 0.01, respectively).

CONCLUSIONS

iCa levels were lower in PD patients with lower residual renal function (RRF) even though their cCa levels were equal to those with maintained RRF, warranting caution in the assessment and management of CKD-MBD in PD patients.

Effect of uric acid levels on mortality in Japanese peritoneal dialysis patients

Background:

Unlike the situation in the general population, most studies of patients receiving hemodialysis have reported lower uric acid (UA) as associated with higher mortality. However, the relationship between UA level and mortality remains unclear among patients receiving peritoneal dialysis (PD).

Methods:

We collected baseline data for 4742 prevalent PD patients (age, 63 ± 14 years; male, 61.5%; diabetes, 29.1%; median dialysis duration, 28 months) from a nationwide dialysis registry in Japan at the end of 2012. One-year all-cause and cardiovascular (CV) mortality and mortality caused by infectious disease were assessed using Cox regression analysis and competing-risks regression analysis, respectively. We used multiple imputation to deal with missing covariate data.

Results:

Within 1 year, 379 patients (8.0%) died, including 129 patients (2.7%) from CV causes and 95 patients (2.0%) from infectious disease. In multivariate analysis, serum UA, treated as a continuous variable, was not associated with any outcome. Conversely, both lower (<297 µmol/L) and higher (≥476 µmol/L) UA levels were independently associated with higher all-cause mortality compared to the reference group (416 to <446 µmol/L) in analyses where serum UA was treated as a categorical variable. Body mass index (BMI) affected the association between serum UA and all-cause mortality (interaction p = 0.049).

Conclusions:

A U-shaped relationship appears to exist between UA levels and all-cause mortality among Japanese PD patients. Additionally, lower BMI significantly enhanced the effect of UA levels on mortality.

Peritonitis-Related Mortality in Patients Undergoing Chronic Peritoneal Dialysis

Peritonitis is a well-known cause of mortality in peritoneal dialysis (PD) patients. We carried out a retrospective study to disclose the clinical spectrum and risk profile of peritonitis-related mortality. We analyzed 693 episodes of infectious peritonitis suffered by 565 patients (follow-up 1149 patient-years). Death was the final outcome in 41 cases (5.9% of episodes), peritonitis being directly implicated in 15.2% of the global mortality and 68.5% of the infectious mortality observed. In 41.5% of patients with peritonitis-related mortality, the immediate cause of death was a cardiovascular event. Highest mortality rates corresponded to fungal (27.5%), enteric (19.3%), and Staphylococcus aureus (15.2%) peritonitis. Multivariate analysis disclosed that the baseline risk of peritonitis-related mortality was significantly higher in female [relative risk (RR) 2.13, 95% confidence interval (CI) 1.24 – 4.09, p = 0.02], older (RR 1.10/year, CI 1.06 – 1.14, p < 0.0005), and malnourished patients (RR 2.51, CI 1.21 – 5.23, p = 0.01) with high serum C-reactive protein (s-CRP) levels (RR 4.04, CI 1.45 – 11.32, p = 0.008) and a low glomerular filtration rate (RR 0.75 per mL/minute, CI 0.64 – 0.87, p < 0.0005). Analysis of risk after a single episode of peritonitis and/or subanalysis restricted to peritonitis caused by more aggressive micro-organisms disclosed that overall comorbidity [odds ratio (OR) 1.21, CI 1.05 – 1.71, p = 0.005], depression (OR 2.35, CI 1.14 – 4.84, p = 0.02), and time on PD at the time of the event (OR 1.02/month, CI 1.00 – 1.03, p = 0.02) were other predictors of mortality.

In summary, the etiologic agent is a definite marker of peritonitis-related mortality but gender, age, residual renal function, inflammation (s-CRP), malnutrition, and depression are other significant correlates of this outcome. Most of these risk factors are common to cardiovascular and peritonitis-related mortality, which may explain the high incidence of cardiovascular event as the immediate cause of death in patients with peritonitis-related mortality.

Impact of residual kidney function on hemodialysis adequacy and patient survival

Background

Both dialysis dose and residual kidney function (RKF) contribute to solute clearance and are associated with outcomes in hemodialysis patients. We hypothesized that the association between dialysis dose and mortality is attenuated with greater RKF.

Methods

Among 32 251 incident hemodialysis patients in a large US dialysis organization (2007-11), we examined the interaction between single-pool Kt/V (spKt/V) and renal urea clearance (rCLurea) levels in survival analyses using multivariable Cox proportional hazards regression model.

Results

The median rCLurea and mean baseline spKt/V were 3.06 [interquartile range (IQR) 1.74-4.85] mL/min/1.73 m2 and 1.32 ± 0.28, respectively. A total of 7444 (23%) patients died during the median follow-up of 1.2 years (IQR 0.5-2.2 years) with an incidence of 15.4 deaths per 100 patient-years. The Cox model with adjustment for case-mix and laboratory variables showed that rCLurea modified the association between spKt/V and mortality (Pinteraction = 0.03); lower spKt/V was associated with higher mortality among patients with low rCLurea (i.e. <3  mL/min/1.73 m2) but not among those with higher rCLurea. The adjusted mortality hazard ratios (aHRs) and 95% confidence intervals of the low (<1.2) versus high (≥1.2) spKt/V were 1.40 (1.12-1.74), 1.21 (1.10-1.33), 1.06 (0.98-1.14), and 1.00 (0.93-1.08) for patients with rCLurea of 0.0, 1.0, 3.0 and 6.0 mL/min/1.73 m2, respectively.

Conclusions

Incident hemodialysis patients with substantial RKF do not exhibit the expected better survival at higher hemodialysis doses. RKF levels should be taken into account when deciding on the dose of dialysis treatment among incident hemodialysis patients.

Impact of body mass index on survival in patients undergoing peritoneal dialysis: Analysis of data from the Insan Memorial End-Stage Renal Disease Registry of Korea (1985-2014)

Background

Significant increases in the prevalence of obesity have been observed among patients with peritoneal dialysis (PD). The impact of body mass index (BMI) on survival remains unknown in Korean PD patients.

Methods

Among data of 80,674 patients on PD acquired from the Insan Memorial ESRD Registry database for the years 1985 to 2014, 6,071 cases were analyzed. Subjects were classified by baseline BMI; < 21.19 kg/m² (quartile 1, n = 1,518), 21.19 to 23.18 kg/m² (quartile 2, reference; n = 1,453), 23.19 to 25.71 kg/m² (quartile 3, n = 1,583), and > 25.71 kg/m² (quartile 4, n = 1,517).

Results

Mean age was 65.8 years, and baseline BMI was 23.57 kg/m². Numbers of male and diabetic patients were 3,492 (57.5%) and 2,192 (36.1%), respectively. Among 6,071 cases, 2,229 (36.7%) all-cause deaths occurred. As a whole, Kaplan–Meier survival curves according to BMI quartiles was significantly different (P = 0.001). All-cause mortality was significantly higher in quartile 4 than in the reference (hazard ratio [HR] = 1.154, 95% confidence interval [CI], 1.025–1.300; P = 0.018). There was no statistical difference in all-cause mortality among BMI quartiles in diabetic patients on PD. In non-diabetic patients, all-cause mortality of quartiles 1 and 3 was not different from the reference, but the HR was 1.176 times higher in quartile 4 (95% CI, 1.024–1.350; P = 0.022).

Conclusion

Baseline BMI > 25.71 kg/m² seems to be an important risk factor for all-cause mortality in Korean PD patients.

Risk factors associated with outcomes of peritoneal dialysis in Taiwan: An analysis using a competing risk model

Peritoneal dialysis (PD) is one option for renal replacement therapy in patients with end-stage renal disease (ESRD). Maintenance of the PD catheter is an important issue for patient outcomes and quality of life. The aim of this retrospective cohort study is to clarify the risk factors of technique failure and outcomes at a single institute in Taiwan.The study enrolled ESRD patients who had received PD catheters in a tertiary hospital in northern Taiwan. Using a competing risks regression model, we reviewed clinical data and analyzed them in terms of the time to technical failure and clinical outcomes, including PD-related peritonitis and mortality.A total of 514 patients receiving PD between 2001 and 2013 were enrolled in the study. According to the multivariate analysis model, we found that diabetes mellitus was a risk factor for PD-related peritonitis (subdistribution hazard ratio [SHR] 1.47, 95% confidence interval [CI] 1.06-2.04, P = .021). Female gender and higher serum albumin levels were associated with lower risks of technique failure (SHR 0.67, 95% CI 0.48-0.94, P = .02; SHR 0.75, 95% CI 0.58-0.96, P = .023, respectively), but Gram-negative and polymicrobial infection increased the technique failure rate (SHR 1.68, 95% CI 1.08-2.61, P = .021; SHR 1.93, 95% CI 1.11-3.36, P = .02, respectively). Female gender was a risk factor associated with overall mortality (SHR 6.4, 95% CI 1.42-28.81, P = .016). Higher weekly urea clearance (Kt/V) and weekly creatinine clearance (WCCr) were associated with a lower risk of mortality (SHR 0.1, 95% CI 0.01-0.89, P = .04; SHR 0.97, 95% CI 0.96-0.99, P = .004, respectively).Diabetes mellitus is a risk factor contributing to PD-related peritonitis. Male patients and lower serum albumin levels were associated with higher rates of technique failure. Female gender, lower Kt/V, and WCCr are risk factors for overall mortality in PD patients.

Clinical Studies of Interventions to Mitigate Cardiovascular Risk in Peritoneal Dialysis Patients

Cardiovascular disease (CVD) is highly prevalent in the peritoneal dialysis (PD) population, affecting up to 60% of cohorts. CVD is the primary cause of death in up to 40% of PD patients in Australia, New Zealand, and the United States. Cardiovascular mortality rates are reported to be approximately 14 per 100 patient-years, which are 10- to 20-fold greater than those of age- and sex-matched controls. The excess risk of CVD is related to a combination of traditional risk factors (such as hypertension, dyslipidemia, obesity, smoking, sedentary lifestyle, and insulin resistance), nontraditional (kidney disease-related) risk factors (such as anemia, chronic volume overload, inflammation, malnutrition, hyperuricemia, and mineral and bone disorder), and PD-specific risk factors (such as dialysis solutions, glycation end products, hypokalemia, residual kidney function, and ultrafiltration failure). Interventions targeting these factors may mitigate cardiovascular risk, although high-level clinical evidence is lacking. This review summarizes the evidence relating to cardiovascular interventions targeting modifiable CVD risk factors in PD patients, as well as highlighting the key recommendations of the International Society for Peritoneal Dialysis Cardiovascular and Metabolic Guidelines.

The Optimal Blood Pressure Target in Different Dialysis Populations

Hypertension is common and contributes to adverse outcomes in patients undergoing dialysis. However, the proper blood pressure (BP) target remains controversial and several factors make this difficult. This study aimed to investigate the adequate BP target in patients undergoing prevalent dialysis. Data were retrieved from the Clinical Research Center for End-Stage Renal Disease (2009–2014). 2,299 patients undergoing dialysis were evaluated. Patients were assigned into eight groups according to predialysis systolic blood pressure (SBP). The primary outcome was all-cause mortality. During the median follow-up of 4.5 years, a U-shape relation between SBP and mortality was found. The risk of mortality was increased in the SBP <110 and ≥170 mmHg groups. In subgroup analysis, the risk of mortality was similarly shown U-shape with SBP in subjects with no comorbidities, and no use of antihypertensive agents. However, only lowest SBP was a risk factor for mortality in patients with older, having diabetes or coronary artery disease, whereas highest SBP was an only risk factor in younger patients. In respect of dialysis characteristics, patients undergoing hemodialysis showed U-shape between SBP and mortality, while patients undergoing peritoneal dialysis did not. Among hemodialysis patients, patients with shorter dialysis vintage and less interdialytic weight gain showed U-shape association between SBP and mortality. This study showed that the lowest or highest SBP group had higher risk of mortality. Nevertheless, the optimal target BP should be applied according to individual condition of each patient.

Baseline and Time-Averaged Values Predicting Residual Renal Function Decline Rate in Japanese Peritoneal Dialysis Patients

Residual renal function (RRF) is a strong prognostic factor of morbidity and mortality in patients undergoing peritoneal dialysis (PD). We determined predictors of the RRF rate of decline using both baseline values and time-averaged ones. We retrospectively analyzed 94 patients being treated with PD at the Japanese Red Cross Medical Center. The decline rate of RRF was calculated by a diminution in the weekly renal Kt/V between the first and last follow up divided by follow-up years. The mean follow-up period was 2.28 years, and the mean decline rate of weekly renal Kt/V was 0.25 per year. A multivariate analysis using baseline parameters identified dialysis-to-plasma ratios of creatinine at 4 h (P = 0.02), urinary protein (P = 0.02), and mean blood pressure (MBP) (P < 0.01) as being positively associated with the RRF rate of decline, while the use of angiotensin converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) had a negative correlation (P = 0.03). When using time-averaged values as independent variables, a lower weekly total renal Kt/V (P < 0.0001), higher urinary protein (P < 0.0001), and higher MBP (P = 0.04) independently predicted a faster RRF rate of decline. We demonstrated that PD patients with a lower MBP and lower urinary protein both at baseline and throughout their PD duration had a slower RRF rate of decline. We recommend strict control of blood pressure and anti-proteinuric therapy for PD patients.

Correlation of Residual Diuresis with MIS Score and Nutritional Status in Peritoneal Dialysis Patients: A Croatian Nationwide Study

Introduction. Residual diuresis (RD) is an important predictor of mortality and cardiovascular (CV) deaths in peritoneal dialysis (PD) patients, and contributes more to overall survival compared to PD clearance. In this study we investigated the correlation between RD and CV outcomes in PD patients.

Methods. A total of 190 PD patients from 13 dialysis centers, a national representation, were included in this analysis. Biomarkers of anemia, nutritional status [malnutrition inflammation score (MIS), subjective global assessment (SGA), serum albumin, anthropometric measurements including body mass index (BMI)], dialysis dose (Kt/V) and laboratory measurements were determined. RD was estimated using the volume of daily urine.

Results. There were 78(41.05 %) females and 112 (58.95 %) males; aged 57.35±14.41 years, on PD for 24.96±24.43 months. Fifty-six patients had diabetes type II (44 as primary kidney disease). The mean RD was 1170±673.6 ml (range 0-3000 mL). Statistically significant correlations between RD and BMI, hip circumference, time on PD, Kt/V, MIS, SGA, erythrocytes (E), Hemoglobin (Hb), PTH, and serum albumin were observed.

Conclusions. We demonstrated a significant correlation between RD and MIS score, SGA, anthropometry and albumin. Every effort should be invested to maintain RD for as long as possible to achieve optimal treatment results and to decrease CV mortality in PD population.

Patient characteristics and risk factors of early and late death in incident peritoneal dialysis patients

This study was conducted to identify key patient characteristics and risk factors for peritoneal dialysis (PD) mortality in terms of different time-point of death occurrence. The incident PD patients from January 1, 2006 to December 31, 2013 in our PD center were recruited and followed up until December 31, 2015. Patients who died in the early period (the first 3 months) were older, had higher neutrophil to lymphocyte ratio (N/L), serum phosphorus, and uric acid level, and had lower diastolic pressure, hemoglobin, serum albumin, and calcium levels. After adjustment of gender, age, and PD inception, higher N/L level [hazard ratio (HR) 1.115, P = 0.006], higher phosphorus lever (HR 1.391, P < 0.001), lower hemoglobin level (HR 0.596, P < 0.001), and lower serum albumin level (HR 0.382, P = 0.017) were risk factors for early mortality. While, presence of diabetes (HR 1.627, P = 0.001), presence of cardiovascular disease (HR 1.847, P < 0.001) and lower serum albumin level (HR 0.720, P = 0.023) were risk factors for late mortality (over 24 months). In conclusion, patient characteristics and risk factors associated with early and late mortality in incident PD patients were different, which indicated specific management according to patient characteristics at the initiation of PD should be established to improve PD patient survival.

Reverse Epidemiology of Blood Pressure in Peritoneal Dialysis Associated with Dynamic Deterioration of Left Ventricular Function

♦

BACKGROUND

Reverse epidemiology of blood pressure (BP) in end-stage kidney disease (ESKD) is manifested as higher mortality at lower blood pressure. We hypothesize that this phenomenon is partially mediated by deterioration of cardiac structure and function. ♦

METHODS

Seventy-seven prevalent ESKD patients starting renal replacement therapy on peritoneal dialysis (PD) from 2007 to 2012 were evaluated for the primary outcome of all-cause mortality. Longitudinal data were obtained from 1,930 patient-encounters including monthly clinic BP and serial echocardiograms. Generalized linear mixed models using data from the last observation moving backward, and time-to-event analysis using time-varying Cox-survival models to estimate mortality risk at different blood pressure categories were applied. ♦

RESULTS

There were 39 males (50.6%). Mean age was 51 years (standard deviation [SD] = 15). During follow-up, 20 patients (25%) died. As compared to systolic blood pressure (SBP) of 140-159 mmHg, unadjusted risk of mortality was 7.3 (95% confidence interval [CI]: 1.5-35.7, p = 0.008) at level < 120 mmHg. Systolic BP trended down to an average of 117 mmHg prior to death in non-survivors as compared to 141 mmHg in survivors (p < 0.05). In non-survivors, percentage with concentric left ventricular hypertrophy (LVH) decreased by 20% at the expense of a 20% reciprocal increase in eccentric hypertrophy associated with a 30% increase in percentage with low ejection fraction (EF) (< 50%). After adjusting for EF, risk of mortality at SBP < 120 mmHg attenuated to 3.4 (95% CI: 0.7-17.7, p = 0.14). ♦

CONCLUSION

We conclude that higher mortality associated with lower BP may be mediated in part by worsening heart function in ESKD patients receiving PD.

Strategies for preserving residual renal function in peritoneal dialysis patients

Although there have been many advancements in the treatment of patients with chronic kidney disease (CKD) over the last 50 years, in terms of reducing cardiovascular risk, mortality remains unacceptably high, particularly for those patients who progress to stage 5 CKD and initiate dialysis (CKD5d). As mortality risk increases exponentially with progressive CKD stage, the question arises as to whether preservation of residual renal function once dialysis has been initiated can reduce mortality risk. Observational studies to date have reported an association between even small amounts of residual renal function and improved patient survival and quality of life. Dialysis therapies predominantly provide clearance for small water-soluble solutes, volume and acid-base control, but cannot reproduce the metabolic functions of the kidney. As such, protein-bound solutes, advanced glycosylation end-products, middle molecules and other azotaemic toxins accumulate over time in the anuric CKD5d patient. Apart from avoiding potential nephrotoxic insults, observational and interventional trials have suggested that a number of interventions and treatments may potentially reduce the progression of earlier stages of CKD, including targeted blood pressure control, reducing proteinuria and dietary intervention using combinations of protein restriction with keto acid supplementation. However, many interventions which have been proven to be effective in the general population have not been equally effective in the CKD5d patient, and so the question arises as to whether these treatment options are equally applicable to CKD5d patients. As strategies to help preserve residual renal function in CKD5d patients are not well established, we have reviewed the evidence for preserving or losing residual renal function in peritoneal dialysis patients, as urine collections are routinely collected, whereas few centres regularly collect urine from haemodialysis patients, and haemodialysis dialysis patients are at risk of sudden intravascular volume shifts associated with dialysis treatments. On the other hand, peritoneal dialysis patients are exposed to a variety of hypertonic dialysates and episodes of peritonitis. Whereas blood pressure control, using an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB), and low-protein diets along with keto acid supplementation have been shown to reduce the rate of progression in patients with earlier stages of CKD, the strategies to preserve residual renal function (RRF) in dialysis patients are not well established. For peritoneal dialysis patients, there are additional technical factors that might aggravate the rate of loss of residual renal function including peritoneal dialysis prescriptions and modality, bio-incompatible dialysis fluid and over ultrafiltration of fluid causing dehydration. In this review, we aim to evaluate the evidence of interventions and treatments, which may sustain residual renal function in peritoneal dialysis patients.

Dialysis adequacy indices and body composition in male and female patients on peritoneal dialysis

OBJECTIVES

Creatinine clearance scaled to body surface area (BSA) and urea KT/V normalized to total body water (TBW) are used as indices for peritoneal dialysis (PD) adequacy. We investigated relationships of indices of dialysis adequacy (including KT/V, KT, clearance, dialysate over plasma concentration ratio) and anthropometric and body composition parameters (BSA, TBW, body mass index (BMI), weight, height, fat mass (FM), and fat-free mass (FFM)) in male and female patients on continuous ambulatory peritoneal dialysis.

METHODS

Ninety-nine stable patients (56 males) performed four 24-hr collections of drained dialysate for four dialysis schedules with three daily exchanges of glucose 1.36% and one night exchange of either: 1) glucose 1.36%, 2) glucose 2.27%, 3) glucose 3.86% or 4) icodextrin 7.5%.

RESULTS

KT and dialysate over plasma concentration ratio, CD/CP, for urea and creatinine were similar for males and females and, in general, did not depend on body-size parameters including V (= TBW), which means that the overall capacity of the transport system in females and males is similar. However, after normalization of KT to V or 1.73/BSA yielding KT/V and creatinine clearance, Cl(1.73/BSA), respectively, the normalized indices were substantially higher in females than in males and correlated inversely with body-size parameters, especially in males.

CONCLUSIONS

As KT/V depends strongly on body size, treatment target values for KT/V should take body size and therefore also gender into account. As KT is less influenced by body size, body composition and gender, KT should be considered as a potential auxiliary index in PD.

Clinical outcomes of peritoneal dialysis patients transferred from hemodialysis: a matched case-control study

OBJECTIVE

Our study aimed to evaluate clinical outcomes of patients transferred to peritoneal dialysis (PD) because of complications related to hemodialysis (HD). ♢

METHODS

In a 1:2 matched case-control study, we compared patient and technique survival between patients initially treated with HD for at least 3 months and then transferred to PD (transfer group) and patients started on and continuing with PD (no-transfer group). ♢

RESULTS

All baseline characteristics except for initial residual urinary output were comparable between the groups. Compared with patients in the transfer group, patients in the no-transfer group had a higher initial daily residual urinary output [850 mL (range: 600 - 1250 mL) vs 0 mL (range: 0 - 775 mL/d), p = 0.000]. The main reasons for transfer to PD were vascular access problems and cardiovascular disease. Patient survival and technique failure rates did not significantly differ between the groups (p > 0.05). The 1-, 3-, and 5-year patient survival rates were 80.0%, 53.7%, and 27.6% in the transfer group and 89.7%, 60.2%, and 43.1% in the no-transfer group. Age (per 10 years) and serum albumin were independent risk factors for long-term survival in PD patients. Relative risk of either death or technique failure was not significantly increased in patients transferred from HD. ♢

CONCLUSIONS

Patients who transferred to PD after failing HD had outcomes on PD similar to those for patients who started with and were maintained on PD. Age (per 10 years) and serum albumin were independent risk factors for long-term survival in PD patients.

Assessment of fluid status in CAPD patients using the body composition monitor

AIMS AND OBJECTIVES

To assess the degree of overhydration in our peritoneal dialysis patients and to examine the factors contributing to overhydration.

BACKGROUND

Volume control is critical for the success of peritoneal dialysis, but dry weight has been difficult to ascertain accurately. Chronic fluid overload and hypertension are among the leading causes of mortality in dialysis patients.

DESIGN

A cross-sectional observational study.

METHODS

The body composition monitor (Fresenius Medical Care, Bad Homburg, Germany) is a bioimpedance spectroscopy device that has been validated for the assessment of overhydration. We used this body composition monitor device on all patients on continuous ambulatory peritoneal dialysis at our institution who met the inclusion criteria to assess their degree of overhydration.

RESULTS

Thirty four (17 men, 17 women; mean age 44·5 ± 14·2 years) of a 45 continuous ambulatory peritoneal dialysis patients were enrolled. The mean overhydration was 2·4 ± 2·4 l. Fifty per cent of the patients were ≥2 l overhydrated. Overhydration correlated with male gender, low serum albumin, increasing number of antihypertensive agents and duration of dialysis. There was no difference in overhydration between diabetic and non-diabetic patients. Men were more overhydrated than women, had lower Kt/V and were older. Although, there was no difference in blood pressure between the genders, men had a trend towards a higher usage of antihypertensive agents.

CONCLUSION

Our study demonstrates that overhydration is common in peritoneal dialysis patients. Blood pressure should ideally be controlled with adherence to dry weight and low salt intake rather than adding antihypertensive agents even in the absence of clinical oedema.

RELEVANCE TO CLINICAL PRACTICE

Body composition monitor is a simple, reliable and inexpensive tool that can be routinely used in the outpatient clinic setting or home visit to adjust the dry weight and avoid chronic fluid overload in between nephrologists review.

Effluent free radicals are associated with residual renal function and predict technique failure in peritoneal dialysis patients

OBJECTIVE

Residual renal function (RRF) is associated with low oxidative stress in peritoneal dialysis (PD). In the present study, we investigated the relationship between the impact of oxidative stress on RRF and patient outcomes during PD.

METHODS

Levels of free radicals (FRs) in effluent from the overnight dwell in 45 outpatients were determined by electron spin resonance spectrometry. The FR levels, clinical parameters, and the level of 8-hydroxy-2'-deoxyguanosine were evaluated at study start. The effects of effluent FR level on technique and patient survival were analyzed in a prospective cohort followed for 24 months.

RESULTS

Levels of effluent FRs showed significant negative correlations with daily urine volume and residual renal Kt/V, and positive correlations with plasma β(2)-microglobulin and effluent 8-hydroxy-2'-deoxyguanosine. A highly significant difference in technique survival (p < 0.05), but not patient survival, was observed for patients grouped by effluent FR quartile. The effluent FR level was independently associated with technique failure after adjusting for patient age, history of cardiovascular disease, and presence of diabetes mellitus (p < 0.001). The level of effluent FRs was associated with death-censored technique failure in both univariate (p < 0.001) and multivariate (p < 0.01) hazard models. Compared with patients remaining on PD, those withdrawn from the modality had significantly higher levels of effluent FRs (p < 0.005).

CONCLUSIONS

Elevated effluent FRs are associated with RRF and technique failure in stable PD patients. These findings highlight the importance of oxidative stress as an unfavorable prognostic factor in PD and emphasize that steps should be taken to minimize oxidative stress in these patients.

Loss of residual renal function was not associated with glycemic control in patients on peritoneal dialysis

BACKGROUND

Better glycemic control has been reported to slow the progression of nephropathy in predialysis diabetic patients. However, the relationship between glycemic control and residual renal function (RRF) in patients on peritoneal dialysis (PD) is uncertain.

METHODS

89 incident diabetic patients on PD were recruited from 5 centers. We measured glomerular filtration rate (GFR) and hemoglobin A1c (HbA1c) within 2 months (baseline) after the start of PD and at 6 and 12 months. GFR was calculated as the average of renal creatinine and urea clearances. We analyzed whether mean HbA1c was associated with change in GFR (ΔGFR) over 1 year.

RESULTS

During the first year of PD, ΔGFR was -1.7 ± 3.4 mL/min/1.73 m² and was not affected by mean HbA1c. Acute hemodialysis before starting PD and mean arterial diastolic pressure were related to the decline of GFR in a multivariate analysis.

CONCLUSION

Glycemic control was not associated with change in RRF in diabetic patients during the first year after starting PD.

Treatment with Angiotensin II Inhibitors and Residual Renal Function in Peritoneal Dialysis Patients

Background

Many studies have shown the renoprotective effect of angiotensin-converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARBs) in patients with chronic kidney disease stages I–IV. Two randomized controlled trials (RCTs) showed a positive effect of AII inhibitors on residual glomerular filtration rate (rGFR) in peritoneal dialysis (PD) patients. However, these studies were small and were performed in a highly selected group of PD patients. Our aim was to confirm the above findings in a larger number of prospectively followed PD patients.

Methods

First we analyzed the time course of decline of rGFR in 452 incident PD patients that were not anuric at the start of dialysis and that had structured follow-up data, with measurements at 3, 6, 12, 18, 24, 30, and 36 months after the start of dialysis. Changes in rGFR over time were analyzed with a linear mixed model for repeated measures. In addition, Cox regression models were used to estimate the risk of developing anuria. In a second approach, we aimed to repeat the above analyses in a selected group of patients that theoretically could have been randomized and therefore resembled the population studied in the 2 mentioned RCTs. In this group the follow-up was restricted to 1 year.

Results

201 patients were treated with ACEi/ARBs and 251 did not take these drugs at the start of PD. More patients from the treated group had diabetes and used more antihypertensive medications. The time course of decline of rGFR was not different between the 2 groups over the 3 years of PD treatment ( p = 0.52). Less than 25% of patients from each group became anuric and there was no difference in time to development of complete anuria between the treated and untreated groups. In the second approach, 130 patients were included: 37 were treated with ACEi/ARBs and 93 were not. Again, no difference was found between the 2 groups with respect to the rate of decline of rGFR and time of anuria development.

Conclusion

Our findings are not in line with the results of previous RCTs. The biggest limitation of observational studies is the inability to avoid confounding by indication. However, a RCT in such a setting also does not give a reliable answer. Given all the benefits of ACEi/ARBs, the medications should not be withheld from PD patients. However, their renoprotective effects may often be overruled by other factors influencing the time course of rGFR.

Simulating inadequate dialysis and its correction using an individualized patient-derived nomogram

Computerized kinetic modeling is a valuable automated peritoneal dialysis (APD) prescription tool for optimizing dialysis adequacy. However, non-compliance results in failure to achieve adequacy targets. The aim of this study was to determine if a nomogram could estimate dialysis compensations for shortfalls in simulated non-compliant patients, such that total weekly urea clearance (Kt/V(urea)) targets are met. Individualized nomograms comprising a series of curves were derived from PD Adequest (ver. 2.0)-predicted Kt/V(urea) data (r (2 ) > 0.99) for different APD prescriptions. The nomogram was then used to estimate the (Nomogram-computed) average of the daily Kt/V(urea) in 14 patients. The study comprised three 1-month phases. Patients were compliant to dialysis in phase I, where Adequest-predicted Kt/V(urea) showed good agreement with both measured (r (I) = 0.72), and Nomogram-computed values (r (I) > 0.99) (p < 0.001). Conversely, in non-compliant phase II, Nomogram-computed values were lower than Adequest-predicted values (p < 0.002). In phase III, the nomogram estimated prescription adjustments required to compensate for shortfalls, such that there was significantly less difference between Nomogram-computed and Adequest-predicted Kt/V(urea) than in phase II (p = 0.005). Thus, despite non-compliance, predicted Kt/V(urea) targets were attained using the nomogram to adjust the daily APD prescriptions. This concept is potentially useful for patients desiring to compensate for inadvertent shortfalls, rather than for 'truly non-compliant' patients.

Blood pressure and mortality risk on peritoneal dialysis

BACKGROUND

The association of baseline blood pressure (BP) and mortality in incident peritoneal dialysis patients has not been adequately studied.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

2,770 patients on PD therapy at 180 days from start of renal replacement therapy in England and Wales between 1997 and 2004.

PREDICTORS

Systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP) measured in the first 6 months of renal replacement therapy and other baseline demographic and laboratory variables.

OUTCOMES

All-cause mortality was studied using time-stratified Cox regression models (to account for nonproportionality) dividing follow-up time into 4 intervals: year 1 (days 180 to 365), years 2 to 3, years 4 to 5, and years 6+. Interactions between BP components and transplant waitlist and diabetes status were explored.

RESULTS

Median follow-up was 3.7 years (range, 0.1 to 9.9 years), and 1,104 deaths were observed. In fully adjusted analyses, greater SBP, DBP, MAP, and PP were associated with decreased mortality in the first year, but greater SBP and PP were associated with increased late mortality (in years 6+). However, in the subgroup of patients placed on the transplant waitlist within 6 months of starting renal replacement therapy, greater SBP, DBP, MAP, and PP were not associated with decreased mortality in the first year.

LIMITATIONS

Exclusion of 3,086 patients because of missing BP data. No data were available for cardiac function or antihypertensive medication.

CONCLUSIONS

Although greater SBP, DBP, MAP, and PP appear protective against early mortality in the overall cohort, this effect is not seen in patients registered on the national transplant waiting list within 6 months of starting renal replacement therapy.

The evaluation incidence and risk factors of mortality among patients with end stage renal disease in southeast Turkey

AIM

End stage renal disease (ESRD) presents with higher morbidity and mortality with respect to the general population. In recent study, the causes of mortality and associated risk factors in ESRD have been evaluated.

MATERIALS AND METHODS

In this study, 1538 patients diagnosed with ESRD in 10-year period were evaluated retrospectively. The patients were divided as dead (group 1) and alive (group 2). The patients' demographic features, causes of death, comorbidity at hospitalization, hematological and biochemical analyses, creatinine clearance at the beginning of hospitalization, daily urine volume, blood gas results, CRP value as inflammatory marker, ejection fraction, interventricular septum diameter, left ventricle posterior wall end-diastolic diameter, and left atrium diameter determined with echocardiography were recorded.

RESULTS

Mortality ratio of ESRD patients in a 10-year period was 14.1%. While the general mean age of all patients was 54.7 +/- 16.6 and male/female ratio was 781/757, these ratios were 66.3 +/- 21.8 and 114/103 in Group 1 and 52.8 +/- 21.7 and 667/654 in Group 2. One or more comorbid pathologies were present in 82.9% of Group 1. The most common cause of mortality was cardiovascular diseases (CVD), and the most common cause of comorbidity was infections. Older age, anemia, absence of residual renal function, hypoalbuminemia, inflammation, impaired Ca and P metabolism, and left ventricular hypertrophy were significantly higher in Group 1 than in Group 2.

CONCLUSION

CVD are the most important preventable causes of morbidity and mortality in all stages of chronic kidney disease. Taking precaution against CVD and the associated complications will provide a positive contribution in reducing morbidity and mortality among ESRD patients.

Evaluation of peritoneal transport and membrane status in peritoneal dialysis: focus on incident fast transporters

BACKGROUND/AIM

The determinants of baseline fast solute transport are still unclear. We prospectively investigated the relationship of peritoneal solute transport with markers of inflammation, angiogenesis, and membrane status, with a focus on fast transporters.

METHODS

Seventy-one incident peritoneal dialysis patients were assessed with baseline and annual peritoneal equilibration tests, using a 3.86% glucose dialysis solution. Residual renal function and markers of inflammation, including systemic and intraperitoneal interleukin-6 (IL-6), effluent cancer antigen 125 (CA-125), and vascular endothelial growth factor (VEGF) appearance rates (ARs), were investigated. The time course of the dialysate-to-plasma ratio of creatinine (D/P creatinine ratio) and its relationship with the biomarkers were investigated by a mixed linear model.

RESULTS

Incident fast/fast average transporters had a similar age, diabetes prevalence, and serum and effluent IL-6 levels, but significantly higher levels of CA-125 and VEGF ARs than the slow/slow average group; the D/P creatinine ratio was not correlated with systemic IL-6, but was correlated with effluent CA-125 AR (r = 0.45, p < 0.0001) and VEGF AR (r = 0.52, p < 0.0001). The D/P creatinine ratio decreased with a U-shaped profile (p = 0.02). Intraperitoneal IL-6 was the significant and positive determinant of the time course of the D/P creatinine ratio (p < 0.0001). Effluent CA-125 decreased with time on peritoneal dialysis (p = 0.013).

CONCLUSIONS

Baseline peritoneal fast transport was not associated with systemic inflammation, but was related to peritoneal locally produced substances able to mediate transitory hyperpermeability. The D/P creatinine ratio changed during the follow-up period with a U-shaped profile. This was associated with effluent IL-6 and partly with VEGF. CA-125 decreased throughout the follow-up period.

End stage polycystic kidney disease: indications and timing of native nephrectomy relative to kidney transplantation

PURPOSE

We evaluated the indications for and outcome of pre-transplant, concomitant and post-transplant native nephrectomy in patients with end stage polycystic kidney disease (PCKD).

MATERIALS AND METHODS

The records of 32 patients were retrospectively reviewed using the electronic database at our institution.

RESULTS

Between January 1992 and December 2002, 171 patients with end stage PCKD received a kidney transplant at University of California-San Francisco. A total of 32 patients (18.7%) underwent pre-transplant (7, group 1), concomitant (16, group 2) or post-transplant (9, group 3) native nephrectomy. Of these patients 25 underwent bilateral nephrectomy. Median followup was 18 months. Indications for nephrectomy were hematuria, a renal mass and chronic pain in group 1, lack of space in group 2 and urinary tract infection in group 3. Mean operative time +/- SEM was 231 +/- 14, 370 +/- 24 and 208 +/- 14 minutes in groups 1 to 3, respectively (p = 0.001). Mean intraoperative blood loss was 533 +/- 105, 573 +/- 155 and 522 +/- 181 ml in groups 1 to 3, respectively (p not significant). Two group 2 patients required blood transfusions. Postoperative complications requiring surgical intervention included wound dehiscence in group 1 and abdominal bleeding in group 3. Mean hospital stay was comparable among groups 1 to 3 at 7 +/- 0.7, 8.6 +/- 1.2 and 6.3 +/- 0.6 days, respectively (p not significant). At 3 months mean serum creatinine was not significantly different between groups 2 and 3 at 1.3 +/- 0.1 and 1.5 +/- 0.2 mg/dl, respectively.

CONCLUSIONS

Unilateral or bilateral nephrectomy for PCKD at transplantation is safe in terms of postoperative patient morbidity and graft function. We perform concomitant native nephrectomy when indicated, preferably in recipients of living donor kidney transplants.

Urologische Betreuung von Patienten vor und nach Nierentransplantation

Patients with end-stage renal disease awaiting kidney transplantation require regular urological evaluation. The urologist's main task is early diagnosis and treatment of genitourinary malignancies and evaluation of the lower urinary tract. Furthermore, urologists are often confronted with the question of whether or not to perform pretransplant urological surgery, i.e., native nephrectomy for polycystic kidney disease. Urological care after kidney transplantation involves diagnosis and treatment of ureteral complications, malignancies, lower urinary tract symptoms, and last but not least erectile dysfunction, which has a prevalence of 20-50% among kidney transplant recipients. For the evaluation and follow-up of the living kidney donor, international guidelines have been developed in recent years to also help the urologist to perform a correct evaluation and follow-up of the kidney donor.

Survival differences between peritoneal dialysis and hemodialysis among "large" ESRD patients in the United States

BACKGROUND

It has been hypothesized that peritoneal dialysis compared to hemodialysis may be less effective in large patients with end-stage renal disease (ESRD).

METHODS

We tested this hypothesis in a cohort of 134,728 new ESRD patients who were initiated on dialysis from May 1, 1995 to July 31, 1997 using data from United States Renal Data System (USRDS). Cox regression models evaluated the association of body mass index (BMI) in quintiles (8.8-20.9, 20.9-23.5, 23.5-26.1, 26.1-30.0, 30.0-75.2 kg/m(2)) with mortality over 2 years in peritoneal dialysis and hemodialysis patients separately, while time-dependent models evaluated the relative risk (RR) of death by modality for each BMI quintile.

RESULTS

For hemodialysis, the adjusted RR of death was greatest for patients with BMI <or = 20.9 (RR = 1.40, 95% CI 1.32-1.50 for diabetics and RR = 1.27, 95% CI 1.21-1.34 for nondiabetics) and lowest for patients with BMI >30.0 (RR = 0.97, 95% CI 0.96-0.99 for diabetic and RR = 0.97, 95% CI 0.95-0.98 for nondiabetic patients) compared with the referent (23.5-26.1; RR = 1.00). For peritoneal dialysis, the RR of death was also higher for patients with a BMI <20.9 (RR = 1.20, 95% CI 1.00-1.43 for diabetic and RR = 1.39, 95% CI 1.19-1.64 for nondiabetic patients) but no survival advantage was associated with higher BMI values. The RR of death (peritoneal dialysis/hemodialysis) for each BMI quintile was 0.99, 1.12, 1.26 (P < 0.01), 1.15 (P < 0.01), and 1.44 (P < 0.0001) for diabetic and were 1.07, 1.01, 0.96, 1.04, and 1.22 (P < 0.01) for nondiabetic patients, respectively.

CONCLUSION

We conclude that body size modifies the impact of dialysis modality on mortality risk among new ESRD patients in the United States. The selection of hemodialysis over peritoneal dialysis was associated with a survival advantage in patients with large body habitus.

Body mass index, dialysis modality, and survival: analysis of the United States Renal Data System Dialysis Morbidity and Mortality Wave II Study

BACKGROUND

The impact of obesity on survival in end-stage renal disease (ESRD) patients as related to dialysis modality (i.e., a direct comparison of hemodialysis with peritoneal dialysis) has not been assessed adjusting for differences in medication use, follow-up > or =2 years, or accounting for changes in dialysis modality.

METHODS

We performed a retrospective cohort study of the United States Renal Data System (USRDS) Dialysis Morbidity and Mortality Wave II Study (DMMS) patients who started dialysis in 1996, and were followed until October 31 2001. Cox regression analysis was used to model adjusted hazard ratios (AHR) for mortality for categories of body mass index (BMI), both as quartiles and as > or =30 kg/m2 vs. lower. Because such a large proportion of peritoneal dialysis patients changed to hemodialysis during the study period (45.5%), a sensitivity analysis was performed calculating survival time both censoring and not censoring on the date of change from peritoneal dialysis to hemodialysis.

RESULTS

There were 1675 hemodialysis and 1662 peritoneal dialysis patients. Among hemodialysis patients, 5-year survival for patients with BMI > or =30 kg/m2 was 39.8% vs. 32.3% for lower BMI (P < 0.01 by log-rank test). Among peritoneal dialysis patients, 5-year survival for patients with BMI >/=30 kg/m2 was 38.7% vs. 40.4% for lower BMI (P > 0.05 by log-rank test). In adjusted analysis, BMI > or = 30 kg/m2 was associated with improved survival in hemodialysis patients (AHR 0.89; 95% CI 0.81, 0.99; P= 0.042) but not peritoneal dialysis patients (AHR = 0.99; 95% CI, 0.86, 1.15; P= 0.89). Results were not different on censoring of change from peritoneal dialysis to hemodialysis.

CONCLUSION

We conclude that any survival advantage associated with obesity among chronic dialysis patients is significantly less likely for peritoneal dialysis patients, compared to hemodialysis patients.

Residual renal function: considerations on its importance and preservation in dialysis patients

Residual renal function (RRF) remains important even after commencement of dialysis. Its role in the adequacy of peritoneal dialysis (PD) is well recognized and is increasingly utilized in incremental PD regimes, but it is also vitally important in hemodialysis (HD) patients, in whom it, as in PD patients, may improve survival. It may allow for a reduction in the duration of HD sessions. It reduces the need for dietary and fluid restrictions in both PD and HD patients. Other contributions include improved middle molecule clearance, better hemoglobin, phosphate, potassium, and urate levels, enhanced nutritional status and quality of life scores, and better outcomes in pregnancy. On the negative side, hypoalbuminemia may be prolonged in patients with persistent nephrotic-range proteinuria. Contrary to popular belief, RRF does not necessarily decline rapidly with the initiation of HD. PD may be better than HD in preserving RRF, although this difference may not persist if biocompatible membranes, bicarbonate buffer, and ultrapure water are used. Nocturnal ambulatory peritoneal dialysis (APD) patients may fare worse than continuous ambulatory peritoneal dialysis (CAPD) patients. RRF can be adversely affected by angiotensin-converting enzyme (ACE) inhibitors, nonsteroidal anti-inflammatory drugs (NSAIDs), aminoglycosides, and radiocontrast agents. Diuretics can help maintain fluid balance but not RRF.

Compared time profiles of ultrafiltration, sodium removal, and renal function in incident CAPD and automated peritoneal dialysis patients

BACKGROUND

Fluid and sodium removal rates may not be equivalent in patients undergoing automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD). This may influence compared cardiovascular outcomes in both groups.

METHODS

The authors compared prospectively the time courses of ultrafiltration, sodium removal, and residual renal function (RRF) in a group of incident patients treated with CAPD (n = 53) or APD (n = 51) for at least 1 year (mean follow-up, 28.9 months; range, 13 to 62). The authors analyzed potential effects of these factors on blood pressure (BP) control and cardiovascular morbidity and mortality.

RESULTS

Ultrafiltration and sodium removal rates were consistently lower in APD patients (mean differences, 236 mL/d; P = 0.012, and 36 mmol/d; P = 0.018, respectively, end of first year). Moreover, univariate and multivariate analysis indicated that APD therapy results in a moderate, but significantly faster decline of RRF than CAPD therapy. Analysis of clinical outcomes showed that CAPD (versus APD) therapy or higher ultrafiltration or sodium removal rates were associated with a better time course of systolic, but not diastolic, BP. We were unable to identify PD modality, ultrafiltration, or sodium removal rates as independent predictors of cardiovascular morbidity and mortality.

CONCLUSION

Ultrafiltration and sodium removal rates are consistently lower in incident APD patients than in their counterparts undergoing CAPD. Moreover, RRF declines faster during APD than during CAPD therapy, although this difference may be partially counteracted by a detrimental effect of ultrafiltration on RRF. Aside from a better control of systolic BP in CAPD patients, these differences do not portend significant cardiovascular consequences during the first years of PD therapy.

Factors that Might Adversely Affect Short-Term Survival of Patients Starting Peritoneal Dialysis and use of those Factors to Predict Outcome—A Single-Center Experience

Objective

Patients initiated on peritoneal dialysis (PD) have significant morbidity and mortality. It would be important to know which factors have an adverse impact on outcome in the first 6 months of PD and whether those factors could be used to predict patient outcome.

Methods

We identified 64 PD patients from a prospectively collected database of all consecutive patients with end-stage renal failure (ESRF) seen at our tertiary referral center between January 2000 and June 2001. The patients were divided into two groups according to whether they were still living or had died by 6 months after the start of PD. Two patients defaulted on follow-up. In the remaining 62 patients, we compared multiple parameters and identified factors that we then evaluated as prediction tools.

Results

Significant differences were noted between the groups (died vs still living) with respect to race (non Chinese: 35.3% vs 13.3%), ischemic heart disease (IHD: 70.6% vs 62.2%), two-dimensional echo ejection fraction (EF: 42% ± 19% vs 53% ± 17%), regional wall motion abnormality (RWMA: 53% vs 22%), serum albumin 28 ± 1 g/L vs 31±5 g/L), alkaline phosphatase (ALP: 140 ± 118 U/L vs 101 ± 36 U/L). No differences were observed with respect to age, sex, cause of ESRF, diabetes status, hypertension, hyperlipidemia, stroke, hemoglobin, or intact parathyroid hormone. As expected, patients in the group that had died by 6 months spent a higher total number of days in hospital (66 ± 47 days vs 43 ± 29 days) and had more cardiovascular events (58.8% vs 6.6%); however, no difference was observed with respect to septic events. The utility of IHD, albumin, ALP, EF, and RWMA as predictors of short-term mortality either singly or in combination were analyzed. We found that those factors were neither sensitive nor specific at predicting mortality in this group of patients.

Conclusions

Race (non Chinese), prior IHD, two-dimensional echo abnormalities (EF and RWMA), low serum albumin, and high serum ALP are factors that affect short-term survival in PD patients. However, it is not possible to predict patient outcome using those factors.

The implications of the ADEMEX study for the peritoneal dialysis prescription: the role of small solute clearance versus salt and water removal

PURPOSE OF REVIEW

This review examines the results of the ADEMEX (Adequacy of Peritoneal Dialysis in Mexico) study in the context of other recent advances in peritoneal dialysis, and assesses the implication of this new knowledge for the optimal peritoneal dialysis prescription.

RECENT FINDINGS

The prospective randomized controlled ADEMEX study demonstrated no survival advantage of an increased dose of peritoneal small molecule clearance delivered by chronic ambulatory peritoneal dialysis. Coincident with this finding, there has been increasing awareness that many peritoneal dialysis patients are volume expanded, and that there are adverse cardiovascular consequences to this chronic overhydration. As a result there has been a shift away from interest in peritoneal small solute clearance with renewed interest in peritoneal removal of salt and water. There is also increasing evidence of the importance of residual renal function in maintaining euvolemia and as a prognostic indicator for survival.

SUMMARY

The ADEMEX study and subsequent investigations have changed the way we perceive the optimal peritoneal dialysis prescription. This has resulted in de-emphasis of peritoneal small molecule clearance and increased emphasis on clinical assessment of dialysis adequacy, preservation of residual renal function, and optimization of salt and water removal.

Impact of dialysis modality on survival of new ESRD patients with congestive heart failure in the United States

BACKGROUND

It is hypothesized, but not proven, that peritoneal dialysis might be the optimal treatment for end-stage renal disease (ESRD) patients with established congestive heart failure (CHF) through better volume regulation compared with hemodialysis.

METHODS

National incidence data on 107,922 new ESRD patients from the Center for Medicare and Medicaid Services (CMS) Medical Evidence Form were used to test the hypothesis that peritoneal dialysis was superior to hemodialysis in prolonging survival of patients with CHF. Nonproportional Cox regression models evaluated the relative hazard of death for patients with and without CHF by dialysis modality using primarily the intent-to-treat but also the as-treated approach. Diabetics and nondiabetics were analyzed separately.

RESULTS

The overall prevalence of CHF was 33% at ESRD initiation. There were 27,149 deaths (25.2%), 5423 transplants (5%), and 3753 (3.5%) patients lost to follow-up over 2 years. Adjusted mortality risks were significantly higher for patients with CHF treated with peritoneal dialysis than hemodialysis [diabetics, relative risk (RR) = 1.30, 95% confidence interval (CI) 1.20 to 1.41; nondiabetics, RR = 1.24, 95% CI 1.14 to 1.35]. Among patients without CHF, adjusted mortality risk were higher only for diabetic patients treated with peritoneal dialysis compared with hemodialysis (RR = 1.11, 95% CI 1.02 to 1.21) while nondiabetics had similar survival on peritoneal dialysis or hemodialysis (RR = 0.97, 95% CI 0.91 to 1.04).

CONCLUSION

New ESRD patients with a clinical history of CHF experienced poorer survival when treated with peritoneal dialysis compared with hemodialysis. These data suggest that peritoneal dialysis may not be the optimal choice for new ESRD patients with CHF perhaps through impaired volume regulation and worsening cardiomyopathy.