Effects of an angiotensin II receptor blocker, valsartan, on residual renal function in patients on CAPD

Long-term effects of spironolactone in peritoneal dialysis patients

ESRD treated with dialysis is associated with increased left ventricular hypertrophy, which, in turn, is related to high mortality. Mineralocorticoid receptor antagonists improve survival in patients with chronic heart failure; however, the effects in patients undergoing dialysis remain uncertain. We conducted a multicenter, open-label, prospective, randomized trial with 158 patients receiving angiotensin-converting enzyme inhibitor or angiotensin type 1 receptor antagonist and undergoing peritoneal dialysis with and without (control group) spironolactone for 2 years. As a primary endpoint, rate of change in left ventricular mass index assessed by echocardiography improved significantly at 6 (P=0.03), 18 (P=0.004), and 24 (P=0.01) months in patients taking spironolactone compared with the control group. Rate of change in left ventricular ejection fraction improved significantly at 24 weeks with spironolactone compared with nontreatment (P=0.02). The benefits of spironolactone were clear in patients with reduced residual renal function. As secondary endpoints, renal Kt/V and dialysate-to-plasma creatinine ratio did not differ significantly between groups during the observation period. No serious adverse effects, such as hyperkalemia, occurred. In this trial, spironolactone prevented cardiac hypertrophy and decreases in left ventricular ejection fraction in patients undergoing peritoneal dialysis, without significant adverse effects. Further studies, including those to determine relative effectiveness in women and men and to evaluate additional secondary endpoints, should confirm these data in a larger cohort.

Comparison of the impact of "fast decline" in residual renal function and "initial anuria" on long-term outcomes in CAPD patients

BACKGROUND

Residual renal function (RRF) is pivotal to long-term outcomes, while rapid RRF decline (RRFD) is associated with mortality risk for continuous ambulatory peritoneal dialysis (CAPD) patients. This study was conducted to compare the impact of "initial anuria" and rapid RRFD on the long-term prognosis of CAPD patients.

METHOD

According to the timing of anuria and the slope of RRFD, a total of 255 incident CAPD patients were divided into 3 groups. For the "anuria" group, anuria was detected from CAPD initiation and persisted for > 6 months (n = 27). Based on the median of the RRFD slope, the other 228 non-anuric patients were divided into a "slow decliner" group (n = 114), and a "rapid decliner" group (n = 114). The maximal observation period was 120 months.

RESULTS

Logistic regression tests indicated that the "anuria" group was associated with previous hemodialysis > 3 months (odds ratio [OR]: 8.52, 95% confidence interval [CI]: 3.12 - 23.28), and female (OR: 0.29, 95% CI: 0.09 - 0.90), while the "fast decliner" group with higher Davies co-morbidity scores (DCS) (OR: 1.52; 95% CI: 1.08 - 2.14), body mass index (BMI) (OR: 1.12; 95% CI: 1.04 - 1.21), and male (OR: 1.12; 95% CI: 1.04 - 1.21). After adjusting for DCS, the "fast decliner" group (hazard ratio [HR]: 0.37; 95% CI: 0.17 - 0.80) showed a better outcome than that of the "anuria" group (reference = 1). Both baseline RRF (β = -0.24; p < 0.001) and DCS (β = -3.76; p < 0.001) showed inverse linear correlations to the slope of RRFD. From the Cox proportional analyses, higher baseline RRF (HR: 0.92; 95% CI: 0.88 -.97) and higher slope of RRFD (slower decline in RRF) (HR: 0.90; 95% CI: 0.85 - 0.96) were independent factors for less mortality risk in patients with DCS = 0. However, only a higher slope of RRFD (HR: 0.97; 95% CI: 0.94 - 0.99) was significant for better survival in CAPD patients with DCS > 0.

CONCLUSION

Compared to the baseline RRF, CAPD patients with co-morbidities that rapidly deteriorate RRFD are more crucially associated with long-term mortality risk.

Predictors of residual renal function decline in patients undergoing continuous ambulatory peritoneal dialysis

BACKGROUND

Residual renal function (RRF) is an important prognostic indicator in continuous ambulatory peritoneal dialysis (CAPD) patients. We determined the predictors of RRF loss in a cohort of incident CAPD patients.

METHODS

We reviewed the record of 645 incident CAPD patients. RRF loss is represented by the slope of decline of residual glomerular filtration rate (GFR) as well as the time to anuria.

RESULTS

The average rate of residual GFR decline was -0.083 ± 0.094 mL/min/month. The rate of residual GFR decline was faster with a higher proteinuria (r = -0.506, p < 0.0001) and baseline residual GFR (r = -0.560, p < 0.0001). Multivariate analysis showed that proteinuria, baseline residual GFR, and the use of diuretics were independent predictors of residual GFR decline. Cox proportional hazard model showed that proteinuria, glucose exposure, and the number of peritonitis episodes were independent predictors of progression to anuria, while a higher baseline GFR was protective. Each 1 g/day of proteinuria is associated with a 13.2% increase in the risk of progressing to anuria, each 10 g/day higher glucose exposure is associated with a 2.5% increase in risk, while each peritonitis episode confers a 3.8% increase in risk.

CONCLUSIONS

Our study shows that factors predicting the loss of residual solute clearance and urine output are different. Proteinuria, baseline residual GFR, and the use of diuretics are independently related to the rate of RRF decline in CAPD patients, while proteinuria, glucose exposure, and the number of peritonitis episodes are independent predictors for the development of anuria. The role of anti-proteinuric therapy and measures to prevent peritonitis episodes in the preservation of RRF should be tested in future studies.

Comparative outcomes between continuous ambulatory and automated peritoneal dialysis: a narrative review

Automated methods for delivering peritoneal dialysis (PD) to persons with end-stage renal disease continue to gain popularity worldwide, particularly in developed countries. However, the endeavor to automate the PD process has not been advanced on the strength of high-level evidence for superiority of automated over manual methods. This article summarizes available studies that have shed light on the evidence that compares the association of treatment with continuous ambulatory PD or automated PD (APD) with clinically meaningful outcomes. Published evidence, primarily from observational studies, has been unable to demonstrate a consistent difference in residual kidney function loss rate, peritonitis rate, maintenance of euvolemia, technique survival, mortality, or health-related quality of life in individuals undergoing continuous ambulatory PD versus APD. At the same time, the future of APD technology appears ripe for further improvement, such as the incorporation of voice commands and expanded use of telemedicine. Given these considerations, it appears that patient choice should drive the decision about PD modality.

Proteinuria as a risk factor for decline in residual renal function in non-diabetic peritoneal dialysis patients

BACKGROUND

Preservation of residual renal function (RRF) is a major issue for patients on peritoneal dialysis (PD). Whether proteinuria is associated with a decline in RRF in patients on PD remains unclear.

PATIENTS AND METHODS

We reviewed the medical records at the Yeungnam University Hospital in Korea and identified patients who started PD between June 1995 and August 2011. A total of 147 non-diabetic patients were enrolled in the study. The patients were divided into 3 groups with respect to the tertile of initial proteinuria level: Low (n = 49; <320 mg/day), Middle (n = 49; 320-822 mg/day), and High groups (n = 49; >822 mg/day).

RESULTS

The mean patient age was 50.2 ± 15.0 years in the Low tertile, 50.2 ± 15.4 years in the Middle tertile, and 49.0 ± 15.1 years in the High tertile. Decline in RRF during follow-up period was greater in the High tertile than that in the other tertiles (P = 0.001). The proportion of patients with RRF >50% of baseline at 24 months after the initiation of PD was 83% in the Low tertile, 66% in the Middle tertile, and 40% in the High tertile (P < 0.001). The multivariate analysis after adjusting for initial RRF, age, gender, underlying disease of end-stage renal disease except diabetes mellitus, PD modality, use of icodextrin, PD-associated peritonitis, and tertile of the initial proteinuria level revealed that High tertile of the initial proteinuria level was associated with a decline in RRF (hazard ratios: 2.442 for the Middle tertile, P = 0.007 ; 3.713 for the Low tertile, P < 0.001).

CONCLUSION

The present study demonstrates that proteinuria may be is associated with a rapid decline in RRF in non-diabetic patients on PD, although the potential role of additional factors should be further investigated in prospective studies.

Effect of frequent hemodialysis on residual kidney function

Frequent hemodialysis can alter volume status, blood pressure, and the concentration of osmotically active solutes, each of which might affect residual kidney function (RKF). In the Frequent Hemodialysis Network Daily and Nocturnal Trials, we examined the effects of assignment to six compared with three-times-per-week hemodialysis on follow-up RKF. In both trials, baseline RKF was inversely correlated with number of years since onset of ESRD. In the Nocturnal Trial, 63 participants had non-zero RKF at baseline (mean urine volume 0.76 liter/day, urea clearance 2.3 ml/min, and creatinine clearance 4.7 ml/min). In those assigned to frequent nocturnal dialysis, these indices were all significantly lower at month 4 and were mostly so at month 12 compared with controls. In the frequent dialysis group, urine volume had declined to zero in 52% and 67% of patients at months 4 and 12, respectively, compared with 18% and 36% in controls. In the Daily Trial, 83 patients had non-zero RKF at baseline (mean urine volume 0.43 liter/day, urea clearance 1.2 ml/min, and creatinine clearance 2.7 ml/min). Here, treatment assignment did not significantly influence follow-up levels of the measured indices, although the range in baseline RKF was narrower, potentially limiting power to detect differences. Thus, frequent nocturnal hemodialysis appears to promote a more rapid loss of RKF, the mechanism of which remains to be determined. Whether RKF also declines with frequent daily treatment could not be determined.

The effects of angiotensin-converting enzyme inhibitors on peritoneal protein loss and solute transport in peritoneal dialysis patients

OBJECTIVE

The objective of this study was to examine the effects of angiotensin-converting enzyme inhibitors on peritoneal membrane transport, peritoneal protein loss, and proteinuria in peritoneal dialysis patients.

METHODS

Fifty-four peritoneal dialysis patients were included in the study. The patients were divided into two groups. Group 1 (n = 34) was treated with angiotensin-converting enzyme inhibitors. Group 2 (n = 20) did not receive any antihypertensive drugs during the entire follow-up. Eleven patients were excluded from the study thereafter. Thus, a total of 30 patients in Group 1 and 13 patients in Group 2 completed the study. We observed the patients for six months. Group 1 patients received maximal doses of angiotensin-converting enzyme inhibitors for six months. Parameters at the beginning of study and at the end of six months were evaluated.

RESULTS

At the end of six months, total peritoneal protein loss in 24-hour dialysate effluent was significantly decreased in Group 1, whereas it was increased in Group 2. Compared to the baseline level, peritoneal albumin loss in 24-hour dialysate effluent and 4-hour D/P creatinine were significantly increased in Group 2 but were not significantly changed in Group 1. A covariance analysis between the groups revealed a significant difference only in the decreased amount of total protein loss in 24-hour dialysate. Proteinuria was decreased significantly in Group 1.

CONCLUSION

This study suggests that angiotensin-converting enzyme inhibitors reduce peritoneal protein loss and small-solute transport and effectively protect peritoneal membrane transport in peritoneal dialysis patients.

Definition and risk factors of rapidly declining residual renal function in peritoneal dialysis: an observational study

BACKGROUND

It is critical to preserve residual renal function (RRF) in peritoneal dialysis (PD), as RRF is associated with lower morbidity and mortality. There is no uniform definition of RRF, and rapidly declining RRF has rarely been studied and predominately limited to single factor analysis and not corrected for lead-time bias.

METHODS

An observational study in 71 incident PD patients. RRF was defined as urine output (UO) ≥500 ml/day and renal glomerular filtration rate (rGFR) ≥2 ml/min/1.73 m(2), rapid declining RRF as UO <500 ml/day and rGFR <2 ml/min/1.73 m(2) occurring within 6 months which were separately evaluated. Independent risk factors associated with rapid RRF decline were identified while correcting for lead-time bias.

RESULTS

RRF declined rapidly by both definitions in 65% patients 2.5 years after PD start. Both definitions of RRF decline were consistent in 96%. Nephrotoxic drugs, renal transplant failure and absent angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II receptor blockers (ARB) were independent risk factors associated with rapidly declining RRF defined both by definitions, intravascular radiocontrast additionally for UO decline.

CONCLUSIONS

Most PD patients demonstrated rapid RRF decline, independent of its definition. Both definitions are highly consistent and interchangeable. Nephrotoxic drugs and radiocontrast were identified as risk factors of acute, absent ACEI or ARB, and renal transplant failure of chronic renal injury.

Peritoneal Dialysis Drop-out: Causes and Prevention Strategies

Peritoneal dialysis (PD) as a renal replacement therapy (RRT) has become wide spread since its inception more than twenty-five years back. Since then, several advances have been made and PD has been accepted as an alternative therapy to hemodialysis (HD), with excellent survival, lower cost, and improved quality of life. In spite of comparable survival of HD and PD, improved PD techniques over the last few years, and lower health care costs with PD, PD prevalence remains low in many countries. An important reason for the low PD prevalence is patient dropouts, that is, transfer to HD. The reasons for dropouts are multifactorial, that is, modality related, system related, and patient related. These include episodes of peritonitis, catheter-related problems, ultrafiltration failure, patient fatigue, and provider comfort. This review discusses the various factors that contribute to PD dropout and the strategies to prevent it.

Can we reduce the cardiovascular risk in peritoneal dialysis patients?

Patients with end-stage renal disease (ESRD), including those treated with peritoneal dialysis (PD), have a high risk for death, particularly from cardiovascular (CV) causes. Traditional risk factors for CV disease – like hypertension, diabetes, and dyslipidemia - are highly prevalent, often severe, and more difficult to treat in dialysis patients. Development of strategies for CV risk reduction in dialysis patients is complicated by epidemiologic studies that demonstrate paradoxical associations of some of the traditional risk factors with mortality. The difficulty is enhanced by either a paucity or negative findings of studies that have tested risk modification by targeting traditional CV risk factors. It is also clear that neither the prevalence nor the severity of traditional risk factors explains the substantial increase in risk for death associated with ESRD; this has led to identification of several nontraditional risk factors. Among these, systemic inflammation, disordered mineral metabolism, and long-term CV risk from infectious complications appear the most promising. However, the evidence in favor of the importance of these risk factors is largely limited to observational studies. In this review, we present a critical analysis of the literature to assist the clinician to reduce the CV risk of ESRD patients treated with PD.

Preserving residual renal function in dialysis patients: an update on evidence to assist clinical decision making

It has been documented that preservation of residual renal function in dialysis patients improves quality of life as well as survival. Clinical trials on strategies to preserve residual renal function are clearly lacking. While waiting for more results from clinical trials, patients will benefit from clinicians being aware of available knowledge. The aim of this review was to offer an update on current evidence assisting doctors in clinical practice.

2009 Japanese Society for Dialysis Therapy guidelines for peritoneal dialysis

The guidelines for peritoneal dialysis (PD) of the Japanese Society for Dialysis Treatment were prepared at 2009. Upon presenting a concrete frame of PD practiced in Japan, it aims to promote PD as a standardized therapy in Japan. Notably, the guidelines recommended combination therapy of PD and hemodialysis as a part of integrated renal replacement therapy for end-stage renal disease, as well as timely PD withdrawal by peritoneal degeneration in order to prevent progression of encapsulating peritoneal sclerosis.

Decline in residual renal function in automated compared with continuous ambulatory peritoneal dialysis

BACKGROUND AND OBJECTIVES

We compared the decline of RRF in patients starting dialysis on APD with those starting on CAPD, because a faster decline on APD has been suggested.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

NECOSAD patients starting dialysis on APD or CAPD with RRF at baseline were included and followed for 3 years. Residual GFR (rGFR) was the mean of urea and creatinine clearances. Differences in yearly decline of rGFR were estimated in analyses with linear repeated measures models, whereas the risk of complete loss of RRF was estimated by calculating hazard ratios (HRs) for APD compared with CAPD. As-treated (AT) and intention-to-treat (ITT) designs were used. All of the analyses were adjusted for age, gender, comorbidity, and primary kidney disease and stratified according to follow-up and mean baseline GFR.

RESULTS

The 505 CAPD and 78 APD patients had no major baseline differences. No differences were found in the analyses on yearly decline of rGFR. APD patients did have a higher risk of losing RRF in the first year (ITT crude HR 2.43 [confidence interval 95%, 1.48 to 4.00], adjusted 2.66 [1.60 to 4.44]; AT crude 1.89 [1.04 to 3.45], adjusted 2.15 [1.16 to 3.98]). The higher risk of losing all RRF was most pronounced in patients with the highest rGFR at baseline (ITT; crude 3.91 [1.54 to 9.94], adjusted 1.85 to 14.17).

CONCLUSIONS

The risk of losing RRF is higher for patients starting dialysis on APD compared with those starting on CAPD, especially in the first year.

Are ACEI/ARBs associated with the decreased peritoneal protein clearance in long-term PD patients?

Objective. Peritoneal protein clearance (PrC) is recognized as a new marker of systemic endothelial dysfunction and predictor of mortality in patients on peritoneal dialysis (PD). Given that angiotensin-converting enzyme inhibitors (ACEI)/angiotensin II receptor blockers (ARBs) could improve endothelial dysfunction in the general population, we aim to explore whether this benefit is present in the PD population.

METHODS

We analysed data from a PD cohort with data prospectively collected. The PrC, defined daily doses (DDDs) of ACEI/ARBs, as well as other clinical variables were recorded at baseline and then repeatedly measured at 3- to 6-month intervals till to death or censoring. A total of 156 patients were treated with ACEI/ARBs with 0.60 of median time-averaged DDDs, the untreated group consisted of 149 patients who received none of the above drugs during the follow-up.

RESULTS

The baseline and time-averaged PrC were 69.9 ± 34.7 mL/day and 75.2 ± 28.3 mL/day, respectively. Time-averaged PrC was an independent predictor of mortality adjusted for recognized confounders in a multivariate Cox regression model (P = 0.037). There were no significant differences in the time course of PrC (P = 0.82) and peritoneal protein loss (P = 0.83) between the ACEI/ARBs group and the untreated group after adjustment for age, gender, diabetes, baseline C-reactive protein, mean blood pressure and baseline PrC or baseline peritoneal protein loss in the generalized linear mixed model.

CONCLUSIONS

We conclude that ACEI/ARBs did not correlate with a decreased PrC in this observational study. The effect of higher doses of ACEI/ARBs needs to be determined in future interventional studys.

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.

Strategies for improving long-term survival in peritoneal dialysis patients

The incidence and prevalence of ESRD in the United States continues to increase. Currently there are over 26,000 patients maintained on peritoneal dialysis. Mortality rates have fallen over the past several years, but long-term survival remains poor, with only 11% of peritoneal dialysis patients surviving past 10 years. Cardiovascular disease accounts for most deaths, and dialysis patients have many traditional and nontraditional cardiovascular risk factors. Lowering of these risk factors has not resulted in reduced cardiovascular morbidity and mortality in dialysis patients. Maneuvers to improve long-term peritoneal dialysis patient survival must therefore focus on modifiable risk factors including residual renal function, peritoneal membrane integrity, rate of infections, and peritoneal dialysis center size. This article reviews strategies for preserving residual renal function and peritoneal membrane integrity as well as strategies for reducing the rate of infections to enhance long-term survival in peritoneal dialysis patients.

Valsartan: more than a decade of experience

Valsartan is a nonpeptide angiotensin receptor antagonist that selectively blocks the binding of angiotensin II to the angiotensin II type 1 receptor. The efficacy, tolerability and safety of valsartan have been demonstrated in large-scale studies in hypertension, heart failure (HF) and post-myocardial infarction (MI). This review focuses on what was learned from the valsartan clinical research programme and other comparative trials published from 1997 to the present. Many studies have demonstrated the efficacy of valsartan in lowering blood pressure (BP) in a variety of patient populations (including elderly, women, children, obese patients, patients with diabetes mellitus, patients with chronic kidney disease [CKD], patients at high risk of cardiovascular [CV] disease, African Americans, Hispanic Americans and Asians) and in improving outcomes in CV disease and CKD. In hypertension, valsartan exhibits dose-dependent efficacy in reducing both systolic and diastolic BP over the once-daily dose range of 80-320 mg; doses as high as 640 mg/day have been studied and found to be efficacious and safe. BP control can be enhanced with a more consistent 24-hour BP-lowering profile by using single-pill, fixed-dose combination therapy with valsartan plus hydrochlorothiazide (HCTZ). The cardioprotective benefits of valsartan have been demonstrated in large-scale outcome trials and include significant reductions in CV morbidity and mortality in HF, following MI, and in patients with co-morbid hypertension and coronary artery disease and/or HF; reductions in HF hospitalizations; and reductions in the incidence of stroke. The magnitude of these effects is comparable with that demonstrated with angiotensin-converting enzyme (ACE) inhibitors; however, valsartan has a more favourable tolerability profile, with a significantly lower incidence of cough and only rare reports of angio-oedema, both class effects of ACE inhibitor use. Consistent with its angiotensin receptor-blocking effects, valsartan also reduces circulating levels of biochemical markers that are associated with angiotensin II-mediated endothelial dysfunction and CV risk (e.g. high-sensitivity C-reactive protein or oxidized low-density lipoprotein). Improvements in CKD with valsartan include statistically and clinically meaningful reductions in urinary albumin and protein excretion in patients with type 2 diabetes and in nondiabetic patients with CKD. In short-term studies, valsartan has improved or stabilized various indices of metabolic function in at-risk patients, including those with co-morbid hypertension, obesity and/or metabolic syndrome. Because of this, valsartan is being prospectively investigated for its ability to reduce the incidence of new-onset diabetes and provide cardioprotection in patients with impaired glucose tolerance. Valsartan and valsartan/HCTZ are well tolerated. In clinical trials, adverse events during valsartan treatment were similar to those occurring with placebo. The combination of valsartan/HCTZ was better tolerated than HCTZ alone. Valsartan is administered once daily for hypertension; doses are usually taken upon awakening. In patients with HF or MI, valsartan is administered twice daily.

Renal protective effect of RAAS blockade across the renal continuum, with a review of the efficacy and safety of valsartan

Abstract Objective: The purpose of this report is to review key data on the angiotensin receptor blocker (ARB) valsartan, along with data from several pivotal studies with other ARBs and angiotensin-converting enzyme (ACE) inhibitors, to highlight the beneficial class effects of renin-angiotensin-aldosterone system (RAAS) blockade throughout the renal continuum.

METHODS

The selection of articles was based on a search of PubMed for clinical trials published between 1997 (the year in which valsartan was approved for sale in the US) and 2009 that involved valsartan and reported effects on renal function, plus a select range of articles on other agents acting on the RAAS, including key guidance documents issued during this time.

SUMMARY

Valsartan has been studied extensively and is widely used for the management of hypertension. Data from clinical studies involving valsartan and other ARBs and ACE inhibitors provide evidence of an additional renal protective effect. This renal protection apparently arises from hemodynamic, endothelial, and anti-inflammatory actions.

LIMITATIONS

Given the extent of the available literature on this topic, this review included only a subset of available publications. This report may reflect inherent heterogeneity between patient populations from these studies and also incorporate the limitations of these individual publications. The inclusion of guidance documents from several organizations may have resulted in apparent minor conflicts in the approaches of the different groups.

Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers in Peritoneal Dialysis: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are widely used in clinical practice. The safety and efficacy of these agents in peritoneal dialysis (PD) patients are unclear.

Objectives

We conducted a systematic review to study the safety and efficacy of ACEI and ARB use in PD patients. Primary outcome measures were mortality and cardiovascular (CV) events; secondary outcome measures were renal function, proteinuria, hyperkalemia, and erythropoietin requirement at 3 months.

Methods

We searched Medline, EMBASE, Cochrane Central Register of Controlled Trials, trial registry Web sites, reference lists of eligible and review articles, as well as abstracts from the American Society of Nephrology and Canadian Society of Nephrology meetings. To be eligible, studies had to be randomized controlled trials that allocated PD patients to ACEI and ARB use or to placebo or other antihypertensive medications, included adult patients, and reported on at least one of the outcome measures.

Results

418 citations were identified. Four met the eligibility criteria. Three examined CV events and mortality, of which two studies did not have any events. The third showed no statistically significant difference between control and treatment groups in either CV events or mortality: odds ratio 1.56 [95% confidence interval (CI) 0.24 – 10.05] for mortality and odds ratio 1.00 (95% CI 0.19 – 5.40) for CV events. Two studies reported renal function at 12 months and the weighted mean difference was 0.91 mL/minute/1.73 m2 (95% CI 0.14 – 1.68), favoring ACEI and ARB use.

Conclusions

In PD patients, evidence for the use of ACEIs and ARBs for reduction of mortality and CV events is lacking. Limited data suggest that they slow the loss of residual renal function.

Therapeutic efficacy of renin—angiotensin blockade in patients receiving dialysis

Observational data in dialysis patients has indicated an increased cardiovascular mortality. One pathophysiological cause of this cardiovascular mortality in these patients is volume overload. In addition, an inappropriately activated renin—angiotensin system (RAS) has been proposed as another possible mechanism for the increased cardiovascular mortality. With these possible causes in mind, blockade of the RAS with an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin receptor blocker (ARB) have both emerged as means of preventing cardiovascular events in this population. This review focuses on clinical evidence of the beneficial effects of ACE inhibitors and ARBs in dialysis patients with regard to the improvement of cardiovascular events as well as blood pressure control and maintenance of dialysis therapy.

Residual renal function improves outcome in incremental haemodialysis despite reduced dialysis dose

BACKGROUND AND METHODS

The importance of residual renal function is well recognized in peritoneal dialysis but its role in haemodialysis (HD) has received much less attention. We studied 650 incident patients in our incremental high-flux HD programme over a 15-year period. Target total Kt/V urea (dialysis plus residual renal) was 1.2 per session and monitored monthly. Renal urea clearance (KRU) was estimated 1-3 monthly.

RESULTS

KRU declined during the first 5 years of HD from 3.1 +/- 1.9 at 3 months to 0.9 +/- 1.2 ml/min/1.73 m(2) at 5 years. The percentage of patients with KRU >or= 1 ml/min at these time points was 85% and 31%, respectively. Patients with KRU >or= 1 ml/min had a significantly lower mean creatinine (all time points), ultrafiltration requirement (all time points) and serum potassium (6, 12, 36 and 48 months). Nutritional parameters were also significantly better in respect to nPCR and serum albumin (6, 12, 24 and 36 months). Patients with KRU >or= 1 ml/min had significantly lower erythropoietin requirements and erythropoietin resistance indices (12, 24, 36 and 48 months). Mortality was significantly lower in patients with a KRU >or= 1 at 6, 12 and 24 months after HD initiation, this benefit being maintained after correcting for albumin, age, comorbidities, HDF use and renal diagnosis. Our unique finding was that these benefits occurred despite those with KRU >or= 1 ml/min having a significantly lower dialysis Kt/V at all time points.

CONCLUSION

The associations demonstrated suggest that residual renal function contributes significantly to outcome in HD patients and that efforts to preserve it are warranted. Comparative outcome studies should be controlled for residual renal function.

Optimal Use of Peritoneal Dialysis in Patients with Diabetes

The survival of patients with end-stage renal disease (ESRD) resulting from diabetes continues to improve, but the survival rate among diabetic ESRD patients remains the lowest among all primary diagnoses probably because of the higher prevalence of cardiovascular comorbidity associated with diabetes. Diabetes, age, and comorbidity all significantly modify the effect of treatment modality on patient survival.

As compared with hemodialysis (HD), peritoneal dialysis (PD) offers an equal or lower risk of death across all subgroups during the first 1 – 2 years of dialysis. The association of PD with better outcomes than are seen with HD is probably a result of a lower prevalence of infections and congestive heart failure and better preservation of residual renal function (RRF) in PD patients.

Use of angiotensin converting-enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) helps to preserve RRF in ESRD patients and to maintain peritoneal membrane integrity longer in PD patients. Antioxidants can also support preservation of peritoneal membrane function.

Peritoneal dialysis should be the initial modality of dialysis in all ESRD patients. Older patients (age ≥ 45 years) with diabetes and patients without diabetes may switch to HD or receive a kidney graft in 1 – 2 years’ time; younger patients (age < 45 years) with diabetes may stay on PD longer. Use of ACEI and ARB or antioxidants can help to maintain peritoneal membrane function longer.

Long-term outcome of chronic dialysis in children

As the prevalence of children on renal replacement therapy (RRT) increases world wide and such therapy comprises at least 2% of any national dialysis or transplant programme, it is essential that paediatric nephrologists are able to advise families on the possible outcome for their child on dialysis. Most children start dialysis with the expectation that successful renal transplantation is an achievable goal and will provide the best survival and quality of life. However, some will require long-term dialysis or may return intermittently to dialysis during the course of their chronic kidney disease (CKD). This article reviews the available outcome data for children on chronic dialysis as well as extrapolating data from the larger adult dialysis experience to inform our paediatric practice. The multiple factors that may influence outcome, and, particularly, those that can potentially be modified, are discussed.

Mineralocorticoid receptor blockade ameliorates peritoneal fibrosis in new rat peritonitis model

Peritoneal fibrosis (PF) is an important complication of long-term peritoneal dialysis. Although mineralocorticoid and mineralocorticoid receptor (MR) have attracted increasing attention in the field of vascular injury, including the heart, kidney, and vessels, little is known about the role of mineralocorticoid in PF. This work was designed to explore the effects of MR blockade on PF. We developed a new model of PF in rats based on mechanical scraping of the peritoneum. This model is characterized by acute-phase inflammation (neutrophil and macrophage infiltration on days 0–3) and late-phase PF (α-smooth muscle actin-positive fibroblast infiltration, type III collagen accumulation, and neoangiogenesis on days 7–14). Peritoneal thickening peaked on day 14. MR was expressed in rat peritoneum and a rat fibroblast cell line. Expression of its effector kinase [serum- and glucocorticoid-induced kinase-1 (Sgk1)], transforming growth factor-β (TGF-β), plasminogen activator inhibitor-1 (PAI-1), and CD31-positive vessels increased during the course of PF. Rats were treated with spironolactone, angiotensin receptor blockade (ARB), or angiotensin-converting enzyme inhibitor (ACEI)-ARB-spironolactone starting at 6 h after peritoneal scraping. All parameters, including peritoneal thickening, number of macrophages and CD31-positive vessels, and expression of monocyte chemoattractant protein-1, TGF-β, PAI-1, and Sgk1, were significantly suppressed by spironolactone (10 mg·kg−1·day−1). The effects of spironolactone (10 and 20 mg·kg−1·day−1) were very similar to those of triple blockade. ARB, but not ACEI, significantly reduced peritoneal thickening. Furthermore, peritoneal function assessed by peritoneal equilibration test was significantly improved by spironolactone. Our results suggest that MR is a potential target to prevent inflammation-induced PF in patients on peritoneal dialysis.

Peritoneal membrane structural and functional changes during peritoneal dialysis

Peritoneal dialysis is now utilized as a renal replacement therapy modality in a substantial percentage of patients with end-stage renal disease, with excellent short-term patient and technique survival rates. However, the potential complications associated with longer-term therapy, such as ultrafiltration failure or encapsulating peritoneal sclerosis, have led to raise some concern about peritoneal dialysis as an adequate mode of treatment of end-stage renal disease in the long term. In the last decade, a substantial amount of information has been gathered on the characteristics of the peritoneal membrane at the onset of peritoneal dialysis, and on the anatomical and pathophysiologic changes that occur with long-term peritoneal dialysis. I will review this subject with a special focus on the various strategies that can help protect the peritoneal membrane during peritoneal dialysis so as to allow peritoneal dialysis to succeed as a long-term dialysis modality.

Phosphate Balance on Peritoneal Dialysis

Hyperphosphatemia is an independent predictor of mortality in end-stage renal disease patients, and 40% – 50% of peritoneal dialysis (PD) patients have suboptimal control of serum phosphate. Systematically addressing this problem requires an understanding of phosphate balance on PD. The present review discusses the determinants of daily phosphate load and focuses on the factors influencing renal and peritoneal clearance of phosphate.