The Effects of Angiotensin Converting Enzyme Inhibitors on Potassium Homeostasis in Dialysis Patients With and Without Residual Renal Function

Hyperkalemia is exacerbated by angiotensin converting enzyme inhibitors (ACE‐I). Distal potassium (K⁺) secretion is negligible in anuric patients. ACE‐I therapy may reduce renal, peritoneal, and colonic K⁺ losses. We examined the effect of ACE‐I therapy on serum, urinary, and dialysate K⁺ in a cross‐section of peritoneal and hemodialysis patients. Serum, 24‐h urine K⁺, and peritoneal dialysate excretion K⁺ levels were measured and the results were compared in the various dialysis and treatment groups. Eighty‐one hemodialysis (HD) and 32 peritoneal dialysis (PD) patients were included. Serum K⁺ in HD patients with no residual renal function (RRF) was higher in those receiving ACE‐I therapy (P = 0.02). Serum K⁺ levels in HD patients receiving ACE‐I treatments with RRF was similar to that in oligoanuric HD patients not receiving an ACE‐I. Urinary K⁺ excretion was significantly reduced in those on ACE‐I therapy versus those not on an ACE‐I (P < 0.05). Mean serum K⁺ was lower in PD versus HD patients (P < 0.05). PD patients with no RRF on ACE‐I therapy had higher serum K⁺ concentrations (P = 0.002) and dialysate K⁺ excretion was lower (P = 0.05), in comparison with PD patients not on an ACE‐I. PD patients with RRF on ACE‐I therapy had higher serum K⁺ concentrations compared with those not on ACE‐I therapy (P = 0.03). Both urinary and dialysate K⁺ excretion were reduced (P = 0.001 and P = 0.002, respectively). ACE‐I therapy increases serum K⁺ concentration in dialysis patients. PD patients have relatively lower serum K⁺ levels compared with HD patients. In PD patients, ACE‐I therapy reduces dialysate K⁺. These changes may result from reduced peritoneal movement of K⁺.     

Ankle brachial index as a predictor for mortality in patients with chronic kidney disease and undergoing haemodialysis

Aim: The ankle brachial index (ABI) is a marker for peripheral artery disease and can predict mortality in advanced chronic kidney disease (CKD) and haemodialysis patients, respectively. However, it is seldom studied in Taiwan, an area with high prevalence of CKD and end‐stage renal disease. The aim of this study was to investigate the predictors for mortality by using ABI value in patients with CKD and undergoing haemodialysis in Taiwan. Methods: One hundred and sixty‐nine patients with CKD stage 3–5 and 231 haemodialysis patients were enrolled in one regional hospital. The mean follow‐up period was 23.3 ± 3.3 months. Patients were stratified into three groups according to ABI value (<0.9, ≥0.9 to <1.3, and ≥1.3). The relative mortality risk was analyzed by Cox‐regression methods. Results: In multivariate analysis, an ABI of 1.3 or more (hazard ratio, 3.846; P = 0.043) and coronary artery disease (P = 0.012) were positively associated with overall mortality, and serum low‐density lipoprotein cholesterol level (P = 0.042) was negatively associated with overall mortality. In addition, an ABI of less than 0.9 (P = 0.049), an ABI of 1.3 or more (P = 0.033), coronary artery disease (P = 0.024) and haemodialysis treatment (P = 0.043) were strong predictors for cardiovascular mortality. Conclusion: Our findings show that an ABI of 1.3 or more predicts for both overall and cardiovascular mortality, and an ABI of less than 0.9 predicts for cardiovascular mortality in CKD and haemodialysis patients. Screening patients with chronic renal failure by means of ABI may help to identify a high‐risk group for increased mortality.     

Effect of renin–angiotensin system inhibitors on prevention of peritoneal fibrosis in peritoneal dialysis patients

Aim: Long‐term peritoneal dialysis (PD) may lead to peritoneal fibrosis and ultrafiltration failure. It had been demonstrated that the renin–angiotensin system (RAS) plays a key role in the regulation of peritoneal function in rats on PD. We investigated the effects of angiotensin‐converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) on long‐term PD patients. Methods: We analyzed data from 66 patients treated with PD therapy at our centre for at least 12 months retrospectively, during which time at least two peritoneal equilibration tests (PET) were performed. Thirty‐eight patients were treated with ACE/angiotensin II (AII) inhibitors (ACE/ARB group); the other 28 received none of the above drugs during the entire follow up (control group). The expression of fibronectin, transforming growth factor‐β1 (TGF‐β1), Aquaporin1 (AQP1) and vascular endothelial growth factor (VEGF) in the overnight effluent were examined by enzyme‐linked immunosorbent assay. Results: The demographic data of the two groups showed no difference during the study. No difference between the groups was found with respect to residual renal function (RRF) at the start for both groups by the end of follow up, decreased in the vast majority of patients from both groups (P = 0.014). After 12 months, a significant difference in ultrafiltration was found between the two groups: in the control group it had decreased, while it had not changed in the ACE/ARB group (P < 0.05). In comparison with the baseline level, expression of fibronectin, TGF‐β1 and VEGF in dialysate effluent were significantly increased except for AQP1 in the control group (P < 0.05), but not in the ACE/ARB group (P > 0.05). Conclusion: The findings suggest that ACE/AII inhibitors appeared to have a slower rate of decline in ultrafiltration and RRF, effectively protect against peritoneal fibrosis in long‐term peritoneal dialysis. Long‐term follow up seems to be required to draw more conclusions.     

Evaluation of advanced glycation end products accumulation, using skin autofluorescence, in CKD and dialysis patients

Purpose

Advanced glycation end products (AGE), biomarkers of metabolic stress, are frequently encountered in chronic kidney disease (CKD) patients with cardiovascular disease. Our aim was to evaluate tissue accumulation of AGEs in CKD patients and possible correlations with traditional and non-traditional cardiovascular risk factors.

Methods

Skin AF was measured using AGE Reader in 310 patients: 157 haemodialysis patients (HD) (mean age 60?years, dialysis vintage 29 months, 19.1% diabetic), 102 peritoneal dialysis patients (PD) (mean age 56.3?years, dialysis vintage 16 months, 17.6% diabetic), 32 CKD patients (mean age 68?years, CKD duration 30 months, 34.4% diabetic) and 19 type 2 diabetic patients, without renal failure (mean age 59?years and median duration of diabetes 36 months).

Results

HD patients have higher AGE levels compared to PD ones. Dialysis patients have the highest skin AF values compared to CKD patients (P?P?P?P?P?Conclusions CKD patients have higher AGE values depending on duration (disease, RRT) and GFR (dialysis adequacy and RRF). Other important determinants were diabetes and age.     

Impact of residual renal function in children on hemodialysis

Residual renal function (RRF) contributes to dialysis adequacy as well as lower mortality and morbidity in dialysis patients. Even very small changes in glomerular filtration rate (GFR) account for considerable improvements in complications of dialysis. The purpose of this cross-sectional study is to determine the possible contribution of RRF to hemodialysis clearance and to compare the biochemical markers of this patient group with anuric patients. Ten patients with RRF on chronic hemodialysis for more than 6 months were enrolled in the study. Duration of dialysis was not different between the two patient populations. Average GFR was 3.4±2.6 ml/min in the group with RRF. Cholesterol, albumin, and triglyceride levels were not different between the groups. Residual renal urea clearance enhanced mean Kt/V of patients from 1.29 to 1.52. However erythropoietin and renin levels were higher in the group with RRF (P=0.019, P=0.044, respectively). There was a positive correlation between erythropoietin, renin levels, and average GFR of all patients (r=0.69, P=0.002, r=0.60, P=0.014). We conclude that RRF plays a greater role in pediatric patients on hemodialysis than previously recognized, and knowledge about patients’ RRF should assist in improved overall management. Received: 31 January 2001 / Revised: 27 June 2001 / Accepted: 28 June 2001     

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

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

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

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

Effect of fluid and sodium removal on mortality in peritoneal dialysis patients

Effect of fluid and sodium removal on mortality in peritoneal dialysis patients. BACKGROUND: Adequacy of peritoneal dialysis (PD) traditionally is assessed using Kt/V(urea) and total creatinine clearance (TCC). However, this approach underestimates the importance of fluid and sodium removal. The aim of this study was to determine the effect of fluid and sodium removal on morbidity and mortality in PD patients. METHODS: One hundred twenty-five PD patients were monitored for three years from the beginning of the treatment. The effects of demographic features, comorbidity, peritonitis rate, blood pressure, medications, blood biochemistry, peritoneal membrane transport characteristics, residual renal function (RRF), Kt/V(urea), TCC, normalized protein nitrogen appearance (nPNA), and removal of sodium and fluid on mortality were evaluated. Total and cardiovascular hospitalization rates were also recorded. A Cox proportional hazards model was used to determine factors predicting mortality. RESULTS: In the Cox model, comorbidity, total sodium and fluid removals, hypertensive status, serum creatinine, and RRF were independent factors affecting survival. In contrast, Kt/V(urea) or TCC did not affect the adjusted survivals. Total sodium and fluid removal and hypertensive status also significantly influenced the hospitalization rate. Systolic and diastolic blood pressures were negatively correlated with total fluid (P < 0.001) and sodium removal (P < 0.001). CONCLUSIONS: Together, these findings suggest that removal of sodium and fluid is a predictor of mortality in PD patients, whereas Kt/V(urea) and TCC are not factors. Adequate fluid and sodium balance is crucial for the management of patients on PD.     

Peritoneal albumin leakage: 2 year prospective cardiovascular event occurrence and patient survival analysis

Aim: High peritoneal transport status is a determinant of morbidity and mortality in peritoneal dialysis (PD) patients. It was hypothesized that 24 h peritoneal albumin leakage predicted 2 year prospective cardiovascular outcome and survival in patients receiving PD. Methods: Sixty‐six patients were included. A simplified peritoneal equilibration test was performed and 24 h peritoneal albumin leakage was calculated. Patients were followed up for 2 years. Patient outcome (alive or dead) and occurrence of a cardiovascular event were recorded. Results: During a 2 year follow‐up period, 10 (15.2%) patients had suffered from a cardiovascular event and seven (10.6%) patients had died. Patients who had suffered from a cardiovascular event during the follow up period were older (54.0 ± 9.4 years vs 44.3 ± 14.5 years, P = 0.025), had lower serum pre‐albumin concentrations (29.3 ± 10.0 g/dL vs 36.0 ± 9.2 g/dL, P = 0.034) and had higher 24 h peritoneal albumin leakage (median, 3.4 g/day (1.66–15.4 g/day) vs 2.4 g/day (0.76–7.31 g/day), P = 0.011) than patients who did not suffer from a cardiovascular event. In the Cox proportional hazards multivariate analysis of factors which differed significantly between patients with and without a cardiovascular event (age, serum pre‐albumin and 24 h peritoneal albumin leakage), only advanced age (hazards ratio, 1.083; 95% confidence interval, 1.023–1.147, P = 0.006) was an independent predictor of a cardiovascular event. Conclusion: In contrast to the hypothesis, 24 h peritoneal albumin leakage is not a predictor of 2 year prospective cardiovascular outcome and patient survival. Only advanced age independently predicts the occurrence of a cardiovascular event in patients receiving PD.     

Estimation of residual renal function using beta-trace protein: Impact of dialysis procedures

Beta-trace protein (BTP), a low molecular weight protein of 23-29 kDa, has been proposed as a promising biomarker to estimate residual renal function (RRF) in patients on maintenance hemodialysis (HD). Indeed, BTP is cleared by native kidney but not during conventional HD session. By contrast, the removal rate of BTP using convective processes (mainly hemodiafiltration [HDF]) and peritoneal dialysis (PD) has been little or not investigated. Therefore, an aim of this study was to evaluate the impact of dialysis procedures (high-flux HD, on-line post-dilution HDF and PD) on BTP removal in comparison with beta-2 microglobulin (B2M) and cystatin C (CYSC) removals after a single session. In addition, the ability of BTP to predict RRF in PD was assessed. This observational cross-sectional study included a total of 82 stable chronic kidney disease patients, 53 patients were on maintenance dialysis (with n = 26 in HD and n = 27 in HDF) and 29 were on PD. Serum concentrations of BTP, B2M, and CYSC were measured (a) before and after a single dialysis session in HD and HDF anuric patients to calculate reduction percentages, (b) in serum, 24-hour-dialysate and 24-hour-urine in PD patients to compute total, peritoneal, and urinary clearance. RRF was estimated using four equations developed for dialysis patients without urine collection and compared to the mean of the urea and creatinine clearances in PD. The concentrations of the three studied molecules were significantly reduced (P < .001) after dialysis session with significantly higher reduction ratio using HDF compared to HD modality (P < .001): BTP 49.3% vs 17.5%; B2M 82.3% vs 69.7%; CYSC 77.4% vs 66% in HDF and HD, respectively. In non-anuric PD patients, B2M and CYSC were partly removed by peritoneal clearance (72.3% and 57.6% for B2M and CYSC, respectively). By contrast, BTP removal by the peritoneum was negligible and a low bias for the BTP-based equation to estimate RRF (−1.4 mL/min/1.73 m²) was calculated. BTP is significantly removed by high-flux HD or HDF, thereby compromising its use to estimate RRF. By contrast, BTP appears as a promising biomarker to estimate RRF in PD patients since it is not affected by peritoneal clearance, unlike B2M and CYSC, and it is well correlated to RRF.     

Inflammation, residual kidney function, and cardiac hypertrophy are interrelated and combine adversely to enhance mortality and cardiovascular death risk of peritoneal dialysis patients

C-reactive protein (CRP), the prototype marker of inflammation, and cardiac hypertrophy are important prognostic indicators in dialysis patients. Residual renal function (RRF) has also been shown to influence survival of peritoneal dialysis (PD) patients. This study examined the relations between inflammation, RRF, and left ventricular hypertrophy (LVH) and determined whether inflammation, RRF, and LVH combine adversely to predict the outcomes of PD patients. A prospective observational study was performed in 231 chronic PD patients. Left ventricular mass index (LVMi), residual glomerular filtration rate (GFR), CRP, hemoglobin, serum albumin, and BP were determined at study baseline and related to outcomes. On univariate analysis, age (P = 0.002), dialysis duration (P = 0.004), coronary artery disease (P < 0.001), pulse pressure (P < 0.001), hemoglobin (P < 0.001), serum albumin (P = 0.032), log-CRP (P < 0.001), and GFR (P < 0.001) were significantly associated with log-LVMi. Log-CRP was positively correlated with pulse pressure (R = 0.218, P = 0.001) and negatively correlated with GFR (R = -0.272, P < 0.001). Multivariate analysis showed that log-CRP (P = 0.008) and RRF (P = 0.003) remained associated with log-LVMi independent of hemoglobin, serum albumin, arterial pulse pressure, and coronary artery disease. After follow-up for 30 +/- 14 mo, 34.2% patients had died. CRP, RRF, and LVMi each were significantly predictive of all-cause mortality and cardiovascular death. Kaplan-Meier analysis showed a significant increase in all-cause (P < 0.0001) and cardiovascular mortality (P < 0.0001) as the number of risk factors, namely CRP >/=50th percentile, no RRF, and LVMi>/= 50th percentile increased with the 2-yr all-cause mortality and cardiovascular death reaching as high as 61% and 46%, respectively, for patients who had all three risk factors. Compared with patients with none of the three risk factors, those with all three risk factors had an adjusted hazards ratio of 6.94 (P < 0.001) and 5.43 (P = 0.001) for all-cause mortality and cardiovascular mortality, respectively. In conclusion, inflammation, RRF, and LVH are interrelated and combine adversely to increase mortality and cardiovascular death risk of PD patients.     

Preservation of residual renal function and factors affecting its decline in patients on peritoneal dialysis

SUMMARY:     The decline of residual renal function (RRF) in peritoneal dialysis (PD) patients was analysed and assessed, and risk factors affecting its decline were identified. Residual glomerular filtration rate (GFR) was calculated from averaging the urea and creatinine clearance by 24-h urine collection, and peritoneal solute removal was evaluated by creatinine clearance calculated from 24-h effluent collection. Both GFR and peritoneal solute removal were chronologically examined in 34 PD patients from the time of initiation, and risk factors associated with rapid GFR decline were investigated. The RRF contributed to 43.1 ± 17.6% of total (peritoneal and renal) weekly creatinine clearance at 1 month after initiation of PD. Residual GFR, however, declined continuously with time (−0.19 ± 0.14 mL/min per month), and the reduction rate was high with a higher GFR, higher normalized dietary protein intake, higher urine volume and higher urine protein excretion at the initiation of PD. Other factors related to the rapid decline of GFR were: being older than 60 years of age, automated peritoneal dialysis (APD) rather than continuous ambulatory peritoneal dialysis, mean blood pressure higher than 110 mmHg, and serum human atrial natriuretic peptide level higher being than 60 pg/dL. These data suggest that while RRF plays an important role in the removal of uraemic solute in PD patients, they show a significant decrease over 2 years. The factors related to the rapid decline of GFR corresponded to older age, modality of PD (APD), higher GFR and higher amount of urine protein at initiation, higher dietary protein intake, and inadequate control of hypertension and body fluid volume.     

A comparison between residual renal function and peritoneal clearance for Na/H2O and urea removal in peritoneal dialysis patients

Background: To compare the Na/H₂O and urea removal between residual renal function (RRF) and peritoneal clearance (PC) in peritoneal dialysis patients. Try to explore the difference between RRF and PC in prognosis of chronic kidney disease patients who need peritoneal dialysis (PD) treatment. Methods: Weekly Na/H₂O and urea removal by PC and RRF were investigated individually. Independent samples t-test was carried out to compare the efficiency of removal between RRF and PC treatment. Pearson correlated analysis was applied to reveal the relationship between Na/H₂O and urea removal and Kt/V. Results: Although a higher Na/H₂O removal rate by RRF was showed in this investigation, the difference was not statistical significant compared to the one by PC. On the other hand, urea removal by RRF was obviously higher than PC. For every 0.1?Kt/V, Na/H₂O removal by RRF was distinctly higher than PD. The Na and H₂O removal of RRF were 147.88?±?83.72?mmol and 46.54?±?39.11?mmol, respectively; and the ones of PD were 11.40?±?6.08?mmol and 4.47?±?4.79?mmol. By using statistical assay, the correlations relevance between Na/H₂O removal and Kt/V in RRF were showed stronger than in PC. However, the total removal of Na/H₂O showed a poor correlation with Kt/V in both RRF and PC. Conclusions: The removal efficiency of RRF is much higher than PC. This study suggests that it is important to adjust dialysis program when RRF gets declined. Also the correlation between Na/H₂O removal rate and Kt/V is an important monitoring factor for the patients who are receiving peritoneal dialysis.     

Potassium metabolism in continuous ambulatory peritoneal dialysis patients

Background: Hypokalemia is common and may have contributed to the poor clinical outcome in peritoneal dialysis (PD) patients. In this study, we made a detailed investigation on the potassium metabolism in continuous ambulatory peritoneal dialysis (CAPD) patients and tried to find out the possible factors associated with the high prevalence of hypokalemia in PD patients. Methods: A cross-sectional survey in 243 clinically stable CAPD patients was made in our PD center in 2010. Patients were divided into four groups according to whether they were anuric or not and different dialysis regimens. Patients’ demographic data and data on potassium metabolism including dietary potassium intakes, residual renal potassium, and peritoneal dialysis potassium removal were collected. Results: The average potassium intake in our 243 PD patients was 32.1?±?11.1?mmol/day. The total potassium removal was significantly higher in non-anuric patients as compared to anuric patients (33.2?±?9.1 vs. 23.0?±?4.7?mmol/day for 3 exchanges per day and 35.2?±?8.9 vs. 28.6?±?6.3?mmol/day for 4 exchanges per day, respectively, p?p?p?p?R² linear?=?0.645, p?Conclusions: Our study suggested that if potassium intake was limited in PD patients, we should be aware of the risk of hypokalemia with high doses of PD when patients have good RRF. Our study also suggested that potassium removal in PD patients may not necessarily reflect potassium intake even if serum potassium is normal, the effect of ICW should be considered when evaluating potassium homeostasis.     

Predictors of the rate of decline of residual renal function in incident dialysis patients

BACKGROUND: Residual renal function (RRF) influences morbidity, mortality and quality of life in chronic dialysis patients. Few studies have been published on risk factors for loss of RRF in dialysis patients. These studies were either retrospective, performed in a small number of patients, or estimated GFR without a urine collection. METHODS: We analyzed the decline rates of residual GFR (rGFR) prospectively in 522 incident HD and PD patients who had structured follow-up assessments. GFR was measured as the mean of urea and creatinine clearance, calculated from urine collections. The initial value was obtained 0 to 4 weeks before the start of dialysis. The measurements were repeated 3, 6, and 12 months after the start of dialysis treatment. After logarithmic transformation, differences in rGFR changes over time were analyzed using repeated measurement analysis of variance. RESULTS: Baseline factors that were negatively associated with rGFR at 12 months were a higher diastolic blood pressure (P < 0.001) and a higher urinary protein loss (P < 0.001). Primary kidney disease did not affect rGFR. Averaged over time, PD patients had a higher rGFR (P < 0.001) than HD patients. This relative difference increased over time (P = 0.04). Investigation of possible effects of the dialysis procedure on the decline rate between 0 and three months showed that dialysis hypotension (P = 0.02) contributed to the decline in HD and the presence of episodes with dehydration contributed in PD (P = 0.004). CONCLUSIONS: rGFR is better maintained in PD patients than in HD patients. The associated factors such as a higher diastolic blood pressure, proteinuria, dialysis hypotension and dehydration can either be treated or avoided.     

Preservation of glomerular filtration rate on dialysis when adjusted for patient dropout

BACKGROUND: Residual renal function (RRF) plays an important role in dialysis patients. Studies in patients on maintenance dialysis suggest that RRF is better preserved in patients receiving peritoneal dialysis (PD) vis-à-vis those receiving hemodialysis (HD). We speculated that regardless of the patient's type of therapy, the estimate obtained for the rate of decline in glomerular filtration rate (GFR) may be biased because of informative censoring associated with patient dropout. Informative censoring occurs when patients who die or transfer to another modality very early have associated with them a lower starting GFR or a higher rate of decline of GFR than patients who either complete the study or who die or transfer much later. If patient dropout is indeed related to the rate of decline in GFR and if this relationship is ignored in the analysis, then the estimate obtained of the rate of decline in GFR may be biased. METHODS: In an attempt to determine if there is a relationship between patient dropout and the decline in GFR, we reanalyzed the CANUSA data by modeling GFR as a nonlinear function of time with the rate of decline being exponential. RESULTS: This article highlights the significance of "informative censoring" when studying the decline of RRF on dialysis. The results show that for the CANUSA cohort, the mean initial GFR was significantly lower, and the rate of decline was significantly higher for patients who died or transferred to HD than for patients who were randomly censored or received a transplant. It is important to emphasize that the impact of informative censoring on previous analyses of the decline of RRF between PD versus HD is presently unclear. If bias caused by informative censoring is the same regardless of what therapy a patient is on, then conclusions from previous studies comparing the decline in GFR between PD and HD would still be valid. However, if the magnitude of the bias differs according to therapy, then additional adjustments would be needed to fairly compare the decline in GFR between PD and HD. Because this analysis is restricted to patients on PD, it would be scientifically incorrect to interpret previous studies solely on the basis of the results from this analysis. CONCLUSION: In any longitudinal study designed to estimate trends in an outcome measured over time, it is important that the analysis of the data takes into account any effect patient dropout may have on the estimated trend. This analysis demonstrates that among PD patients, both the starting GFR and the rate of decline in GFR are associated with patient dropout. Consequently, future studies aimed at estimating the rate of decline in GFR among PD patients should also account for any dependencies between dropout and GFR. Similarly, data analyzing for apparent differences in the rate of decline of GFR between PD and HD should also adjust for possible informative censoring.     

Survival analysis of pediatric dialysis patients in Taiwan

Aim: The long‐term survival of Taiwanese children with end‐stage renal disease (ESRD) has not been reported before. This study aimed to determine the long‐term survival, mortality hazards and causes of death in paediatric patients receiving dialysis. Methods: Paediatric patients (aged 19 years and younger) with incident ESRD who were reported to the Taiwan Renal Registry from 1995 to 2004 were included. A total of 319 haemodialysis (HD) and 156 peritoneal dialysis (PD) patients formed the database. After stratification by dialysis modality, multivariate Cox proportional‐hazards model was constructed with age, sex and co‐morbidity as predictive variables. Results: The annual paediatric ESRD incidence rate was 8.12 per million of age‐related populations. The overall 1‐, 5‐, and 10‐year survival rates for PD patients were 98.1%, 88.0% and 68.4%, respectively, and were 96.9%, 87.3% and 78.5% for HD patients. The survival analysis showed no significant difference between HD and PD (P = 0.4878). Using ‘15–19 years’ as a reference group, the relative risk (RR) of the youngest group (0–4 years) was 6.60 (95% CI: 2.50–17.38) for HD, and 5.03 (95% CI: 1.23–20.67) for PD. The death rate was 24.66 per 1000 dialysis patient‐years. The three major causes of death were infection (23.4%), cardiovascular disease (13.0%) and cerebrovascular disease (10.4%). Hemorrhagic stroke (87.5%) was the main type of foetal cerebrovascular accident. Conclusion: We conclude that there was no significant difference of paediatric ESRD patient survival between HD and PD treatment in Taiwan. The older paediatric ESRD patients had better survival than younger patients.     

Peripheral Arterial Disease Predicts Overall and Cardiovascular Mortality in Peritoneal Dialysis Patients

Background: Peripheral arterial disease (PAD) is an important manifestation of systemic atherosclerosis and is common among dialysis patients. Cardiovascular disease (CVD) accounts for the leading cause of mortality in dialysis patients, and PAD has been found as a predictor for cardiovascular as well as overall mortality in general population. However, the study on the role of PAD in the prognosis of peritoneal dialysis patients is rather limited. Methods: Prevalent continuous ambulatory peritoneal dialysis patients over 60 years old were recruited in this study and were followed-up regularly to death or the end of the study. The diagnosis of PAD was based on ankle-brachial pressure index (ABI) < 0.9 or intermittent claudication. Univariate and multivariate Cox proportional hazard models were used to identify the risk factors for cardiovascular and overall mortality. Survival curves were estimated by the Kaplan–Meier method followed by log-rank test to compare the mortality rate between PAD and non-PAD patients. Results: One hundred and seventy-one patients were included and 62 (36%) had PAD complication. In the follow-up of 24.4 (median 34.6) months, 36 deaths were recorded: 19 from PAD group and 17 from non-PAD group. Twenty-one patients died due to CVD: 13 from PAD group and 8 from non-PAD group. The presence of PAD and serum albumin was found independently associated with cardiovascular and overall mortality using Cox proportional hazards model. Conclusion: PAD is very common in aged peritoneal dialysis patients and independently associated with both cardiovascular and overall mortality.     

Atherosclerotic Risk Factors Among Ankle-Brachial Index and Toe-Brachial Index in Peritoneal Dialysis Patients

Background. Atherosclerotic vascular change affecting the lower extremities is the most common peripheral vascular disease. Ankle-brachial index (ABI) and toe-brachial index (TBI) are common, non-invasive diagnostic tests for atherosclerosis in the lower extremities. Peritoneum is a vascular-based structure. The use of glucose-based hyperosmolar solutions for PD patients results in a significant increase in blood glucose load and can be considered atherogenic. The association between ABI or TBI values and peritoneal function in patients undergoing peritoneal dialysis remains unclear. We presumed that the risk factors for atherosclerosis in large and small vessels may differ. Methods. A total of 146 peritoneal dialysis patients, 41 males and 105 females (119 without diabetes and 27 with diabetes), received peritoneal dialysis for more than four months. Patients who had dialysis-related peritonitis within six months prior to this study were excluded. The ABI or TBI was determined using an automated, non-invasive, waveform analysis device. Results. The ABI value correlated positively with mean arterial pressure and TBI value. The TBI value correlated positively with ABI value and inversely with fasting serum glucose and serum total cholesterol concentrations. Peritoneal function was not correlated with ABI or TBI. Conclusion. This cross-sectional study demonstrated that risk factors in peritoneal dialysis patients for atherosclerosis in large vessels and small vessels differed. Interestingly, peritoneal function test is not associated with ABI or TBI value. However, further investigation of the association between ABI or TBI value and cardiovascular events is required for this patient group.     

Cardiac high-sensitivity troponin T measurement: A layer of complexity in managing haemodialysis patients

Aim: To determine: (i) the proportion of stable asymptomatic haemodialysis patients with elevated troponin; (ii) stability of troponin values after dialysis and over a 2‐week interval; and (iii) whether high‐sensitivity troponin T (hsTnT) was associated with higher prevalence of cardiovascular risk factors or cardiovascular disease in these patients. Methods: We measured hsTnT and the fourth generation troponin I before and after dialysis in 103 stable in‐centre haemodialysis patients without ischaemic symptoms. Patients were divided into quartiles to test for associations with established cardiovascular risk factors or disease. Results: hsTnT was above the 99th percentile for the general population in 99% of haemodialysis patients compared with only 13% elevation for the troponin I assay (P < 0.001). Median pre‐dialysis hsTnT concentrations were unchanged after a 2‐week interval (69 vs 69 ng/L, P = 0.55) but fell slightly immediately following dialysis (69 vs 61 ng/L, P < 0.001). Established coronary artery disease (59% vs 22%), peripheral vascular disease (38% vs 4%) and diabetes (18% vs 7%) were more prevalent (P < 0.05) in those in the highest quartile for hsTnT compared with those in the lowest quartile. Conclusion: Almost all in‐centre haemodialysis patients have elevated troponin T in their baseline stable state and this appears unchanged over a 2‐week interval. Such a high rate of baseline elevation of hsTnT may lead to confusion in managing acute coronary syndrome in this group of patients, particularly when symptoms are atypical. We recommend that if Troponin I assay is unavailable then baseline hsTnT concentrations are measured periodically in all haemodialysis patients.