Presence of Peripheral Arterial Disease Predicts Loss of Residual Renal Function in Incident CAPD Patients

♦ Background: Accelerated cardiovascular disease (CVD), including peripheral arterial disease (PAD), is very common in patients with end-stage renal disease. Residual renal function (RRF) is a strong predictor of patient survival that is suggested to be linked to the degree of CVD. However, the relationship between PAD and decline in RRF has not previously been measured.♦ Methods: We studied incident continuous ambulatory peritoneal dialysis patients from Peking University Third Hospital. An ankle brachial index of less than 0.9 was used to diagnose PAD. Residual renal function (RRF) was determined as the mean of 24-hour urea and creatinine clearances (glomerular filtration rate). The Cox proportional hazards model was used to identify factors predicting loss of RRF.♦ Results: The study included 86 patients (age: 61 ± 14 years; men: 51%), 23 of whom had PAD at baseline. Mean follow-up was 19 months (median: 18 months; range: 6 – 30 months). In univariate analysis, baseline PAD, peritonitis during follow-up, inflammation (C-reactive protein), serum uric acid, Ca×P, and serum phosphate were all significantly associated with a greater-than-50% decrease in RRF during follow-up. In multivariate analysis, only baseline PAD, Ca×P, and peritonitis were independently associated with a decline in RRF.♦ Conclusions: Our study suggests that PAD may be a clinically important marker of CVD predicting the loss of RRF. It remains to be determined whether interventions aimed at decreasing PAD may also improve renal vascular status and thus slow the rate of RRF decline.     

Utility of Urinary Biomarkers in Predicting Loss of Residual Renal Function: The balANZ Trial

♦ Background: The ability of urinary biomarkers to predict residual renal function (RRF) decline in peritoneal dialysis (PD) patients has not been defined. The present study aimed to explore the utility of established biomarkers from kidney injury models for predicting loss of RRF in incident PD patients, and to evaluate the impact on RRF of using neutral-pH PD solution low in glucose degradation products.♦ Methods: The study included 50 randomly selected participants from the balANZ trial who had completed 24 months of follow-up. A change in glomerular filtration rate (GFR) was used as the primary clinical outcome measure. In a mixed-effects general linear model, baseline measurements of 18 novel urinary biomarkers and albumin were used to predict GFR change. The model was further used to evaluate the impact of biocompatible PD solution on RRF, adjusted for each biomarker.♦ Results: Baseline albuminuria was not a useful predictor of change in RRF in PD patients (p = 0.84). Only clusterin was a significant predictor of GFR decline in the whole population (p = 0.04, adjusted for baseline GFR and albuminuria). However, the relationship was no longer apparent when albuminuria was removed from the model (p = 0.31). When the effect of the administered PD solutions was examined using a model adjusted for PD solution type, baseline albuminuria, and GFR, higher baseline urinary concentrations of trefoil factor 3 (TFF3, p = 0.02), kidney injury molecule 1 (KIM-1, p = 0.04), and interferon γ-induced protein 10 (IP-10, p = 0.03) were associated with more rapid decline of RRF in patients receiving conventional PD solution compared with biocompatible PD solution.♦ Conclusions: Higher urinary levels of kidney injury biomarkers (TFF3, KIM-1, IP-10) at baseline predicted significantly slower RRF decline in patients receiving biocompatible PD solutions. Findings from the present investigation should help to guide future studies to validate the utility of urinary biomarkers as tools to predict RRF decline in PD patients.     

Reduced Residual Renal Function is Associated with Endothelial Dysfunction in Patients Receiving Peritoneal Dialysis

♦ Background: Endothelial dysfunction, which contributes to atherosclerosis and arteriosclerosis, commonly accompanies end-stage renal disease (ESRD). However, little is known about the role of residual renal function (RRF) in endothelial protection in ESRD patients. This study aimed to investigate the relationship between endothelial function and RRF in patients undergoing peritoneal dialysis (PD).♦ Methods: This was a cross-sectional study involving 72 prevalent PD patients. Demographic and clinical data were recorded and residual glomerular filtration rate (GFR), Kt/V urea, and serum concentrations of inflammatory markers were measured. Endothelial function was assessed by brachial artery endothelium-dependent vasodilation [flow-mediated dilation (FMD)] to reactive hyperemia following 5 minutes of forearm ischemia.♦ Results: In patients with FMD% above the median value (FMD > 2.41%), residual GFR was significantly higher compared to that in patients with FMD% below the median [1.50 (0 – 9.64) vs 0.48 (0 – 3.89) mL/min/1.73 m², P = 0.026]. Correlation analyses revealed that residual GFR (ρ = 0.381, P = 0.001) and total Kt/V urea (γ = 0.408, P < 0.001) were positively correlated with FMD%, whereas PD duration (γ = –0.351, P = 0.003), high-sensitivity C-reactive protein (ρ = –0.345, P = 0.003), pulse pressure (γ = –0.341, P = 0.003), and age (γ = –0.403, P < 0.001) were inversely correlated with FMD%. In contrast, there was no correlation between peritoneal Kt/V urea and FMD%. In multivariate linear regression analysis adjusted for these factors, residual GFR was found to be an independent determinant of FMD% (β = 0.317, P = 0.017).♦ Conclusion: This study shows that RRF is independently associated with endothelial dysfunction in ESRD patients on PD, suggesting that RRF may contribute to endothelial protection in these patients.     

Prognostic Value of Serum Von Willebrand Factor,but Not Soluble ICAM and VCAM,for Mortality and Cardiovascular Events is Independent of Residual Renal Function in Peritoneal Dialysis Patients

♦ Objective: We explored associations between markers of endothelial dysfunction and outcome events, and whether those associations were independent of residual renal function (RRF) in patients on peritoneal dialysis.♦ Methods: The study enrolled 261 incident patients and 68 healthy control subjects who were followed till death, censoring, or study end. Demographics, biochemistry, markers of inflammation (C-reactive protein) and endothelial dysfunction [soluble intercellular adhesion molecule 1 (sICAM), soluble vascular adhesion molecule 1 (sVCAM), and von Willebrand factor (vWf)] were examined at baseline. Outcome events included all-cause death and fatal and nonfatal cardiovascular (CV) events.♦ Results: Mean levels of vWf, sICAM, and sVCAM were significantly higher in patients than in healthy control subjects. Levels of sICAM and sVCAM, but not vWf, were significantly correlated with RRF. Levels of sICAM and vWf both predicted all-cause mortality and fatal and nonfatal CV events after adjustment for recognizable CV risk factors. The association between sICAM and outcome events disappeared after further adjustment for RRF. However, RRF did not change the predictive role of vWf for outcome events. Compared with the lowest vWf quartile (6.6% - 73.9%), the highest vWf quartile (240.9% - 1161%) predicted the highest risk for fatal and nonfatal CV events (adjusted hazard ratio: 2.05; 95% confidence interval: 1.15 to 3.64; p = 0.014). We observed no associations between sVCAM and RRF, or sVCAM and any outcome event.♦ Conclusions: The prognostic value of vWf, but not sICAM, is independent of RRF in predicting mortality and CV events.     

Serum Cystatin C Does Not Predict Mortality or Treatment Failure in Peritoneal Dialysis: A Prospective Study

♦ Background:

Small solute clearance, especially that derived from residual renal function (RRF), is an independent risk factor for death in peritoneal dialysis (PD) patients. Assessment of solute clearance is time-consuming and prone to multiple errors. Cystatin C is a small protein which has been used as a glomerular filtration rate (GFR) marker. We investigated whether serum cystatin C concentrations are related to mortality in patients receiving PD.

♦ Methods:

New and prevalent PD patients (n = 235) underwent assessment of Kt/V_urea, RRF, weekly creatinine clearance (C_Cr), normalized protein catabolic rate (nPCR) and a peritoneal equilibration test (PET) at intervals. Blood was collected simultaneously for cystatin C measurement. Patients were followed for a median of 1,429 days (range 12 to 2,964 days) until death or study closure. Cause of death was recorded where given. Cox regression was performed to determine whether cystatin C had prognostic value either independently or with adjustment for other factors (age, sex, dialysis modality, diabetic status, cardiovascular comorbidity, Kt/V, C_Cr, RRF, nPCR or 4 h dialysate to plasma creatinine ratio (4 h D/P_cr) during the PET). The primary outcomes were all-cause mortality and treatment failure.

♦ Results:

There were 93 deaths. Increasing age and 4 h D/P_cr ratio, decreased RRF and presence of diabetes were significantly [p < 0.05] negatively associated with survival and treatment failure. Serum cystatin C was not related to either outcome.

♦ Conclusions:

Serum cystatin C concentration does not predict mortality or treatment failure in patients receiving PD.     

Identification of Targets for Prevention of Peritoneal Catheter Tunnel and Exit-Site Infections in Low Incidence Settings

♦ Background:

Peritoneal catheter tunnel and exit-site infection (TESI) complicates the clinical course of peritoneal dialysis (PD) patients. Adherence to recommendations for catheter insertion, exit-site care, and management of Staphylococcus aureus (SAu) carriage reduces, but does not abrogate the risk of these infections.

♦ Objective:

To reappraise the risk profile for TESI in an experienced center with a long-term focus on management of SAu carriage and a low incidence of these infections.

♦ Method:

Following a retrospective, observational design, we investigated 665 patients incident on PD. The main study variable was survival to the first episode of TESI. We considered selected demographic, clinical, and technical variables, applying multivariate strategies of analysis.

♦ Main results:

The overall incidence of TESI was 1 episode/68.5 patient-months. Staphylococcus aureus carriage disclosed at inception of PD (but not if observed sporadically during follow-up) (hazard ratio [HR] 1.53, p = 0.009), PD started shortly after catheter insertion (HR 0.98 per day, p = 0.011), PD after kidney transplant failure (HR 2.18, p = 0.017), lower hemoglobin levels (HR 0.88 per g/dL, p = 0.013) and fast peritoneal transport rates (HR 2.92, p = 0.03) portended an increased risk of TESI. Delaying PD ≥ 30 days after catheter insertion markedly improved the probability of TESI. Carriage of methicillin-resistant SAu since the start of PD was associated with a high incidence of TESI by these bacteria. On the contrary, resistance to mupirocin did not predict such a risk, probably due to the use of an alternative regime in affected patients.

♦ Conclusions:

Adherence to current recommendations results in a low incidence of TESI in PD patients. Interventions on specific risk subsets have a potential to bring incidence close to negligible levels. Despite systematic screening and management, SAu carriage is still a predictor of TESI. Antibiotic susceptibility patterns may help to refine stratification of the risk of TESI by these bacteria. Early insertion of the peritoneal catheter should be considered whenever possible, to reduce the risk of later TESI.     

The Mutual Relationship Between Peritonitis and Peritoneal Transport

♦ Background:

Preservation of the peritoneum is required for long-term peritoneal dialysis (PD). We investigated the effect of multiple peritonitis episodes on peritoneal transport.

♦ Methods:

Prospectively collected data from 479 incident PD patients treated between 1990 and 2010 were analyzed, using strict inclusion criteria: follow-up of at least 3 years with the availability of a Standard Peritoneal Permeability Analysis (SPA) in the first year after start of PD and within the third year of PD, without peritonitis preceding the first SPA. For the purpose of the study, we only included patients who remained peritonitis-free (n = 28) or who experienced 3 or more peritonitis episodes (n = 16).

♦ Results:

At baseline the groups were similar with regard to small solute and fluid transport. However, the frequent peritonitis group had lower peritoneal protein clearances compared to the no peritonitis group, resulting in lower dialysate concentrations of proteins: albumin 196.5 mg/L vs 372.5 mg/L, IgG 36.4 mg/L vs 65.0 mg/L, and α-2-macroglobulin (A2M) 1.9 mg/L vs 3.6 mg/L, p <0.01. No differences in serum concentrations were present. A comparison between the transport slopes over time in both groups showed a positive time trend of mass transfer area coefficient (MTAC) creatinine (p = 0.03) and glucose absorption (p = 0.09) and a negative trend of transcapillary ultrafiltration (p = 0.06), when compared to the no peritonitis group. Frequent peritonitis did not affect free water transport.

♦ Conclusions:

Slow initial peritoneal transport rates of serum proteins result in lower dialysate concentrations, and likely a lower opsonic activity, which is a risk factor for peritonitis. Patients with frequent peritonitis show an increase in small solute transport and a concomitant decrease of ultrafiltration. In long-term peritonitis-free PD patients, small solute transport decreased, while ultrafiltration increased. This suggests that frequent peritonitis leads to an increase of the vascular peritoneal surface area without all the structural membrane alterations that may develop after long-term PD.     

Effect of Biocompatible Peritoneal Dialysis Solution on Residual Renal Function: A Systematic Review of Randomized Controlled Trials

♦ Introduction: Residual renal function (RRF) plays an important role in outcome of peritoneal dialysis (PD) including mortality. It is, therefore, important to provide a strategy for the preservation of RRF. The objective of this study was to evaluate relative protective effects of new glucose-based multicompartmental PD solution (PDS), which is well known to be more biocompatible than glucose-based conventional PDS, on RRF compared to conventional PDS by performing a systematic review (SR) of randomized controlled trials.♦ Methods: We searched studies presented up to January 2014 in MEDLINE, EMBASE, the COCHRANE library, and local databases. Three independent reviewers reviewed and extracted prespecified data from each study. The random effects model, a more conservative analysis model, was used to combine trials and to perform stratified analyses based on the duration of follow-up. Study quality was assessed using the Cochrane Handbook for risk of bias. Eleven articles with 1,034 patients were identified for the SR.♦ Results: The heterogeneity of the studies under 12 months was very high, and the heterogeneity decreased substantially when we stratified studies by the duration of follow-up. The mean difference of the studies after 12 months was 0.46 mL/min/1.73 m² (95% confidence interval = 0.25 to + 0.67).♦ Conclusion: New PDS showed the effect to preserve and improve RRF for long-term use compared to conventional PDS, even though it did not show a significant difference to preserve RRF for short-term use.     

Risk Factors for Mortality in Chinese Patients on Continuous Ambulatory Peritoneal Dialysis

♦ Objective: The intent of this study was to evaluate the clinical outcome and risk factors affecting mortality of the continuous ambulatory peritoneal dialysis (CAPD) patients in a single peritoneal dialysis (PD) center over a period of 10 years.♦ Patients and methods: We retrospectively analyzed patients on PD from June 2001 to June 2011. The clinical and biochemical data were collected from the medical records. Clinical variables included gender, age at the start of PD, smoking status, body mass index (BMI), cause of end-stage renal disease (ESRD), presence of diabetes mellitus and blood pressure. Biochemical variables included hemoglobin, urine volume, residual renal function (RRF), serum albumin, blood urea nitrogen (BUN), creatinine, total cholesterol, triglyceride, comorbidities, and outcomes. Survival curves were made by the Kaplan-Meier method. Univariate and multivariate analyses to identify mortality risk factors were performed using the Cox proportional hazard regression model.♦ Results: A total of 421 patients were enrolled, 269 of whom were male (63.9%). The mean age at the start of PD was 57.9 ± 14.8 years. Chronic glomerulonephritis was the most common cause of ESRD (39.4%). Estimation of patient survival by Kaplan-Meier was 92.5%, 80.2%, 74.4%, and 55.7% at 1, 3, 5, and 10 years, respectively. Patient survival was associated with age (hazard ratio [HR]: 1.641 [1.027 – 2.622], p = 0.038), cardiovascular disease (HR: 1.731 [1.08 – 2.774], p = 0.023), hypertriglyceridemia (HR: 1.782 [1.11 – 2.858], p = 0.017) in the Cox proportional hazards model analysis. Estimation of technique survival by Kaplan-Meier was 86.7%, 68.8%, 55.7%, and 37.4% at 1, 3, 5, and 10 years, respectively. In the Cox proportional hazards model analysis, age (HR: 1.672 [1.176 – 2.377], p = 0.004) and hypertriglyceridemia (HR: 1.511 [1.050 – 2.174], p = 0.026) predicted technique failure.♦ Conclusion: The PD patients in our center exhibited comparable or even superior patient survival and technical survival rates, compared with reports from other centers in China and other countries.     

Baseline Serum Interleukin-6 Predicts Cardiovascular Events in Incident Peritoneal Dialysis Patients

♦ Background: The utility of local and systemic interleukin 6 (IL-6) as a prognostic marker in incident peritoneal dialysis (PD) patients remains to be fully defined. The present study aimed to explore the capacity of systemic IL-6 concentrations to predict cardiovascular events (CVEs) and mortality in PD patients, and to evaluate the influence of neutral-pH PD solutions low in glucose degradation products (GDPs) on systemic IL-6.♦ Methods: The study included 175 incident participants from the balANZ trial with at least one stored serum sample. A composite CVE score was used as the primary clinical outcome measure. Multilevel linear regression and Poisson regression models were fitted to describe, respectively, the trend of serum IL-6 over time and its ability to predict composite CVE.♦ Results: A significant increase in serum IL-6 from baseline to 24 months was observed in the study population (mean difference: 1.68 pg/mL; p = 0.006). The type of PD solution received by patients exerted no significant effect on serum IL-6 (p = 0.12). Composite CVE was significantly and independently associated with baseline serum IL-6 (incidence rate ratio per picogram per milliliter: 1.06; 95% confidence interval: 1.02 to 1.10; p = 0.003).♦ Conclusions: Baseline serum IL-6 was a significant independent predictor of composite CVE. Serum IL-6 concentrations increased with increasing PD duration and were not significantly modified with the use of biocompatible fluid over the study period. The present study is the first to link systemic IL-6 concentrations with CVE outcomes in incident PD patients.     

Endogenous Markers for Estimation of Renal Function in Peritoneal Dialysis Patients

♦ Objective: This method comparison study, conducted at the peritoneal dialysis (PD) outpatient clinic of the Department of Renal Medicine, Aarhus University Hospital, Denmark, set out to evaluate the accuracy and reproducibility of methods for estimating glomerular filtration rate (GFR) based on endogenous markers in PD patients.♦ Patients: The 12 consecutive patients included in the study were examined twice while in a stable condition. All patients finished the study. Inclusion criteria were age 18 years or older, ability to collect 24-hour urine, and urine production greater than 300 mL in 24 hours.♦ Main Outcome Measures: The methods for estimating GFR using endogenous markers included the average of urinary clearances of creatinine and urea [U-Cl(crea-urea)] and two equations using the serum concentration of cystatin C [eGFR(CysC)]. The resulting GFR estimates were compared with those obtained using urinary and corrected plasma clearances of ⁵¹Cr-EDTA [U-Cl(EDTA) and cP-Cl(EDTA)], the corrected plasma clearance being plasma clearance minus dialysate clearance.♦ Results: Compared with the U-Cl(EDTA), the U-Cl(crea-urea) GFR estimate was 12% higher [95% confidence limits (CL): 3%, 21%]. Although significantly different (p = 0.01), the latter two methods showed the best agreement. The estimates obtained using the eGFR(CysC) methods were skewed from y = x compared with the estimates obtained using other methods, indicating strong bias, probably because of extrarenal elimination. The cP-Cl(EDTA) estimate was 34% (95% CL: 26%, 42%), higher than the U-Cl(EDTA) estimate (p < 0.001). The reproducibility (coefficients of variation) differed significantly between methods: cP-Cl(EDTA), 7%; U-Cl(EDTA), 14%; U-Cl(crea-urea), 18%; and both eGFR(CysC) methods, 3%.♦ Conclusions: In PD patients, GFR may be estimated as U-Cl(crea-urea) when complete urine collection is performed, taking into account an overestimation of approximately 12%. The available equations for eGFR(CysC) seem to be inaccurate; further development and validation is desirable. Omitting the eGFR(CysC) methods, cP-Cl(EDTA) was the most reproducible method and might be useful in certain situations.Key words: Chromium radioisotopes, creatinine, cystatin C, glomerular filtration rate, ureaPreservation of residual renal function (RRF) in peritoneal dialysis (PD) patients is associated with decreased morbidity and mortality, independent of dialysis dose (1-4). Thus, reliable and validated methods for estimation of the glomerular filtration rate (GFR) in PD patients are greatly needed.The most reliable methods for the estimation of GFR involve an exogenous marker. After injection of ⁵¹Cr-EDTA, for example, GFR can be measured using a plasma clearance technique based on blood samples (5,6). However, the former method is labor-intensive and expensive, and data in PD patients are scarce.In clinical practice, guidelines recommend that GFR be estimated using the average of creatinine and urea clearances based on a 24-hour urine sample [U-Cl(crea-urea)]; however, handling of those substances in the renal tubules influences the result. Moreover, urine collection may be incomplete and even impossible to obtain in some patients.Estimated GFR based on plasma creatinine [eGFR(crea)] and no urine sampling is increasingly used in clinical practice. However, dialysis removes creatinine, and the plasma concentration of creatinine does not solely depend on GFR, thus making eGFR(crea) useless in PD patients.Serum cystatin C (CysC) was proposed to be a marker of RRF in PD patients (7,8). Two equations based on serum CysC [eGFR(CysC)] for use in dialysis patients were developed: one from Hoek and colleagues (9) for all dialysis patients, and another from Yang and colleagues (10) for patients on continuous ambulatory PD. The eGFR(CysC) proposed by Hoek was tested in 28 PD patients (11). Compared with U-Cl(crea-urea), the eGFR(CysC) results did not differ significantly. However, compared with 7-hour ⁵¹Cr-EDTA plasma clearance, eGFR(CysC) showed a mean bias of -20%. The equation proposed by Yang has not been externally validated.The aim of the present study was to compare estimated GFR based on U-Cl(crea-urea) and the CysC-based equations with clearances determined using ⁵¹Cr-EDTA in PD patients. We also investigated the week-to-week reproducibility of GFR estimates, and we propose standard deviations for power calculations to be used in clinical studies on the preservation of RRF.     

The Role of Monitoring Vancomycin Levels in Patients with Peritoneal Dialysis-Associated Peritonitis

♦ Background: There is limited available evidence regarding the role of monitoring serum vancomycin concentrations during treatment of peritoneal dialysis (PD)-associated peritonitis.♦ Methods: A total of 150 PD patients experiencing 256 episodes of either gram-positive or culture-negative peritonitis were included to investigate the relationship between measured serum vancomycin within the first week and clinical outcomes of cure, relapse, repeat or recurrence of peritonitis, catheter removal, temporary or permanent transfer to hemodialysis, hospitalization and death.♦ Results: Vancomycin was used as an initial empiric antibiotic in 54 gram-positive or culture-negative peritonitis episodes among 34 patients. The median number of serum vancomycin level measurements in the first week was 3 (interquartile range; IQR 1 – 4). The mean day-2 vancomycin level, measured in 34 (63%) episodes, was 17.5 ± 5.2 mg/L. Hospitalized patients were more likely to have serum vancomycin levels measured on day 2 and ≥ 3 measurements in the first week. The peritonitis cure rates were similar between patients with < 3 and ≥ 3 measurements in the first week (77% vs 57%, p = 0.12) and if day-2 vancomycin levels were measured or not (68% vs 65%, p = 0.84). The average day-2 (18.0 ± 5.9 vs 16.6 ± 3.2, p = 0.5), first-week average (18.6 ± 5.1 vs 18.6 ± 4.3, p = 0.9) and nadir (14.5 ± 4.1 vs 13.6 ± 4.2, p = 0.5) vancomycin levels were comparable in patients who did or did not achieve peritonitis cure. Similar results were observed for all other clinical outcomes.♦ Conclusion: The clinical outcomes of gram-positive and culture-negative peritonitis episodes are not associated with either the frequency or levels of serum vancomycin measurements in the first week of treatment when vancomycin is dosed according to International Society for Peritoneal Dialysis (ISPD) Guidelines.     

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.     

Peritoneal Resting with Heparinized Lavage Reverses Peritoneal Type I Membrane Failure. A Comparative Study of the Resting Effects on Normal Membranes

♦ Background: Ultrafiltration failure (UFF) is a serious complication of long-term peritoneal dialysis (PD). Peritoneal rest (PR) has been demonstrated as a valid treatment to reverse the functional changes that occur in UFF. The effects of PR on a normally functioning human peritoneum are unknown but are expected to be neutral. Our hypothesis was that PR positively modifies peritoneal function in patients with UFF, in contrast to the absence of effects when PR is applied under normal conditions.♦ Patients and Methods: We studied 84 PR periods, comparing 35 patients with UFF and 49 controls (resting for abdominal surgery with temporary discontinuation of PD). We analyzed peritoneal transport pre-PR and post-PR by calculating the mass transfer coefficients of creatinine (Cr-MTAC), the dialysate/plasma creatinine ratio (D/P Cr) and the ultrafiltration (UF).♦ Results: Baseline data was similar for the 2 groups, although the UFF group had a longer median time in PD (39 [18 - 60] vs 10 [5 - 23] months; p = 0.00001). Peritoneal rest induced a decrease in D/P Cr, Cr-MTAC and an increase in UF capacity in the UFF group (p = 0.0001, p = 0.004 and p = 0.001, respectively), without causing changes in the control group. Peritoneal rest in patients with more than 6 months of UFF was not able to reduce peritoneal solute transport or improve UF capacity. Response to PR did not differ among UFF patients with or without a previous history of peritonitis. Peritoneal rest enabled patients with UFF to continue on PD for a median time of 23 months (range, 13 - 46 months).♦ Conclusions: Peritoneal rest induces functional changes in patients with UFF but not in those with no functional abnormalities. This demonstrates that PR works only when abnormal but reversible functional conditions are present. However, the effect is highly dependent on how early PR is applied.     

Microbiology and Outcomes of Peritonitis in Northern India

♦ Background: Peritoneal dialysis (PD) is an established treatment modality for end-stage renal disease (ESRD). Peritonitis remains a serious complication in PD patients and an important cause of drop-out from the program. Types of pathogens and their drug resistance patterns may determine the outcome of peritonitis. The present study was undertaken to determine the microbiology of peritonitis in PD patients, antibiotic resistance in commonly isolated bacterial pathogens and clinical outcomes.♦ Method: We enrolled 211 patients with ESRD undergoing PD who developed peritonitis during 2002 to 2011. PD fluids were cultured and antibiotic susceptibility test of the bacterial isolates was performed.♦ Result: A total of 303 peritonitis episodes with an overall incidence of 0.41 episodes per patient-year were recorded. Gram-positive, gram-negative, fungi, Mycobacterium tuberculosis and ≥ 2 organisms were isolated from 102 (33.7%), 89 (29.4%), 41 (13.5%), 11 (3.6%) and five (1.6%) episodes respectively; 55 (18.2%) episodes were culture negative. Coagulase-negative Staphylococcus spp. (CONS) was the most common isolate. Catheter loss and hospital admission in gram-negative peritonitis were significantly higher than in gram-positive peritonitis (36/89 (40.4%) vs 20/102 (19.6%), p < 0.001; and 56/89 (62.9%) vs 42/102 (41.2%), p = 0.004 respectively). Antibiotic susceptibility tests showed 54.3% of Enterobacteriaceae isolates were extended spectrum β-lactamase (ESBL) producers, 23.5% of Acinetobacter species and 11.5% of Pseudomonas aeruginosa were metallo-β-lactamase (MBL) producers; 15.4% of enterococci and 28.6% of staphylococci were resistant to vancomycin and methicillin respectively. Mortality was significantly higher in patients having peritonitis due to vancomycin-resistant enterococci, ESBL- and MBL-producing bacteria.♦ Conclusion: Emerging antimicrobial resistance calls for prompt diagnosis and aggressive empiric therapy based on the local sensitivity data.     

Predictors and Outcomes of Transfers from Peritoneal Dialysis to Hemodialysis

♦ Introduction:

Peritoneal dialysis (PD) patients are commonly required to transfer to hemodialysis (HD), however the literature describing the outcomes of such transfers is limited. The aim of our study was to describe the predictors of these transfers and their outcomes according to vascular access at the time of transfer.

♦ Methods:

A retrospective cohort study using registry data of all adult patients commencing PD as their initial renal replacement therapy in Australia or New Zealand between 2004 – 2010 was performed. Follow-up was until 31 December 2010. Logistic regression models were constructed to determine possible predictors of transfer within both 6 and 12 months of PD commencement. Cox analysis and competing risks regression were used to determine the predictors of survival and transplantation post-transfer.

♦ Results:

The analysis included 4,781 incident PD patients, of whom 1,699 transferred to HD during the study period. Logistic models did not identify any clinically useful predictors of transfer within 6 or 12 months (c-statistics 0.54 and 0.55 respectively). 67% of patients commenced HD with a central venous catheter (CVC). CVC use at transfer was associated with increased mortality (hazard ratio 1.37, 95% confidence interval (CI) 1.11 – 1.68, p = 0.003) and a borderline significant reduction in the incidence of transplantation (subhazard ratio 0.76, 95% CI 0.58 – 1.00, p = 0.05).

♦ Conclusions:

It is difficult to predict the transfer to HD for incident PD patients. PD patients who commence HD with a CVC have a higher risk of mortality and a lower likelihood of undergoing renal transplantation.     

Predictors of Peritonitis and the Impact of Peritonitis on Clinical Outcomes of Continuous Ambulatory Peritoneal Dialysis Patients in Taiwan—10 Years’ Experience in a Single Center

♦ Objective: Peritoneal dialysis (PD) has become more prevalent as a treatment modality for end-stage renal disease, and peritonitis remains one of its most devastating complications. The aim of the present investigation was to examine the frequency and predictors of peritonitis and the impact of peritonitis on clinical outcomes.♦ Methods: Our retrospective observational cohort study enrolled 391 patients who had been treated with continuous ambulatory PD (CAPD) for at least 90 days. Relevant demographic, biochemical, and clinical data were collected for an analysis of CAPD-associated peritonitis, technique failure, drop-out from PD, and patient mortality.♦ Results: The peritonitis rate was 0.196 episodes per patient-year. Older age (>65 years) was the only identified risk factor associated with peritonitis. A multivariate Cox regression model demonstrated that technique failure occurred more often in patients experiencing peritonitis than in those free of peritonitis (p < 0.001). Kaplan-Meier analysis revealed that the group experiencing peritonitis tended to survive longer than the group that was peritonitis-free (p = 0.11). After multivariate adjustment, the survival advantage reached significance (hazard ratio: 0.64; 95% confidence interval: 0.46 to 0.89; p = 0.006). Compared with the peritonitis-free group, the group experiencing peritonitis also had more drop-out from PD (p = 0.03).♦ Conclusions: The peritonitis rate was relatively low in the present investigation. Elderly patients were at higher risk of peritonitis episodes. Peritonitis independently predicted technique failure, in agreement with other reports. However, contrary to previous studies, all-cause mortality was better in patients experiencing peritonitis than in those free of peritonitis. The underlying mechanisms of this presumptive “peritonitis paradox” remain to be clarified.     

Pilot Experience in Senegal with Peritoneal Dialysis for End-Stage Renal Disease

♦ Introduction: Peritoneal dialysis (PD) is occasionally used in western sub-Saharan Africa to treat patients with end-stage renal disease (ESRD). The present study is a retrospective review of the initial six years’ experience with PD for ESRD therapy in Senegal, a West African country with a population of over 12 million.♦ Material and Methods: Single-center retrospective cohort study of patients treated with PD between March 2004 and December 2010. Basic demographic data were collected on all patients. Peritonitis rates, causes of death and reasons for transfer to hemodialysis (HD) were determined in all patients.♦ Results: Sixty-two patients were included in the study. The median age was 47 ± 13 years with a male/female ratio of 1.21. Nephrosclerosis and diabetic nephropathy were the main causes of ESRD. The mean Charlson score was 3 ± 1 with a range of 2 to 7. Forty five peritonitis episodes were diagnosed in 36 patients (58%) for a peritonitis rate of 1 episode/20 patient-months (0.60 episodes per year). Staphylococcus aureus and Pseudomonas aeruginosa were the most commonly identified organisms. Touch contamination has been implicated in 26 cases (57.7%). In 23 episodes (51%), bacterial cultures were negative. Catheter removal was necessary in 12 cases (26.6%) due to mechanical dysfunction, fungal or refractory infection. Sixteen patients died during the study.♦ Conclusion: Peritoneal dialysis is a suitable therapy which may be widely used for ESRD treatment in western sub-Saharan Africa. A good peritonitis rate can be achieved despite the difficult living conditions of patients. Challenges to the development of PD programs include training health care providers, developing an infrastructure to support the program, and developing a cost structure which permits expansion of the PD program.     

Clinical Outcome of Home Hemodialysis in Patients with Previous Peritoneal Dialysis Exposure: Evaluation of the Integrated Home Dialysis Model

♦ Background:

Home dialysis is a cost-effective modality of renal replacement therapy associated with excellent outcomes. Peritoneal dialysis (PD) is the most common home-based modality, but technique failure remains a problem. Transfer from PD to home hemodialysis (HHD) allows the patient to continue with a home-based modality, but the outcomes of patients transitioning to HHD after PD are largely unknown.

♦ Methods:

In a retrospective cohort study, including all consecutive HHD patients between January 1996 and December 2011, we evaluated the outcomes of patients with previous PD exposure compared to those without. The primary outcome was the cumulative patient and technique survival. Secondary outcomes included time to first hospitalization and hospitalization rate. Data were compared using the log-rank test and a multivariable Cox proportional hazards model.

♦ Results:

Among our cohort of 207 consecutive HHD patients, 35 (17%) had previous exposure to PD. Median renal replacement therapy (RRT) vintage (12.3 years, interquartile range (IQR) 8.5 – 18.9 vs 0.9 years, IQR 0.2 – 7.5, p < 0.001) and Charlson comorbidity index (CCI) (4, IQR 2 – 6 vs 3, IQR 2 – 4, p = 0.044) were higher among patients with PD exposure than those without. Despite the difference in vintage, cumulative patient and technique survival was similar in the two groups, in both unadjusted (log-rank p = 0.893) and Cox adjusted models (hazard ratio (HR) 1.15, 95% confidence interval (CI) 0.51 – 2.59) for patients with PD exposure compared to those without. The time to first hospitalization was shorter in patients with previous PD exposure compared to PD-naïve patients (log-rank p = 0.021). This association was preserved in the Cox proportional model (HR 1.65, 95% CI 1.08 – 2.54).

♦ Conclusion:

Despite a higher burden of comorbidity, patients with previous PD exposure had similar cumulative patient and technique survival on HHD compared to those without PD exposure. Whenever possible, HHD should be considered in PD patients in need of a new dialysis modality.