Generation of TNFα and Interleukin-6 by Peritoneal Macrophages after Overnight Dwells with Bicarbonate- or Lactate-Buffered Dialysis Fluid

Objective

In order to evaluate the biocompatibility profile of a newly designed peritoneal dialysis fluid (PDF), we evaluated peritoneal leukocyte (PMΦ) cytokine release following overnight in vivo dwells using standard, lactate-buffered, single-chamber bag PDF (Lac-PDF) and purely bicarbonate-buffered, double-chamber bag PDF containing 34 (Bic-PDF) or 39 (Bic Hi-PDF) mmol/L bicarbonate.

Design

A randomized, open, crossover clinical trial with single weekly test dwells was performed in stable, long-term continuous ambulatory PD patients ( n = 8). During 8-hour overnight dwells, PMΦ were exposed to different PDF containing 1.5% glucose. After drainage, peritoneal cells were isolated and incubated with RPMI 1640 medium for 2 or 3 hours, with and without stimulation by lipopolysaccharide (LPS). Ex vivo release of tumor necrosis factor (TNF)-α and interleukin (IL)-6 was measured by specific ELISA technique.

Results

After pre-exposure to Lac-PDF, PMΦ generated 242 ± 279 pg TNFα/106 cells and 157 ± 105 pg IL-6/106 cells. When pre-exposed to Bic-PDF and Bic Hi-PDF, TNFα and IL-6 production of PMΦ was not significantly different from Lac-PDF. After LPS stimulation (100 ng/mL), PMΦ secretion of TNFα and IL-6 pre-exposed to three PDF revealed no significant differences between groups: TNFα was 2864 ± 1216, 2910 ± 1202, and 3291 ± 558 pg/106 cells after overnight dwells with Lac-PDF, Bic-PDF, and Bic Hi-PDF, respectively. Comparably, LPS-stimulated (100 pg/mL) PMΦ showed IL-6 secretion of 891 ± 335, 1380 ± 1149, and 1442 ± 966 pg/106 cells for Lac-PDF, Bic-PDF, and Bic Hi-PDF.

Conclusion

After long-term overnight dwells, initial pH, the different buffers, and varying glucose degradation product levels of PDF do not strongly affect PMΦ function with respect to cytokine release. The lack of significant differences between fluids may result from the complete dialysate equilibration achieved during the overnight intraperitoneal dwell.

The Role of Peritoneal Dialysis as the First-Line Renal Replacement Modality

Twenty years after its introduction, peritoneal dialysis (PD) is a well-established alternative to hemodialysis (HD) as a modality of renal replacement therapy. Much debate and research is apparent in the literature, comparing hemodialysis and PD as “opposite” modalities and trying to ascertain which modality should be more optimal.

In our opinion, HD and PD are two distinct modalities, each with its own advantages and disadvantages. In addition, it is clear that for both HD and PD, rates of technique failure are high, causing patients to transfer between modalities. The question is thus not which modality is best, but rather, which flow-chart of modalities makes best use of the advantages of each modality, while avoiding its disadvantages. In this respect, HD and PD appear to be complementary modalities.

The better preservation of residual renal function, lower risk of infection with hepatitis B and C, better outcome after transplantation, preservation of vascular access, and lower costs are arguments to promote PD as a good initial treatment. When PD-related problems arise (adequacy, ultrafiltration, peritonitis, patient burnout), a timely transfer to HD has to be planned.

This editorial tries to review arguments supporting the complementary nature of both modalities, and especially the role of PD as the first-line renal replacement therapy.

Recurrent Infection and Catheter Loss in Patients on Continuous Ambulatory Peritoneal Dialysis

Objective

To elucidate the factors leading to catheter loss from recurrent infection in patients on continuous ambulatory peritoneal dialysis (CAPD).

Design

All catheters removed from patients were prospectively examined for infection.

Setting

CAPD unit in large tertiary-care general hospital.

Patients

Sixty-five consecutive patients undergoing catheter removal for whatever cause; 20 catheters rejected because of desiccation or contamination in transit.

Interventions

None.

Main Outcome Measures

Micro-organisms linked to catheter removal; their locations on removed catheters.

Results

Of 45 catheters removed between January 1994 and August 1995, 26 were infected: 13/26 infections were caused by Staphylococcus aureus and 7/26 by Pseudomonas aeruginosa. In only one case was S. epidermidis associated with catheter removal. The most striking finding was that the inner cuff harbored large numbers of the infecting organisms, even when antibiotics had eradicated them from the peritoneal cavity and exit site, where present, and the catheter lumen.

Conclusion

The importance of S. aureus and Ps. aeruginosa rather than S. epidermidis in catheter loss due to relapsing infection is confirmed. Persistence of the causative organisms in the inner cuff is a likely explanation for relapse after treatment, and might be due to the predominantly intraperitoneal administration of antibiotics. A clinical trial of the effect on catheter retention of empirical use of systemic or oral agents that give high tissue levels and are active against intracellular microorganisms, along with recommended intraperitoneal regimens, is indicated.

The Effect of Small Solute Clearances on Survival of Anuric Peritoneal Dialysis Patients

Objective

Primarily, to determine whether peritoneal small solute clearance is related to patient and technique survival among anuric peritoneal dialysis [continuous ambulatory (CAPD) and automated peritoneal dialysis (APD)] patients. A secondary goal was to describe the ability to attain Dialysis Outcomes Quality Initiative (DOQI) targets among anuric patients on peritoneal dialysis.

Design

Retrospective cohort study via chart reviews.

Setting

Peritoneal Dialysis Unit of Toronto Hospital (Western Division).

Patients

The study included 122 CAPD and APD patients between January 1992 and September 1997, with 24-hour urine volume less than 100 mL, or renal creatinine clearance (CCr) less than 1 mL/minute. Adequacy data were available for 115 patients.

Outcome Measures

Mortality and technique failure (TF). Regression analysis was used to estimate the mortality and TF rate ratios (RR) for peritoneal Kt/V urea (pKt/V) and pCCr, adjusting for age, gender, diabetes, months of follow-up prior to anuria, albumin, transport status, coronary artery disease, cardiovascular disease, and peripheral vascular disease.

Results

Fifty seven per cent (51/89) of patients on CAPD and 81% (21/26) on APD had a weekly pKt/V ≥ 2 and ≥ 2.2, respectively (DOQI targets); whereas only 35% on CAPD (31/89) and 35% (9/26) on APD had a weekly pCCr ≥ 60 L/1.73 m2 and 66 L/1.73 m2, respectively. Median follow-up times among patients were 16.5 and 19.5 months pre- and postanuria, respectively. Patients with pKt/V ≥ 1.85 experienced a strong decrease in patient mortality (RR = 0.54, p = 0.10); the effect was less pronounced for pCCr ≥ 50 L/1.73 m2 (RR = 0.63, p = 0.25). No relationship was observed between pKt/V or pCCr and TF.

Conclusion

Mortality was noticeably less frequent among patients with a pKt/V ≥ 1.85 compared with those with a Kt/V < 1.85 ( p = 0.10). Given the magnitude of the association, the failure to observe statistical significance relates to the size of the patient cohort. Our results imply that it is, in fact, possible to achieve DOQI targets among anuric patients on peritoneal dialysis.

Attitudes of Canadian Nephrologists toward Dialysis Modality Selection

Objective

To determine the opinions and attitudes of Canadian nephrologists about dialysis modality decisions and optimal dialysis system design.

Participants

Members of the Canadian Society of Nephrology.

Intervention

A mailed survey questionnaire.

Results

A 66% response rate was obtained. Decisions about modality are reported to be based most strongly on patient preference (4.4 on a scale from 1 to 5), followed by quality of life (4.06), morbidity (3.97), mortality (3.85), and rehabilitation (3.69), while neither facility (1.78) nor physician (1.62) reimbursement are important. When asked about the current relative utilization of each modality, nephrologists felt that hospital-based hemodialysis (HD) is slightly overutilized (2.53), continuous ambulatory peritoneal dialysis (CAPD) is about right (3.00), while cycler peritoneal dialysis (PD) (3.53), community-based full (3.83) and self-care HD (3.91), and home HD (4.02) are underutilized. A hypothetical question about optimal distribution to maximize survival revealed that a type of HD should constitute 62.8% of the mix, with more emphasis on cycler PD (14.9%), community-based full care HD (13.8%), self-care HD (14.5%), and home HD (9.0%) than is current practice. However, when the goal was to maximize cost effectiveness, HD fell slightly to 57.8%.

Conclusions

These survey results suggest that the current national average 66%/34% HD/PD ratio is reasonable. However, there appears to be a consensus that Canada could evolve to a more cost-effective, community-based dialysis system without compromising patient outcomes.

The Effect of Technique Failure on Outcome in Black Patients on Continuous Ambulatory Peritoneal Dialysis

Background

We previously reported that, while black patients have a better patient survival than white patients on peritoneal dialysis (PD), they also have a significantly higher technique failure rate (39% vs 8%, p < 0.0001). The purpose of this study was to determine the effect of technique failure/transfer to hemodialysis (HD) on patient survival in black PD patients.

Methods

We retrospectively evaluated 137 incident black patients entering our PD program from January 1987 to December 1997. During the course of follow-up, 82 (60%) patients remained on PD (PD group) while 55 (40%) patients were permanently transferred to HD (PD–HD group). The primary outcome measured was patient survival.

Results

Average age was 49 ± 15 years, 42% were male, and 40% had diabetes mellitus. At baseline, serum creatinine was 10.8 ± 5.4 mg/dL, serum albumin 3.4 ± 0.7 g/dL, body mass index 27.3 ± 6.5 kg/m2, peritoneal transport status was high in 18% and high-average in 61%, and residual glomerular filtration rate was 3.4 ± 3.5 mL/minute. There were no significant differences in clinical features, nutritional status, peritoneal transport, residual renal function, or dialysis adequacy at baseline between the PD group and PD–HD group. While a greater proportion of patients transferring to HD had cardiac disease (53% vs 32%, p < 0.05), there were no other significant differences in 15 comorbid conditions assessed at baseline. The primary reason for transfer was peritonitis (64%) and the overall peritonitis rate in the PD–HD group was significantly higher than in the PD group (2.21 vs 1.17 episodes/patient-year, p < 0.0001). Overall follow-up was 34 ± 25 months for PD group and 44 ± 26 months for PD–HD group ( p < 0.01), with a mean time on PD prior to transfer to HD of 22 ± 18 months. During the course of follow-up, there were no significant differences between the two groups in the number of patients transplanted or deaths. Patient survival at 1, 2, and 5 years was 91%, 80%, and 57% for PD group and 96%, 92%, and 55% for PD–HD group [ p = not significant (NS)]. A risk-adjusted time-dependent Cox regression analysis resulted in an adjusted relative risk of death that was not significantly different for those who transferred from PD to HD versus those who remained on PD (relative risk 1.49; 95% confidence interval 0.77–2.89; p = NS).

Conclusions

In black patients on PD, transfer to HD is not associated with any significant difference in patient survival compared to patients remaining on PD. While a high rate of peritonitis predisposes to technique failure, we found no features at baseline predictive of patients at greatest risk to fail PD. Since technique failure does not portend a poorer prognosis, PD remains a viable option for black patients entering an end-stage renal disease program.

Taking Peritoneal Dialysis beyond the Year 2000

Over the past 25 years, peritoneal dialysis (PD) has steadily improved so that now its outcomes, in the form of patient survival, are equivalent to, and at times better than, those for hemodialysis. We now have a better understanding of the pathophysiology of peritoneal membrane function and damage and the importance of appropriate prescription to meet agreed-upon targets of solute and fluid removal. In the next millennium, greater emphasis will be put on prescription setting and subsequent monitoring. This will entail an increase in automated PD, especially for lifestyle reasons as well as for patients with a hyperpermeable peritoneal membrane.

To improve outcomes, dialysis should be started earlier than is currently the case. It is easy to do this with PD, where an incremental approach is made easier by the introduction of icodextrin for long-dwell PD. In the future, solutions will be tailored to be more biocompatible and to provide improved nutrition and better cardiovascular outcomes.

Finally, economic considerations favor PD, which is cheaper than in-centre hemodialysis. Thus, for many, PD has become a first-choice therapy, and with further improvements this trend will continue.

Is Technique Survival on Peritoneal Dialysis Better in Japan?

Technique failure resulting in transfer to hemodialysis (HD) remains one of the most important challenges in long-term peritoneal dialysis (PD). In general, the proportion of patients transferring from PD to HD is much greater than the proportion transferring from HD to PD. However, technique failure rates differ considerably between and within countries.

The question arises as to how technique failure rates in Japan compare with those in other countries. To address this issue, we reviewed the literature and our experience of 139 incident continuous ambulatory peritoneal dialysis (CAPD) patients from January 1995 to December 1999.

Based on our review, we estimate that the 5-year technique survival rate in Japanese CAPD patients is approximately 70%, and that technique failure rate is around 7% per year. This rate is significantly lower than that in many other countries. The most common reasons for technique failure in Japan are peritoneal membrane failure, ultrafiltration loss, and inadequate dialysis. Another factor contributing to the low technique failure rate in Japan is an extremely low peritonitis rate. This may be related to good sanitation and excellent PD training programs. Peritoneal membrane failure continues to be the major challenge for long-term technique survival on PD in Japan.

A Comparison of Outcomes between Diabetic and Nondiabetic Capd Patients in India

Background

Continuous ambulatory peritoneal dialysis (CAPD) has been an established modality of renal replacement therapy in India for a decade, but there is a paucity of published data on the outcome of CAPD patients in India. We analyzed our data to determine the overall predictors of survival and compared patient survival between diabetic and nondiabetic end-stage renal disease patients on CAPD.

Methods

Of 373 patients, 197 were diabetic (165 males, 32 females) and 176 nondiabetic (104 males, 72 females). Patients were followed for 22 ± 14 patient-months. Patients were prospectively followed until the study end point or death.

Results

Overall median survival was 48 patient-months. Median survival of diabetics (34.5 patient-months) was significantly inferior to nondiabetic patients (59 patient-months) p = 0.001. Overall patient survival at 1, 2, 3, 4, and 5 years was 90%, 72%, 60%, 49%, and 39%, respectively. Patient survival of diabetics versus nondiabetics at 1, 2, 3, 4, and 5 years was 85% versus 96%, 62% vs 82%, 48% vs 72%, 39% vs 62%, and 34% vs 42%, respectively. The relative risk of mortality in nondiabetics (34/176) was less than that in diabetic patients (71/197): odds ratio (OR) 0.43, 95% confidence interval (CI) 0.26 – 0.68; p = 0.001. On Cox regression analysis, diabetes (OR 1.95, 95% CI 1.23 – 3.07; p = 0.004), comorbidities (OR 0.39, 95% CI 0.25 – 0.61; p = 0.001), peritonitis (OR 1.79, 95% CI 1.19 – 2.68; p = 0.005), malnutrition (OR 0.52, 95% CI 0.29 – 0.94; p = 0.03), and residual glomerular filtration rate at initiation of CAPD (OR 0.87, 95% CI 0.81 – 0.93; p = 0.001) were significant predictors of overall mortality. Age (OR 0.68, 95% CI 0.45 – 1.03; p = 0.07), gender (OR 0.66, 95% CI 0.42 – 1.03; p = 0.06), and albumin level at initiation of CAPD (OR 0.92, 95% CI 0.64 – 1.33; p = 0.68) were not predictors of mortality. Age (56 ± 10 vs 46 ± 15 years, p = 0.001), comorbidities (51/197 vs 16/176, p = 0.001), peritonitis rate (0.68 vs 0.50 episodes/patient-year, p = 0.056), and severe malnutrition (27/197 vs 10/176, p = 0.002) were higher in diabetic than in nondiabetic patients.

Conclusion

In India the majority of CAPD patients are diabetic. Patient survival was inferior in diabetic compared to nondiabetic patients on CAPD, but survival was statistically similar after adjustment for comorbidities. Diabetes, comorbidities, residual glomerular filtration rate, peritonitis, and severe malnutrition are predictors of mortality in CAPD patients.

Patient and Technique Survival and Factors Affecting Mortality on Peritoneal Dialysis in Turkey: 12 Years’ Experience in a Single Center

Background

We investigated patient and technique survival and factors affecting mortality in Turkish peritoneal dialysis (PD) patients.

Patients and Methods

This was a retrospective study. 423 PD patients were included. The demographic, clinical, and biochemical data were collected from the medical records. Clinical outcomes were mortality and technique failure.

Results

Mean age at the start of PD was 46.0 ± 14.3 years and mean PD duration was 37.1 ± 28.3 (median: 30, range: 4 – 137) months. Diabetes mellitus was the most common cause of end-stage renal disease (35.2%), followed by hypertension (14.7%). There were 89 (21.0%) deaths. 25 (5.9%) patients received a kidney transplant, 74 (17.4%) patients were transferred to hemodialysis. Estimation of technique survival by Kaplan–Meier was 96.1%, 83.2%, 67.6%, 45.8%, and 33.6% at 1, 3, 5, 8, and 10 years. Technique failure was associated with peritonitis rate [relative risk (RR): 3.22, p < 0.001] and peritoneal Kt/V urea (RR: 0.38, p = 0.001) in the Cox proportional hazards model analysis. Estimation of patient survival by Kaplan–Meier was 96.9%, 83.8%, 68.8%, 50.2%, and 40.7% at 1, 3, 5, 8, and 10 years, respectively. In the Cox proportional hazards model analysis, age (RR: 1.01, p = 0.05), transfer to PD from hemodialysis (RR: 1.84, p = 0.03), comorbid cardiovascular disease (RR: 1.90, p = 0.004), serum creatinine level (RR: 0.75, p < 0.001), total Kt/V urea (RR: 0.34, p < 0.001), peritonitis rate (RR: 1.87, p < 0.001), and dialysate-to-plasma creatinine ratio (RR: 6.49, p = 0.04) predicted mortality.

Conclusions

Even though we cannot conclude with certainty that survival rates in Turkish patients are better than those in the United States and Europe, our results seem to suggest this and warrant further studies adjusted for more extensive demographic features and comorbidities. The factors affecting mortality in Turkish PD patients are similar to other populations.

Analysis of outcome and factors correlated with maintenance peritoneal dialysis

Objectives

This study aimed to analyze the outcome and factors correlated with maintenance peritoneal dialysis (PD) to provide guidance for improving prognosis, and prolonging the catheterization and survival times of patients on PD with end-stage renal disease.

Methods

Clinical data of patients at The Third Xiangya Hospital of Central South University were retrospectively analyzed. We compared the survival and technique survival rates of patients, and analyzed relevant factors.

Results

A total of 510 cases of PD were included. Two hundred thirty-nine patients continued to receive PD treatment, 73 received kidney transplants, 72 transferred to hemodialysis, and 126 died. The main reasons of death were cardiovascular (27.00%) and cerebrovascular diseases (23.80%). The main reasons of transfer to HD were peritonitis and inadequate dialysis. The survival rates at 1, 2, 3, 5, and 7 years were 95.75%, 90.34%, 82.35%, 66.21%, and 54.32%, respectively. The technique survival rates at 1, 2, 3, 5, and 7 years were 93.22%, 86.76%, 77.91%, 63.16%, and 47.67%, respectively. Female sex and older age were protective factors that affected patients’ withdrawal from PD and survival time.

Conclusions

Death is the primary reason for withdrawal from PD. Female sex and older age affect patients’ withdrawal from PD and survival.

Characteristics and Clinical Outcomes of End-Stage Renal Disease Patients on Peritoneal Dialysis for over 15 Years: A Single-Center Experience

Background

Maintaining peritoneal dialysis (PD) for a long time is problematic owing to a number of factors. This study aimed to clarify the characteristics and examine the clinical outcomes of patients who received PD as a long-term dialysis modality.

Methods

All end-stage renal disease (ESRD) patients who initiated PD at Yonsei University Health System between 1987 and 2000 were screened. Patients who maintained PD for over 15 years were classified as the long-term PD group and those who were treated with PD for less than 5 years were included in the short-term PD group. Demographic and biochemical data and clinical outcomes were compared between the groups. Independent factors associated with long-term PD maintenance were ascertained using multivariate logistic regression analysis.

Results

Among 1,116 study patients, 87 (7.8%) were included in the long-term group and 293 (26.3%) were included in the short-term group. In the long-term group, the mean patient age at PD initiation was 39.6 ± 11.5 years, 35 patients (40.2%) were male, and the mean PD duration was 205.3 ± 32.7 months. Patients were younger, body weight was lower, the proportion of patients with diabetes or cardiovascular diseases was lower, and the proportion of low to low-average transporters was higher in the long-term group than in the short-term group ( p < 0.001). Multiple logistic regression analysis revealed that age, body mass index (BMI), serum creatinine, type of PD solution, and diabetes were significant independent factors associated with long-term PD maintenance.

Conclusion

Peritoneal dialysis can be considered as a long-term renal replacement therapy option, especially in non-diabetic, not overweight, and young ESRD patients.

Peritoneal Dialysis as a First versus Second Option after Previous Haemodialysis: A Very Long-Term Assessment

For renal replacement therapy, overall survival is more important than the choice of currently available individual therapy. Objectives. To compare patients and technique survival on peritoneal dialysis as first treatment (PDF) versus after previous haemodialysis (HDPD) and other indicators of follow-up. Methods. We prospectively studied 110 incident patients, during the period from August 4, 1993, to June 30, 2012, for patients and technique survival (Kaplan-Meier) (log rank P < 0.05). Results. Groups: (A) PDF: 37 patients, 24 females, age: 52.2 ± 14.9 years old, time at risk: 2123 patient-months (p/m), mean: 57 ± 42 months; (B) HDPD: 73 patients, 42 females, age: 52.45 ± 14.7 years old, time in haemodialysis: 3569.2 (p/m), range: 3-216 months, mean: 49 ± 45 months, time at risk in PD: 3700 (p/m), mean: 51 ± 49 months. Patients' survival: (A) PDF: 100%, 76.6%, 65.6%, and 19.7%; (B) HDPD: 95.4%, 65.6%, 43%, and 43% at 12, 60, 120, and 144 months, respectively, P = 0.34.

TECHNIQUE

(A) PDF: 100%, 90%, 59.8%, and 24%; (B) HDPD: 94%, 75%, 32%, and 32% at 12, 60, 120, and 144 months, respectively, P = 0.40. Conclusions. Comparable patient and technique survival were observed. Peritoneal dialysis enables a greater extension of renal replacement therapy for patients with serious difficulties continuing with haemodialysis.

Janus kinase signaling activation mediates peritoneal inflammation and injury in vitro and in vivo in response to dialysate

Peritoneal membrane pathology limits long-term peritoneal dialysis (PD). Here, we tested whether JAK/STAT signaling is implicated and if its attenuation might be salutary. In cultured mesothelial cells, PD fluid activated, and the pan-JAK inhibitor P6 reduced, phospho-STAT1 and phospho-STAT3, periostin secretion, and cleaved caspase-3. Ex vivo, JAK was phosphorylated in PD effluent cells from long-term but not new PD patients. MCP-1 and periostin were increased in PD effluent in long term compared with new patients. In rats, twice daily, PD fluid infusion induced phospho-JAK, mesothelial cell hyperplasia, inflammation, fibrosis, and hypervascularity after 10 days of exposure to PD fluid. Concomitant instillation of a JAK1/2 inhibitor virtually completely attenuated these changes. Thus, our studies directly implicate JAK/STAT signaling in the mediation of peritoneal membrane pathology as a consequence of PD.

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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Previous renal replacement therapy time at start of peritoneal dialysis independently impact on peritoneal membrane ultrafiltration failure

Background. Peritoneal membrane changes are induced by uraemia per se. We hypothesise that previous renal replacement therapy (RRT) time and residual renal function (RRF) at start of peritoneal dialysis impact on ultrafiltration failure (UFF). Methods. The time course of PET parameters from 123 incident patients, followed for median 26 (4-105) months, was evaluated by mixed linear model. Glucose 3.86% solutions were not used in their standard therapy. Sex, age, diabetes, previous RRT time, RRF, comorbidity score, PD modality and peritonitis episodes were investigated as possible determinants of UFF-free survival. Results. PET parameters remained stable during follow up. CA125 decreased significantly. Inherent UFF was diagnosed in 8 patients, 5 spontaneously recovering. Acquired UFF group presented type I UFF profile with compromised sodium sieving. At baseline they had lower RRF and longer previous time of RRT which remained significantly associated with UFF-free survival by Cox multivariate analysis (HR 0.648 (0.428-0.980), P = 0.04) and (HR 1.016 (1.004-1.028), P = 0.009, resp.). UFF free survival was 97%, 87% and 83% at 1, 3 and 5 years, respectively. Conclusions. Inherent UFF is often unpredictable but transitory. On the other hand baseline lower RRF and previous RRT time independently impact on ultrafiltration failure free survival. In spite of these detrimental factors generally stable long-term peritoneal transport parameters is achievable with a 5-year cumulative UFF free survival of 83%. This study adds a further argument for a PD-first policy.

Association of interleukin-1β gene polymorphism and peritonitis in uremic patients undergoing peritoneal dialysis

OBJECTIVE

Interleukin-1 (IL-1) is involved in the disease process of peritonitis. We hypothesize that IL-1 gene polymorphism may have an impact on the occurrence of peritonitis in uremic patients undergoing peritoneal dialysis (PD).

METHODS

Uremic patients were recruited for the study of IL-1β (-511) C/T gene polymorphism in 2002. These patients were then prospectively followed up to monitor their peritoneal membrane characteristics, biochemical parameters, occurrence of peritonitis and patient as well as PD technique survival.

RESULTS

A total of 74 patients were enrolled in the study. During follow-up, at least one episode of peritonitis occurred in 36 patients. Compared with patients without peritonitis, the carriage of C allele in IL-1β gene polymorphism (C/C and C/T genotypes) was significantly associated with the occurrence of peritonitis (p = 0.013). This was further confirmed in the multivariate logistic regression analysis (odds ratio 8.18, p = 0.017).

CONCLUSION

Carriers of C allele were associated with an increased risk of peritonitis.

Profile of Hospitalisation and Death in the First Year after Diagnosis of End-stage Renal Disease in a Multi-ethnic Asian Population

Introduction: The increasing prevalence of end-stage renal disease (ESRD) is an important public health issue due to the high costs of kidney replacement therapies. We examined the impact of ethnicity and other factors in ESRD management and hospitalisation in a multiracial Asian population in the first year after diagnosis. Materials and Methods: We analysed a prospectively collected database of 168 new ESRD patients from the National University Hospital, Singapore (NUH) in 2005. Univariate and multivariate analyses were performed to assess factors for mortality and hospitalisation. Results: Sixteen patients eventually chose conservative treatment, 102 haemodialysis, 41 peritoneal dialysis and 9 patients underwent kidney transplantation for their long-term treatment. Although more Chinese patients had dialysis plans (56.7% vs 36.8%, P = 0.022), many still required urgent dialysis initiation via catheters (61.3%). These dialysed patients who required urgent treatment had more admissions (3.6 vs 2.6, P = 0.023) and longer length of stay (9.3 days, P = 0.014). Approximately 40 (7.4%) admissions were related to vascular access complications (thromboses, dislodgements and infections), and 15 (2.8%) were for new tunnelled catheter insertions. Deaths were 23.8% in the first year after diagnosis and median survival was 125 days. Age, final treatment modality, type of therapy centre, history of coronary artery disease, left ventricular ejection fraction (LVEF) <50%, and having no plans for dialysis were associated with mortality. Conclusions: The care of ESRD patients requires substantial commitment of healthcare resources particularly in the first year after diagnosis. Steps to reduce urgent initiation of dialysis will help reduce resource utilisation and improve patient outcomes. Key words: Dialysis, Kidney failure, Palliation

Technique Failure and Center Size in a Large Cohort of Peritoneal Dialysis Patients in a Defined Geographic Area

Background

Hemodialysis (HD) and peritoneal dialysis (PD) are both viable options for renal replacement therapy. Technique failure has been shown to be a major problem in PD therapy.

Objective

To examine the relationship between center size and PD technique failure.

Setting

ESRD Network #1 (NW1).

Design

Retrospective review of NW1 database.

Patients and Methods

5003 incident PD patients between 2001 and 2005 in 105 PD units were included. Patients were grouped into 2 based on center size: group A, patients in units with ≤25 patients, and group B, patients in units with >25 patients. Outcome measures were analyzed for the first and second years of PD therapy. Patients were censored at transplantation, transfer to HD, or death.

Outcome Measures

Technique failure and mortality reported as death in Standard Information Management Systems (SIMS) database (NW1 data system).

Results

Technique failure rates were significantly higher in group A for year 1 (odds ratio: 1.36, p = 0.005) and for year 2 (odds ratio: 1.35, p = 0.03). Mortality rates were not statistically different between the 2 groups.

Conclusion

Technique failure was higher in units with ≤25 patients than in units with >25 patients. There was no difference in mortality between the 2 groups. The majority of patients in NW1 receive care in small units.

Timing, causes, predictors and prognosis of switching from peritoneal dialysis to hemodialysis: a prospective study

BACKGROUND

The use of peritoneal dialysis (PD) has declined in the United States over the past decade and technique failure is also reportedly higher in PD compared to hemodialysis (HD), but there are little data in the United States addressing the factors and outcomes associated with switching modalities from PD to HD.

METHODS

In a prospective cohort study of 262 PD patients enrolled from 28 peritoneal dialysis clinics in 13 U.S. states, we examined potential predictors of switching from PD to HD (including demographics, clinical factors, and laboratory values) and the association of switching with mortality. Cox proportional hazards regression was used to assess relative hazards (RH) of switching and of mortality in PD patients who switched to HD.

RESULTS

Among 262 PD patients, 24.8% switched to HD; with more than 70% switching within the first 2 years. Infectious peritonitis was the leading cause of switching. Patients of black race and with higher body mass index were significantly more likely to switch from PD to HD, RH (95% CI) of 5.01 (1.15-21.8) for black versus white and 1.09 (1.03-1.16) per 1 kg/m2 increase in BMI, respectively. There was no difference in survival between switchers and non-switchers, RH (95% CI) of 0.89 (0.41-1.93).

CONCLUSION

Switching from PD to HD occurs early and the rate is high, threatening long-term viability of PD programs. Several patient characteristics were associated with the risk of switching. However, there was no survival difference between switchers and non-switchers, reassuring providers and patients that PD technique failure is not necessarily associated with poor prognosis.

Five-year survival in comparable HD and PD patients: one center's experience

Several studies have yielded conflicting results regarding morbidity and mortality in peritoneal dialysis (PD) and hemodialysis (HD) patients. We performed a retrospective analysis in end-stage renal disease (ESRD) patients in our department, who were equally distributed between HD and PD, in order to compare 5-year survival probabilities and hospitalization rates in the two modalities. Of the total 94 new ESRD patients who initiated dialysis in our department from January 1995 to December 2000, 48 were allocated to PD and 46 to HD. All patients were followed up for five years. There were no significant differences regarding demographics and serious co-morbidities upon dialysis initiation between HD and PD patients. Unadjusted 5-year survival probability in as-treated analysis was higher in PD patients (0.79 vs 0.6, p=0.04), whereas there was no significant difference in intent-to-treat analysis between HD and PD patients (p=0.5). Hospitalization rates were similar in both modalities. Despite the small number of patients included in our study, it seems that when HD and PD are both available in one department they have equivalent results regarding morbidity and mortality rates. Therefore we suggest that, when possible, PD and HD should be equally offered to all ESRD patients.

Risk Factors for Adverse Outcomes after Peritonitis-Related Technique Failure

Background

Peritonitis is the leading cause of technique failure in peritoneal dialysis (PD) patients. Some patients experience recurrent ascites, encapsulating peritoneal sclerosis (EPS), and even death after catheter removal. Little is known, however, about the risk factors for such complications.

Methods

The study subjects were 117 patients that had their PD catheter removed due to peritonitis between January 2000 and June 2006. Biochemical and clinical data were reviewed retrospectively. Serum C-reactive protein (CRP) and blood and effluent white blood cell counts (WBC) were measured at baseline and at 72 hours of peritonitis. Based on adverse outcomes, patients were classified into 4 groups: non-complication (NC; n = 73), recurrent ascites (A; n = 26), EPS (E; n = 10), and death directly related to peritonitis (D; n = 8).

Results

Age at PD catheter removal was significantly higher in D group compared to NC group (62.0 ± 10.6 vs 51.2 ± 11.5 years, p < 0.05). In addition, mean PD duration was significantly longer in E group compared to NC and A groups (130.5 ± 48.1 vs 58.8 ± 42.4 vs 74.8 ± 47.4 months, p < 0.01). Compared to baseline, effluent WBC was significantly decreased in NC group after 72 hours of peritonitis. In addition, serum CRP level was significantly decreased in NC and A groups, whereas it was significantly increased in D group. Multivariate analyses adjusted for age, PD duration, blood and effluent WBC, serum CRP, and micro-organisms revealed that serum CRP level at 72 hours predicted significantly the development of EPS [odds ratio (OR) 1.15, p < 0.05] and peritonitis-related death (OR 1.18, p < 0.01). In addition, PD duration (per 1 month increase: OR 1.03, p < 0.05) and age at PD catheter removal (per 1 year increase: OR 1.11, p < 0.05) were identified as significant determinants of EPS and peritonitis-related death respectively. Only effluent WBC at 72 hours was significantly associated with the development of ascites (OR 1.27, p < 0.05).

Conclusion

Older patients with long PD duration and those with persistently elevated serum CRP levels were likely to develop complications after peritonitis-related technique failure. Our study suggests that serial measurement of CRP may be helpful in predicting the development of complications after PD catheter removal.

Peritoneal dialysis in the US: evaluation of outcomes in contemporary cohorts

Secular trends in dialysis therapy delivery require a frequent re-examination of outcomes in patients on renal replacement modalities. We examined four large cohorts of patients initiating peritoneal dialysis (PD) in 2000-2003 (total of >40 000 patients) to ascertain trends in patient outcomes, technique success, and predictors of both parameters of interest. Age, end-stage renal disease vintage, and diabetes were clear predictors of patient survival. Technique success was higher in patients on automated PD than in patients on continuous ambulatory PD. Center size was a powerful predictor of technique success. We conclude that the current state of PD in the United States is characterized by improving patient outcomes, higher technique success, and a predominance of use of cycler-based therapy. Several opportunities for improving technique success amenable to practice interventions have been identified.

Survival analysis of Korean end-stage renal disease patients according to renal replacement therapy in a single center

This study was to investigate clinical characteristics and any differential trends in survival among renal replacement therapy (hemodialysis [HD], peritoneal dialysis [PD], and kidney transplantation [KT]) in Korean end-stage renal disease (ESRD) population. We tried to analyze retrospectively the survival rate adjusted by risk factors and the relative risk stratified by key risk factors among 447 ESRD patients who began dialysis or had a kidney transplant at Ajou University Hospital from 1994 to 2004. In adjusted Cox survival curves, the KT patients had the best survival rate, and the HD patients had better survival than PD patients. The consistent trends in different subgroups stratified by age and diabetes were as following: 1) The risk of death for PD and HD was not proportional over time, 2) The relative risk of PD was similar or lower than that of HD for the first 12 months, but it became higher at later period. The significant predictors for mortality were age (over 55 yr), presence of diabetes, cerebrovascular accident at ESRD onset, and more than one time of hospitalization caused by malnutrition. Further large-scaled, multicenter-based comparative study is needed in Korean ESRD patients and more meticulous attention is required in high-risk patients.

Increases in peritoneal small solute transport in the first month of peritoneal dialysis predict technique survival

BACKGROUND

Peritoneal transport of small solutes generally increases during the first month of peritoneal dialysis (PD). The aim of this study was to prospectively evaluate the ability of the peritoneal equilibration test (PET), carried out 1 and 4 weeks after the commencement of PD, to predict subsequent technique survival.

METHODS

Fifty consecutive patients commencing PD at the Princess Alexandra Hospital between 1 February 2001 and 31 May 2003 participated in the study. Paired 1 week and 1 month PET data were collated and correlated with subsequent technique survival.

RESULTS

A significant increase was observed in the dialysate : plasma creatinine ratio at 4 h (D/P Cr) between 1 and 4 weeks after the onset of PD (0.55 +/- 0.12 vs 0.66 +/- 0.11, P <0.001). Mean death-censored technique survival was superior in patients who experienced > or =20% rise in D/P Cr during the first month of PD compared with those who did not (2.3 +/- 0.2 vs 1.6 +/- 0.2 years, P <0.05). Using a multivariate Cox proportional hazards model analysis, the significant independent predictors of death-censored technique survival were an increase in D/P Cr of greater than 20% during the first month (adjusted hazard ratio [HR] 0.20, 95% CI 0.05-0.75), the absence of diabetes mellitus, the absence of ischaemic heart disease, body mass index and baseline peritoneal creatinine clearance.

CONCLUSIONS

A 20% or greater rise in D/P Cr during the first month of commencing PD is independently predictive of PD technique survival. Further investigations of the mechanisms underlying this phenomenon are warranted.

Antimicrobial agents for preventing peritonitis in peritoneal dialysis patients

BACKGROUND

Peritoneal dialysis (PD) is used as substitutive treatment of renal function in a large proportion (15-50%) of the end-stage kidney disease (ESRD) population. The major limitation is peritonitis which leads to technique failure, hospitalisation and increased mortality. Oral, nasal, topical antibiotic prophylaxis, exit-site disinfectants and other antimicrobial interventions are used to prevent peritonitis.

OBJECTIVES

The objective of this systematic review of randomised controlled trials (RCTs) was to evaluate what evidence supports the use of different antimicrobial approaches to prevent peritonitis in PD.

SEARCH STRATEGY

The Cochrane CENTRAL Registry (issue 1, 2004), MEDLINE (1966-May 2003), EMBASE (1988-May 2003) and reference lists were searched for RCTs of antimicrobial agents in PD.

SELECTION CRITERIA

Trials of the following agents were included: antibiotics by any route (oral, nasal, topical), exit-site disinfectants (chlorhexidine, povidone iodine, soap and water), vaccines, and ultraviolet germicidal devices.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data on the number of patients with one or more episodes and rates of peritonitis and exit-site/tunnel infection, catheter removal, catheter replacement, technique failure, toxicity of antibiotic treatments, all-cause mortality. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) with 95% confidence intervals (CI).

MAIN RESULTS

Nineteen trials, enrolling 1949 patients met our inclusion criteria. Nasal mupirocin compared with placebo significantly reduced the exit-site and tunnel infection rate (one trial, 2716 patient months, RR 0.58, 95% CI 0.40 to 0.85) but not peritonitis rate (one trial, 2716 patient months, RR 0.84, 95% CI 0.44 to 1.60). Perioperative intravenous antibiotics compared with no treatment significantly reduced the risk of early peritonitis (four trials, 335 patients, RR 0.35, 95% CI 0.15 to 0.80) but not exit site and tunnel infection (three trials, 114 patients, RR 0.32, 95% CI 0.02 to 4.81). No intervention reduced the risk of catheter removal or replacement.

REVIEWERS' CONCLUSIONS

This review demonstrates that nasal mupirocin reduces exit-site/tunnel infection but not peritonitis. Preoperative intravenous prophylaxis reduces early peritonitis but not exit-site/tunnel infection. No other antimicrobial interventions have proven efficacy. Given the large number of patients on PD and the importance of peritonitis, the lack of adequately powered RCTs to inform decision making about strategies to prevent peritonitis is striking.

Hemodialysis and peritoneal dialysis: comparison of adjusted mortality rates according to the duration of dialysis: analysis of The Netherlands Cooperative Study on the Adequacy of Dialysis 2

Various studies indicate that fair comparisons of mortality rates between hemodialysis (HD) patients and peritoneal dialysis (PD) patients are difficult because of differences in patient characteristics, because of nonconstant relative risks of death (RR), and because the survival times of patients who switch treatment modalities can be censored in different ways. The differences in mortality rates between HD and PD patients were investigated in an analysis in which these potential sources of bias were taken into account. The Netherlands Cooperative Study on the Adequacy of Dialysis is a multicenter, prospective, observational, cohort study in which new patients with ESRD are monitored until transplantation or death. A multivariate Cox regression analysis was used to analyze the mortality data according to treatment modality (HD, n = 742; PD, n = 480). No statistically significant differences in adjusted mortality rates between HD and PD patients were observed during the first 2 yr of dialysis. In the years thereafter, increases in mortality rates for PD patients and resulting decreases in RR in favor of HD were observed (e.g., months 24 to 36, adjusted RR, 0.53; 95% confidence interval, 0.31 to 0.91). This tendency was observed especially among patients >/=60 yr of age and was not influenced by the censoring strategy. These results suggest that long-term use of PD, especially among elderly patients, is associated with increases in mortality rates. Further analyses are required to determine the potential role of dialysis adequacy in the observed long-term differences in mortality rates between HD and PD patients and to establish the possible survival benefits for PD patients who switch to HD in time.

Patient and technique survival on peritoneal dialysis in the United States: Evaluation in large incident cohorts

Patient and technique survival on peritoneal dialysis in the United States: Evaluation in large incident cohorts. Secular trends in dialysis require a frequent re-examination of outcomes in patients on renal replacement modalities. We examined three large cohorts of patients initiating peritoneal dialysis (PD) in 1999, 2000, and 2001 (total of > 30,000 patients) to ascertain trends in patient outcomes, technique success, and predictors of both parameters of interest. Trends toward improved patient survival, higher technique success, and increasing use of cycler-based therapy, with more recent calendar years were noted. Age and diabetes were clear predictors of patient survival, but did not appear to influence technique success. Technique success was higher in patients on automated PD (APD) than in patients on continuous ambulatory PD (CAPD), but this difference was mostly concentrated in the first year on therapy. Patients starting PD after a failed allograft had excellent survival. We conclude that the current state of PD in the United States is characterized by improving patient outcomes, higher technique success, and a predominance of use of cycler-based therapy. Several opportunities for improving technique success amenable to practice interventions have been identified. The high success of PD in patients with failed allograft suggests that it is beneficial to utilize this modality more frequently in this patient group than current practice.

Medical decision-making and information needs in end-stage renal disease patients

Health information and decision-making are increasingly important to patients with diverse illnesses. The aim of this study was to examine health information needs and decision-making in individuals with end-stage renal disease (ESRD) and to examine the influence of age and gender. A self-report survey was administered to 197 consecutive ESRD patients receiving renal replacement therapy. Their mean age was 52.8 years; 58.2% were male, 64.3% were on hemodialysis, and 35.7% on peritoneal dialysis. Actual participation levels in decision-making were not necessarily in agreement with the preferred degree of participation. Eighty percent of patients wanted the health care team (HCT) to make their treatment decisions for them, but only 40% of those who preferred autonomous and 30% of those who preferred shared decision making with their HCT reported that this was their actual experience. Consequently, many more patients perceived that their decision-making was made by their HCT than preferred this. No significant gender differences were observed; however, older participants preferred and experienced their HCT make their treatment decisions (P<.05). All patients wanted high levels of information with some differences by gender and age. HCT should strive to ascertain and meet the information needs and treatment decision-making roles preferred by individual patients.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Nutritional status in peritoneal dialysis: studies in body composition, lipoprotein metabolism and peritoneal function

This thesis is based on clinical studies including virtually all patients treated with peritoneal dialysis in Gothenburg during the 1990s. The patients had a fundamentally altered body composition compared to healthy subjects, characterised by a reduction in body cell mass and body fat already at start of dialysis. During PD treatment. a further decrease in body cell mass was observed. Energy stores tended to normalise during the first years of treatment and remained constant thereafter, or declined subsequently. Extracellular water, calculated from the four-compartment model, was increased when patients started PD treatment and increased further, in parallel to the reduction in body cell mass. These alterations were seen in combination with a normal. or slightly reduced, body weight. Standard methods of assessing nutritional status may therefore not be valid in the dialysis population. Prediction equations to estimate total body water, used in measurements of dialysis adequacy, give erroneous results in PD patients, as shown in a study on our PD population. This may have important clinical consequences, especially in wasted patients. Reduced muscle mass is a marker of protein-energy malnutrition, and therefore simple and reliable methods to measure muscle mass are warranted. When lean body mass was calculated from creatinine generation rate and compared to lean body mass estimated from measurements of total body potassium. the agreement between the two methods was low. Furthermore, when repeated measurements of creatinine generation rate were performed, the variation coefficient was unacceptably high. Thus. creatinine generation rate cannot be recommended as a method to evaluate somatic protein status in PD patients. The lipoprotein metabolic derangements are pronounced in PD patients. in which a further increase in cholesterol and cholesterol-rich apoB-containing lipoproteins are added to the already pre-existing renal dyslipidemia. characterised by increased concentration of triglycerides and triglyceride-rich complex lipoproteins. There are indications that dialytic variables may influence this development. When peritoneal function was assessed by the Peritoneal Dialysis Capacity test at start of dialysis, it was observed that peritoneal function reflected patient characteristics and co-morbidity. Patients with systemic disease had enhanced diffusion capacity compared to patients with primary renal disorders. Furthermore, in patients with more severe co-morbidity. peritoneal protein losses were increased. Finally, elderly patients had ultrafiltration conditions that were different from those of younger patients. Peritoneal function remained essentially stable during medium-long term follow up. Body composition features in dialysis patients are similar to those seen in severe disease in general. Thus, it is difficult to separate the effects of malnutrition from the effects of the underlying disease. Specific standards for nutritional status adapted for patients with renal failure are required.

Comparing mortality of elderly patients on hemodialysis versus peritoneal dialysis: a propensity score approach

The objective of this study was to evaluate differences in mortality over the first year of renal replacement therapy (RRT) between elderly patients starting treatment on hemodialysis (HD) versus peritoneal dialysis (PD). For the period of 1991 to mid-1996, this study defined an inception cohort of all patients aged >65 yr with new-onset chronic RRT who were New Jersey Medicare and/or Medicaid beneficiaries in the year before RRT and who had been diagnosed with renal disease more than 1 yr before RRT. Propensity scores were calculated for first treatment assignment from a large number of baseline covariates. Mortality was then compared among patients initially assigned to HD versus PD using multivariate 90-d interval Cox models controlled for propensity scores and center stratification. Peritoneal dialysis starters had a 16% higher rate of death during the first 90 d of RRT compared with HD patients (hazard ratio [HR], 1.16; 95% confidence interval [CI], 0.96 to 1.42)]. Mortality did not differ between day 91 and 180 (HR, 1.03; 95% CI, 0.71 to 1.51). Thereafter, PD starters again died at a higher rate (HR, 1.45; 95% CI, 1.07 to 1.98). These findings were more pronounced among patients with diabetes. Sensitivity analyses using more stringent criteria to ensure that first treatment choice reflected long-term treatment choice confirmed the presence of an association between PD and mortality. In conclusion, compared with HD, peritoneal dialysis appears to be associated with higher mortality among older patients, particularly among those with diabetes, even after controlling for a large number of risk factors for mortality, propensity scores to control for nonrandom treatment assignment, and center stratification.

Peritoneal and hemodialysis: II. Mortality risk associated with initial patient characteristics

BACKGROUND

Patients initiating with peritoneal dialysis (PD) have favorable clinical conditions compared with hemodialysis (HD) patients, which may contribute to the varying results found in studies of mortality across the two therapies.

METHODS

National incidence data of end-stage renal disease patients from 1995 to 1997 were used, excluding the first 90 days of treatment and including all patients who were on either PD or HD on day 91. Patients were then followed for a one-year period. A Cox proportional hazards regression analysis was used, separating diabetics and non-diabetics, and two statistical models were applied. Model 1 included race, gender, age, initial modality, and incidence year as explanatory variables. Model 2 added body mass index (BMI), initial levels of serum albumin, creatinine, and blood urea nitrogen.

RESULTS

Age was most highly associated with mortality, followed by biochemical variables, BMI, gender, and dialysis modality. In diabetics, the hazard ratio (HR) from Model 1 indicated no difference [1.046, 95% confidence limits (CL) 0.989-1.105; P> 0.1, HD was the reference] in mortality between PD and HD, while Model 2 demonstrated that PD patients had a 13.4% (1.134, CL 1.072-1.100, P < 0.0001) higher chance of death. In non-diabetics, hazard ratios (HRs) from Models 1 and 2 indicated that PD patients had a 23.5% (0.765, 0.722-0.812, P < 0.0001) and 11.9% (0.881, 0.30-0.935, P < 0.0001), respectively, lower likelihood of death than HD patients.

CONCLUSION

Our study indicates that the results changed depending on the analytical methods used. We recommend that, due to the unequally distributed clinical conditions of patients at initiation, comparisons of mortality outcomes between dialysis modalities should be made with caution.

Peritoneal and hemodialysis: I. Differences in patient characteristics at initiation

BACKGROUND

Comparisons of mortality outcomes between peritoneal dialysis (PD) and hemodialysis (HD) patients have shown varying results, which may be caused by the unequally distributed clinical conditions of patients at initiation. To address this issue, we evaluated the clinical characteristics of 105,954 patients at the initiation of PD and HD, using the U.S. national incidence data on treated end-stage renal disease from the Medical Evidence Form, 1995 to 1997.

METHODS

A general linear model was used to analyze differences of age, albumin, creatinine, blood urea nitrogen (BUN), and hematocrit; categorical data analysis to evaluate body mass index (BMI), grouped into four categories: < 19, 19-25 (< 25), 25-30 (< 30), and 30+; and logistic regression to assess the likelihood of initiating PD versus HD. Diabetics (DM) were analyzed separately from non-diabetics (NDM). Explanatory variables in the logistic regression included incidence year, race, gender, age, BMI, albumin, creatinine, BUN, and hematocrit. Race included white and black. Age was categorized into four groups: 20-44, 45-64, 65-74, and 75+.

RESULTS

At the initiation of dialysis PD patients were approximately 6 years younger (P < 0.0001) than HD patients. PD patients also had higher (P < 0.0001) albumin (+0.35 g/dL for DM and +0.23 g/dL for NDM) and hematocrit (+1.64% for DM and +1.71% for NDM) levels, and lower (P < 0.04) BUN (-8.75 mg/dL for DM and -5.24 mg/dL for NDM) and creatinine (-0.51 mg/dL for DM and -0.23 mg/dL for NDM) levels than HD patients. Whites had a higher (P < 0.0001) likelihood of starting PD than blacks, and patients with BMI <19 had a lower (P < 0.0001) chance of beginning on PD.

CONCLUSION

PD patients had favorable clinical conditions at the initiation of dialysis, which should be taken into consideration when comparing dialysis outcomes between the two modalities.