Peritoneal Dialysis Reduces the Number of Hospitalization Days in Heart Failure Patients Refractory to Diuretics

♦ Background: Previous small studies have reported favorable results of peritoneal dialysis (PD) in the setting of chronic refractory heart failure (CRHF). We evaluated the impact of PD in a larger cohort of patients with CHRF where end-stage renal disease was excluded.♦ Methods: All patients who received PD therapy for CRHF between January 1995 and December 2010 in two medical centers in France were included in this retrospective study. Baseline characteristics were compared with clinical parameters during the first year after initiation of PD. Mortality, safety, and sustainability of PD were also analyzed.♦ Results: The 126 patients included had a mean age of 72 ± 11 years and an estimated glomerular filtration rate of 33.5 ± 15.1 mL/min/1.73 m2. Mean time on PD was 16 ± 16.6 months. During the first year, patients with a left ventricular ejection fraction (LVEF) of 30% or less experienced improvement in cardiac function (30% ± 10% vs 20% ± 6%, p < 0.0001). We observed a significant reduction in the number of days of hospitalization for acute decompensated heart failure after PD initiation (3.3 ± 2.6 days/patient-month vs 0.3 ± 0.5 days/patient-month, p < 0.0001). One-year mortality was 42%.♦ Conclusions: In CRHF, PD significantly reduces the number of days of hospitalization for acute heart failure. Improved LVEF may have led to the comparatively good 1-year survival in this cohort.     

The consequences of sudden fluid shifts on body composition in critically ill patients

Introduction

Estimation of body composition as fat-free mass (FFM) is subjected to many variations caused by injury and stress conditions in the intensive care unit (ICU). Body cell mass (BCM), the metabolically active part of FFM, is reported to be more specifically correlated to changes in nutritional status. Bedside estimation of BCM could help to provide more valuable markers of nutritional status and may promote understanding of metabolic consequences of energy deficit in the ICU patients. We aimed to quantify BCM, water compartments and FFM by methods usable at the bedside for evaluating the impact of sudden and massive fluid shifts on body composition in ICU patients.

Methods

We conducted a prospective experimental study over an 6 month-period in a 18-bed ICU. Body composition of 31 consecutive hemodynamically stable patients requiring acute renal replacement therapy for fluid overload (ultrafiltration ≥5% body weight) was investigated before and after the hemodialysis session. Intra-(ICW) and extracellular (ECW) water volumes were calculated from the raw values of the low- and high-frequency resistances measured by multi-frequency bioelectrical impedance. BCM was assessed by a calculated method recently developed for ICU patients. FFM was derived from BCM and ECW.

Results

Intradialytic weight loss was 3.8 ± 0.8 kg. Percentage changes of ECW (-7.99 ± 4.60%) and of ICW (-7.63 ± 5.11%) were similar, resulting ECW/ICW ratio constant (1.26 ± 0.20). The fall of FFM (-2.24 ± 1.56 kg, -4.43 ± 2.65%) was less pronounced than the decrease of ECW (P < 0.001) or ICW (P < 0.001). Intradialytic variation of BCM was clinically negligible (-0.38 ± 0.93 kg, -1.56 ± 3.94%) and was significantly less than FFM (P < 0.001).

Conclusions

BCM estimation is less driven by sudden massive fluid shifts than FMM. Assessment of BCM should be preferred to FFM when severe hydration disturbances are present in ICU patients.     

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.     

Low-Polydispersity Glucose Polymers as Osmotic Agents for Peritoneal Dialysis

♦ Background:

Peritoneal dialysis (PD) solutions containing icodextrin as the osmotic agent have advantages during long dwells. The glucose polymers that constitute icodextrin are a heterogeneous mix of molecules with a polydispersity [ratio of weight-average to number-average molecular weight (Mw/Mn)] of approximately 2.6. The present study evaluates whether modifications in the polydispersity and concentration of glucose polymers can improve ultrafiltration (UF) without an associated increase in carbohydrate absorption (CA).

♦ Methods:

Computer simulations using a three-pore model of peritoneal transport during a long dwell in PD patients predict that, in general, compared with 7.5% icodextrin, glucose polymers with a Mw greater than or equal to 7.5 kDa, a polydispersity less than 2.6, and concentrations greater than 7% could achieve higher UF without higher CA. Based on the simulations, we hypothesized that, compared with 7.5% icodextrin, glucose polymers with a Mw of 18 – 19 kDa and a polydispersity of 2.0 at 11% concentration could achieve higher UF without a higher CA. We tested this hypothesis in experimental studies using 8-hour dwells in New Zealand White rabbits. In those studies, UF was measured by complete fluid collection, and CA was measured by subtracting the total carbohydrate in the collected fluid from the carbohydrate initially infused.

♦ Results:

The UF was higher with 11% 19 kDa glucose polymer than with 7.5% icodextrin (mean ± standard deviation: 89 ± 31 mL vs 49 ± 15 mL; p = 0.004) without higher CA (5.2 ± 0.9 g vs 5.0 ± 0.9 g, p = 0.7). Similar results were seen with the 11% 18 kDa glucose polymer, which, compared with 7.5% icodextrin, resulted in higher UF (mean ± standard deviation: 96 ± 18 mL vs 66 ± 17 mL; p < 0.001) without higher CA (4.8 ± 0.7 g vs 5.2 ± 0.6 g, p = 0.2).

♦ Conclusions:

The findings demonstrate that, compared with 7.5% icodextrin solution, long-dwell PD solutions containing 11% glucose polymers with a Mw of 18–19 kDa and a polydispersity of 2.0 can provide higher UF without higher CA.     

Intraperitoneal Fluid Overestimates Hydration Status Assessment by Bioimpedance Spectroscopy

♦ Background: Bioimpedance spectroscopy (BIS) is a valuable tool to assess nutrition and volume status in peritoneal dialysis (PD) patients. However, data about the influence of intraperitoneal fluid on body composition measures are conflicting, and there is no clear consensus about whether the abdomen should be drained before the procedure. We designed a comparison study to detect the influence of intra-abdominal fluid on BIS results.♦ Methods: We performed 73 pairs of BIS measurements in 34 stable PD patients, first with the peritoneum filled with a 1.36% glucose dialysate solution and then after the solution was drained. Patients stayed in the supine position for 10 minutes before the BIS procedure, and the electrodes were not moved between measures. Clinical and demographic data were collected, as were analytic parameters of nutrition and volume status.♦ Results: Fluid overload is overestimated when BIS is performed with a full abdomen (1.82 ± 1.73 L vs 1.64 ± 1.68 L, p = 0.043). We also found a spurious overestimation in extracellular water (16.40 ± 3.21 L vs 16.24 ± 3.16 L, p < 0.001) and in relative overhydration (8.29% ± 6.96% vs 7.14% ± 6.79%, p = 0.017). No differences in intracellular water or parameters of nutrition were found. We observed negative correlations for the extracellular water overestimation with age (r = –0.245, p = 0.037), serum B-type natriuretic peptide (r = –0.366, p = 0.036), body mass index (r = –0.248, p = 0.035), and lean tissue index (r = –0.427, p = 0.001). The difference in extracellular water correlated only with body mass index (r = –0.259, p = 0.039). We also found that, assessed at 50 KHz, whole-body impedance (–4.52 ± 8.37, p = 0.001) and phase angle (–0.08 ± 0.23 degrees, p = 0.002) were both lower when BIS was performed in patients with a full abdomen.♦ Conclusions: Fluid overload is overestimated by BIS when performed in patients with dialysate in the peritoneum. The observed differences are greater in younger, more poorly nourished, or less overhydrated patients. If more precise results are required, we suggest that the abdomen be drained before BIS is performed.     

Body Mass Index and Mortality Risk in Asian Peritoneal Dialysis Patients in Hong Kong—Impact of Diabetes and Cardiovascular Disease Status

♦ Background: Obesity increases mortality in the general population, but improves survival in hemodialysis patients. In peritoneal dialysis (PD) patients, the reported effect is controversial. We investigated the effect of body mass index (BMI) on patient survival in Asian PD patients.♦ Methods: The survival of incident Asian PD patients from 2001 to 2008 in a single center in Hong Kong was analyzed retrospectively. Baseline demographic and clinical data were collected from patient records. Patients who had a total Kt/V below 1.7 or who died within 6 months were excluded. The BMI was categorized using the World Health Organization recommendation for Asian populations.♦ Results: In the 274 study patients [154 men (56%); 138 with diabetes (50.4%); mean age: 63.4 ± 14.6 years; mean BMI: 21.97 ± 3.23 kg/m²; 37 underweight (13.5%); 35 obese (12.8%)], the relative risk (RR) for mortality [adjusted for age, diabetes status, and cardiovascular disease (CVD)] was similar for the normal and overweight groups, but higher for the underweight (RR: 1.909; p = 0.028) and obese groups (RR: 1.799; p = 0.048). The increased mortality in obese patients was more prominent in patients with diabetes (RR: 1.9 vs 1.19 in patients without diabetes; p = 0.074 and 0.76 respectively), and in patients with CVD (RR: 8.895 vs 1.642 in patients without CVD; p = 0.012 and 0.122 respectively).♦ Conclusions: In Asian PD patients, the relationship between BMI and mortality was U-shaped, with higher mortality in the underweight and obese patients. The negative impact of obesity was more prominent in patients with diabetes and CVD.     

Impact of Break-In Period on the Short-Term Outcomes of Patients Started on Peritoneal Dialysis

♦ Objectives: Peritoneal dialysis (PD) is one of the first-line modalities of renal replacement therapy in patients with end-stage renal disease. Guidelines recommended a break-in period of at least 2 weeks before full PD start. However, the optimal duration of the break-in period is still unclear. In the present study, we investigated the effect of various break-in periods on short-term outcomes in patients on PD.♦ Methods: All patients who underwent Tenckhoff catheter implantation and initiated PD in Renji Hospital, Shanghai Jiao Tong University School of Medicine, between 1 January 2001 and 31 December 2010 were included. Patients were grouped according to the duration of their break-in period: 7 days or less (BI_≤7), 8 - 14 days (BI_8-14), and more than 14 days (BI_>14). Kaplan-Meier curves and log-rank tests were used to compare short-term outcomes in the various groups.♦ Results: Our study enrolled 657 patients (44.5% men), of whom 344, 137, and 176 patients were in the respective break-in groups. Compared with BI_>14 patients, BI_≤7 patients had a lower estimated glomerular filtration rate (5.34 ± 1.86 mL/min/1.73 m² vs 6.55 ± 1.71 mL/min/1.73 m², p < 0.001) and lower serum albumin (33.29 ± 5.36 g/L vs 36.64 ± 5.40 g/L, p < 0.001). The incidence of mechanical complications during the first 6 months was significantly higher in BI_≤7 patients than in BI_>14 patients (8.4% vs 1.7%, p = 0.004). However, we observed no significant differences between the three groups with respect to the prevalence of catheter dysfunction requiring surgical intervention (p > 0.05). Logistic regression analysis showed that BI_≤7 [relative risk: 4.322; 95% confidence interval (CI): 1.278 to 14.608; p = 0.019] was an independent predictor of catheter dysfunction, but not of catheter dysfunction requiring surgical intervention (p > 0.05). Catheter dysfunction [hazard ratio (HR): 20.087; 95% CI: 7.326 to 55.074; p < 0.001] and peritonitis (HR: 4.533; 95% CI: 1.748 to 11.751; p = 0.002) were risk factors for technique failure during the first 6 months, but BI_≤7 was not correlated with technique failure.♦ Conclusions: Patients starting PD with a break-in period of less than 1 week might experience a minor increased risk of mechanical complications, but no major effect on technique survival.     

Can EPS Development Be Avoided with Early Interventions? The Potential Role of Tamoxifen—A Single-Center Study

♦ Background: Encapsulating peritoneal sclerosis (EPS) is a severe complication of peritoneal dialysis (PD). Identification of patients at high risk for EPS (“EPS-prone”) and delivery of appropriate interventions might prevent its development. Our aim was to evaluate the clinical characteristics and outcomes of all EPS and EPS-prone patients diagnosed at our PD unit.♦ Methods: For a 30-year period representing our entire PD experience, we retrospectively identified all patients with EPS (diagnosed according to International Society for Peritoneal Dialysis criteria) and all patients defined as EPS-prone because they met at least 2 established criteria (severe peritonitis, PD vintage greater than 3 years, severe hemoperitoneum, overexposure to glucose, and acquired ultrafiltration failure).♦ Results: Of 679 PD patients, we identified 20 with EPS, for an overall prevalence of 2.9%. Mean age at diagnosis was 50.2 ± 16.4 years, with a median PD time of 77.96 months (range: 44.36 - 102.7 months) and a median follow-up of 30.91 months (range: 4.6 - 68.75 months). Of patients with EPS, 10 (50%) received tamoxifen, 10 (50%) received parenteral nutrition, and 2 (10%) underwent adhesiolysis, with 25% mortality related to EPS. Another 14 patients were identified as EPS-prone. Median follow-up was 54.05 months (range: 11.9 - 87.04 months). All received tamoxifen, and 5 (36%) received corticosteroids; none progressed to full EPS. We observed no differences in baseline data between the groups, but the group with EPS had been on PD longer (84 ± 53 months vs 39 ± 20 months, p = 0.002) and had a higher cumulative number of days of peritoneal inflammation from peritonitis (17.2 ± 11.1 days vs 9.8 ± 7.9 days, p = 0.015). Overall mortality was similar in the groups. The incidence of EPS declined during our three decades of experience (5.6%, 3.9%, and 0.3%).♦ Conclusions: Being a serious, life-threatening complication of PD, EPS requires high suspicion to allow for prompt diagnosis and treatment. Early detection of EPS-prone states and delivery of appropriate intervention might prevent EPS development. Tamoxifen seems to be a key strategy in prevention, but caution should be used in interpreting our results. Additional randomized controlled studies are needed.     

Time Course of Peritoneal Function in Automated and Continuous Peritoneal Dialysis

♦ Background and Objectives: In automated peritoneal dialysis (APD), a patient’s peritoneal membrane is more intensively exposed to fresh dialysate than it is in continuous ambulatory peritoneal dialysis (CAPD). Our aim was to study, in incident peritoneal dialysis (PD) patients, the influence of APD—compared with that of CAPD—on peritoneal transport over 4 years.♦ Design, Setting, Participants, and Measurements: Patients were included if at least 2 annual standard permeability analyses (SPAs) performed with 3.86% glucose were available while the patient was using the same modality with which they had started PD (APD or CAPD). Patients were followed until their first modality switch. Differences in the pattern of SPA outcomes over time were tested using repeated-measures models adjusted for age, sex, comorbidity, primary kidney disease, and year of PD start.♦ Results: The 59 CAPD patients enrolled were older than the 47 APD patients enrolled (mean age: 58 ± 14 years vs 49 ± 14 years; p < 0.01), and they had started PD earlier (mean start year: 2000 vs 2002). Over time, no differences in solute (p > 0.19) or fluid transport (p > 0.13) were observed. Similarly, free water transport (p = 0.43) and small-pore transport (p = 0.31) were not different between the modalities. Over time, patients on APD showed a faster decline in effective lymphatic absorption rate (ELAR: p = 0.02) and in transcapillary ultrafiltration (TCUF: p = 0.07, adjusted p = 0.05). Further adjustment did not change the results.♦ Conclusions: Compared with patients starting on CAPD, those starting on APD experienced a faster decline in ELAR and TCUF. Other transport parameters were not different over time between the groups.     

Long-Term Clinical Outcomes of Peritoneal Dialysis Patients: 9-Year Experience of a Single Center from North India

♦ Objective: There is a paucity of published data on the outcome of maintenance peritoneal dialysis (PD) since the initiation of continuous ambulatory PD (CAPD) in India in 1991. The purpose of this study is to report long-term clinical outcomes of PD patients at a single center.♦ Design: Retrospective study.♦ Setting: A government-owned tertiary-care hospital in North India.♦ Patients: Patients who were initiated on CAPD between October 2002 and June 2011, and who survived and/or had more than 6 months’ follow-up on this treatment with last follow-up till December 31, 2011, were studied.♦ Results: A total of 60 patients were included in the analysis. The mean age of the patients was 60.2 ± 9.2 years. The majority (65%) of the patients lived in rural areas. A high proportion (47%) were diabetic and 62% had ≥ 2 comorbidities. Total duration on peritoneal dialysis treatment was 1,773 patient-months (148 patient-years) with a mean duration of 29.6 ± 23 patient-months and median duration of 25 patient-months (range 6 - 110 patient-months). Overall patient and technique survival at 1, 2, 3, 4 and 5 years was 77%, 53%, 25%, 15%, and 10% respectively. Patient survival of diabetics vs non-diabetics at 1, 2, 3, 4, and 5 years was 68% vs 84%, 54% vs 53%, 14% vs 34%, 11% vs 19%, and 11% vs 13%, respectively. The mortality in non-diabetics (16/32) was less than that in diabetic (18/28) patients (p = not significant). The main cause of mortality in these patients was cardiac followed by sepsis. There were 58 episodes of peritonitis. The rate of peritonitis was 1 episode per 30.6 patient-months or 0.39 episodes per patient-year. Furthermore, the total number of episodes of peritonitis and number of episodes of peritonitis per patient were higher in the non-survival group (p < 0.05). The incidence of tuberculosis (TB), herpes zoster (HZ) and hernias was 15%, 10% and 5% respectively.♦ Conclusion: The study reports long-term outcomes of the PD patients, the majority of whom were elderly with a high burden of comorbidities. There was a high proportion of diabetics. The survival of diabetic vs non-diabetic and elderly vs non-elderly PD patients was similar in our study. The mortality in non-diabetics was less than that in diabetic patients. TB and HZ were common causes of morbidity. Peritonitis was associated with mortality in these patients.     

Structured Outpatient Peritoneal Dialysis Catheter Insertion Is Safe and Cost-Saving

♦ Background: Data about outcomes and costs for peritoneal catheter insertion on an outpatient basis are scarce.♦ Methods: Using patient files, all peritoneal dialysis (PD) catheter insertions performed between 2004 and 2009 in a single-center tertiary care institution for adult patients were located. Patient demographics, complications, hospitalizations, survival, and treatment modality changes were recorded. Procedure-related expenses were valued as actual production costs.♦ Results: During the study period, 106 PD catheters were inserted. In 46 cases, the patients were admitted electively for catheter insertion; 19 catheters were placed during admission for other medical reasons; and 41 catheters were placed on an outpatient basis. Among the study patients (54.7 ± 16.0 years of age), 45% were diabetic. Early (<30 days) catheter-related complications occurred in 22% of patients. The incidences of technique failure and any complication within 90 days were 10% and 38% respectively. The occurrence of complications was not statistically significantly different for outpatients and electively admitted patients. Average costs for catheter insertion were higher in electively hospitalized patients than in outpatients (€2320 ± €960 vs €1346 ± €208, p < 0.000).♦ Conclusions: Compared with an inpatient procedure, outpatient insertion of a PD catheter results in similar outcomes at a lower cost.     

Blood Pressure Measurement in Peritoneal Dialysis: Which Method Is Best?

♦ Background: The optimal approach to monitoring blood pressure (BP) in the peritoneal dialysis (PD) population is unclear. Ambulatory BP monitoring reliably predicts prognosis, but can be inconvenient. The accuracy of home BP monitoring in this population is unproven. The automated BpTRU device (BpTRU Medical Devices, Coquitlam, BC, Canada), which provides an average of up to 6 successive in-office BP measurements, has not been studied in this patient group.♦ Methods: We studied 17 patients (average age: 54 ± 12 years; 12 men, 5 women; 94% on automated PD) attending a single center. All patients underwent office, home, BpTRU, and ambulatory BP measurement. The reference standard for analysis was daytime ambulatory BP. Correlation between the referent method and each comparator method was determined (Pearson correlation coefficient), and Bland-Altman scatter plots depicting the differences in the BP measurements were constructed.♦ Results: Mean office BP (126.4 ± 16.9/78.8 ± 11.6 mmHg) and BpTRU BP (123.8 ± 13.7/80.7 ± 11.1 mmHg) closely approximated mean daytime ambulatory BP (129.3 ± 14.8/78.2 ± 7.9 mmHg). Mean home BP (143.8 ± 15.0/89.9 ± 28.1 mmHg) significantly overestimated mean daytime systolic BP by 14.2 mmHg (95% confidence interval: 4.3 mmHg to 24.1 mmHg; p = 0.008). Bland-Altman plots demonstrated poorest agreement between home BP and daytime ambulatory BP. No patient had “white-coat hypertension,” and only 1 patient had false-resistant hypertension. Most patients showed abnormal nocturnal dipping patterns (non-dipping: n = 11; reverse-dipping: n = 5; normal dipping: n = 1).♦ Conclusions: We report a novel finding that BP measurement using the BpTRU device is more accurate than home BP measurement in a PD population. Potential explanations for this observation include poor home BP measurement technique, use of poorly validated home BP measurement devices, or a reduced prevalence of white-coat effect among PD patients. Our study also confirms that, in the PD population, BP measurements vary considerably with patient location, time of day, and measurement technique.     

Peritoneal Morphology After Long-Term Peritoneal Dialysis with Biocompatible Fluid: Recent Clinical Practice in Japan

♦ Background: Morphology changes of the peritoneal membrane after long-term peritoneal dialysis (PD) consist of denudation of peritoneal mesothelial cells, interstitial sclerosis, and hyalinizing vasculopathy. Those changes are considered to be the result of uremia and bioincompatible effects of conventional acidic lactate-buffered dialysate with glucose degradation products (GDPs). In the last decade, biocompatible dialysate with neutral pH and low GDPs has become widely used. Clinical practice has been modified in Japan, especially for anuric patients, and now includes the use of hybrid therapy. The impact on peritoneal morphology has not been well reported.♦ Objective: The aim of the present study was to investigate the long-term effect on peritoneal morphology and function of biocompatible fluid use and current clinical practice in Japan, including hybrid dialysis therapy.♦ Methods: We evaluated peritoneal biopsy specimens from patients who had undergone PD for more than 3 years. We used the average peritoneal thickness (APT) of the submesothelial compact zone as a marker of interstitial sclerosis and the lumen/vessel diameter ratio (L/V ratio) at postcapillary venules as a marker of hyalinizing vasculopathy. Demography and other data for the patients, including dialysate-to-plasma (D/P) ratio of creatinine, were obtained at baseline and every 6 months by peritoneal equilibration test.♦ Results: Between 2002 and 2009, 110 patients started PD therapy with biocompatible dialysate at Tokyo University Hospital. Among them, 11 patients (8 men, 3 women; age: 54.2 ± 11.8 years; 1 with diabetes mellitus) were enrolled into this morphology study. The mean duration of PD in this group was 61 ± 11.3 months, and the mean time to peritoneal biopsy was 58 ± 15.1 months. The median APT was 180 μm (96 – 1424 μm), and the median L/V ratio was 0.66 (0.46 – 0.74). No obvious correlations between APT, L/V ratio, and PD duration were detected. The D/P creatinine of the 11 patients was maintained at a favorably low value, comparable with that of the other 99 patients.♦ Conclusions: Peritoneal dialysis therapy using biocompatible dialysate in conjunction with modification of clinical practice may minimize the progression of peritoneal interstitial sclerosis and hyalinizing vasculopathy, preserving favorable peritoneal function for more than 3 years.     

Lifetime Costs for Peritoneal Dialysis and Hemodialysis in Patients in Taiwan

♦ Background: This study compared the lifetime costs for peritoneal dialysis (PD) and hemodialysis (HD) patients in Taiwan.♦ Methods: Using the National Health Insurance (NHI) database of all end-stage renal disease patients on maintenance dialysis registered from July 1997 to December 2005, we matched eligible PD patients with eligible HD patients on age, sex, and diabetes status. The matched patients were followed until 31 December 2006. Patients were excluded if they were less than 18 years of age, had been diagnosed with cancer before dialysis, or had been dialyzed at centers or clinics other than hospitals. Outcomes—including life expectancy, total lifetime costs, and costs per life-year paid by the NHI—were estimated and compared.♦ Results: The 3136 pairs of matched PD and HD patients had a mean age of 53.2 ± 15.4 years. The total lifetime cost for PD patients (US$139 360 ± US$8 336) was significantly lower than that for HD patients (US$185 235 ± US$9 623, p < 0.001). Except for patients with diabetes (who had a short life expectancy), the total lifetime cost was significantly lower for PD patients than for HD patients regardless of sex and age (p < 0.01).♦ Conclusion: In Taiwan, the total lifetime costs paid by the NHI were lower for PD than for HD patients.     

The Effect of Fluid Overload on Clinical Outcome in Southern Chinese Patients Undergoing Continuous Ambulatory Peritoneal Dialysis

♦ Background:

Fluid overload is frequently present in dialysis patients and one of the important predictors of patient outcome. This study aimed to investigate the influence of fluid overload on all-cause mortality and technique failure in Southern Chinese continuous ambulatory peritoneal dialysis (CAPD) patients.

♦ Methods:

This was a post hoc study from a cross-sectional survey originally designed to investigate the prevalence and associated risk factors of fluid overload defined by bioimpedance analysis (BIA) in CAPD patients from January 1, 2008, to December 31, 2009. All 307 CAPD patients completing the original study were followed up until December 31, 2012.

♦ Results:

With a median follow-up period of 38.4 (19.2 – 47.9) months, 52 patients died. Patients with fluid overload (defined by extracellular water/total body water [ECW/TBW] ≥ 0.40) had a significantly higher peritonitis rate (0.016 vs 0.011 events/month exposure, p = 0.018) and cerebrovascular event rate (3.9 vs 1.1 events/100 patient years, p = 0.024) than the normal hydrated patients. Moreover, the results showed a significant rising of all-cause mortality (log-rank test = 5.59, p = 0.018), and a trend of increasing cardiovascular disease (CVD) mortality (log-rank test = 2.90, p = 0.089) and technique failure (log-rank test = 3.78, p = 0.052) in the patients with fluid overload. Fluid overload independently predicted all-cause mortality (hazard ratio [HR] = 12.98, 95%, confidence interval [CI] = 1.06 – 168.23, p = 0.042) and technique failure (HR = 13.56, 95% CI = 2.53 – 78.69, p = 0.007) in CAPD patients after adjustment for confounders.

♦ Conclusions:

Fluid overload defined by BIA was an independent predictor for all-cause mortality and technique failure in CAPD patients. Continuous ambulatory peritoneal dialysis patients with fluid overload had a higher peritonitis rate, cardiovascular event rate, and poorer clinical outcome than those patients with normal hydration.     

Persistent Sterile Peritoneal Inflammation After Catheter Removal for Refractory Bacterial Peritonitis Predicts Full-Blown Encapsulating Peritoneal Sclerosis

♦ Background: Encapsulating peritoneal sclerosis (EPS) is the most serious complication of peritoneal dialysis, having high morbidity and mortality. To improve outcomes, early diagnosis is needed to direct treatment during the early inflammatory phase. However, in the early inflammatory phase, clinical features are nonspecific, and no reliable diagnostic criteria have been established. Because bacterial peritonitis and termination of dialysis are two important risk factors triggering the progression of EPS, patients with refractory bacterial peritonitis necessitating dialysis catheter removal are at particularly high risk of developing EPS. Many of these patients might indeed experience non-resolving sterile peritonitis (probably the inflammatory phase of EPS) before progression to full-blown disease (that is, the presence of intestinal obstruction). We undertook a retrospective study to compare, in this particular situation, the clinical characteristics of patients with or without sterile peritoneal inflammation, assessing their clinical outcomes in terms of short-term mortality and the chance of developing full-blown EPS.♦ Methods: Our retrospective review included 62 patients whose dialysis catheter was removed because of refractory peritonitis between January 2005 and December 2010.♦ Results: Of the 62 patients identified, 39 (63%) had persistent sterile peritoneal inflammation (“high-risk” group, n = 39), and 23 (37%) had resolution of inflammation without significant intra-abdominal collection after catheter withdrawal (“control” group, n = 23). Compared with the control group, the high-risk group had a significantly longer PD duration (71.6 ± 43.3 months vs 42.3 ± 29.9 months, p = 0.003), a higher dialysate-to-plasma ratio (D/P) of creatinine (0.768 ± 0.141 vs 0.616 ± 0.091, p = 0.004), and a higher computed tomography score for EPS (7.69 ± 2.98 vs 1.00 ± 1.00, p < 0.001). During the 6-month study period, the high-risk group had a higher chance of developing full-blown EPS (31% vs 0%, p = 0.002) and a higher 6-month all-cause mortality (36% vs 4.3%, p = 0.004).♦ Conclusions: Persistent sterile peritoneal inflammation was common after dialysis catheter removal for refractory bacterial peritonitis, and the patients with such inflammation were at high risk of progression to full-blown EPS.     

Can Dialysis Patients Be Accurately Identified Using Healthcare Claims Data?

♦ Background: While health insurance claims data are often used to estimate the costs of renal replacement therapy in patients with end-stage renal disease (ESRD), the accuracy of methods used to identify patients receiving dialysis — especially peritoneal dialysis (PD) and hemodialysis (HD) — in these data is unknown.♦ Methods: The study population consisted of all persons aged 18 - 63 years in a large US integrated health plan with ESRD and dialysis-related billing codes (i.e., diagnosis, procedures) on healthcare encounters between January 1, 2005, and December 31, 2008. Using billing codes for all healthcare encounters within 30 days of each patient’s first dialysis-related claim (“index encounter”), we attempted to designate each study subject as either a “PD patient” or “HD patient.” Using alternative windows of ± 30 days, ± 90 days, and ± 180 days around the index encounter, we reviewed patients’ medical records to determine the dialysis modality actually received. We calculated the positive predictive value (PPV) for each dialysis-related billing code, using information in patients’ medical records as the “gold standard.”♦ Results: We identified a total of 233 patients with evidence of ESRD and receipt of dialysis in healthcare claims data. Based on examination of billing codes, 43 and 173 study subjects were designated PD patients and HD patients, respectively (14 patients had evidence of PD and HD, and modality could not be ascertained for 31 patients). The PPV of codes used to identify PD patients was low based on a ± 30-day medical record review window (34.9%), and increased with use of ± 90-day and ± 180-day windows (both 67.4%). The PPV for codes used to identify HD patients was uniformly high — 86.7% based on ± 30-day review, 90.8% based on ± 90-day review, and 93.1% based on ± 180-day review.♦ Conclusions: While HD patients could be accurately identified using billing codes in healthcare claims data, case identification was much more problematic for patients receiving PD.     

Peritoneal Ultrafiltration in Refractory Heart Failure: A Cohort Study

♦ Introduction: Acutely decompensated heart failure (HF) in patients with diuretic resistance is often treated with extracorporeal ultrafiltration. Peritoneal ultrafiltration (PUF) has been proposed for the long-term management of severe HF after resolution of the acute episode. The aim of the present study was to evaluate the use of PUF in the treatment of chronic refractory HF in patients without end-stage renal disease.♦ Methods: This multicenter (10 nephrology departments throughout Italy) retrospective observational study included patients with severe HF refractory to maximized drug treatment. The patients were proposed for PUF because they had experienced at least 3 hospital admissions in the preceding year for acutely decompensated HF requiring extracorporeal ultrafiltration.♦ Results: Of the 48 study patients (39 men, 9 women; mean age 74 ± 9 years), 30 received 1 nocturnal icodextrin exchange, 5 required 2 daily exchanges, and 13 received 2 - 4 sessions per week of automated peritoneal dialysis. During the first year, renal function remained stable (initial: 20.8 ± 10.0 mL/min/1.73 m²; end: 22.0 ± 13.6 mL/min/1.73 m²), while pulmonary artery systolic pressure declined to 40 ± 6.09 mmHg from 45.5 ± 9.18 mmHg (p = 0.03), with a significant concomitant improvement in New York Heart Association functional status. Hospitalizations decreased to 11 ± 17 days/patient-year from 43 ± 33 days/patient-year before the start of PUF (p < 0.001). The incidence of peritonitis was 1 episode in 45 patient-months. Patient survival was 85% at 1 year and 56% at 2 years.♦ Conclusions: This study confirms the satisfactory results of using PUF for chronic HF in elderly patients.     

The Role of Monitoring Gentamicin Levels in Patients with Gram-Negative Peritoneal Dialysis-Associated Peritonitis

♦ Background: There is limited available evidence regarding the role of monitoring serum gentamicin concentrations in peritoneal dialysis (PD) patients receiving this antimicrobial agent in gram-negative PD-associated peritonitis.♦ Methods: Using data collected in all patients receiving PD at a single center who experienced a gram-negative peritonitis episode between 1 January 2005 and 31 December 2011, we investigated the relationship between measured serum gentamicin levels on day 2 following initial empiric antibiotic therapy and subsequent clinical outcomes of confirmed gram-negative peritonitis.♦ Results: Serum gentamicin levels were performed on day 2 in 51 (77%) of 66 first gram-negative peritonitis episodes. Average serum gentamicin levels on day 2 were 1.83 ± 0.84 mg/L with levels exceeding 2 mg/L in 22 (43%) cases. The overall cure rate was 64%. No cases of ototoxicity were observed. Day-2 gentamicin levels were not significantly different between patients who did and did not have a complication or cure. Using multivariable logistic regression analysis, failure to cure peritonitis was not associated with either day-2 gentamicin level (adjusted odds ratio (OR) 0.96, 95% confidence interval (CI) 0.25 - 3.73) or continuation of gentamicin therapy beyond day 2 (OR 0.28, 0.02 - 3.56). The only exception was polymicrobial peritonitis, where day-2 gentamicin levels were significantly higher in episodes that were cured (2.06 ± 0.41 vs 1.29 ± 0.71, p = 0.01). In 17 (26%) patients receiving extended gentamicin therapy, day-5 gentamicin levels were not significantly related to peritonitis cure.♦ Conclusion: Day-2 gentamicin levels did not predict gentamicin-related harm or efficacy during short-course gentamicin therapy for gram-negative PD-related peritonitis, except in cases of polymicrobial peritonitis, where higher levels were associated with cure.     

Effect of Body Mass Index on Outcomes of Peritoneal Dialysis Patients in India

♦ Objectives: We studied the effect of body mass index (BMI) at peritoneal dialysis (PD) initiation on patient and technique survival and on peritonitis during follow-up.♦ Methods: We followed 328 incident patients on PD (176 with diabetes; 242 men; mean age: 52.6 ± 12.6 years; mean BMI: 21.9 ± 3.8 kg/m²) for 20.0 ± 14.3 months. Patients were categorized into four BMI groups: obese, ≥25 kg/m²; overweight, 23 - 24.9 kg/m²; normal, 18.5 - 22.9 kg/m² (reference category); and underweight, <18.5 kg/m². The outcomes of interest were compared between the groups.♦ Results: Of the 328 patients, 47 (14.3%) were underweight, 171 (52.1%) were normal weight, 53 (16.2%) were overweight, and 57 (17.4%) were obese at commencement of PD therapy. The crude hazard ratio (HR) for mortality (p = 0.004) and the HR adjusted for age, subjective global assessment, comorbidities, albumin, diabetes, and residual glomerular filtration rate (p = 0.02) were both significantly greater in the underweight group than in the normal-weight group. In comparison with the reference category, the HR for mortality was significantly greater for underweight PD patients with diabetes [2.7; 95% confidence interval (CI): 1.5 to 5.0; p = 0.002], but similar for all BMI categories of nondiabetic PD patients.Median patient survival was statistically inferior in underweight patients than in patients having a normal BMI. Median patient survival in underweight, normal, overweight, and obese patients was, respectively, 26 patient-months (95% CI: 20.9 to 31.0 patient-months), 50 patient-months (95% CI: 33.6 to 66.4 patient-months), 57.7 patient-months (95% CI: 33.2 to 82.2 patient-months), and 49 patient-months (95% CI: 18.4 to 79.6 patient-months; p = 0.015). Death-censored technique survival was statistically similar in all BMI categories. In comparison with the reference category, the odds ratio for peritonitis occurrence was 1.8 (95% CI: 0.9 to 3.4; p = 0.086) for underweight patients; 1.7 (95% CI: 0.9 to 3.2; p = 0.091) for overweight patients; and 3.4 (95% CI: 1.8 to 6.4; p < 0.001) for obese patients.♦ Conclusions: In our PD patients, mean BMI was within the normal range. The HR for mortality was significantly greater for underweight diabetic PD patients than for patients in the reference category. Death-censored technique survival was similar in all BMI categories. Obese patients had a greater risk of peritonitis.