Non-valvular atrial fibrillation in patients on peritoneal dialysis, prevalence, treatment and professionals involved

Atrial fibrillation is the most frequent chronic arrhythmia in patients with chronic kidney disease. Oral anticoagulation with vitamin K antagonists and now direct oral anticoagulants have been and are the fundamental pillars for the prevention of thromboembolic events. However, there are no randomized clinical trials on the risk-benefit profile of oral anticoagulation in patients with chronic kidney disease stage 5 on peritoneal dialysis and there is little evidence in the literature in this population. The objective of our study was to know the prevalence, treatment and professionals involved in the management of atrial fibrillation in peritoneal dialysis patients. For this purpose, we performed a descriptive analysis through a survey sent to different peritoneal dialysis units in Spain. A total of 1,403 patients on peritoneal dialysis were included in the study, of whom 186 (13.2%) had non-valvular atrial fibrillation. In addition, the assessment of the scores of thromboembolic and bleeding risks for the indication of oral anticoagulation was mainly carried out by the cardiologist (60% of the units), as well as its prescription (cardiologist 47% or in consensus with the nephrologist 43%). In summary, patients on peritoneal dialysis have a remarkable prevalence of non-valvular atrial fibrillation. Patients frequently receive oral anticoagulation with vitamin K antagonists, as well as direct oral anticoagulants. The data obtained regarding the scores used for the assessment of thromboembolic and bleeding risk, treatment and involvement by Nephrology indicates that there is a need for training and involvement of the nephrologist in this pathology.

COVID-19 incidence and outcomes in a home dialysis unit in Madrid (Spain) at the height of the pandemic

INTRODUCTION

The 2019 coronavirus (COVID-19) is a viral infection caused by a new coronavirus that is affecting the entire world. There have been studies of patients on in-center hemodialysis (HD), but home dialysis population data are scarce. Our objective is to study the incidence and course of COVID-19 in a home dialysis unit (HDU) at the height of the pandemic.

METHODS

an observational, retrospective study enrolling all patients diagnosed with COVID-19 from the HDU of Hospital Universitario La Paz [La Paz University Hospital] (Madrid, Spain) between March 10 and May 15, 2020. We collected clinical data from the HDU (57 patients on peritoneal dialysis [PD] and 22 patients on home hemodialysis [HHD]) and compared the clinical characteristics and course of patients with and without COVID-19 infection.

RESULTS

twelve patients were diagnosed with COVID-19 (9 PD; 3 HHD). There were no statistically significant differences in terms of clinical characteristics between patients with COVID-19 and the rest of the unit. The mean age was 62 ± 18.5 years; most were men (75%). All patients but one required hospitalization. Ten patients (83%) were discharged following a mean of 16.4 ± 9.7 days of hospitalization. Two patients were diagnosed while hospitalised for other conditions, and these were the only patients who died. Those who died were older than those who survived.

CONCLUSION

The incidence of COVID-19 in our HDU in Madrid at the height of the pandemic was high, especially in patients on PD. No potential benefit for preventing the infection in patients on home dialysis was observed. Advanced age and nosocomial transmission were the main factors linked to a worse prognosis.

[COVID-19 incidence and outcomes in a home dialysis unit in Madrid (Spain) at the height of the pandemic]

Introducción

La enfermedad por coronavirus 2019 (COVID-19) es una infección viral causada por un nuevo coronavirus que está afectando a todo el mundo. Hay estudios previos de pacientes en hemodiálisis en centro, pero hay pocos datos sobre población en diálisis domiciliaria. Nuestro objetivo es estudiar la incidencia y evolución de la COVID-19 en una unidad de diálisis domiciliaria (UDD) durante el pico de la pandemia.

Métodos

Estudio observacional y retrospectivo que incluye todos los pacientes diagnosticados de COVID-19 de la UDD del Hospital Universitario La Paz (Madrid, España) entre el 10 de marzo y el 15 de mayo de 2020. Se recogieron los datos clínicos de la UDD (57 pacientes en diálisis peritoneal y 22 pacientes en hemodiálisis domiciliaria) y comparamos las características clínicas y la evolución de los pacientes con o sin infección por COVID-19.

Resultados

Doce pacientes fueron diagnosticados de COVID-19 (9 diálisis peritoneal, 3 hemodiálisis domiciliaria). No hubo diferencias estadísticamente significativas entre las características clínicas de los pacientes con COVID-19 y el resto de la unidad. La edad media fue 62 ± 18,5 años; la mayoría eran varones (75%). Todos los pacientes menos uno necesitaron hospitalización. Diez pacientes (83%) fueron dados de alta tras una media de 16,4 ± 9,7 días de hospitalización. Dos pacientes fueron diagnosticados durante su hospitalización por otro motivo y fueron los únicos que fallecieron. Los fallecidos eran de mayor edad que los supervivientes.

Conclusión

La incidencia de COVID-19 en nuestra UDD en Madrid durante el pico de la pandemia fue alto, especialmente en los pacientes en diálisis peritoneal, sin observarse un potencial beneficio para prevenir la infección en los pacientes en diálisis domiciliaria. La edad avanzada y la transmisión nosocomial fueron los principales factores relacionados con peor pronóstico.

Risk Factors Responsible for Ultrafiltration Failure in Early Stages of Peritoneal Dialysis

Objective

To define risk factors for ultrafiltration failure (UFF) during early stages of peritoneal dialysis (PD).

Design

Retrospective analysis of a group of patients whose peritoneal function was prospectively followed.

Setting

A tertiary-care public university hospital.

Patients

Nineteen of 90 long-term PD patients required a peritoneal resting period to recover UF capacity: 8 had this requirement before the third year on PD (early, EUFF group) and 11 had a late requirement (LUFF group). The remaining 71 patients, those with stable peritoneal function over time, constituted the control group.

Main Outcome Measures

Peritoneal UF capacity under standard conditions (monthly) and small solute peritoneal transport (yearly).

Results

None of the conditions appearing at the start of PD or during the observation period could be definitely identified as the cause of UFF. There were no differences in characteristics between the EUFF group and the other two groups, except for the higher prevalence of diabetes in the EUFF group. Residual renal function (RRF) declined in all three groups during the first 2 years, with rapid loss during the third year in the EUFF group. This rapid loss in RRF was coincident with UFF. Peritoneal solute and water transport at baseline was similar in the three groups. After 2 years on PD, individuals in the EUFF group showed a significantly lower UF and higher creatinine mass transfer coefficient values than those in the LUFF group. Diabetic patients in the control group showed remarkable stability in UF capacity over time. During the second year on PD, requirement for increases in dialysate glucose concentration was 3.4 ± 0.5% in the LUFF group, but as high as 25.5 ± 24.2% in the EUFF group. The accumulated days of active peritonitis (APID, days with cloudy effluent) were similar for the three groups after 1, 2, and 3 years on PD. Interestingly, diabetic patients in the control group showed an APID index significantly lower than the overall EUFF group. Diabetics in the control group also had significantly lower APID versus nondiabetics in the control group ( p = 0.016).

Conclusions

Our findings suggest that certain patients develop early UFF type I. Diabetic state and a higher glucose requirement to obtain adequate UF suggest that glucose on both sides of the peritoneal membrane could be responsible. The mechanisms for this higher requirement remain to be elucidated. The identification of a larger cohort of these early UFF patients should lead to a better exploration of the primary pathogenic mechanisms.

Increased Severity of Escherichia Coli Peritonitis in Peritoneal Dialysis Patients Independent of Changes in in Vitro Antimicrobial Susceptibility Testing

Objective

Despite improvements in peritoneal dialysis (PD) technique, peritonitis continues to be one of the most frequent complications of PD. Nonresolving peritonitis remains a risk for severe anatomical peritoneal changes that may limit the viability of the membrane for dialysis purposes. We have observed remarkably poor outcome of peritonitis caused by Escherichia coli in the past 6 years. With its very low response rate to broad-spectrum antibiotics, the increased severity of E. coli peritonitis deteriorates peritoneal function and affects patient outcome.

Design

Retrospective study.

Setting

Two large PD units in two university hospitals.

Patients and Methods

The total number of patients reviewed was 456. The records of 49 E. coli peritonitis episodes were studied. The observation period started in 1980 and ended in March 2001. Sixteen males and 19 females were included. Severity was defined in terms of days of peritoneal inflammation, lack of response to a potentially useful antibiotic, requirement for catheter removal, and/or laparotomy. Study cases (study group) were those episodes appearing after 1996 (when the first severe cases appeared) and historic controls were episodes occurring before1996.

Results

In the study group, 18 peritonitis episodes developed in 15 patients. In the control group, 31 peritonitis episodes developed in 20 patients. There were no significant differences in clinical presentation; however, the outcome was significantly poorer for the later period. A severe outcome occurred in 50% of study versus 10% of control patients. In fact, 68% of the episodes registered before 1996 were cured in 3 days or less. Concurring with this trend, the numbers of surgical interventions and catheter removals were also higher in the study group. Strikingly, E. coli did not show changes in in vitro susceptibility testing to antibiotics, although the in vivo response was much worse.

Conclusions

We describe a change in the virulence of E. coli peritonitis episodes over the past 5 years leading to a high percentage of treatment failure, which does not depend on antibiotic sensitivity and seems to be dependent on changes in host response mechanisms.

Increased Response to Subcutaneous Erythropoietin on Type I Diabetic Patients on Capd: Is There a Synergistic Effect with Insulin?

Objective

To evaluate the effect of subcutaneous erythropoietin (SC EPO) on the treatment of anemia in diabetic and nondiabetic continuous ambulatory peritoneal dialysis (CAPD) patients.

Design

A resistance index was designed for measuring the relative EPO response, dividing EPO dose (U/kg/ week) by the hemoglobin (Hb) increment with respect to the basallevel.

Patients

Eleven nonselected type I diabetic patients using subcutaneous insulin compared with 16 nondiabetic controls, all on CAPD therapy.

Results

The two groups showed similar mean baseline hemoglobin levels (7.4 D- l and 7.7 non-D, g/dL). There was a statistically significant lower resistance index for diabetics (13.8±9.7 U/kg/g Hb increment) compared to nondiabetic (55.8±128, p < 0.001). Multivariate analysis confirmed an independent association between diabetes and resistance index. The response to EPO was slightly better among those diabetic patients with lower levels of serum parathyroid hormone (iPTH) (PTH-resistance index, correlation coefficient, r = 0.7, p < 0.05). No other differences, apart from the use of subcutaneous insulin, were found between diabetics and controls. Although diabetic patients had an increased response to EPO, they had no more frequent side effects than nondiabetics.

Conclusions

According to our results, we suggest that factors related to insulin-dependent diabetes seem to be involved in a favorable response to SC EPO. Hyperinsulinemia derived from subcutaneous use of insulin might act as a comitogen with the induced increments of serum erythropoietin.

Ultrafiltration and Small Solute Transport at Initiation of PD: Questioning the Paradigm of Peritoneal Function

Background

Human peritoneal function on commencing peritoneal dialysis (PD) is not yet adequately understood. The objective of this study was to determine peritoneal functional patterns on commencing PD.

Methods

367 end-stage renal disease (ESRD) patients on PD for the first time were studied between their initial second to sixth weeks on PD. Urea and creatinine mass transfer area coefficients (MTAC) and standardized ultrafiltration (UF) capacity were determined.

Results

Mean parametric values were MTAC urea 22.9 ± 7.04 mL/min, MTAC creatinine 10.31 ± 4.68 mL/min, and UF 896 ± 344 mL. Gender, patient size, and diabetes or kidney disease did not affect these parameters. The relationship between values of MTAC creatinine and UF reached statistical significance, although with a low value for Pearson's coefficient ( r=–0.30, p = 0.001). Age showed a significant inverse linear correlation with UF capacity ( r = –0.15, p = 0.003) and MTAC urea ( r = –0.11, p < 0.05). Logistic regression analysis demonstrated that UF below 400 mL was independently related to a high MTAC creatinine and older age. Diabetes was least frequent in patients with the lowest UF. However, in the analysis of MTAC creatinine quintiles, UF values did not follow the expected inverse pattern. The lack of differences in UF between the second and third to fourth MTAC creatinine quintiles is remarkable; MTAC creatinine ranged from 6.71 to 13.54.

Conclusions

The functional characteristics of human peritoneum varied markedly and there was a less intense than expected relationship between solute and water transports. This mild inverse relationship is intriguing and suggestive of the necessity of redefining some basic concepts. Age was associated with a lower peritoneal UF capacity, in part independently of small solute transport.

Diverticular Disease and Treatment with Gastric Acid Inhibitors do not Predispose to Peritonitis of Enteric Origin in Peritoneal Dialysis Patients

Objective

Enteric peritonitis (EP) is an infrequent complication of peritoneal dialysis (PD), with severe consequences for peritoneal membrane viability and patient outcome. Factors such as diverticular disease and gastric acid inhibitors have been implicated in its appearance. We investigated several risk factors, including those mentioned below, that can influence the development of EP.

Design

Retrospective cross-sectional study.

Setting

Tertiary-care public university hospital.

Patients

Fifty-seven PD patients treated in our PD unit during August 1998.

Main Outcome Measures

A barium enema was performed on 50 of the 57 patients (the remaining 7 patients refused it) in order to exclude the presence of diverticulosis. All episodes of peritonitis occurring in those patients, including EP, were registered. Enteric peritonitis was defined as that caused by gram-positive, gram-negative, or fungus micro-organisms that colonized the intestinal tract, excluding episodes secondary to genitourinary tract or peritoneal catheter exit-site infections.

Results

Twenty-four patients showed diverticular disease in the barium enema, but only 5 of them (21%) had any EP episode. Five of the 26 patients with no diverticula (19%) had EP. Fifty-five episodes of peritonitis were reported in 21 patients; 15 episodes of EP (27.3% of all) developed in 11 patients. Seven of the 11 patients (64%) required peritoneal catheter removal and 3 of them (27%) finally were transferred to hemodialysis due to consequences of the EP episode. Logistic regression analysis did not find any of the independent variables analyzed (age, sex, time on PD, type of PD, peritoneal transport parameters, presence of polycystic kidney disease, constipation or diverticulosis, or treatment with gastric acid inhibitors, or phosphate-binding agents) to be risk factors for developing EP.

Conclusions

Neither diverticulosis nor treatment with gastric acid inhibitors seem to be risk factors for developing peritonitis of enteric origin in PD patients. This type of peritonitis has to be promptly identified and treated in order to diminish the high frequency of peritoneal catheter removal and PD dropout due to such episodes.

Erythropoietin Treatment Decreases Cardiovascular Morbidity and Mortality in Capd Patients

Objective

To analyze the effects of recombinant human erythropoietin (rHuEPO) therapy on cardiovascular (CV) morbidity and mortality among continuous ambulatory peritoneal dialysis (CAPD) patients.

Design

Retrospective comparative study.

Setting

CAPD unit in a university hospital.

Patients

Forty-two patients on rHuEPO treatment for at least one year were compared with an rHuEPO nonuser group of 113 patients. Subcutaneous rHuEPO doses were adjusted to a hemoglobin objective level of 10.5 -13.5 g/ dL. Fifty-seven patients were considered as high cardiovascular risk (HCVR), 17 in the rHuEPO group and 40 in the rHuEPO nonuser group. Ninety-eight patients were classified as low cardiovascular risk (LCVR), 25 of whom were in the rHuEPO group.

Results

The incidence of cardiovascular morbidity was more frequent in the rHuEPO nonuser than in the rHuEPO user group (40% vs 22%) and in HCVR than in LCVR patients (59.6% vs 20.4%). By multiple logistic regression analysis, the best model to explain the development of cardiovascular morbidity comprises rHuEPO treatment, CV risk, and age. In the rHuEPO user group, HCVR and LCVR patients did not show significant differences in survival, while in the rHuEPO nonuser group, HCVR patients had a lower survival rate than LCVR patients (p = 0.0003). Cox proportional hazards model revealed that LCVR patients had an excellent prognosis compared with HCVR patients in the rHuEPO nonuser group, but this difference disappeared in the rHuEPO user group.

Conclusion

These data show a beneficial effect of rHuEPO treatment on cardiovascular morbidity and mortality in CAPD patients, evidenced by the elimination of the correlation between prior cardiovascular risk and subsequent mortality.

Risk Factors for Abdominal Wall Complications in Peritoneal Dialysis Patients

← Background

Patients treated with peritoneal dialysis (PD) have increased intra-abdominal pressure and a high prevalence of abdominal wall complications.

← Objective

The purpose of this study was to determine the incidence of hernias and peritoneal leaks in our PD patients and to investigate their potential risk factors.

← Patients

We studied 142 unselected patients treated with PD during the past 5 years, including those that were already on PD and those that started PD during this period. Mean age was 54 years and mean follow-up on PD was 39 months. 72 patients had been treated with only continuous ambulatory PD (CAPD), 8 with automated PD (APD), and 62 with both modalities.

← Results

53 patients (37%) developed hernia and/or leak. A total of 39 hernias and 63 leaks were registered. The overall rates were 0.08 hernias/patient/year and 0.13 leaks/patient/year, 17 patients had both abdominal complications. Hernia was most frequently located in the umbilical region, and the most frequent site of leakage was the pericatheter area. Both complications appeared more frequently during the CAPD period (87% of hernias, 81% of leaks). The rate of hernias was higher in patients treated only with CAPD than in those that used only cyclers [0.08 vs 0.01 hernias/patient/year, not significant (NS)]. No patient treated only with APD had peritoneal leak; 25% (18/72) of patients treated with CAPD developed this complication ( p = 0.18, NS). Dialysate exchange volumes ranged from 2000 to 2800 mL. 25 (66%) patients required surgical repair of the hernia, with recurrence in 7 patients (28%). 27 (84%) patients with leaks were initially treated with transitory temporary transfer to hemodialysis, low volume APD, or intermittent PD for 4 weeks. The leak recurred in half of the cases and surgical repair was necessary in 12 cases. The development of hernia and/or leak did not correlate with gender, diabetes, duration of follow-up, type of PD, history of abdominal surgery, or with the largest peritoneal exchange volume used. Polycystic kidney disease was the only factor associated with higher rate of hernias ( p = 0.005), whereas increased age ( p = 0.04) and higher body mass index ( p = 0.03) were significantly associated with the appearance of leaks.

← Conclusion

Abdominal hernias and peritoneal leaks are very frequent in the PD population. Advanced age, polycystic kidney disease, and high body mass index are independent risk factors for their development. Automated PD with low daytime fill volume should be considered in all patients at risk for hernias and/or leaks.

Icodextrin Effluent Leads to a Greater Proliferation than Glucose Effluent of Human Mesothelial Cells StudiedEx Vivo

Objective

To compare the effect of glucose (Glu) and icodextrin (Ico) dialysate on in vitro culture of mesothelial cells (MC) from peritoneal dialysis (PD) patients.

Design

Prospective, controlled comparative study on the effects of two PD solutions.

Setting

A tertiary-care public university hospital.

Patients

Sixteen PD patients regularly using Glu dialysate were asked to collect an 8-hour dwell peritoneal effluent on 2 different days, with an interval shorter than 7 days. In the first collection, 2.27% Glu solution and in the last, 7.5% Ico solution was infused. Human MC were isolated from the nocturnal peritoneal effluent bags and grown ex vivo.

Main Outcome Measures

Mesothelial cell proliferative capacity ex vivo.

Results

Mesothelial cells were present in all patient dialysates except that of a single patient's Glu dialysate. The number of MC drained was similar with both solutions. After the initial culture reached confluence, MC were identified in 14 and 12 patients receiving Ico and Glu, respectively. However, in 1 patient using Ico and in 2 using Glu, the MC count at this stage was so low that further subculture could not be performed. Cells from Ico-derived solutions exhibited a higher degree of proliferation than cells from Glu-derived solutions. The morphology of MC was also different. Cells from drained effluent were typical in 11 patients using Glu solution in contrast with 14 patients using Ico. At confluence, the percentages of typical appearance were 50% and 92.9% ( p < 0.05) in Glu and Ico respectively.

Conclusions

Mesothelial cells taken from icodextrin effluent show a greater proliferation ex vivo than those taken from glucose effluent.

Increased Response to Subcutaneous Erythropoietin on Type I Diabetic Patients on CAPD: Is There a Synergistic Effect with Insulin?

Objective

To evaluate the effect of subcutaneous erythropoietin (SC EPO) on the treatment of anemia in diabetic and nondiabetic continuous ambulatory peritoneal dialysis (CAPD) patients.

Design

A resistance index was designed for measuring the relative EPO response, dividing EPO dose (U/kg/ week) by the hemoglobin (Hb) increment with respect to the basallevel.

Patients

Eleven nonselected type I diabetic patients using subcutaneous insulin compared with 16 nondiabetic controls, all on CAPD therapy.

Results

The two groups showed similar mean baseline hemoglobin levels (7.4 D- l and 7.7 non-D, g/dL). There was a statistically significant lower resistance index for diabetics (13.8±9.7 U/kg/g Hb increment) compared to nondiabetic (55.8±128, p < 0.001). Multivariate analysis confirmed an independent association between diabetes and resistance index. The response to EPO was slightly better among those diabetic patients with lower levels of serum parathyroid hormone (iPTH) (PTH-resistance index, correlation coefficient, r = 0.7, p < 0.05). No other differences, apart from the use of subcutaneous insulin, were found between diabetics and controls. Although diabetic patients had an increased response to EPO, they had no more frequent side effects than nondiabetics.

Conclusions

According to our results, we suggest that factors related to insulin-dependent diabetes seem to be involved in a favorable response to SC EPO. Hyperinsulinemia derived from subcutaneous use of insulin might act as a comitogen with the induced increments of serum erythropoietin.

Helicobacter Pylori Infection: A New Cause of Anorexia in Peritoneal Dialysis Patients

♦ Objective

Helicobacter pylori (HP) infection has frequently been found in dialysis patients. Chronic infections induce overproduction of pro-inflammatory substances. Inflammation has been associated with cachexia and anorexia. We explored the relationship between HP infection, anorexia, and malnutrition in peritoneal dialysis (PD) patients.

♦ Patients and Methods

The study included 48 clinically stable PD patients divided into four groups: HP+ with anorexia (group I, n = 12); HP+ without anorexia (group II, n = 4); HP- with anorexia (group III, n = 5); and HP- without anorexia (group IV, n = 27). Infection with HP was diagnosed by breath test. Anorexia was evaluated using a personal interview and an eating motivation scale (VAS). The VAS included five questions that are answered before and after eating. The questions concern desire to eat, hunger, feeling of fullness, prospective consumption, and palatability. Biochemical markers of nutrition and inflammation were also determined.

♦ Results

At baseline, group I showed lower scores for desire to eat, hunger sensation, prospective consumption, and palatability. They also showed lower lymphocyte counts, prealbumin, transferrin, serum albumin, normalized equivalent of protein–nitrogen appearance (nPNA), and residual renal function (RRF). In addition, the same group showed higher levels of C-reactive protein (CRP) and more sensation of fullness than the remaining groups. In the entire series, we found significant linear correlations between the following markers of nutrition and certain questions on the VAS: albumin with before-lunch desire to eat ( r = 0.38, p < 0.05), and prealbumin with before-lunch hunger ( r = 0.41, p < 0.05) and after-lunch hunger ( r = -0.35, p < 0.05). Negative linear correlations were found between albumin and fullness before lunch ( r = -0.45, p < 0.01), and between prealbumin and before-lunch desire to eat ( r = -0.39, p < 0.05). Negative linear correlations were also seen between CRP and albumin ( r = -0.35, p < 0.05) and between CRP and prealbumin ( r = -0.36, p < 0.05). Similarly, CRP showed a negative correlation with before-lunch desire to eat ( r = -0.38, p < 0.05) and after-lunch desire to eat ( r = -0.45, p < 0.01). After HP eradication, group I showed a significant increase in markers of nutrition and in VAS scores for almost all questions. Simultaneously, they showed a decrease in CRP level. Significant differences were also found in lymphocyte count (1105 ± 259.4 cells/mm3 vs 1330.8 ± 316 cells/mm3, p < 0.05), nPNA (0.9 ± 0.16 g/kg/day vs 1.07 ± 0.3 g/kg/day, p < 0.05), prealbumin (26.7 ± 6.5 mg/dL vs 33.9 ± 56.6 mg/dL, p < 0.01), albumin (3.48 ± 0.3 g/dL vs 3.67 ± 0.35 g/dL, p < 0.05), CRP (1.16 ± 1.14 mg/dL vs 0.88 ± 1.2 mg/dL, p < 0.054), before-lunch desire to eat (56.6 ± 6.8 vs 72.2 ± 4, p < 0.001), after-lunch desire to eat (5.4 ± 2.6 vs 12.3 ± 2, p < 0.01), hunger before lunch (55.4 ± 5.4 vs 73.1 ± 4.6, p < 0.001), hunger after lunch (5.8 ± 2.9 vs 11 ± 4, p < 0.01), fullness before lunch (36.6 ± 10.3 vs 18.7 ± 8.8, p < 0.001), consumption after lunch (5 ± 4.7 vs 17.5 ± 18, p < 0.05), and palatability (61 ± 5.3 vs 74.1 ± 4.1, p < 0.001).

♦ Conclusion

Infection with HP is associated with anorexia, inflammation, and malnutrition in PD patients. Eradication of HP significantly improves this syndrome. Residual renal function seem to have a protective effect on appetite preservation. The present study supports the hypothesis of the involvement of inflammation in the pathogenesis of malnutrition in PD patients.

Peritoneal Dialysis in Liver Disorders

The purpose of this paper is to review the specific role of peritoneal dialysis (PD) in patients with liver disorders. We will pay attention to the confluence of liver diseases and situations for which chronic dialysis treatment is required.

Hemodialysis (HD) and peritoneal membranes are safe barriers against the passage of the hepatitis C virus; consequently, while peritoneal effluent or HD ultrafiltrate drained from hepatitis S patients/carriers is infective, that from hepatitis C patients does not appear to present this risk. An important issue is horizontal transmission, which appears to occur with both viruses in HD units, and which is absent in peritoneal dialysis units. The incidence of hepatitis C among continuous ambulatory peritoneal dialysis (CAPD) patients is quite low, while it may reach almost 50% -60% of HD patients in some units. While hepatitis C transmission mechanisms are not completely understood and a vaccine is not available, PD provides some degree of protection when compared with HD, for end-stage renal disease patients.

In summary, our experience and that of others, with a total of 19 PD-treated chronic liver disease patients, supports CAPD as the treatment of choice for cirrhotic patients with ascites who require chronic dialysis. Data on peritoneal diffusion of low molecular weight substances revealed a marked increase in most patients. The ultrafiltration capacity was clearly augmented with respect to noncirrhotic patients, making the use of hypertonic bags unnecessary. Hemodynamic tolerance was excellent. Complications and death were mainly related to liver disease complications.

Spontaneous bacterial peritonitis (SSP), caused by gram-negative germs, is the most important complication directly related to ascites and may have some points in common with PD-related peritonitis. However, and in contrast to most PD peritonitis, two pathogenetic mechanisms have been suggested for SSP: (1) translocation of bacteria from the gut to the mesenteric lymph nodes, and (2) bacteremia in these patients is secondary to the general abnormal host defense mechanisms. Local factors such as intrahepatic shunting and the impairment of bactericidal activity in ascitic fluid favor the bacteria ascites. The hypothesis of a direct transmural contamination from bowel to ascitic fluid has been relegated to secondary bacterial peritonitis. Would cirrhotic patients with temporal or permanent renal function compromise benefit from peritoneal catheter placement and other PD practices to perform repetitive small ascitic drainages at home? Perhaps the time has arrived when hepatologists and PD nephrologists begin to work shoulder to shoulder in this particular field, as we have a common problem, the peritoneal cavity filled with fluid.

Protein-Losing Enteropathy is Associated with Peritoneal Functional Abnormalities in Peritoneal Dialysis Patients

Objective

To evaluate the relationship between acquired peritoneal transport disorders and the presence of protein-losing enteropathy (PLE), and their contribution to the protein malnutrition in peritoneal dialysis (PD) patients.

Patients and Methods

We studied 31 clinically stable PD patients that received a fat overload diet for 3 days. We measured intestinal absorption of fecal fat (normal < 6 g/24-hour stool) and nitrogen (normal < 2 g/24-hr stool), intestinal protein permeability [fecal clearance of α1-antitrypsin (Cα1AT) (normal < 12 mL/24-hr stool)], and nutritional markers [normalized protein nitrogen appearance (nPNA), half-life medium-term proteins, and body mass index]. Peritoneal solute transport was measured by mass transfer coefficient (MTC), and water transport by peritoneal ultrafiltration (UF) capacity. To define protein maldigestion it was necessary to find high fecal nitrogen values with normal Cα1AT; PLE was defined when both values were elevated.

Results

High fecal nitrogen (mean 2.1 ± 1 g/24-hr stool) and fat (mean 5.8 ± 3.6 g/24-hr stool) were found in 15 patients; 6 patients had high Cα1AT levels (PLE). These 6 patients showed a worse nutritional status: lower albumin (3.57 ± 0.57 g/dL vs 3.98 ± 0.38 g/dL, p < 0.05) and transferrin (243 ± 70 mg/dL vs 272 ± 44.3 mg/dL, p < 0.05), as well as lower triglycerides (131.3 ± 31.7 mg/dL vs 187 ± 116 mg/dL, p < 0.05). Higher urea MTCs were found in 10 patients, normal in 7, and lower in 14. Higher creatinine MTCs were found in 8 patients, normal in 15, and lower in 8. Normal peritoneal UF capacity was found in 25 and lower in 6 patients. These 6 patients showed higher urea and creatinine MTCs and Cα1AT. A positive linear correlation between Cα1AT, urea MTC ( r = 0.56, p < 0.01), and creatinine MTC ( r = 0.46, p < 0.01) was found. A similar situation occurred between Cα1AT, fecal fat ( r = 0.45, p < 0.05), and fecal nitrogen ( r = 0.43, p < 0.05). Thirteen patients with previous history of peritonitis showed higher Cα1AT than those without peritonitis (10.2 ± 8 mL/24-hr stool vs 5.2 ± 4.4 mL/24-hr stool, p < 0.05).

Conclusions

We confirm that protein and fat malabsorption, maldigestion, and PLE are present in some PD patients. Higher fecal Cα1AT is associated with malnutrition and poorer showings of the viability markers of peritoneal membrane function.

Peritoneal Dialysis in the Comprehensive Management of End-Stage Renal Disease Patients with Liver Cirrhosis and Ascites: Practical Aspects and Review of the Literature

The treatment of cirrhotic patients with ascites and end-stage renal disease is complex, due mainly to decreased effective arterial volume and hemodynamic instability. Peritoneal dialysis as a continuous therapy represents an alternative to hemodialysis-related intolerance. We report on our experience and that of others with cirrhotic patients with ascites treated by peritoneal dialysis. Hemodynamic tolerance was excellent in all patients and solute and water peritoneal transport increased to above the normal range in almost all cases. Morbidity and mortality were related principally to liver disease and other comorbidities. Peritoneal protein losses, initially high, decreased over time, maintaining serum albumin within the low normal range. The incidence of peritonitis was similar or slightly higher than usual in these patients, with peculiar etiology. The experiences with peritoneal dialysis suggest consideration of this treatment as the first choice for cirrhotic patients with ascites and that need to start dialysis.

The ideal position of the peritoneal dialysis catheter is not always ideal

PURPOSE

Peritoneal catheter dysfunction is a frequent complication of peritoneal dialysis (PD). Traditionally, dysfunction has been attributed to catheter malposition, but whether the location of the catheter tip in the small pelvis really determines proper function is unclear.

METHODS

We reviewed 900 abdominal X-ray images of PD patients from a 7-year period in two PD units that use different catheter types (straight and Swan Neck Curled).

RESULTS

In 52% of the images, the dialysis catheter tip was located in the ideal position in the small pelvis and in 48% in other sites. Peritoneal catheter function was normal at the time of imaging in 87% of those with ideal catheter tip position, and in 74% of those with other than ideal position. The tip was located in small pelvis in 35% of images performed during catheter dysfunction and in 56% of those performed during normal catheter function. There were no differences between two catheter types. The positive predictive value of abdominal X-ray images to predict catheter function was 26%, and the negative predictive value 87%. We also found a significant positive correlation between polycystic kidney disease and normal catheter function. In contrast, obese patients were more likely to have catheter malfunction. Previous abdominal surgery was not associated with catheter dysfunction.

CONCLUSION

Our data showed a higher probability of normal function of peritoneal catheters whose tips were located in the small pelvis. However, also malpositioned catheters generally functioned well, and malpositioning of the PD catheter did not in itself explain its malfunction.

Abnormalities in Glucose Metabolism, Appetite-Related Peptide Release, and Pro-nflammatory Cytokines Play a Central Role in Appetite Disorders in Peritoneal Dialysis

Background: Appetite disorders are frequent and scantly studied in peritoneal dialysis (PD) patients and are associated with malnutrition and cardiovascular complications. Objective: We investigated the relationship between uremic insulin resistance, pro-inflammatory cytokines, and appetite-related peptides release (ARPr) with eating-behavior disorders in PD patients. Methods: We included 42 PD patients (12 suffering anorexia, 12 obese with high food-intake, and 18 asymptomatic) and 10 controls. We measured blood levels of ARPr including orexigens [neuropeptide-Y (NPY), ghrelin, and nitric-oxide], anorexigens [cholecystokinin, insulin, corticotropin-releasing factor, leptin, and adiponectin (Ad)], and cytokines (TNF-α, sTNFα-R2, and IL-6) both at baseline and after administering a standard-food stimulus (SFS). We also measured the expression of TNF-α, leptin and Ad-encoding mRNAs in abdominal adipose tissue. We compared these markers with eating motivation measured by a Visual Analog Scale (VAS). Results: Anorexics showed both little appetite, measured by a VAS, and low levels of orexigens that remained constant after SFS, coupled with high levels of anorexigens at baseline and after SFS. Obeses showed higher appetite, increased baseline levels of orexigens, lower baseline levels of anorexigens and cytokines and two peaks of NPY after SFS. The different patterns of ARPr and cytokines pointed to a close relationship with uremic insulin resistance. In fact, the euglycemic-hyperglycemic clamp reproduced these disorders. In anorexics, TNF-α fat expression was increased. In obese patients, leptin expression in fat tissue was down-regulated and showed correlation with the appetite. Conclusion: In PD, appetite is governed by substances that are altered at baseline and abnormally released. Such modulators are controlled by insulin metabolism and cytokines and, while anorexics display inflammatory predominance, obese patients predominantly display insulin resistance.

Paricalcitol and Peritoneal Protein Loss in Peritoneal Dialysis: A Double-Center Study

BACKGROUND/AIMS

Peritoneal protein loss (PPL) is associated with cardiovascular disease and mortality in peritoneal dialysis (PD). Controversial results have been published about the effect of paricalcitol in PPL among PD patients. This study intends to analyze the relationship between paricalcitol and PPL in PD.

METHODS

In a retrospective study, prevalent PD patients were divided into 2 groups: "with paricalcitol" and "without paricalcitol". X2-test, Student's t test, Pearson correlation coefficient and Logistic Regression analysis were applied.

RESULTS

Eighty-two patients were included. PPL was lower among patients medicated with paricalcitol (5.17 ± 1.71 vs. 6.79 ± 2.10 g/24 h, p = 0.0001). In multivariate analysis, paricalcitol and dialysate/plasma ratio of creatinine (D/P creatinine) were independently related to PPL (OR 4.270 [1.437-12.684], p = 0.009 and OR 0.205 [0.064-0.659], p = 0.008, respectively), adjusted for diabetes.

CONCLUSION

Paricalcitol and D/P creatinine were independently related to PPL. Paricalcitol may have an effect on PPL in PD patients.

Peritoneal Membrane Preservation

Peritoneal dialysis (PD) is a successfully used method for renal replacement therapy. However, long-term PD may be associated with peritoneal fibrosis and ultrafiltration failure. The key factors linked to their appearance are repeated episodes of inflammation associated with peritonitis and long-term exposure to bioincompatible PD fluids. Different strategies have been proposed to preserve the peritoneal membrane. This article reviews the functional and structural alterations related to PD and strategies whereby we may prevent them to preserve the peritoneal membrane. The use of new, more biocompatible, PD solutions is promising, although further morphologic studies in patients using these solutions are needed. Blockade of the renin-angiotensin-aldosterone system appears to be efficacious and strongly should be considered. Other agents have been proven in experimental studies, but most of them have not yet been tested appropriately in human beings.

Nebivolol, a β1-adrenergic blocker, protects from peritoneal membrane damage induced during peritoneal dialysis

Peritoneal dialysis (PD) is a form of renal replacement treatment, which employs the peritoneal membrane (PM) to eliminate toxins that cannot be removed by the kidney. The procedure itself, however, contributes to the loss of the PM ultrafiltration capacity (UFC), leading consequently to the technique malfunction. β-blockers have been considered deleterious for PM due to their association with loss of UFC and induction of fibrosis. Herein we analyzed the effects of Nebivolol, a new generation of β₁-blocker, on PM alterations induced by PD fluids (PDF).

In vitro: We found that mesothelial cells (MCs) express β₁-adrenergic receptor. MCs were treated with TGF-β to induce mesothelial-to-mesenchymal transition (MMT) and co-treated with Nebivolol. Nebivolol reversed the TGF-β effects, decreasing extracellular matrix synthesis, and improved the fibrinolytic capacity, decreasing plasminogen activator inhibitor-1 (PAI-1) and increasing tissue-type plasminogen activator (tPA) supernatant levels. Moreover, Nebivolol partially inhibited MMT and decreased vascular endothelial growth factor (VEGF) and IL-6 levels in supernatants.

In vivo: Twenty-one C57BL/6 mice were divided into 3 groups. Control group carried a catheter without PDF infusion. Study group received intraperitoneally PDF and oral Nebivolol during 30 days. PDF group received PDF alone. Nebivolol maintained the UFC and reduced PM thickness, MMT and angiogenesis promoted by PDF. It also improved the fibrinolytic capacity in PD effluents decreasing PAI-1 and IL-8 and increased tPA levels.

Conclusion: Nebivolol protects PM from PDF-induced damage, promoting anti-fibrotic, anti-angiogenic, anti-inflammatory and pro-fibrinolytic effects.

Improvement in Nutritional Status in Patients With Chronic Kidney Disease-4 by a Nutrition Education Program With No Impact on Renal Function and Determined by Male Sex

OBJECTIVE

Protein-energy wasting (PEW) is associated with increased morbidity and mortality and a rapid deterioration of kidney function in patients with chronic kidney disease (CKD). However, there is little information regarding the effect of nutrition intervention. The aims of this study were to evaluate the efficacy and safety of a nutrition education program (NEP) in patients with nondialysis dependent CKD (NDD-CKD), based on the diagnostic criteria for PEW proposed by the International Society of Renal Nutrition and Metabolism. The design of the study was a 6-month longitudinal, prospective, and interventional study. The study was conducted from March 2008 to September 2011 in the Nephrology Department of La Paz University Hospital in Madrid, Spain.

SUBJECTS

A total of 160 patients with NDD-CKD started the NEP, and 128 finished it.

INTERVENTION

The 6-month NEP consisted of designing an individualized diet plan based on the patient's initial nutritional status, and 4 nutrition education sessions.

MAIN OUTCOME MEASURES

Changes in nutritional status (PEW) and biochemical, anthropometric and body composition parameters.

RESULTS

After 6 months of intervention, potassium and inflammation levels decreased, and an improved lipid profile was found. Body mass index lowered, with increased muscle mass and a stable fat mass. Men showed increased levels of albumin and prealbumin, and women showed decreased proteinuria levels. The prevalence of PEW decreased globally (27.3%-10.9%; P = .000), but differently in men (29.5%-6.5%; P = .000) and in women (25.4%-14.9%; P = .070), 3 of the women having worsened. Kidney function was preserved, despite increased protein intake.

CONCLUSION

The NEP in NDD-CKD generally improved nutritional status as measured by PEW parameters, but individual poorer results indicated the need to pay special attention to female sex and low body mass index at the start of the program.

Markers of endothelial damage in patients with chronic kidney disease on hemodialysis

Patients with Stage 5 chronic kidney disease who are on hemodialysis (HD) remain in a chronic inflammatory state, characterized by the accumulation of uremic toxins that induce endothelial damage and cardiovascular disease (CVD). Our aim was to examine microvesicles (MVs), monocyte subpopulations, and angiopoietins (Ang) to identify prognostic markers in HD patients with or without diabetes mellitus (DM). A total of 160 prevalent HD patients from 10 centers across Spain were obtained from the Biobank of the Nephrology Renal Network (Madrid, Spain): 80 patients with DM and 80 patients without DM who were matched for clinical and demographic criteria. MVs from plasma and several monocyte subpopulations (CD14²⁺/CD16⁺, CD14⁺/CD16²⁺) were analyzed by flow cytometry, and the plasma concentrations of Ang1 and Ang2 were quantified by ELISA. Data on CVD were gathered over the 5.5 yr after these samples were obtained. MV level, monocyte subpopulations (CD14⁺/CD16²⁺ and CD14²⁺/CD16⁺), and Ang2-to-Ang1 ratios increased in HD patients with DM compared with non-DM patients. Moreover, MV level above the median (264 MVs/µl) was associated independently with greater mortality. MVs, monocyte subpopulations, and Ang2-to-Ang1 ratio can be used as predictors for CVD. In addition, MV level has a potential predictive value in the prevention of CVD in HD patients. These parameters undergo more extensive changes in patients with DM.

The Communication and Bioethical Training (CoBiT) Program for assisting dialysis decision-making in Spanish ACKD units

Healthcare professionals currently working in Advanced Chronic Kidney Disease (ACKD) units must cope with difficult situations regarding assisting patients with the dialysis decision-making process, and they are often untrained for these conversations. Although we have evidence from the literature that these skills can be learned, few professionals feel confident in this area. A Communication and Bioethical Training (CoBiT) Program for ACKD staff (physicians, nurses and allied health professionals) was developed to improve their ability and self-confidence in conducting these conversations. A four-stage study was conducted: (1) development of the CoBiT program, beginning with the creation of an interdisciplinary focus group (N = 10); (2) design of a questionnaire to assess self-confidence based on the areas identified by the focus group. The face validity of the instrument was tested using an inter-judge methodology (N = 6); (3) design of the format and contents of the program; (4) piloting the program. Thirty-six health professionals took an 8-h workshop based on role-playing methodology. Participants assessed their self-confidence in their communication skills before and after the program using self-report measures. The results show that after the program, participants reported significantly higher levels of self-confidence measured with a five-point Likert scale (p < 0.001). Participants felt that communication with colleagues of other professions significantly increased after the workshop (p = 0.004). The CoBiT program improves ACKD Unit healthcare professionals' self-confidence in their ability to perform a specific communication task.

Preventing peritoneal membrane fibrosis in peritoneal dialysis patients

Long-term peritoneal dialysis causes morphologic and functional changes in the peritoneal membrane. Although mesothelial-mesenchymal transition of peritoneal mesothelial cells is a key process leading to peritoneal fibrosis, and bioincompatible peritoneal dialysis solutions (glucose, glucose degradation products, and advanced glycation end products or a combination) are responsible for altering mesothelial cell function and proliferation, mechanisms underlying these processes remain largely unclear. Peritoneal fibrosis has 2 cooperative parts, the fibrosis process itself and the inflammation. The link between these 2 processes is frequently bidirectional, with each one inducing the other. This review outlines our current understanding about the definition and pathophysiology of peritoneal fibrosis, recent studies on key fibrogenic molecular machinery in peritoneal fibrosis, such as the role of transforming growth factor-β/Smads, transforming growth factor-β β/Smad independent pathways, and noncoding RNAs. The diagnosis of peritoneal fibrosis, including effluent biomarkers and the histopathology of a peritoneal biopsy, which is the gold standard for demonstrating peritoneal fibrosis, is introduced in detail. Several interventions for peritoneal fibrosis based on biomarkers, cytology, histology, functional studies, and antagonists are presented in this review. Recent experimental trials in animal models, including pharmacology and gene therapy, which could offer novel insights into the treatment of peritoneal fibrosis in the near future, are also discussed in depth.

Peritoneal resting with heparinized lavage reverses peritoneal type I membrane failure. A comparative study of the resting effects on normal membranes

BACKGROUND

Ultrafiltration failure (UFF) is a serious complication of long-term peritoneal dialysis (PD). Peritoneal rest (PR) has been demonstrated as a valid treatment to reverse the functional changes that occur in UFF. The effects of PR on a normally functioning human peritoneum are unknown but are expected to be neutral. Our hypothesis was that PR positively modifies peritoneal function in patients with UFF, in contrast to the absence of effects when PR is applied under normal conditions.

PATIENTS AND METHODS

We studied 84 PR periods, comparing 35 patients with UFF and 49 controls (resting for abdominal surgery with temporary discontinuation of PD). We analyzed peritoneal transport pre-PR and post-PR by calculating the mass transfer coefficients of creatinine (Cr-MTAC), the dialysate/plasma creatinine ratio (D/P Cr) and the ultrafiltration (UF).

RESULTS

Baseline data was similar for the 2 groups, although the UFF group had a longer median time in PD (39 [18 - 60] vs 10 [5 - 23] months; p = 0.00001). Peritoneal rest induced a decrease in D/P Cr, Cr-MTAC and an increase in UF capacity in the UFF group (p = 0.0001, p = 0.004 and p = 0.001, respectively), without causing changes in the control group. Peritoneal rest in patients with more than 6 months of UFF was not able to reduce peritoneal solute transport or improve UF capacity. Response to PR did not differ among UFF patients with or without a previous history of peritonitis. Peritoneal rest enabled patients with UFF to continue on PD for a median time of 23 months (range, 13 - 46 months).

CONCLUSIONS

Peritoneal rest induces functional changes in patients with UFF but not in those with no functional abnormalities. This demonstrates that PR works only when abnormal but reversible functional conditions are present. However, the effect is highly dependent on how early PR is applied.

Peritoneal Dialysis Can Be an Option for Dominant Polycystic Kidney Disease: an Observational Study

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) has been considered a relative contraindication for peritoneal dialysis (PD), although there are few specific studies available.

METHODS

A multicenter historical prospective matched-cohort study was conducted to describe the outcome of ADPKD patients who have chosen PD. All ADPKD patients starting PD (n = 106) between January 2003 and December 2010 and a control group (2 consecutive patients without ADPKD) were studied. Mortality, PD-technique failure, peritonitis, abdominal wall leaks and cyst infections were compared.

RESULTS

Patients with ADPKD had similar age but less comorbidity at PD inclusion: Charlson comorbidity index (CCI) 4.3 (standard deviation [SD] 1.6) vs 5.3 (SD 2.5) p < 0.001, diabetes mellitus 5.7% vs 29.2%, p < 0.001 and previous cardiovascular events 10.4% vs 27.8%, p < 0.001. No differences were observed in clinical events that required transient transfer to hemodialysis, nor in peritoneal leakage episodes or delivered dialysis dose. The cyst infection rate was low (0.09 episodes per patient-year) and cyst infections were not associated to peritonitis episodes. Overall technique survival was similar in both groups. Permanent transfer to hemodialysis because of surgery or peritoneal leakage was more frequent in ADPKD. More ADPKD patients were included in the transplant waiting list (69.8 vs 58%, p = 0.04) but mean time to transplantation was similar (2.08 [1.69 - 2.47] years). The mortality rate was lower (2.5 vs 7.6 deaths/100 patient-year, p = 0.02) and the median patient survival was longer in ADPKD patients (6.04 [5.39 - 6.69] vs 5.57 [4.95 - 6.18] years, p = 0.024).

CONCLUSION

Peritoneal dialysis is a suitable renal replacement therapy option for ADPKD patients.

[Normal values of bioimpedance vector in Spanish population]

BACKGROUND AND OBJECTIVE

The bioelectrical impedance vector analysis is useful for the determination of body composition in patients with altered hydration status. The original tolerance ellipses were made in Italian healthy individuals. Due to differences in body composition between populations, the aim of the study was to establish specific tolerance ellipses for the Spanish population and compare them with those ellipses made in the original reference population.

METHODS

We studied 311 Spanish healthy subjects of both sexes, between 18 and 80 years old, with a BMI between 18 and 31 Kg/m², who underwent measurements of weight, height and bioelectrical impedance. The values of resistance and reactance standardized by height (R/H and Xc/H) derived from the impedance measurement, were used to determine the body composition and construct the specific tolerance ellipses for this population.

RESULTS

The characteristics of body composition were different between sex and age groups. We plotted values of R/H and Xc/H of the Spanish population on the Italian tolerance ellipses finding that vectors were placed in left quadrants, indicating different body composition. We therefore built specific tolerance ellipses for Spanish population based on values of R/H and Xc/H. Spanish tolerance ellipses were statistically different from the Italian.

CONCLUSIONS

The vectors of the Spanish population were different from those of the Italian, hence the importance of having a self-reference pattern.

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.

[Evaluation of a Nutritional Intervention Program in advanced chronic kidney disease (ACKD) patients]

INTRODUCTION AND OBJECTIVES

Advanced Chronic Kidney Disease (ACKD) is associated with high prevalence of malnutrition. The habitual continuous dietary restrictions used in clinical practice. increased the malnutrition risk. The aim of this study was to evaluate the effects of a Nutritional intervention Program (NIP) on renal function and nutritional status in patients with ACKD.

PATIENTS AND METHODS

93 patients, (53.7% men, 66±17 years) were included in a prospective longitudinal study. The patients recived a NIP during 6 months with mensual visits. At baseline and six months the outcome assessed were: nutritional status by Chang criteria, anthropometric, dietetic and biochemical parameters (albumin, prealbumin, creatinine clearance, serum phosphorus, potassium, total-Cholesterol, LDL, HDL, triglycerides, and PCR).

RESULTS

After intervention, caloric intake decreased in nourished patients (1833 ±318 vs. 1571±219 kcal p=.001). and it was constant in malnourished patients. The intake of protein (69,9 ± 16,6 vs 54,9 ± 11 g p < 0.001), potassium (2938 ± 949 vs 2377 ± 743 mg p < 0.001) and phosphorus (1180 ± 304 vs 946,6 ± 211 mg p < 0.001) significantly decreased. 16.5% patients required supplementation. A total of 41.7% of patients were malnourished at baseline (27.8% mild, 10.10% moderate and 3.8% severe), and 16.8% at the end (8% mild, 5% moderate and 3.8% severe) by Chang criteria. At the end of NIP, patients significantly increased creatinine clearance (17,8 ± 5,2 vs 19,4 ± 6,9 ml/min, p < 0,01), albumin (3,3 ± 0,5 vs. 3,5 ± 0,4 g/dL, p < 0,05), and decreased serum potassium (4,8 ± 0,6 vs 4,5 ± 0,5 mmol/L, p < 0,05), total cholesterol (179,8 ± 44,3 vs 170,0 ± 15,1 mg/dL, p < 0,05), LDL (113,2 ± 37,0 vs 108,3 ± 27,3 mg/dL, p < 0.01) and tryglicerides (141.9 ± 60.8 vs 129.9 ± 52.7 mg/dL, p < 0.05).\

CONCLUSIONS

The study reflected a NIP usefulness in the nutritional status and renal function improvements within an interdisciplinary framework during ACKD consultations.

The influence of initial peritoneal transport characteristics, inflammation, and high glucose exposure on prognosis for peritoneal membrane function

BACKGROUND

Fast transport status, acquired with time on peritoneal dialysis (PD), is a pathology induced by peritoneal exposure to bioincompatible solutions. Fast transport has important clinical consequences and should be prevented.

OBJECTIVE

We analyzed the repercussions of initial peritoneal transport characteristics on the prognosis for peritoneal membrane function, and also whether the influence of peritonitis and high exposure to glucose are different according to the initial peritoneal transport characteristics or the moment when such events occur.

METHODS

The study included 275 peritoneal dialysis patients with at least 2 peritoneal function studies (at baseline and 1 year). Peritoneal kinetic studies were performed at baseline and annually. Those studies consist of a 4-hour dwell with glucose (1.5% during 1981 - 1990, and 2.27% during 1991 - 2002) to calculate the peritoneal mass transfer coefficients of urea and creatinine (milliliters per minute) using a previously described mathematical model.

RESULTS

Membrane prognosis and technique survival were independent of baseline transport characteristics. Fast transport and ultrafiltration (UF) failure are reversible conditions, provided that peritonitis and high glucose exposure are avoided during the early dialysis period. The first year on PD is a main determining factor for the membrane's future, and the mass transfer coefficient of creatinine at year 1 is the best functional predictor of future PD history. After 5 years on dialysis, permeability frequently increases, and UF decreases. Icodextrin is associated with peritoneal protection.

CONCLUSIONS

Peritoneal membrane prognosis is independent of baseline transport characteristics. Intrinsic fast transport and low UF are reversible conditions when peritonitis and high glucose exposure are avoided during the early dialysis period. Icodextrin helps in glucose avoidance and is associated with peritoneal protection.

Effect of self-administered intraperitoneal bemiparin on peritoneal transport and ultrafiltration capacity in peritoneal dialysis patients with membrane dysfunction. A randomized, multi-centre open clinical trial

BACKGROUND

Progressive peritoneal membrane injury and dysfunction are feared repercussions of peritoneal dialysis (PD), and may compromise the long-term feasibility of this therapy. Different strategies have been attempted to prevent or reverse this complication with limited success.

METHODS

We performed a randomized, open multi-centre trial, aimed at scrutinizing the efficacy of self-administered intraperitoneal (i.p.) bemiparin (BM) to modulate peritoneal membrane dysfunction. The main outcome variables were peritoneal creatinine transport and the ultrafiltration (UF) capacity, estimated during consecutive peritoneal equilibration tests. The trial included a control group who did not undergo intervention. The treatment phase lasted 16 weeks with a post-study follow-up of 8 weeks.

RESULTS

Intraperitoneal BM did not significantly improve creatinine transport or the UF capacity, when the whole group was considered. However, we observed a time-limited improvement in the UF capacity for the subgroup of patients with overt UF failure, which was not observed in the control group. Intraperitoneal injection of BM did not carry an increased risk of peritoneal infection or major haemorrhagic complications.

CONCLUSIONS

Our data do not support the systematic use of BM for management of peritoneal membrane dysfunction in PD patients. Further studies on the usefulness of this approach in patients with overt UF failure are warranted. Intraperitoneal administration of BM is safe in PD patients, provided regulated procedures are respected.

Peritoneal membrane phosphate transport status: a cornerstone in phosphate handling in peritoneal dialysis

BACKGROUND AND OBJECTIVES

Phosphate control impacts dialysis outcomes. Our aim was to define peritoneal phosphate transport in peritoneal dialysis (PD) and to explore its association with hyperphosphatemia, phosphate clearance (PPhCl), and PD modality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Two hundred sixty-four patients (61% on continuous ambulatory PD [CAPD]) were evaluated at month 12. PPhCl was calculated from 24-hour peritoneal effluent. Phosphate (Ph) and creatinine (Cr) dialysate/plasma (D/P) were calculated at a 4-hour 3.86% peritoneal equilibration test.

RESULTS

D/PPh correlated with D/PCr. PPhCl correlated better with D/PPh than with D/PCr. Prevalence of hyperphosphatemia (>5.5 mg/dl) was 30%. In a multiple regression analysis, only residual renal function was independently, negatively associated with hyperphosphatemia; in anuric patients, only D/PPh was an independent factor predicting hyperphosphatemia. D/PPh was 0.57 ± 0.10, and according to this, 16% of the patients were fast, 31% were fast-average, 35% were slow-average, and 17% were slow transporters. PPhCl was 37.5 ± 11.7 L/wk; it was lower in the slow transporter group (31 ± 14 L/wk). Among fast and fast-average transporters, PPhCl was comparable in both PD modalities. In comparison to automated PD, CAPD was associated with increased PPhCl among slow-average (36 ± 8 versus 32 ± 7 L/wk) and slow transporters (34 ± 15 versus 24 ± 9 L/wk).

CONCLUSIONS

In hyperphosphatemic, particularly anuric, patients, optimal PD modality should consider peritoneal phosphate transport characteristics. Increasing dwell times and transfer to CAPD are effective strategies to improve phosphate handling in patients with inadequate phosphate control on automated PD.

Bowel bacterial overgrowth as another cause of malnutrition, inflammation, and atherosclerosis syndrome in peritoneal dialysis patients

Bowel bacterial overgrowth syndrome (BBOS) is an important cause of gastrointestinal (GI) abnormalities. Proinflammatory cytokines (PICs) are excessively produced and accumulate because of kidney failure in dialysis patients who experience chronic infections such as BBOS. We explored the association between GL function, BBOS, and the malnutrition, inflammation, and atherosclerosis (MIA) syndrome. We studied GI malabsorption and maldigestion by analyzing fecal starch, sugar, fat, and nitrogen; intestinal protein permeability (alpha1-antitrypsin fecal clearance); and fecal chymotrypsin. We evaluated BBOS by breath hydrogen test (BHT) after a 3-day fat-and-carbohydrate-overload diet. Positive BHT was present in 10 patients, showing a high prevalence of GI macronutrient malabsorption and maldigestion, and compared with the other patients, the highest plasma levels of tumor necrosis factor alpha and interleukin 6 and lower levels of albumin and prealbumin. Those 10 patients were treated with a combination of several antibiotics, including neomycin, amoxicillin-clavulanate, and quinolones. Between 2 and 3 months later, the BHT, markers of nutrition, and PIC were re-tested. All treated patients showed an improvement in nutrition status and a lesser inflammatory pattern. The BBOS infectious process is found frequently in dialysis patients in association with GI malabsorption and maldigestion, malnutrition, and systemic inflammation. Hyperproduction of PIC because of BBOS induces MIA through a double pathway: GI disorders and deleterious systemic effects.

Previous comorbidity and lack of patient free choice of technique predict early mortality in peritoneal dialysis

OBJECTIVE

To study the prognostic factors for mortality and hospital admission for patients on peritoneal dialysis (PD).

METHOD

Biannual data on individual characteristics, clinical and analytical progress, treatment, and events were studied for a cohort of incident patients undergoing PD (2003-2006) in a reference area of 8.8 million people.

RESULTS

489 patients (age 53.58 years, 61.6% male) with 3-year follow-up were included. They presented at inclusion with Charlson Comorbidity Index (CCI) of 5.25; previous cardiovascular (CV) event, 23.7%; diabetes mellitus (DM), 19.1%; and hypertension (HT), 89.9%. Annual hospitalization rate per patient-year at risk was 0.6. The variables that predicted admission were CCI [odds ratio (OR) 1.14 per point], DM (OR 1.66), and previous CV event (OR 1.90). Anemia maintained significance when corrected for CCI: hemoglobin, 0.79 per 1 g/dL Hb; CCI, 1.15 per point. Annual mortality rate was 5.4%. Those that died were older (67.47 vs 52.78 years) and had a higher CCI (8.35 vs 5.0), a lower initial Hb (11.5 vs 12.2 g/dL), a higher hospital admission rate, a higher annual rate of peritonitis, more previous CV events (50.0% vs 22.1%), and higher prevalence of DM (38.5% vs 17.9%). Survival analysis identified the following prognostic factors: CCI [hazard ratio (HR) 1.51 per point], CV event (HR 2.85), DM (HR 2.52), age (HR 1.06 per year), and mandatory referral to PD (HR 6.54). The effect of CV events and DM persisted after correction for age, and that of choice of technique after correcting for CCI and/or age.

CONCLUSIONS

The CCI is useful for risk estimation in PD patients. Previous CV event, DM, and age are the most relevant risk factors. Control of anemia has prognostic value for hospital admissions. Mandatory referral to PD is associated with higher mortality. The prognosis in PD depends on predialysis patient management.

Peritoneal dialysis in the comprehensive management of end-stage renal disease patients with liver cirrhosis and ascites: practical aspects and review of the literature

The treatment of cirrhotic patients with ascites and end-stage renal disease is complex, due mainly to decreased effective arterial volume and hemodynamic instability. Peritoneal dialysis as a continuous therapy represents an alternative to hemodialysis-related intolerance. We report on our experience and that of others with cirrhotic patients with ascites treated by peritoneal dialysis. Hemodynamic tolerance was excellent in all patients and solute and water peritoneal transport increased to above the normal range in almost all cases. Morbidity and mortality were related principally to liver disease and other comorbidities. Peritoneal protein losses, initially high, decreased over time, maintaining serum albumin within the low normal range. The incidence of peritonitis was similar or slightly higher than usual in these patients, with peculiar etiology. The experiences with peritoneal dialysis suggest consideration of this treatment as the first choice for cirrhotic patients with ascites and that need to start dialysis.

Inherent high peritoneal transport and ultrafiltration deficiency: their mid-term clinical relevance

BACKGROUND

High peritoneal transport has been associated with poorer outcome in peritoneal dialysis (PD) patients, but not necessarily because of PD-dependent conditions. Our primary objective was to analyse the influences of baseline peritoneal small solute transport and ultrafiltration (UF) capacity on patient and technique survival, after adjusting for comorbid conditions. A secondary objective was to determine whether high transport was associated with basal comorbidity.

METHODS

In this prospective observational patient/technique survival study, we followed 410 patients who started PD. At the baseline, we collected data to define comorbidities, tally the Charlson index, determine the baseline mass transfer area coefficients (MTAC) of urea and creatinine, net UF, plasma albumin and residual renal function (RRF). No data other than the information on patient and technique survival were recorded after baseline.

RESULTS

The mean follow-up was 33 +/- 28 months. Dropouts during the study were due to renal transplantation in 140 cases, death in 142 cases and transfer to haemodialysis (HD) in 77 cases. Patients with inherent UF deficiency, high transport rate or both were not significantly different in the survival analysis from the rest. In the Cox hazards analysis, only age, Charlson index and a lower RRF were the significant mortality risk factors. None of the baseline parameters studied was a predictor of technique failure. High transporter patients had lower plasma albumin and UF capacity, comorbidity and more frequent liver diseases than the rest. Moderate to severe liver disease (n = 14) was significantly associated with the inherent high transport status, but was never accompanied by UF failure (UFF). UFF patients showed higher RRF, creatinine-MTAC and age.

CONCLUSIONS

Neither the high transport nor the inherent UFF status has any influence on patient and technique survival. The inherent high small solute transport status is associated with hypoalbuminaemia and a greater comorbidity index. The Charlson index, age and lower RRF are the only independent predictors of mortality. Technique dropout is not predicted by any of the variables studied at the baseline.

Epithelial-to-mesenchymal transition of the mesothelial cell—its role in the response of the peritoneum to dialysis

Peritoneal membrane fibrosis, ranging from mild inflammation to severe sclerosing peritonitis, is one of the complications of peritoneal dialysis (PD). In parallel with fibrosis, the peritoneum shows a progressive increase of capillaries and vasculopathy, involved in increased small solute transport across the membrane and ultrafiltration failure. Glucose and glucose degradation products from PD solutions are responsible of stimulating transforming growth factor-beta (TGF-beta) and vascular endothelial growth factor (VEGF) production by mesothelial cells (MCs). TGF-beta is a potent pro-fibrotic factor and inducer of epithelial-to-mesenchymal transition (EMT) of the MC. Local production of VEGF by transitional MC appears to play a central role in the processes leading to peritoneal angiogenesis. This review addresses the mechanism involved in peritoneal structural alteration by dialysis and points to the EMT of MC as the initiating mechanism of peritoneal injury. Information from multiple origins about TGF-beta and VEGF is integrated into EMT process in a comprehensive manner. Regulation and new targets for inhibition of EMT or its deleterious effects are discussed.

Risk factors for abdominal wall complications in peritoneal dialysis patients

BACKGROUND

Patients treated with peritoneal dialysis (PD) have increased intra-abdominal pressure and a high prevalence of abdominal wall complications.

OBJECTIVE

The purpose of this study was to determine the incidence of hernias and peritoneal leaks in our PD patients and to investigate their potential risk factors.

PATIENTS

We studied 142 unselected patients treated with PD during the past 5 years, including those that were already on PD and those that started PD during this period. Mean age was 54 years and mean follow-up on PD was 39 months. 72 patients had been treated with only continuous ambulatory PD (CAPD), 8 with automated PD (APD), and 62 with both modalities.

RESULTS

53 patients (37%) developed hernia and/or leak. A total of 39 hernias and 63 leaks were registered. The overall rates were 0.08 hernias/patient/year and 0.13 leaks/patient/year. 17 patients had both abdominal complications. Hernia was most frequently located in the umbilical region, and the most frequent site of leakage was the pericatheter area. Both complications appeared more frequently during the CAPD period (87% of hernias, 81% of leaks). The rate of hernias was higher in patients treated only with CAPD than in those that used only cyclers [0.08 vs 0.01 hernias/patient/year, not significant (NS)]. No patient treated only with APD had peritoneal leak; 25% (18/72) of patients treated with CAPD developed this complication (p = 0.18, NS). Dialysate exchange volumes ranged from 2000 to 2800 mL. 25 (66%) patients required surgical repair of the hernia, with recurrence in 7 patients (28%). 27 (84%) patients with leaks were initially treated with transitory temporary transfer to hemodialysis, low volume APD, or intermittent PD for 4 weeks. The leak recurred in half of the cases and surgical repair was necessary in 12 cases. The development of hernia and/or leak did not correlate with gender, diabetes, duration of follow-up, type of PD, history of abdominal surgery, or with the largest peritoneal exchange volume used. Polycystic kidney disease was the only factor associated with higher rate of hernias (p = 0.005), whereas increased age (p = 0.04) and higher body mass index (p = 0.03) were significantly associated with the appearance of leaks.

CONCLUSION

Abdominal hernias and peritoneal leaks are very frequent in the PD population. Advanced age, polycystic kidney disease, and high body mass index are independent risk factors for their development. Automated PD with low daytime fill volume should be considered in all patients at risk for hernias and/or leaks.

A Comparative Study of C-Reactive Protein Plasma Levels in Patients on Hemodialysis and Peritoneal Dialysis

In dialysis patients, C-reactive protein (CRP), a well-recognized marker of inflammation, predicts mortality. Higher levels have been described in hemodialysis (HD) patients as compared with peritoneal dialysis (PD) patients. Our aim was to determine, based on CRP plasma levels, the degree of inflammation in HD patients using low-permeability polysulfone membranes and relatively pure dialysate, and that in PD patients. A secondary objective was to study factors associated with hypoalbuminemia and inflammation in both populations. We studied 69 stable patients on dialysis (32 on HD and 37 on PD). The mean age was 69.9 ± 8.2 years, and the mean time on dialysis was 27 months. The two populations were comparable for overall and cardiovascular comorbidities. Nephelometry was used to measure CRP plasma levels (normal levels < 0.6 mg/dL). The Kt/V_urea , corrected for residual renal clearance, and the equivalent of protein nitrogen appearance (PNA) were also calculated. Of the patients studied, 53% showed CRP plasma levels higher than 0.6 mg/dL; in 36%, the levels were higher than 1 mg/dL. No significant differences in these percentages were noted between the two dialysis groups. Patients with CRP levels higher than 1 mg/dL showed lower serum albumin, iron, hemoglobin, and transferrin levels, and higher ferritin values and leukocyte counts. Under logistic regression analysis, CRP levels higher and lower than 1 mg/dL were significantly associated with serum albumin [p = 0.01; odds ratio (OR): 0.15], iron (p = 0.006; OR: 0.96), transferrin (p = 0.004; OR: 0.97), and hemoglobin (p = 0.02; OR: 0.67). Serum albumin levels were significantly lower in PD patients. Under regression analysis, serum albumin levels correlated with cholesterol (r: 0.25; p = 0.04), serum iron (r: 0.5; p = 0.0001), transferrin (r: 0.3; p = 0.015), ultrafiltration capacity (r: 0.42; p = 0.008), and CRP values above 0.6 mg/dL (r: -0.65; p = 0.001). In conclusion, the frequent elevation of CRP plasma levels observed in both HD and PD patients suggests the presence of a silent inflammatory state. Hemodialysis performed with biocompatible, low-permeability membranes is not associated with higher CRP plasma levels than those seen in PD. In both groups, hypoalbuminemia is related to CRP level. Levels of serum albumin, slightly lower in PD patients, are also related to peritoneal ultrafiltration capacity.