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Background: The evidence linking low serum sodium levels with the risk of mortality in peritoneal dialysis (PD) patients is controversial. Considering the different mechanisms contributing to hyponatremia in these patients, it is conceivable that the prognostic significance of this factor may vary, according to the clinical setting.Methods: Following a retrospective, observational design, we analyzed the association between hyponatremia and mortality in 748 patients incident on PD. We applied multivariate strategies of analysis, with the main objective of identifying subgroups of patients in whom hyponatremia could sustain different degrees of association with mortality (main outcome variable). For this purpose, we performed preliminary analyses to: (1) disclose predictors of serum sodium levels before and after (mean of first 3 months) initiation of PD (main study variable) and (2) investigate the overall prognostic significance of hyponatremia, in our patients.Results: Comorbidity, hypoalbuminemia, and lower glomerular filtration rate (GFR) were main predictors of hyponatremia. Use of icodextrin was another inverse correlate of serum sodium, and the only consistent predictor of a decline of natremia, once PD was started. Multivariate analysis confirmed early hyponatremia as an independent marker of survival. However, stratified analyses showed that this association was most apparent in specific subsets, namely, hypoalbuminemic, more anemic patients with higher baseline levels of GFR and C-reactive protein and faster peritoneal solute transport rates. Other factors potentially reinforcing the prognostic significance of hyponatremia included lower lean body mass levels, nonprescription of renin-angiotensin-aldosterone system antagonists, and use of icodextrin-based PD solution. On the contrary, baseline overhydration or categorization by classic predictors of mortality (age, comorbidity, diabetes) did not appear to influence the risk pattern associated with lower serum sodium levels.Conclusions: Our results suggest that hyponatremia performs as a consistent correlate of the risk of mortality mainly in PD patients manifesting direct or indirect signs of inflammation and wasting, while this association is not apparently linked to the presence of overhydration or nominal, preexisting comorbid conditions. [ABSTRACT FROM AUTHOR]

Introduction: Prior abdominal surgery may result in peritoneal membrane adhesions and fibrosis, compromising the success of peritoneal dialysis (PD). The impact of this factor on peritoneal membrane function and PD technique survival has not been adequately investigated. Methods: Following an observational, retrospective design, we studied 171 incident PD patients, with the main objective of analyzing the influence of prior abdominal surgical procedures (main study variable) on baseline and evolutionary peritoneal transport characteristics (main outcome) and PD patient and technique survival (secondary outcomes). Abdominal surgeries were categorized according to the degree of presumed injury to the peritoneal membrane. We also considered the additive effect of aggressions to the membrane during the first year on PD therapy. Results: All patients had a baseline peritoneal equilibration test with complete drainage at 60′, and 113 patients had a second study at the end of the first year. Sixty-one patients (35.7%) had a record of prior abdominal surgery, including 29 patients with at least one major intraperitoneal surgery, 22 having undergone minor intraperitoneal procedures, and 21 with a background of major abdominopelvic extraperitoneal surgery. We did not observe differences, at baseline or after 1 year, among patients with or without previous abdominal procedures regarding small solute transport, overall capacity of ultrafiltration, free water transport, small pore ultrafiltration, or peritoneal protein excretion. Stratified analysis, considering prior and first-year-on-PD peritoneal aggressions, did not reveal any differences, although in this case our analysis was hampered by a limited statistical power. Abdominal surgical events did not influence patient or PD technique survival. Conclusion: Prior abdominal surgical procedures do not appear to compromise peritoneal membrane function or technique survival in patients successfully started on PD. [ABSTRACT FROM AUTHOR]

Background: Overhydration (OH) complicates frequently the clinical course of Peritoneal Dialysis (PD) patients, and keeps a controversial association with the risk of peritoneal infection. The main objective of this study was to disclose an association between persistent OH and the risk of enteric peritonitis in a relatively large sample of patients undergoing PD., Method: Following a prospective design, we monitorized systematically body composition of patients treated with PD in our unit (2011-2016), searching for a correlation with the ensuing risk of peritonitis, with an emphasis on the association between persistent OH (main study variable) and the risk of infection by enteric pathogens (main outcome). Essential demographic, clinical and laboratory variables with a potential influence on the risk of peritonitis were recorded. We used multivariate survival analysis to clarify the specific effect of different body composition parameters on the main outcome., Main Results: We included 139 patients for analysis (mean follow-up 24 months). Sixty-three patients suffered at least one peritonitis, and 17 had at least one diagnosis of enteric peritonitis. Univariate analysis disclosed a general trend to an increased risk of enteric peritonitis in overhydrated patients, as evidenced by associations of this outcome with mean extracellular water/intracellular water (ECW/ICW) (p=.007), OH/ECW (p=.033) and ECW/total body water (ECW/TBW) (p=.004) ratios, but not with absolute OH values. Multivariate analysis confirmed similar associations or trends (RR: 3.48, 95% CI: 1.03-14.59; p=.046, highest versus lowest tertile of ECW/ICW, RR: 2.31, 95% CI: 0.98-6.56; p=.061, highest versus lowest tertile of OH/ECW, and RR: 6.33, 95% CI: 1.37-19.37; p=.011, highest versus lowest tertile of ECW/TBW). On the contrary, no apparent association was detected between OH and the overall risk of peritoneal infection., Conclusion: Persistent overhydration portends a significant risk of peritoneal infection by enteric pathogens, among patients undergoing chronic PD., (Copyright © 2019 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

Background: Irisin is an adipomyokine with claimed anti-obesity and anti-diabetic effects. This hormone has been insufficiently studied in patients with advanced chronic kidney disease (CKD)., Objective: To perform an exploratory analysis of serum irisin levels in patients undergoing different CKD treatments., Method: Following a cross-sectional design, we estimated serum levels of irisin in 95 patients with CKD managed conservatively (advanced CKD), with peritoneal dialysis (PD) or with haemodialysis, and compared our findings with a control group of 40 healthy individuals. We investigated the correlations between serum irisin and demographic, clinical, body composition and metabolic variables., Results: Irisin levels were lower in all the CKD groups than in the control group. The univariate analysis revealed limited correlations between irisin, on the one hand, and fat (but not lean) mass, glomerular filtration rate (GFR) and plasma albumin and bicarbonate, on the other. The multivariate analysis confirmed that advanced CKD patients managed conservatively (difference 111.1ng/ml), with PD (25.9ng/ml) or haemodialysis (61.4ng/ml) (all P<.0005) presented lower irisin levels than the control group. Furthermore, PD patients presented higher serum levels of irisin than those on haemodialysis (difference 39.4ng/ml, P=.002) or those managed conservatively (24.4 ng/ml, P=.036). The multivariate analysis also identified plasma bicarbonate (B=3.90 per mM/l, P=.001) and GFR (B=1.89 per ml/minute, P=.003) as independent predictors of irisin levels. Conversely, no adjusted correlation between irisin and body composition markers was found., Conclusions: Serum irisin levels are low in patients with CKD and show a consistent correlation with GFR and plasma bicarbonate levels. PD patients present higher levels of irisin than those managed conservatively or with haemodialysis. Our study confirms a general inconsistency of the association between serum irisin levels, on the one hand, and body composition and metabolic markers, on the other., (Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

Unlabelled: ♦, Background: Peritoneal catheter tunnel and exit-site infection (TESI) complicates the clinical course of peritoneal dialysis (PD) patients. Adherence to recommendations for catheter insertion, exit-site care, and management of Staphylococcus aureus (SAu) carriage reduces, but does not abrogate the risk of these infections. ♦, Objective: To reappraise the risk profile for TESI in an experienced center with a long-term focus on management of SAu carriage and a low incidence of these infections. ♦, Method: Following a retrospective, observational design, we investigated 665 patients incident on PD. The main study variable was survival to the first episode of TESI. We considered selected demographic, clinical, and technical variables, applying multivariate strategies of analysis. ♦, Main Results: The overall incidence of TESI was 1 episode/68.5 patient-months. Staphylococcus aureus carriage disclosed at inception of PD (but not if observed sporadically during follow-up) (hazard ratio [HR] 1.53, p = 0.009), PD started shortly after catheter insertion (HR 0.98 per day, p = 0.011), PD after kidney transplant failure (HR 2.18, p = 0.017), lower hemoglobin levels (HR 0.88 per g/dL, p = 0.013) and fast peritoneal transport rates (HR 2.92, p = 0.03) portended an increased risk of TESI. Delaying PD ≥ 30 days after catheter insertion markedly improved the probability of TESI. Carriage of methicillin-resistant SAu since the start of PD was associated with a high incidence of TESI by these bacteria. On the contrary, resistance to mupirocin did not predict such a risk, probably due to the use of an alternative regime in affected patients. ♦, Conclusions: Adherence to current recommendations results in a low incidence of TESI in PD patients. Interventions on specific risk subsets have a potential to bring incidence close to negligible levels. Despite systematic screening and management, SAu carriage is still a predictor of TESI. Antibiotic susceptibility patterns may help to refine stratification of the risk of TESI by these bacteria. Early insertion of the peritoneal catheter should be considered whenever possible, to reduce the risk of later TESI., (Copyright © 2016 International Society for Peritoneal Dialysis.)

Patients on renal replacement therapy (RRT) infected with the human immunodeficiency virus (HIV) are a special group with growing interest. In order to study the epidemiological data of HIV+ patients on RRT in Spain, we collected individual information from 2004-2011 (period of use of highly active antiretroviral therapy [HAART] in the Autonomous Communities of Andalusia, Aragon, Asturias, Catalonia, Valencia, Castilla la Mancha, Castilla León, Galicia, Madrid, La Rioja and the Basque Country, comprising 85% of the Spanish population. A total of 271 incident and 209 prevalent patients were analysed. They were compared with the remaining patients on RRT during the same period. The annual incidence was 0.8 patients per one million inhabitants, with a significant increase during the follow-up period. The proportion of prevalent HIV+ patients was 5.1 per 1,000 patients on RRT (95% confidence interval [CI] 4.4-5.8. Although glomerular diseases constituted the majority of cases (42%), diabetic nephropathy was the cause in 14% of patients. The nation-wide totals for these percentages were 13 and 25%, respectively. Compared to the total of patients in treatment, the risk of death was significantly higher in the HIV+ group: hazard ratio (HR) adjusted for age, sex and diabetes was 2.26 (95% CI 1.74 - 2.91). Hepatitis C coinfection increased the risk of death in the HIV+ group (HR 1.77; 95% CI 1.10 - 2.85). The probability of kidney transplantation in HIV+ was only 17% after 7 years, comparing with total RTT patients (HR 0.15; 95% CI: 0.10-0.24). Despite the use of HAART, the incidence of HIV+ patients on dialysis has increased; their mortality still exceeds non-HIV patients, and they have a very low rate of transplantation. It is necessary to further our knowledge of this disease in order to improve results., (Copyright © 2015 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

Background: Diabetes mellitus, especially if complicated by poor glycemic control, portends an increased risk of infection. The significance of this association in the case of diabetic patients undergoing peritoneal dialysis (PD) has not been assessed., Methods: Using a retrospective observational design, we analyzed the association between glycemic control at the start of PD (estimated from glycosylated hemoglobin levels) and the risk of peritoneal and catheter tunnel and exit-site infections during follow-up in 183 incident patients on PD. We used the median value of glycosylated hemoglobin to classify patients into good (group A) or poor (group B) glycemic control groups. We applied multivariate strategies of analysis to control for other potential predictors of PD-related infection., Results: Groups A and B differed significantly in age, dialysis vintage, use of insulin, and rate of Staphylococcus aureus carriage. Neither the incidence (0.60 episodes in group A vs 0.56 episodes in group B per patient-year) nor the time to a first peritoneal infection (median: 42 months vs 38 months) differed significantly between the study groups. In contrast, group B had a significantly higher incidence of catheter tunnel and exit-site infections (0.23 episodes vs 0.12 episodes per patient-year) and shorter time to a first infection episode (64 months vs 76 months, p = 0.004). The difference persisted in multivariate analysis (adjusted hazard ratio: 2.65; 95% confidence interval: 1.13 to 6.05; p = 0.013). We observed no differences between the study groups in the spectrum of causative organisms or in the outcomes of PD-related infections., Conclusions: Poor glycemic control is a consistent predictor of subsequent risk of catheter tunnel and exit-site infection, but not of peritoneal infection, among diabetic patients starting PD therapy., (Copyright © 2014 International Society for Peritoneal Dialysis.)

Background: There is a deficit of information regarding the factors that influence peritoneal protein excretion (PPE) during PD therapy. In particular, the effects of the modality of PD and other conditions of the dialysis prescription remain unclear., Method: This prospective, observational study analysed the effects of prescription characteristics on 24-hour PPE (study variable) in a cohort of patients starting PD. Our statistical analysis included a multi-level mixed model and standardised estimations of peritoneal protein transport during serial four-hour peritoneal equilibrium tests in order to control for disparities in the characteristics of patients managed on different regimens., Results: We evaluated 284 patients, 197 on CAPD and 87 on automated PD (APD), at the start of PD treatment. The two groups differed in terms of clinical characteristics and peritoneal function. Univariate, serial estimates of 24-hour PPE were marginally higher in CAPD patients, and remained essentially stable over time in both groups. Multivariate analyses identified CAPD (B=888.5mg, 95% CI: 327.5/1448.6), total dialysate volume infused per day (B=275.9 mg/Ll; 153.9/397.9) and ultrafiltration (B=0.41 mg/mL; 0.02/0.80) as independent predictors of 24-hour PPE. The model also revealed a minor trend for a lower 24-hour PPE as time on PD increases., Conclusions: The individual characteristics of peritoneal protein transport are the major determinants of 24-hour PPE. The use of CAPD as the dialysis modality is associated with higher PPE rates than the APD technique, although this difference is counterbalanced by a direct correlation between PPE and the volume of dialysate infused per day. Ultrafiltration and time on dialysis also act as minor independent predictors of PPE during PD therapy.

Background: The peritoneal equilibration test (PET) permits assessment of peritoneal protein transport, but this potential marker of outcome in peritoneal dialysis (PD) patients lacks adequate standardization. ♢, Objectives: To assess various approaches for estimation of peritoneal protein transport in PD patients during 2.27% and 3.86% glucose-based PETs, and to uncover the demographic, clinical, and biochemical correlates of this phenomenon. ♢, Patients and Methods: We studied 90 PD patients who underwent 2.27% and 3.86% PETs in random order, and we used multivariate analysis to compare assessments of peritoneal protein transport in both tests, searching for correlations between D₂₄₀' - D₀' protein concentration (PETΔPConc), total peritoneal protein excretion (PET-PPE), or total protein clearance (PET-PC) on the one hand (the main study variables), and PET-derived markers of peritoneal function and selected demographic, clinical, and biochemical variables on the other. ♢, Results: The PETΔPConc was higher during the 2.27% PET (mean: 45.2 mg/dL vs 37.0 mg/dL for the 3.86% test; p = 0.003); the PET-PPE and PET-PC were comparable (1121.8 mg vs 1168.9 mg, p = 0.52, and 17.1 mL vs 17.8 mL, p = 0.66, respectively). All three variables sustained a significant, yet moderate correlation (all r² values < 0.30) with the 24-hour PPE rate. Multivariate analysis identified dialysate-to-plasma ratio (D/P₂₄₀') of creatinine, end-to-initial dialysate ratio (D₂₄₀'/D₀') of glucose, current daily peritoneal glucose load, ultrafiltration during PET, systolic blood pressure, and previous cardiovascular events (3.86% test only) as independent predictors of protein transport during PET. ♢, Conclusions: Either PET-PPE or PET-PC seems preferable to PETΔPConc for characterization of peritoneal protein transport. Small-solute transport characteristics, ultrafiltration, and current peritoneal glucose load sustain independent correlations with peritoneal protein transport. The latter variable shows also a moderate association with markers of cardiovascular disease in PD patients.

Background: Optimization of ultrafiltration and preservation of the peritoneal membrane are desirable objectives in peritoneal dialysis (PD) patients. Mixtures of glucose- and non-glucose-based solutions may help to meet both targets simultaneously., Aim: To analyze the effects, in terms of ultrafiltration and peritoneal glucose load, of including icodextrin-based dialysate in the nocturnal schedule of patients undergoing automated PD (APD)., Method: Following a randomized crossover design, 17 APD patients underwent two 10-day study periods under identical prescription (including amino acid-based solution for the night schedule), except for the substitution of 2 L glucose-based dialysate in the nocturnal mixture (control) by a similar amount of icodextrin-based dialysate (icodextrin phase) in one period. Dependent variables included ultrafiltration, sodium removal, peritoneal glucose load, and residual renal function. We measured serum and urine levels of icodextrin metabolites at the end of each phase., Results: Ultrafiltration was marginally higher during the icodextrin phase (median 815 vs 763 mL/day, p = 0.07), while peritoneal sodium removal was similar in both phases (74 vs 71 mmol/L/day). Peritoneal glucose load (median 67.5 vs 104.0 g/day, p < 0.005) and absorption (14.0 vs 35.6 g/day, p < 0.005) were lower during the icodextrin phase. Diuresis was also modestly lower during the icodextrin phase (500 vs 600 mL/day, p < 0.05). Serum levels of icodextrin metabolites were moderately higher in the icodextrin phase (p < 0.005) in patients both on and off diurnal icodextrin., Conclusion: Inclusion of amino acid- and icodextrin-based solutions in the nocturnal schedule of APD patients may allow sustained ultrafiltration and sodium removal while significantly reducing the peritoneal glucose load in these patients.