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Background: Residual renal function (RRF) is an important determinant of mortality and morbidity in patients receiving peritoneal dialysis (PD). Recent studies have shown a positive effect of angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARBs) on RRF in PD patients., Objective: To compare enalapril and losartan for RRF preservation in automated peritoneal dialysis (APD) patients., Material and Methods: An open label randomized controlled trial (RCT) with a 12 month follow-up period was conducted to compare the effect of enalapril vs. losartan on RRF preservation in 60 APD patients. Measurements were done at the start of the study (baseline), 3, 6, 9, and 12 months. A historical control group (HCG) without treatment was included to assess the natural history of RRF loss., Results: RRF in the enalapril group dropped from 3.65 +/- 1.6 (baseline) to 2.36 +/- 0.38 mL/min/1.73 m2 (12 months). In the losartan group RRF was reduced from 4.1+/- 2.01 (baseline) to 2.54 +/- 0.47 mL/min/ 1.73 m2 (12 months). There were not significant differences between the two groups regarding RRF at 12 months. In the HCG, RRF declined from 3.68 +/- 0.48 to 1.4 +/- 0.29 mL/min/ 1.73 m2 (12 months). RRF in the HCG was significantly lower than RRF in the two treated groups at 12 months (P < 0.05)., Conclusions: There was not significant difference on RRF preservation between enalapril and losartan groups. Comparing these results to those of the HCG suggests that the treatment with any of the drugs is useful in preserving RRF.

Background and Objectives: Twenty-four-hour urine and dialysate collections provide accepted means to assess adequacy in peritoneal dialysis (PD). Recent publications suggest that creatinine clearance (CrCl) estimated from the Modification of Diet in Renal Disease (MDRD) equations (eCrCl) accurately approximates measured CrCl (mCrCl) derived from 24-hour collections of urine and dialysate and might serve as an alternative means to assess small-solute clearance and adequacy in PD., Design, Setting, Participants, & Measurements: Post hoc analysis of data from patients enrolled in ADEMEX was used to assess agreement between mCrCl and eCrCl derived by four- and six-variable MDRD equations (4V-MDRDE and 6V-MDRDE, respectively). Additionally, associations among mCrCl, eCrCl, and survival were determined., Results: Acceptable precision was observed between mCrCl and 4V-MDRDE-eCrCl and 6V-MDRDE-eCrCl for the entire cohort. Precision was markedly diminished when analysis was limited to functionally anuric patients with mCrCl < 12 ml/min per 1.73 m². Although there was no association between survival and mCrCl, for every 1-ml/min per 1.73 m² increase in 4V- and 6V-MDRDE-eCrCl, there was a 6% and 4% increase in risk of death, respectively. There was a negative association between MDRDE-eCrCl and creatinine appearance rates, suggesting MDRDE-eCrCl is significantly confounded by individual differences in muscle mass., Conclusions: MDRDE-eCrCl provides demographically comparable values to 24-hour urine and dialysate collections across the ADEMEX cohort. However, MDRDEs should not be used to assess small-solute removal or adequacy in individual PD patients or to predict outcome in any cohort of patients over narrow ranges of limited clearance.

Background: N-terminal fragment of B-type natriuretic peptide (NT-proBNP) is a marker of both fluid volume overload and myocardial damage, and it has been useful as a predictor of mortality in patients with end-stage renal disease (ESRD). It has been suggested that continuous ambulatory peritoneal dialysis (CAPD), automated peritoneal dialysis (APD) and haemodialysis (HD) may have different effects on fluid volume and blood pressure control; however, whether the independent predictive value of NT-proBNP for mortality is preserved when analysed in conjunction with fluid overload and dialysis modality is not clear., Methods: A prospective multicentre cohort of 753 prevalent adult patients on CAPD, APD and HD was followed up for 16 months. Plasmatic levels of NT-proBNP, extracellular fluid volume/total body water ratio (ECFv/TBW) and traditional clinical and biochemical markers for cardiovascular damage risk were measured, and their role as predictors of all-cause and cardiovascular mortality was analysed., Results: NT-proBNP level, ECFv/TBW and other cardiovascular damage risk factors were not evenly distributed among the different dialysis modalities. NT-proBNP levels and ECFv/TBW were correlated with several inflammation, malnutrition and myocardial damage markers. Multivariate analysis showed that NT-proBNP levels and ECFv/TBW were predictors of both all-cause and cardiovascular mortality, independently of dialysis modality and the presence of other known clinical and biochemical risk factors., Conclusions: NT-proBNP is a reliable predictor of death risk independently of the effect of dialysis modality on fluid volume control, and the presence of other clinical and biochemical markers recognized as risk factors for all-cause and cardiovascular mortality. NT-pro-BNP is a good predictor of mortality independently of fluid volume overload and dialysis modality.

Objective: To determine the risk of pediatric end stage renal disease patients undergoing continuous ambulatory peritoneal dialysis to develop a subsecuent peritonitis episode caused by an identical Staphylococcus aureus (SA) strain., Methods: Longitudinal survey carried out in a CAPD center at the nephrology department of a tertiary care (reference) pediatric hospital. At recruitment, swabs were collected from the nares, exit site, and hands, respectively from 29 patients who were followed-up for a mean period of 369 +/- 80 days (range 224-516 days), and from the nares and hands of their mothers. Isolated SA strains were kept in BHI glycerol at -20 degrees C for subsequent analysis. Peritonitis episodes were monitored and registered. When a SA strain was isolated from the dialysate effluent it was compared with the preexisting strain by PFGE., Results: We report 7 SA-mediated peritonitis episodes among 6 patients. Only one of these patients was a previous nasal carrier, and 2 were previous exit site carriers of the same SA strain. The relative risk of developing a peritonitis episode caused by a preexistent SA strain colonizing the exit site was 0.948. The relative risk of developing a peritonitis episode caused by a preexistent SA strain colonizing the nares was 0.525., Conclusions: SA carriers do not appear to be at higher risk of developing peritonitis by an SA related strain than non-carriers. Our results do not lend support to the recommendation of monitoring nasal or exit site carrier status in CAPD patients. The need of attempting to eradicate SA from nose or exit site is also questioned.

Background and Objectives: Natriuretic peptides have been suggested to be of value in risk stratification in dialysis patients. Data in patients on peritoneal dialysis remain limited., Design, Setting, Participants, & Measurements: Patients of the ADEMEX trial (ADEquacy of peritoneal dialysis in MEXico) were randomized to a control group [standard 4 x 2L continuous ambulatory peritoneal dialysis (CAPD); n = 484] and an intervention group (CAPD with a target creatinine clearance > or =60 L/wk/1.73 m(2); n = 481). Natriuretic peptides were measured at baseline and correlated with other parameters as well as evaluated for effects on patient outcomes., Results: Control group and intervention group were comparable at baseline with respect to all measured parameters. Baseline values of natriuretic peptides were elevated and correlated significantly with levels of residual renal function but not with body size or diabetes. Baseline values of N-terminal fragment of B-type natriuretic peptide (NT-proBNP) but not proANP(1-30), proANP(31-67), or proANP(1-98) were independently highly predictive of overall survival and cardiovascular mortality. Volume removal was also significantly correlated with patient survival., Conclusions: NT-proBNP have a significant predictive value for survival of CAPD patients and may be of value in guiding risk stratification and potentially targeted therapeutic interventions.

The increasing rates in incidence and prevalence of chronic kidney disease (CKD) are important challenges for health systems around the world, and are even more significant for undeveloped countries. In Mexico the prevalence of CKD seems to be similar to that in highly developed nations, with diabetes as the leading cause of CKD; however, human and economic resources seem to be insufficient for treatment needs. This is reflected in the unacceptably high mortality rates and in noncompliance with established standards and guidelines. Several measures need to be taken to improve this picture, such as more efficient programs for the prevention of obesity, diabetes, and hypertension. Organizing a national registry of patients with CKD is now a pressing need, as is a continuous search for additional funding and budgets to increase the number of qualified nephrologists and specialized nurses and to continue the much-needed research on CKD.

Background: Inflammation is a risk factor for mortality in patients with chronic renal failure (CRF). Prevention of extracellular fluid volume expansion and the use of certain drugs such as pentoxifylline (PF) may reduce inflammation and oxidative stress. The aim of this study is to analyze the effect of dietary sodium and PF treatment on the levels of inflammation and oxidative stress markers in rats with CRF., Methods: CRF was induced in rats by 5/6 nephrectomy. Different groups of rats with CRF received low sodium (LNa, 0.01% sodium chloride [NaCl] in the diet), normal sodium (NNa, 0.05% NaCl in the diet), or high sodium diet (HNa, as in NNa plus 0.015% NaCl in the drinking water). An additional group received HNa plus PF treatment (25 mg/kg in the drinking water) for 60 days. Circulating creatinine, tumor necrosis factor alpha (TNF-alpha), nitrites, thiols, malondialdehyde (MDA), and advanced oxidation protein products (AOPP) were measured., Results: Higher sodium intake was associated with higher serum creatinine levels (median; interquartile range), LNa, 1.255; 0.715, NNa, 1.305; 0.495, HNa, 2.015; 1.115 mg/dL (p < 0.05), TNF-alpha levels, LNa, 2.7; 23.6, NNa, 36.7; 47.7, HNa, 263.7; 126.5 pg/mL, and AOPP, LNa, 31.72; 7.55, NNa, 45.89; 9.38, HNa, 60.41; 37.42 microg/mL. MDA was not modified by sodium intake. PF treatment decreased serum TNF-alpha (151.7 pg/mL, p < 0.5) and AOPP (49.83 micromol/L, p < 0.03), and increased nitrites and thiols levels when compared with HNa rats., Conclusions: High sodium intake increases the serum concentration of inflammation and oxidative stress markers; these changes are prevented by PF treatment.

Background: Inflammation is an important risk for mortality in dialysis patients. Extracellular fluid volume (ECFv) expansion, a condition commonly seen in peritoneal dialysis (PD) patients, may be associated with inflammation. However, published support for this relationship is scarce., Objectives: To quantify the proportion of patients on PD with inflammation and to analyze the role of ECFv expansion and the factors related to these conditions., Design: A prospective, multicenter cross-sectional study in six hospitals with a PD program., Patients and Methods: Adult patients on PD were studied. Clinical data, body composition, and sodium and fluid intake were recorded. Biochemical analysis, C-reactive protein (CRP), and peritoneal and urinary fluid and sodium removal were also measured., Results: CRP values positive (>or=3.0 mg/L) for inflammation were found in 147 (80.3%) and negative in 36 patients. Patients with positive CRP had higher ECFv/total body water (TBW) ratio (women 47.69 +/- 0.69 vs 47.36 +/- 0.65, men 43.15 +/- 1.14 vs 42.84 +/- 0.65; p < 0.05), higher serum glucose (125.09 +/- 81.90 vs 103.28 +/- 43.30 mg/dL, p < 0.03), and lower serum albumin (2.86 +/- 0.54 vs 3.17 +/- 0.38 g/dL, p < 0.001) levels. They also had lower ultrafiltration (1003 +/- 645 vs 1323 +/- 413 mL/day, p < 0.005) and total fluid removal (1260 +/- 648 vs 1648 +/- 496 mL/day, p < 0.001), and less peritoneal (15.59 +/- 162.14 vs 78.11 +/- 110.70 mEq/day, p < 0.01) and total sodium removal (42.06 +/- 142.49 vs 118.60 +/- 69.73 mEq/day, p < 0.001). In the multivariate analysis, only ECFv/TBW was significantly (p < 0.04) and independently associated with inflammation. ECFv/TBW was correlated with fluid removal (r = 0.16, p < 0.03) and renal sodium removal (r = 0.2, p < 0.01)., Conclusion: The data suggest that ECFv expansion may have a significant role as an inflammatory stimulus. The results disclose a relationship between the two variables, ECFv expansion and inflammation, identified as independent risk factors for mortality in PD patients.

Background: The frequency of low-turnover bone disease (LTBD) in patients with chronic kidney disease (CKD) has increased in past years. This change is important because LTBD is associated with bone pain, growth delay, and higher risk for bone fractures and extraosseous calcifications. LTBD is a histological diagnosis. However, serum markers such as parathyroid hormone (PTH) and calcium levels offer a noninvasive alternative for diagnosing these patients., Objective: To describe the prevalence of LTBD in pediatric patients with renal failure undergoing some form of renal replacement therapy, using serum calcium and intact PTH levels as serum markers., Methods: In this cross-sectional study, 41 children with CKD undergoing dialysis treatment (31 on continuous ambulatory peritoneal dialysis and 10 on hemodialysis) were included. There were no inclusion restrictions with respect to gender, cause of CKD, or dialysis modality. The children were studied as outpatients. The demographic data, CKD course, time on dialysis, phosphate-binding agents, and calcitriol prescription were registered, as well as weight, height, Z-score for height, linear growth rate, and Z-score for body mass index. Serum calcium, phosphorus, aluminum, PTH, alkaline phosphatase, osteocalcin, glucose, creatinine, urea, cholesterol, and triglycerides were measured., Results: There were 20 (48.8%) children with both PTH < 150 pg/mL and corrected total calcium >10 mg/dL who were classified as having LTBD[(+)]; the remaining 21 (51.2%) children were classified as having no LTBD[(-)]. The LTBD(+) patients were younger (11.2 +/- 2.7 vs 13.2 +/- 2.4 years, p < 0.01) but they had no differences regarding Z-scores for height. Linear growth in 6 months was less than expected in both groups (-0.15 +/- 0.23 cm/month), but the difference between expected and observed growth was higher in the LTBD(+) group (-0.24 +/- 0.14 vs -0.07 +/- 0.28 cm/mo, p < 0.03). LTBD(+) patients also had lower serum creatinine (8.69 +/- 2.75 vs 11.19 +/- 3.17 mg/dL, p < 0.01), higher serum aluminum levels [median (range) 38.4 (9 - 106) vs 28.1 (9 - 62) microLg/L, p < 0.05], and lower systolic blood pressure (112.0 +/- 10.3 vs 125.0 +/-1 2.9 mmHg, p < 0.015) and diastolic blood pressure (76.0 +/- 9.7 vs 84.5 +/- 8.2 mmHg, p < 0.017). A significant correlation was found between PTH and alkaline phosphatase (r = 0.68, p < 0.001), but not between PTH and aluminum., Conclusion: The LTBD(+) biochemical profile was found in 48.8% of the children and was associated with impaired linear growth. Aluminum contamination, evidenced by higher serum aluminum levels, may have had a pathogenic role in these disorders. Higher systolic and diastolic blood pressure levels may be related to higher serum PTH levels.

Objective: To test the effect of zinc supplementation on the nutritional status of patients on continuous ambulatory peritoneal dialysis (CAPD)., Material and Methods: Double-blinded randomized controlled clinical trial. Twenty-five patients with end stage renal disease (ESRD) on CAPD program, from 16 to 60 years old were studied. Two weeks before the beginning of the study all the drugs with a known effect on zinc absorption were withdrawn. Patients were randomly allocated into one of two groups. The control group consisted of 12 patients receiving placebo, and the intervention group of 13 patients receiving 100 mg/day of elemental zinc for 3 months. The diet was individually adjusted to 35 kcal/kg/day, and 1.5 g/day of proteins. Subjective global assessment (SGA), anthropometric measurements, electric bioimpedanciometry, measurements of albumin, prealbumin, and transferrin, and evaluation of energy, proteins, carbohydrates, and lipids consumption were done to classify the nutritional status at the beginning and at the end of the study. Therapeutic compliance was assessed by measuring plasma zinc levels and by capsule counting., Results: There were no statistically significant differences between groups regarding age, gender, time on CAPD, and ESRD causes. The proportion of patients classified as well nourished, or with mild or moderate malnutrition by SGA did not show significant differences between the group receiving Zn supplementation and the group receiving placebo. Anthropometric measurements and body composition assessed by bioelectric impedance were similar in the two groups. In the control group, serum levels of albumin (3,621 +/- 838 vs. 3,068 +/- 842 mg/dL), prealbumin (49 +/- 14 vs. 44 +/- 12 mg/dL), and transferrin (238 +/- 94 vs. 195 +/- 79 mg/dL) decreased significantly at the end of the follow-up period respect to the baseline values (p < 0.05). In the intervention group albumin (3,320 +/- 910 vs. 2,696 +/- 964 mg/dL), prealbumin (43 +/- 9 vs. 38 +/- 8 mg/dL), and transferrin (236 +/- 99 vs. 193 +/- 66 mg/dL) also decreased significantly (p < 0.05). In the control group baseline zinc level was low (60 +/- 5 micrograms/dL) and remained stable along the follow-up period, while in the intervention group it increased from 52 +/- 5 (baseline) to 92 +/- 9 micrograms/dL (end of the follow-up, p < 0.05)., Conclusions: Zinc supplementation did not improve the nutritional status in patients on CAPD.

Objective: Recently it has been pointed out that inflammation and infections caused by germs such as Chlamydia pneumoniae are independent cardiovascular risk factors for the general population, but information about these relationships in dialysis patients is scarce. This work was done to analyze the association of C-reactive protein (CRP) and IgG anti-Chlamydia pneumoniae antibodies (anti-Chlp-IgG) as independent cardiovascular risk factors in incident patients on continuous ambulatory peritoneal dialysis (CAPD)., Design: Single-cohort, prospective observational study., Setting: Three CAPD centers from the Instituto Mexicano del Seguro Social, and one from the Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado, Mexico., Patients: A cohort of 75 adult incident patients on CAPD, without clinical signs of congestive heart failure, coronary heart disease, or peripheral arterial insufficiency. No restrictions for age, gender, or cause of renal failure were applied., Primary Outcome: Mortality., Methods: Demographic variables, body composition by electrical bioimpedance, serum glucose, urea, creatinine, lipids, homocysteine, nutritional markers (albumin, prealbumin, and transferrin), CRP, and anti-Chlp-IgG were measured and registered at the time of the first admission. When a patient died, the cause of death was determined by review of the clinical chart., Results: Mean follow-up time was 10.25 patient-months. There were 14 cardiovascular deaths. CRP was positive (> 10 mg/L) in 64% of the patients, and anti-Chlp-IgG in 64%; 29% of the patients were positive for both markers. The relative risk for cardiovascular mortality was 6.23 for patients positive for either CRP or anti-Chlp-IgG, and increased to 9.52 when both markers were positive. Multivariate analysis revealed that CRP and anti-Chlp-IgG were stronger cardiovascular death predictors than age, diabetes, and nutritional status., Conclusion: These data suggest that inflammation and the presence of Chlamydia pneumoniae infections are important predictors of cardiovascular death in patients on CAPD.

Small-solute clearance targets for peritoneal dialysis (PD) have been based on the tacit assumption that peritoneal and renal clearances are equivalent and therefore additive. Although several studies have established that patient survival is directly correlated with renal clearances, there have been no randomized, controlled, interventional trials examining the effects of increases in peritoneal small-solute clearances on patient survival. A prospective, randomized, controlled, clinical trial was performed to study the effects of increased peritoneal small-solute clearances on clinical outcomes among patients with end-stage renal disease who were being treated with PD. A total of 965 subjects were randomly assigned to the intervention or control group (in a 1:1 ratio). Subjects in the control group continued to receive their preexisting PD prescriptions, which consisted of four daily exchanges with 2 L of standard PD solution. The subjects in the intervention group were treated with a modified prescription, to achieve a peritoneal creatinine clearance (pCrCl) of 60 L/wk per 1.73 m(2). The primary endpoint was death. The minimal follow-up period was 2 yr. The study groups were similar with respect to demographic characteristics, causes of renal disease, prevalence of coexisting conditions, residual renal function, peritoneal clearances before intervention, hematocrit values, and multiple indicators of nutritional status. In the control group, peritoneal creatinine clearance (pCrCl) and peritoneal urea clearance (Kt/V) values remained constant for the duration of the study. In the intervention group, pCrCl and peritoneal Kt/V values predictably increased and remained separated from the values for the control group for the entire duration of the study (P < 0.01). Patient survival was similar for the control and intervention groups in an intent-to-treat analysis, with a relative risk of death (intervention/control) of 1.00 [95% confidence interval (CI), 0.80 to 1.24]. Overall, the control group exhibited a 1-yr survival of 85.5% (CI, 82.2 to 88.7%) and a 2-yr survival of 68.3% (CI, 64.2 to 72.9%). Similarly, the intervention group exhibited a 1-yr survival of 83.9% (CI, 80.6 to 87.2%) and a 2-yr survival of 69.3% (CI, 65.1 to 73.6%). An as-treated analysis revealed similar results (overall relative risk = 0.93; CI, 0.71 to 1.22; P = 0.6121). Mortality rates for the two groups remained similar even after adjustment for factors known to be associated with survival for patients undergoing PD (e.g., age, diabetes mellitus, serum albumin levels, normalized protein equivalent of total nitrogen appearance, and anuria). This study provides evidence that increases in peritoneal small-solute clearances within the range studied have a neutral effect on patient survival, even when the groups are stratified according to a variety of factors (age, diabetes mellitus, serum albumin levels, normalized protein equivalent of total nitrogen appearance, and anuria) known to affect survival. No clear survival advantage was obtained with increases in peritoneal small-solute clearances within the range achieved in this study.