Multifrequency bioimpedance by spectroscopy vs. routine methods in the management of hydration status in peritoneal dialysis patients: A randomized control trial.

Background: Overhydration (OH) is common in peritoneal dialysis (PD) and increases the cardiovascular risk. Multifrequency bioimpedance spectroscopy (BIS) has been proposed to estimate the hydration in dialysis. Our objective was to evaluate if BIS is superior than control based on clinical assessment plus single-frequency bioimpedance (SF-BIA) on the fluid control and intermediate cardiovascular outcomes. Methods: Randomized controlled study in adult PD patients, with a 9-month follow-up, allocated into two groups: control and BIS. Data were collected from medical records. SF-BIA and BIS, laboratory exams, ambulatory blood pressure monitoring, echocardiography (ECHO), and pulse wave velocity (PWV) were evaluated. The BIS data were available to the medical team only in BIS group. Results: 34 patients completed the study, 17 in each group. At the endpoint the BIS group had a significant (p < 0.05) greater proportion of patients with OH/extracellular water (OH/ECW%) ≤ 15% than the control (94.1% vs. 52.9%), and a lower OH mean (2.1 ± 1.6 vs. 0.9 ± 1.1 L). The control group has a significant increase in the tumor necrosis factor alpha median concentration from baseline to six [11.9 (6.0-24.1) vs. 44.7 (9.4-70.6) pg/ml] and 9 months [11.9 (6.0-24.1) vs. 39.4 (27.9-62.6) pg/ml], and in the N-terminal fragment of pro-B-type natriuretic peptide median [239 (171.5-360.5) vs. 356 (219-1,555) pg/ml]. For cardiovascular parameters, BIS group presented a significant reduction in radial PWV [7.7 (6.9-9.2) vs. 6.5 (5.5-8.4) m/s] at 9 month, while in the control presented a significant increase in mean central systolic blood pressure (BP) (106.8 ± 11.2 vs. 117.6 ± 16.5 mmHg) and in central diastolic BP (90.4 ± 9.8 vs. 103.3 ± 12.5 mmHg) at 9 months. The left ventricular mass (LVM)/body surface presented a significant reduction in the control (109.6 ± 30.8 vs. 101.2 ± 28.9 g/m2) and BIS group (107.7 ± 24.9 vs. 96.1 ± 27.0 g/m2) at 9 months. Conclusion: The results suggest BIS is superior than the clinical evaluation plus SF-BIA for the fluid control of PD patients. Clinical trial registration: [https://www.ClinicalTrials.gov], identifier [RBR-10k8j3bx].

Agreement of Single-Frequency Electrical Bioimpedance in the Evaluation of Fat Free Mass and Fat Mass in Peritoneal Dialysis Patients.

Background: Protein-energy wasting is related to impairment of quality of life and lower survival of end-stage kidney disease (ESKD) patients. The evaluation of body composition, especially fat free mass (FFM) and fat mass (FM), is important for the prediction of outcomes in these individuals. The aim of this study was to compare the FFM and FM measurements obtained by single-frequency bioimpedance (SF-BIA) and by a multiple frequency bioimpedance (MF-BIA) device, using dual energy X-ray absorptiometry (DXA) peritoneal dialysis (PD) patients. Methods: This was a cross-sectional study involving adult patients undergoing regular PD, in which we performed SF-BIA, MF-BIA, and DXA at the same visit. To compare the bioimpedance values with DXA, we used: Person correlation (r), intraclass correlation coefficient (ICC), and Bland-Altman concordance analysis. Results: The sample consisted of 50 patients in the PD, with mean age of 55.1 ± 16.3 years. Both bioimpedance methods showed a strong correlation (r > 0.7) and excellent reproducibility (ICC > 0.75) compared to DXA. According to the Bland-Altman diagram, SF-BIA showed agreement in body compartment measurements, with no proportionality bias (p > 0.05), without systematic bias for FFM (-0.5 ± 4.9, 95% CI -1.8 to 0.9, p = 0.506), and for FM (0.3 ± 4.6, p = 0.543). MF-BIA did not present a proportionality bias for the FFM, but it underestimated this body compartment by 2.5 ± 5.4 kg (p = 0.002). In addition, MF-BIA presented proportionality bias for FM. Conclusion: SF-BIA was a more accurate assessing method than MBIA for FFM and FM measurements in PD patients. Because it is a low-cost, non-evaluator-dependent measurement and has less systematic bias, it can also be recommended for fat mass and free-fat mass evaluation in PD patients.

Association between vitamin D levels and mortality in hemodialysis patients: a cohort study.

Introduction: Low vitamin D levels are associated with mortality in hemodialysis (HD) patients; however, the serum vitamin D thresholds are unclear. This study aimed to identify the vitamin D level below which mortality increases in HD patients.Methods: A cohort of HD patients enrolled from January 2014 to January 2017 was evaluated. The variables were analyzed according to the season, namely, summer, winter, and annual average, mortality was the primary outcome. The patients were assigned to vitamin D quintiles, and multivariate Cox regression analysis adjusted for age, ethnicity, gender, body mass index (BMI), inhibitors of the renin-angiotensin system, statin, calcitriol, and antiplatelet drugs use, hemodialysis vintage, hypertension, diabetes mellitus, atherosclerotic disease, and C-reactive protein was performed.Results: There were studied 306 patients. Vitamin D levels of 18.0-23.6 ng/mL (hazard ratio [HR] = 4.30; 95% confidence interval [CI] 1.60-11.54, p = 0.004) and <18.0 ng/mL (HR = 3.83; 95% CI: 1.42-10.35, p = 0.008) in summer and vitamin D levels of 21.5-27.1 ng/mL (HR = 3.70; 95% CI: 1.50-9.11, p = 0.004) and ≤17.5 ng/mL (HR = 2.84; 95% CI: 1.13-7.13, p = 0.026) in winter were associated with mortality. The average annual values of vitamin D associated with all-cause mortality were <17.7 ng/dL (adjusted HR = 4.25, 95% CI: 1.57-11.48, p = 0.004), and between >17.7 ng/dL and ≤23.1 ng/dL (adjusted HR = 3.91, 95% CI: 1.47-10.42, p = 0.006).Conclusions: Annual average vitamin D levels <23.1 ng/mL were associated with higher all-cause mortality, regardless of the confounding variables evaluated.

Association between Sodium Intake and Urinary Fractional Albumin and Immunoglobulin G Excretion in Chronic Nondialytic Renal Disease: A Prospective Longitudinal Study.

BACKGROUND/AIMS: Previous studies reported that fractional clearance of urinary proteins is better than total proteinuria in predicting chronic kidney disease (CKD) progression. However, the role of sodium in the fractional excretion of proteins has not been established. We aimed to evaluate the association between sodium intake and fractional albumin and immunoglobulin G (IgG) excretion in nondialytic CKD. METHODS: We did a longitudinal, observational, and prospective study that included CKD patients aged 18-80. Included patients performed basal routine laboratory evaluations, urinary sodium excretion, and fractional albumin and IgG excretion that were repeated after 6-month of follow-up. RESULTS: We evaluated 84 patients, mean age 55 ± 15.6 years, 40 women, and 74 whites. The change of estimated sodium intake had an association with the change of fractional albumin (R = 0.54; p < 0.001) and IgG (R = 0.56; p < 0.001) excretion in univariate analysis (increases in sodium intake were paralleled by increases in albumin and IgG excretion fractions). This association was maintained in a multiple generalized linear model even after adjusting for age and for changes in blood pressure, urinary potassium, protein intake, and blood glucose. CONCLUSION: In CKD patients, changes in estimated sodium intake were associated with changes in the fractional albumin and IgG excretion regardless of confounding factors. Findings of this study support the idea that reducing salt intake, and consequently, albumin and IgG fractional excretions could help to slow CKD progression. This hypothesis must be tested in long-term interventional studies.

Influence of the intra-peritoneal segment of the swan neck peritoneal catheter on infectious and mechanical complications and technique survival.

BACKGROUND: There is no consensus about the preferable type of catheter for successful peritoneal dialysis. Intra- and extra-peritoneal catheter configuration may be associated with mechanical and infectious complications affecting technique survival. The objective of this study was to compare the mechanical and infectious complications of coiled versus straight swan neck (SN) peritoneal dialysis catheters. METHODS: A prospective randomized trial was performed to compare mechanical (tip migration with dysfunction) and infectious (peritonitis and exit site infection) complications between catheters randomly divided into two groups: swan neck straight tip and swan neck coiled tip. The follow-up was 1 year. RESULTS: A total of 49 catheters, in 46 patients, were included from April 2015 to February 2016. The catheters groups were constituted as: 25 coiled tip SN and 24 straight tip SN. The baseline demographics were similar among the groups. Kaplan-Meier survival estimates were not different for time to first exit site infection, peritonitis and time to first catheter tip migration (log-rank test, p = 0.07, p = 0.54 and p = 0.83, respectively). Catheter survival and method survival were also similar (log-rank p = 0.88 and p = 0.91, respectively). CONCLUSIONS: The two types of intra-peritoneal segments of SN catheters studied presented similar infectious and mechanical rates with no differences in catheter and technique survival curve. These results were consistent with the recommendations of the International Society for Peritoneal Dialysis.