Longitudinal change in proteinuria and kidney outcomes in C3 glomerulopathy.

INTRODUCTION: The association between a change in proteinuria over time and its impact on kidney prognosis has not been analysed in complement component 3 (C3) glomerulopathy. This study aims to investigate the association between the longitudinal change in proteinuria and the risk of kidney failure. METHODS: This was a retrospective, multicentre observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. Patients diagnosed with C3 glomerulopathy between 1995 and 2020 were enrolled. A joint modelling of linear mixed-effects models was applied to assess the underlying trajectory of a repeatedly measured proteinuria, and a Cox model to evaluate the association of this trajectory with the risk of kidney failure. RESULTS: The study group consisted of 85 patients, 70 C3 glomerulonephritis and 15 dense deposit disease, with a median age of 26 years (range 13-41). During a median follow-up of 42 months, 25 patients reached kidney failure. The longitudinal change in proteinuria showed a strong association with the risk of this outcome, with a doubling of proteinuria levels resulting in a 2.5-fold increase of the risk. A second model showed that a ≥50% proteinuria reduction over time was significantly associated with a lower risk of kidney failure (hazard ratio 0.79; 95% confidence interval 0.56-0.97; P < 0.001). This association was also found when the ≥50% proteinuria reduction was observed within the first 6 and 12 months of follow-up. CONCLUSIONS: The longitudinal change in proteinuria is strongly associated with the risk of kidney failure. The change in proteinuria over time can provide clinicians a dynamic prediction of kidney outcomes.

Comparison of 3 anti-PLA2R inmmunoassaysfor the diagnosis of idiopathic membranous nephropathy in an european population. A pilot study.

Membranous nephropathy (MN) is one of the most frequent causes of nephrotic syndrome. Renal biopsy is nowadays the gold standard for the diagnosis of MN. The presence of circulating PLA2R antibody is a very specific tool for the diagnosis of this disease, especially associated with primary or idiopathic MN (IMN), even though it can be also found in a small proportion of patients with secondary MN (SMN). This pilot study compares three different techniques for the detection of anti-PLA2R autoantibodies (immunofluorescence, ELISA immunoassay, and multiplex laser bead technology). Serum of 12 IMN and 9 SMN patients was obtained at diagnosis. Additionally, we employed serum samples of 15 healthy volunteers. From our patient cohort, we obtained a 7.75 RU/ml cut-off for the ELISA and 3104 MFI for the Luminex assays. The agreement between the three techniques improved considerably when applying the new cut-off points. As several authors have suggested, cut-offs may be calculated for each specific population instead of establishing global cut-off points. Patients with IMN showed significantly lower serum albumin levels and higher 24 h proteinuria compared to those with SMN. Analysis of ROC curves suggests that ELISA and LUMINEX assays are more useful than biochemical variables to differentiate patients with IMN and SMN. This pilot study contributes to confirming that the combination of ELISA and Luminex assays provide excellent sensitivity and specificity for the identification of IMN.

Validation of a Histologic Scoring Index for C3 Glomerulopathy.

RATIONALE & OBJECTIVE: A previous study that evaluated associations of kidney biopsy findings with disease progression in patients with C3 glomerulopathy (C3G) proposed a prognostic histologic index (C3G-HI) that has not yet been validated. Our objective was to validate the performance of the C3G-HI in a new patient population. STUDY DESIGN: Multicenter, retrospective cohort study. SETTING & PARTICIPANTS: 111 patients fulfilling diagnostic criteria of C3G between January 1995 and December 2019, from 33 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases (GLOSEN). PREDICTORS: Demographic, clinical parameters, C3G-HI total activity score, and the C3G-HI total chronicity score. OUTCOME: Time to kidney failure. ANALYTICAL APPROACH: Intraclass correlation coefficients and κ statistic were used to summarize inter-rater reproducibility for assessment of histopathology in kidney biopsies. The nonlinear relationships of risk of kidney failure with the total activity score and total chronicity score were modeled using Cox proportional hazards analysis that incorporated cubic splines. RESULTS: The study group included 93 patients with C3 glomerulonephritis and 18 with dense-deposit disease. Participants had an overall meanage of 35±22 (SD) years. Forty-eight patients (43%) developed kidney failure after a mean follow-up of 65±27 months. The overall inter-rater reproducibility was very good for the total activity score (intraclass correlation coefficient [ICC]=0.63) and excellent for total chronicity score (ICC=0.89). Baseline estimated glomerular filtration rate (eGFR), 24-hour proteinuria, and treatment with immunosuppression were the main determinants of kidney failure in a model with only clinical variables. Only tubular atrophy and interstitial fibrosis were identified as predictors in a model with histological variables. When the total activity score and total chronicity score were added to the model, only the latter was identified as an independent predictor of kidney failure. LIMITATIONS: Only a subset of the kidney biopsies was centrally reviewed. Residual confounding. CONCLUSIONS: We validated the performance of C3G-HI as a predictor of kidney failure in patients with C3G. The total chronicity score was the principal histologic correlate of kidney failure.

Arteriovenous fistulae after renal biopsy: diagnosis and outcomes using Doppler ultrasound assessment.

BACKGROUND: Percutaneous renal biopsy (PRB) is an important technique providing relevant information to guide diagnosis and treatment in renal disease. As an invasive procedure it has complications. Most studies up to date have analysed complications related to bleeding. We report the largest single-center experience on routine Doppler ultrasound (US) assessment post PRB, showing incidence and natural history of arteriovenous fistulae (AVF) post PRB. METHODS: We retrospectively analysed 327 consecutive adult PRB performed at Ramon Cajal University Hospital between January 2011 and December 2014. All biopsies were done under real-time US guidance by a trained nephrologist. Routine Doppler mapping and kidney US was done within 24 h post biopsy regardless of symptoms. Comorbidities, full blood count, clotting, bleeding time and blood pressure were recorded at the time of biopsy. Post biopsy protocol included vitals and urine void checked visually for haematuria. Logistic regression was used to investigate links between AVF, needle size, correcting for potential confounding variables. RESULTS: 46,5% were kidney transplants and 53,5% were native biopsies. Diagnostic material was obtained in 90,5% (142 grafts and 154 native). Forty-seven AVF's (14.37%) were identified with routine kidney Doppler mapping, 95% asymptomatic (n = 45), 28 in grafts (18.4%) and 17 natives (9.7%) (p-value 0.7). Both groups were comparable in terms of comorbidities, passes, cylinders or biopsy yield (p-value NS). 80% were <1 cm in size and 46.6% closed spontaneously in less than 30 days (range 3-151). Larger AVF's (1-2 cm) took a mean of 52 days to closure (range 13-151). Needle size was not statistically significant factor for AVF (p-value 0.71). CONCLUSIONS: Contrary to historical data published, AVF's are a common complication post PRB that can be easily missed. Routine US Doppler mapping performed by trained staff is a cost-effective, non-invasive tool to diagnose and follow up AVF's, helping to assess management.

Incremental hemodialysis and vascular access complications: a 12-year experience in a hospital hemodialysis unit.

BACKGROUND: Incremental hemodialysis (HD) is considered a valid alternative for patients with residual kidney function. Evidence concerning its effect on vascular access is scarce. We present our 12-year experience of an incremental hemodialysis program with the aim of evaluating survival and complications of arteriovenous fistula in these patients compared to the thrice-weekly scheme. METHODS: From January 1st, 2006 to December 31st, 2017, 220 incident patients started hemodialysis, 132 (60%) of whom began hemodialysis with two sessions per week and 88 (40%) with three sessions per week. Demographic and clinical variables were assessed at the start of treatment. Data regarding arteriovenous fistula survival and complications were collected. RESULTS: Both groups had similar baseline sociodemographic and clinical characteristics. A total of 188 (85%) patients were dialyzed with an arteriovenous fistula during follow-up. Eighty-three patients had one or more fistula complications, with no differences between incremental and conventional groups (p = 0.55). Fistula survival rates showed no significant difference between the two groups, whether analyzed from the date of fistula creation (Log Rank p = 0.810) or from the date of initial fistula cannulation (Log Rank p = 0.695). CONCLUSIONS: We found no differences in arteriovenous fistula survival or complication rate between patients who started HD with an incremental versus a conventional treatment scheme. Randomized controlled clinical trials may be warranted to achieve a higher degree of evidence.

Individually adjusted absolute blood volume feedback control: A promising solution for intradialytic hypotension.

INTRODUCTION: Intradialytic hypotension (IDH) remains one of the most frequent complications associated to hemodialysis (HD), frequently triggered by a reduction in absolute blood volume (ABV) not compensated by vascular refilling. A recently developed dilutional method allows routinary measurement of ABV and, by a simple algorithm, may turn blood volume monitor (BVM) guided UF (ultrafiltration) biofeedback into an ABV control, automatically adjusting UF rate to maintain ABV above a preset threshold. The aim of this study is to identify an individual critical ABV threshold and test the ability of an ABV feedback control to avoid IDH. METHODS: We studied 24 patients throughout three consecutive midweek HD treatments. ABV and blood pressure (BP) were measured every 30 min and anytime the patient referred any symptoms to identify each patient's critical ABV (ABV at the time of hypotension). A fixed bolus dilution approach at the start of HD was used to calculate ABV. Then, patients were followed through three additional HD treatments and IDH development was analyzed. FINDINGS: Seventy-one treatments performed in 24 patients. ABV monitoring showed a constant decrease as HD treatment progressed. Thirteen IDH events were observed in eight different patients, with a mean systolic BP drop in IDH treatments of 37.38 ± 4.31 mmHg and a mean adjusted ABV at hypotension of 71.07 ± 14.88 mL/kg. Critical ABV was individually set in patients prone to IDH. As expected, ABV feedback control successfully maintained ABV over preset critical ABV. IDH events were avoided in 21 out of 22 treatments performed. ABV drop was successfully reduced, as well as SBP drop (despite similar UF than prior to ABV feedback control implementation). DISCUSSION: ABV feedback control avoided IDH in 21 out of 22 treatments performed by maintaining blood volume above critical ABV, significantly reducing ABV variations without compromising prescribed UF.

Development and validation of a nomogram to predict kidney survival at baseline in patients with C3 glomerulopathy.

Background: C3 glomerulopathy is a rare and heterogeneous complement-driven disease. It is often challenging to accurately predict in clinical practice the individual kidney prognosis at baseline. We herein sought to develop and validate a prognostic nomogram to predict long-term kidney survival. Methods: We conducted a retrospective, multicenter observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. The dataset was randomly divided into a training group (n = 87) and a validation group (n = 28). The least absolute shrinkage and selection operator (LASSO) regression was used to screen the main predictors of kidney outcome and to build the nomogram. The accuracy of the nomogram was assessed by discrimination and risk calibration in the training and validation sets. Results: The study group comprised 115 patients, of whom 46 (40%) reached kidney failure in a median follow-up of 49 months (range 24-112). No significant differences were observed in baseline estimated glomerular filtration rate (eGFR), proteinuria or total chronicity score of kidney biopsies, between patients in the training versus those in the validation set. The selected variables by LASSO were eGFR, proteinuria and total chronicity score. Based on a Cox model, a nomogram was developed for the prediction of kidney survival at 1, 2, 5 and 10 years from diagnosis. The C-index of the nomogram was 0.860 (95% confidence interval 0.834-0.887) and calibration plots showed optimal agreement between predicted and observed outcomes. Conclusions: We constructed and validated a practical nomogram with good discrimination and calibration to predict the risk of kidney failure in C3 glomerulopathy patients at 1, 2, 5 and 10 years.

Effect of oral administration of docohexanoic acid on anemia and inflammation in hemodialysis patients: A randomized controlled clinical trial.

BACKGROUND & AIMS: Docohexanoic acid (DHA), a dietary n-3 polyunsaturated fatty-acid omega-3 (n-3, PUFA), showed potential beneficial effects in reducing all-cause mortality in hemodialysis (HD) patients. This randomized trial aimed to analyze whether DHA supplementation was a modulator of erythropoietin (EPO) response and inflammation in hemodialysis (HD) patients. METHODS: In this controlled clinical trial, 52 HD patients were randomized to either DHA supplementation (650 mg DHA/3 times/wk/post-HD session) or controls (usual care), with 8-weeks of follow-up. The primary outcome was to determine the correction of anemia measured by changes in the erythropoiesis-resistance index (ERI) to keep the hemoglobin level at recommended target value. Secondary outcomes include changes in inflammatory biomarkers: serum C-reactive protein, total homocysteine (tHcy) and expression of miR-146a. Laboratory measures were determined at baseline and at 8-weeks after the DHA supplementation or usual care in controls. Linear regression analysis was used to assess the effect of DHA supplementation, adjusting for baseline values and intervention. RESULTS: Forty-two HD patients (men: 69%; aged:66.7 ± 15.5 yrs; DM:19%), completed this study. The DHA effect significantly decreased EPO doses (-4158.7 UI/weekly; CI95%:-8123.7 to 193,6; p = 0.04), ERI (-9.25 UI weekly/kg BW/g/dL; CI95%:-15.5 to -2.9; p = 0.006), tHcy (-5.1 µmol/L; CI95%:-9.7 to -0.3; p = 0.03), and levels of miR-146a (-1.43; CI95%:-2.7 to -0.19; p = 0.03) in regression model. No adverse effects were found. CONCLUSION: The DHA supplementation enhances anemia management and attenuates inflammation response in this controlled trial in HD patients, when provided as coadjutant therapy together with usual medical care. REGISTERED UNDER CLINICALTRIALS. GOV IDENTIFIER NUMBER: 04536636.

Mycophenolate Mofetil in C3 Glomerulopathy and Pathogenic Drivers of the Disease.

BACKGROUND AND OBJECTIVES: C3 glomerulopathy is a complement-mediated disease arising from abnormalities in complement genes and/or antibodies against complement components. Previous studies showed that treatment with corticosteroids plus mycophenolate mofetil (MMF) was associated with improved outcomes, although the genetic profile of these patients was not systematically analyzed. This study aims to analyze the main determinants of disease progression and response to this therapeutic regimen. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted a retrospective, multicenter, observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. Patients diagnosed with C3 glomerulopathy (n=81) or dense deposit disease (n=16) between January 1995 and March 2018 were enrolled. Multivariable and propensity score matching analyses were used to evaluate the association of clinical and genetic factors with response to treatment with corticosteroids and MMF as measured by proportion of patients with disease remission and kidney survival (status free of kidney failure). RESULTS: The study group comprised 97 patients (84% C3 glomerulopathy, 16% dense deposit disease). Forty-two patients were treated with corticosteroids plus MMF, and this treatment was associated with a higher rate of remission and lower probability of kidney failure (79% and 14%, respectively) compared with patients treated with other immunosuppressives (24% and 59%, respectively), or ecluzimab (33% and 67%, respectively), or conservative management (18% and 65%, respectively). The therapeutic superiority of corticosteroids plus MMF was observed both in patients with complement abnormalities and with autoantibodies. However, patients with pathogenic variants in complement genes only achieved partial remission, whereas complete remissions were common among patients with autoantibody-mediated forms. The main determinant of no remission was baseline proteinuria. Relapses occurred after treatment discontinuation in 33% of the patients who had achieved remission with corticosteroids plus MMF, and a longer treatment length of MMF was associated with a lower risk of relapse. CONCLUSIONS: The beneficial response to corticosteroids plus MMF treatment in C3 glomerulopathy appears independent of the pathogenic drivers analyzed in this study.

IgA Nephropathy in Elderly Patients.

BACKGROUND AND OBJECTIVES: Some studies suggest that the incidence of IgA nephropathy is increasing in older adults, but there is a lack of information about the epidemiology and behavior of the disease in that age group. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In this retrospective multicentric study, we analyzed the incidence, forms of presentation, clinical and histologic characteristics, treatments received, and outcomes in a cohort of 151 patients ≥65 years old with biopsy-proven IgA nephropathy diagnosed between 1990 and 2015. The main outcome was a composite end point of kidney replacement therapy or death before kidney replacement therapy. RESULTS: We found a significant increase in the diagnosis of IgA nephropathy over time from six patients in 1990-1995 to 62 in 2011-2015 (P value for trend =0.03). After asymptomatic urinary abnormalities (84 patients; 55%), AKI was the most common form of presentation (61 patients; 40%). Within the latter, 53 (86%) patients presented with hematuria-related AKI (gross hematuria and tubular necrosis associated with erythrocyte casts as the most important lesions in kidney biopsy), and eight patients presented with crescentic IgA nephropathy. Six (4%) patients presented with nephrotic syndrome. Among hematuria-related AKI, 18 (34%) patients were receiving oral anticoagulants, and this proportion rose to 42% among the 34 patients older than 72 years old who presented with hematuria-related AKI. For the whole cohort, survival rates without the composite end point were 74%, 48%, and 26% at 1, 2, and 5 years, respectively. Age, serum creatinine at presentation, and the degree of interstitial fibrosis in kidney biopsy were risk factors significantly associated with the outcome, whereas treatment with renin-angiotensin-aldosterone blockers was associated with a lower risk. Immunosuppressive treatments were not significantly associated with the outcome. CONCLUSIONS: The diagnosis of IgA nephropathy among older adults in Spain has progressively increased in recent years, and anticoagulant therapy may be partially responsible for this trend. Prognosis was poor. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2019_07_16_CJASNPodcast_19_08_.mp3.

Choosing conservative therapy in chronic kidney disease.

INTRODUCTION: Incidence of use for various renal replacement therapies is well-known, but no data are available on conservative treatment use. OBJECTIVE: To assess the proportion of patients with chronic kidney failure receiving a conservative treatment. RESULTS: From July 1, 2013 to June 30, 2014, 232 patients with stage 5 CKD were seen in the Nephrology Department. After having received information on existing therapeutic options and having known the opinion of their treating physicians, 81 patients (35%) selected hemodialysis, 56 (24%) preferred peritoneal dialysis, 5 (2%) selected a preemptive transplant from a living donor, and in 90 (39%) a conservative treatment option was selected. In a univariate analysis using logistic regression, variables associated to a preference for conservative treatment were age, Charlson index excluding age, degree of walking difficulties, and functional dependence level, with the first three factors achieving statistical significance in a multivariate analysis. Presence of a severe disease resulting in a poor prognosis was the main reason for selecting a conservative treatment (49%), with the second one being patient refusal to receive a renal replacement therapy (26%). Mortality rate was 8.2/100 patient-months in conservative therapy group versus 0.6/100 patient-months in patients receiving renal replacement therapy (P<.001). In patients receiving conservative therapy, baseline glomerular filtration rate at the time of study enrollment was the sole variable showing a significant impact on survival. CONCLUSIONS: About 39% of patients with stage 5 CKD seen over a 1-year period in the Nephrology Department received conservative therapy. Age, co-morbidity, and functional disability were the factors associated to selecting a conservative therapy option.

Home care programme for patients with advanced chronic kidney disease. A two-year experience.

INTRODUCTION:  Healthcare for patients with advanced chronic kidney disease (ACKD) on conservative treatment very often poses healthcare problems that are difficult to solve. Many patients are elderly and have mobility problems, and it is very difficult for them to travel to hospital. At the end of 2011, we began a programme based on the care and monitoring of these patients by Primary Care teams.  MATERIAL AND METHOD:  ACKD patients who opted for conservative treatment were offered the chance to be cared for mainly at home by the Primary Care doctor, under the coordination of the Palliative Care Unit and the Nephrology Department.  RESULTS:  During 2012 and 2013, 50 patients received treatment in this programme. Mean age: 81 years, Charlson age-comorbidity index: 10 and mean glomerular filtration rate: 11.8ml/min/1.73.m². The mean patient follow-up time (until death or until 31/12/2013) was 184 days. During this period, 44% of patients did not have to visit the hospital’s Emergency Department and 58% did not require hospitalisation. 29 of the 50 patients died after a mean time of 163 days on the programme; 14 (48%) died at home.  CONCLUSIONS:  Our experience indicates that with the support of the Palliative Care Unit and the Nephrology Department, ACKD patients who are not dialysis candidates may be monitored at home by Primary Care.

Progression of residual renal function with an increase in dialysis: haemodialysis versus peritoneal dialysis.

OBJECTIVE: The main objective of the study was to analyse the progression of residual renal function according to the dialysis technique (peritoneal dialysis or haemodialysis) and the frequency of treatment (two or three sessions of haemodialysis per week). As secondary objectives, we studied the progression of the serum concentration levels of ß2 microglobulin and the response of anaemia to erythropoietic agents. MATERIAL AND METHOD: 193 non-anuric patients were included and began renal replacement therapy with dialysis in our hospital between 1 January 2006 and 31 December 2011, with a follow-up period of over three months. 61 patients (32%) began treatment with two haemodialysis sessions per week, 49 patients (25%) with three haemodialysis sessions per week and 83 patients (43%) with peritoneal dialysis. The glomerular filtration rate was measured as the mean of the renal clearances of urea and creatinine. RESULTS: The rate of decrease in glomerular filtration was the same in patients who began treatment with two haemodialysis sessions per week and with peritoneal dialysis (median 0.18 ml/min/month) and it was higher in patients who began treatment with three sessions of haemodialysis per week (median 0.33 ml/min/month, P<.05). Throughout progression, the glomerular filtration rate did not display differences between the group that began with two weekly sessions of haemodialysis and the group on peritoneal dialysis, and it was lower in the group that began treatment with three sessions of haemodialysis per week with statistical significance during the first 24 months of follow up. In the three patient groups, ß2-microglobulin concentration increased as the glomerular filtration rate decreased and it was higher in the group on three weekly haemodialysis sessions for the first 12 months of follow up. In all the controls carried out, there was a negative correlation between the beta-2 microglobulin concentration and the glomerular filtration rate (P<.001). The erythropoietin dose was negatively related to glomerular filtration. Patients who began with two sessions of haemodialysis per week required a lower dose of erythropoietin than patients that began renal replacement therapy with three weekly sessions. The erythropoietin dose in the peritoneal dialysis group was below that of the group of two weekly haemodialysis sessions despite maintaining a similar glomerular filtration rate. CONCLUSIONS: Patients who begin treatment with two sessions of haemodialysis per week experience the same rate of decrease in residual renal function as patients treated with peritoneal dialysis. The progression of the concentration of ß2-microglobulin is parallel to that of the glomerular filtration rate. Patients treated with two haemodialysis sessions require a lower dose of erythropoietin than those who receive three sessions per week, but a significantly higher dose than those treated with peritoneal dialysis, which suggests that the response of anaemia to erythropoietic agents is not only related to residual renal function, but also to other factors that are inherent to the dialysis technique.

Analysis of concordance between the bioelectrical impedance vector analysis and the bioelectrical impedance spectroscopy in haemodialysis patients.

INTRODUCTION: The values of body composition provided by the two most commonly used bioelectrical impedance systems in Spain, single-frequency bioelectrical impedance vector analysis (SF-BIVA) and multi-frequency bioelectrical impedance spectroscopy (MF-BIS) are different and not comparable. OBJECTIVE: Analyse whether the inter-method variability is due to bioelectrical variables measured by the different monitors, or rather due to the equations used to calculate body volume and mass. Another objective was to determine whether, despite the inter-method variability, the classification of hydration status by the two methods is consistent. MATERIAL AND METHODS: Bioelectrical impedance was measured by SF-BIVA and MF-BIS immediately before a dialysis session in 54 patients on haemodialysis. In 38 patients, the study was repeated by SF-BIVA at the end of the same dialysis session. RESULTS: Resistance and phase angle values provided by the two monitors at a frequency of 50kHz were consistent. For resistance, variability was 1.3% and the intra-class correlation coefficient was 0.99. For phase angle, variability and the intra-class correlation coefficient were 11.5% and 0.92, respectively. The volume values for total body water, extracellular water, fat mass and body cell mass were biased, with a level of variability that would not be acceptable in clinical practice. The intra-class correlation coefficient also suggested a poor level of agreement. SF-BIVA systems define overhydration or dehydration as a vector below or above the tolerance ellipse of 75% on the longitudinal axis. MF-BIS uses two criteria for pre-dialysis hyper-hydration: overhydration (OH) greater than 2.5 litres, or greater than 15% of extracellular water. The degree of equivalence with the results of the SF-BIVA monitor was better with the second criterion (kappa: 0.81, excellent agreement) than with the first one (kappa: 0.71, acceptable agreement). The MF-BIS system defines post-dialysis normal hydration as a difference between OH and ultrafiltratation volume between ­1.1 and 1.1 litres and agreement with the SF-BIVA system for this parameter was acceptable (weighted kappa index: 0.64). CONCLUSIONS: The MF-BIS and SF-BIVA systems provide similar readings for bioelectrical parameters, and the wide variation in the quantification of volume and body mass must be attributed to the different equations used for calculation. Furthermore, the criteria used by both systems to define both pre- and post-dialysis hydration have an acceptable level of equivalence.