Bioimpedance analysis and cardiovascular status in pediatric patients on chronic hemodialysis

Sodium intake and urinary losses in children on dialysis: a European multicenter prospective study

BACKGROUND

Sodium (Na) balance is unexplored in dialyzed children. We assessed a simplified sodium balance (sNaB) and its correlates in pediatric patients receiving maintenance dialysis.

METHODS

Patients < 18 years old on hemodialysis (HD) or peritoneal dialysis (PD) in six European Pediatric Dialysis Working Group centers were recruited. sNaB was calculated from enteral Na, obtained by a 3-day diet diary, Na intake from medications, and 24-h urinary Na (uNa). Primary outcomes were systolic blood pressure and diastolic blood pressure standard deviation scores (SBP and DBP SDS), obtained by 24-h ambulatory blood pressure monitoring or office BP according to age, and interdialytic weight gain (IDWG).

RESULTS

Forty-one patients (31 HD), with a median age of 13.3 (IQR 5.2) years, were enrolled. Twelve patients (29.3%) received Na-containing drugs, accounting for 0.6 (0.7) mEq/kg/day. Median total Na intake was 1.5 (1.1) mEq/kg/day, corresponding to 60.6% of the maximum recommended daily intake for healthy children. Median uNa and sNaB were 0.6 (1.8) mEq/kg/day and 0.9 (1.7) mEq/kg/day, respectively. The strongest independent predictor of sNaB in the cohort was urine output. In patients receiving HD, sNaB correlated with IDWG, pre-HD DBP, and first-hour refill index, a volume index based on blood volume monitoring. sNaB was the strongest predictor of IDWG in multiple regression analysis (β = 0.63; p = 0.005). Neither SBP SDS nor DBP SDS correlated with sNaB.

CONCLUSIONS

Na intake is higher than uNa in children on dialysis, and medications may be an important source of Na. sNaB is best predicted by urine output in the population, and it is a significant independent predictor of IDWG in children on HD. A higher resolution version of the Graphical abstract is available as Supplementary information.

Low dialysate sodium in children and young adults on maintenance hemodialysis: a prospective, randomized, crossover study

BACKGROUND

The optimal dialysate sodium concentration (dNa) in children on hemodialysis (HD) is unknown. The aim of this study was to compare the effect on interdialytic weight gain (IDWG) and blood pressure (BP) of a low (135 mmol/l) and standard dNa (138 mmol/l) in children and young adults on maintenance HD.

METHODS

This prospective single-blind randomized crossover study consisted of a randomized sequence of two phases: "standard dNa" of 138 mmol/L and "low dNa" of 135 mmol/L. Each phase lasted 4 weeks. Inclusion criteria were age < 25 years, hypertension, pre-HD serum Na (sNa) ≥ 130 mmol/L, and occurrence of symptoms in less than 25% of sessions. Primary outcomes were pre-HD systolic and diastolic BP and IDWG.

RESULTS

Fifteen patients were recruited, mean age 17.8 ± 4.4 years. Pre-HD SBP and DBP were not different between the two treatments. Mean IDWG was significantly lower with low dNa than with standard dNa: 2.12 ± 1.39% vs. 2.77 ± 1.53%, respectively (p = 0.008). The first-hour refill index (a volume index based on blood-volume monitoring) was significantly lower with dNa 135 mmol/L (p = 0.018). The mean Na gradient (dNa-sNa) was - 2.53 ± 2.4 mmol/L with dNa 135 mmol/L and 0.17 ± 2.8 mmol/L with dNa 138 mmol/L (p = 0.0001). The incidence of symptomatic sessions was similar (1.0% vs. 1.0%).

CONCLUSIONS

In a selected population of hypertensive pediatric and young adult HD patients, a dNa of 135 mmol/L was associated with a significant reduction of IDWG compared with a dNa of 138 mmol/L. Furthermore, long-term studies are needed to investigate the effect of lowering dNa on BP. A higher resolution version of the Graphical abstract is available as Supplementary information.

Nutritional status and volume control in adolescents on chronic hemodialysis

BACKGROUND

Pediatric patients on maintenance hemodialysis (HD) are at risk of both malnutrition and fluid overload. This pilot study aimed to assess correlates of normalized protein catabolic rate (nPCR) in adolescents on chronic HD, in particular fluid status markers.

METHODS

All patients aged 10-18 years on chronic HD in our center between 2017 and 2019 were enrolled. For each patient, mean nPCR was calculated and correlations with the following parameters investigated: dry body weight change in subsequent 3 months in kg (∆BW) and percentage of BW (∆BW%), change in body mass index (∆BMI), preHD systolic and diastolic blood pressure (SBP, DBP), residual urine output, biochemistry, and blood volume monitoring-derived first hour refill index (RI), calculated as ratio between ultrafiltration rate and reduction in relative blood volume in first hour of dialysis.

RESULTS

Seventy-nine nPCR determinations were collected in 23 patients, median age 14.8 years. nPCR significantly correlated with ∆BW, ∆BW%, ∆BMI, spKT/V, and preHD serum creatinine, and negatively correlated with age, DBP SDS (r=-0.466, p=0.025) and RI (r=-0.435, p=0.043). RI was significantly higher in patients with nPCR <1 than those with nPCR above this threshold: 3.2 (1.9-4.7) vs. 1.4 (0.7-1.8) ml/kg/h/% (p=0.021). At multivariable analysis, nPCR remained positively correlated with creatinine and spKt/V, and inversely correlated with RI.

CONCLUSIONS

nPCR is a significant predictor of weight change in adolescents on maintenance HD, and seems associated with creatinine and dialysis adequacy. Inverse correlation with RI suggests possible associations between malnutrition and fluid overload, but larger prospective studies are needed to confirm this. A higher resolution version of the Graphical abstract is available as Supplementary information.

Clinical Relevance of Fluid Volume Status Assessment by Bioimpedance Spectroscopy in Children Receiving Maintenance Hemodialysis or Peritoneal Dialysis

Bioimpedance spectroscopy (BIS) is a noninvasive method used to evaluate body fluid volume status in dialysis patients, but reports on its effectiveness in pediatrics are scarce. We investigated the correlation between BIS and clinical characteristics and identified the changes in patients whose dialysis prescription was modified based on BIS. The medical records of children on maintenance dialysis who had undergone BIS between 2017 and 2019 were reviewed. Of the 49 patients, 14 were overhydrated, based on the >15% proportion of overhydration relative to extracellular water (OH/ECW) measured by BIS. Intake of ≥two antihypertensive medications was noted in the majority (85.7%) of children with fluid overload and only in 48.6% of those without fluid overload (p = 0.017). Elevated blood pressure despite medication use was significantly more common in patients with fluid overload than in those without fluid overload (78.6% vs. 45.7%, p = 0.037). Of the 14 overhydrated children, 13 (92.9%) had significant changes in body weight, OH/ECW, the number of antihypertensive drugs, left ventricular end-diastolic diameter, and cardiothoracic ratio after the change in dialysis prescription. BIS is a useful and noninvasive method to assess fluid status in dialysis children. Long-term follow-up and correlation with a more objective clinical indicator of fluid overload is necessary to verify the clinical effectiveness of BIS.

Tracking hydration status changes by bioimpedance spectroscopy in children on peritoneal dialysis

BACKGROUND

This 6-month prospective longitudinal study investigates the association between hydration status changes using bioimpedance spectroscopy (BIS) and systolic blood pressure (SBP), pulse pressure (PP), and serum albumin (sAlb) changes in children on peritoneal dialysis (PD).

METHODS

Thirteen patients (median age: 12.58 years) were enrolled. Normal hydration, moderate hydration, severe overhydration, and dehydration were defined as -7% ≤ relative overhydration (Re-OH) < +7%, +7% ≤ Re-OH < +15%, Re-OH ≥ +15%, and Re-OH < -7%, respectively. Automated office blood pressure z-score, sAlb, and weight z-score were recorded.

RESULTS

Fifty-two Re-OH measurements were recorded: three in five, four in five, five in two, and seven in one patient, respectively. SBP was higher and sAlb lower in cases with severe overhydration (9 readings) (p < 0.001, p < 0.001), but distribution of these parameters did not differ between normal hydration/dehydration (28 readings) and moderate overhydration (15 readings) cases. In patients with hydration status change, SBP and PP were higher while sAlb lower in cases with higher hydration status level (p = 0.026, p = 0.05, and p = 0.109, respectively). In all patients, visit-to-visit SBP, PP, and sAlb changes were correlated to Re-OH changes (rs = 0.693, p < 0.001; rs = 0.643, p < 0.001; rs = -0.444, p = 0.008, respectively) but not to weight changes (rs = 0.052, p = 0.754; rs = 0.034, p = 0.838; rs = -0.156, p = 0.378, respectively). Visit-to-visit Re-OH changes, which were >+4% or <-4%, were linearly correlated to SBP (r = 0.858, p < 0.001), PP (r = 0.757, p < 0.001), and sAlb (r = -0.699, p = 0.002) changes.

CONCLUSION

In children on PD, longitudinal Re-OH changes are superior to weight changes in assessing volume-dependent variations of SBP, PP, and sAlb. Routine BIS application, rather than single BIS measurements, seems useful in the intra-patient monitoring of hydration status.

Assessment and management of fluid overload in children on dialysis

Dysregulation of intravascular fluid leads to chronic volume overload in children with end-stage kidney disease (ESKD). Sequelae include left ventricular hypertrophy and remodeling and impaired cardiac function. As a result, cardiovascular complications are the commonest cause of mortality in the pediatric dialysis population. The clinical need to optimize intravascular volume in children with ESKD is clear; however, its assessment and management is the most challenging aspect of the pediatric dialysis prescription. Minimizing chronic fluid overload is a key priority; however, excessive ultrafiltration is toxic to the myocardium and can precipitate intradialytic symptoms. This review outlines emerging objective techniques to enhance the assessment of fluid overload in children on dialysis and outlines evidence for current management strategies to address this clinical problem.

Hypertension in Pediatric Dialysis Patients: Etiology, Evaluation, and Management

PURPOSE OF REVIEW

Review epidemiology, pathophysiology, and management of hypertension in the pediatric dialysis population.

RECENT FINDINGS

Interdialytic blood pressure measurement, especially with ambulatory blood pressure monitoring, is the gold standard to assess for hypertension. Tools to assess dry weight aid in achievement of euvolemia, the primary therapy for management of hypertension. Persistent hypertension should be treated with antihypertensive medications and potentially with native nephrectomies. Cardiovascular disease continues to be the primary cause of morbidity and mortality in the dialysis population with hypertension as an important modifiable factor. Achievement on dry weight and limiting both aggressiveness of interdialytic weight gain and ultrafiltration rate underlie the best approach. Tools to assess volume status beyond clinical assessment have shown promise in achieving euvolemia. When hypertension persists despite achievement of euvolemia, antihypertensive medications may be required and in some cases native nephrectomies. Future studies in children are needed to determine the best antihypertensive class and ideal rate of ultrafiltration on hemodialysis towards achievement of normotension and reduction of cardiovascular risk.

Blood pressure management in children on dialysis

Hypertension is a leading cause of cardiovascular complications in children on dialysis. Volume overload and activation of the renin-angiotensin-aldosterone system play a major role in the pathophysiology of hypertension. The first step in managing blood pressure (BP) is the careful assessment of ambulatory BP monitoring. Volume control is essential and should start with the accurate identification of dry weight, based on a comprehensive assessment, including bioimpedance analysis and intradialytic blood volume monitoring (BVM). Reduction of interdialytic weight gain (IDWG) is critical, as higher IDWG is associated with a worse left ventricular mass index and poorer BP control: it can be obtained by means of salt restriction, reduced fluid intake, and optimized sodium removal in dialysis. Optimization of peritoneal dialysis and intensified hemodialysis or hemodiafiltration have been shown to improve both fluid and sodium management, leading to better BP levels. Studies comparing different antihypertensive agents in children are lacking. The pharmacokinetic properties of each drug should be considered. At present, BP control remains suboptimal in many patients and efforts are needed to improve the long-term outcomes of children on dialysis.

Validating the use of bioimpedance spectroscopy for assessment of fluid status in children

BACKGROUND

Bioimpedance spectroscopy (BIS) with a whole-body model to distinguish excess fluid from major body tissue hydration can provide objective assessment of fluid status. BIS is integrated into the Body Composition Monitor (BCM) and is validated in adults, but not children. This study aimed to (1) assess agreement between BCM-measured total body water (TBW) and a gold standard technique in healthy children, (2) compare TBW_BCM with TBW from Urea Kinetic Modelling (UKM) in haemodialysis children and (3) investigate systematic deviation from zero in measured excess fluid in healthy children across paediatric age range.

METHODS

TBW_BCM and excess fluid was determined from standard wrist-to-ankle BCM measurement. TBW_D2O was determined from deuterium concentration decline in serial urine samples over 5 days in healthy children. UKM was used to measure body water in children receiving haemodialysis. Agreement between methods was analysed using paired t test and Bland-Altman method comparison.

RESULTS

In 61 healthy children (6-14 years, 32 male), mean TBW_BCM and TBW_D2O were 21.1 ± 5.6 and 20.5 ± 5.8 L respectively. There was good agreement between TBW_BCM and TBW_D2O (R² = 0.97). In six haemodialysis children (4-13 years, 4 male), 45 concomitant measurements over 8 months showed good TBW_BCM and TBW_UKM agreement (mean difference - 0.4 L, 2SD = ± 3.0 L). In 634 healthy children (2-17 years, 300 male), BCM-measured overhydration was - 0.1 ± 0.7 L (10-90th percentile - 0.8 to + 0.6 L). There was no correlation between age and OH (p = 0.28).

CONCLUSIONS

These results suggest BCM can be used in children as young as 2 years to measure normally hydrated weight and assess fluid status.

The role of bioelectrical impedance analysis, NT-ProBNP and inferior vena cava sonography in the assessment of body fluid volume in children with nephrotic syndrome

BACKGROUND

Assessment of volume status and differentiating "underfill" and "overfill" edema is essential in the management of patients with nephrotic syndrome (NS).

OBJECTIVES

Our aim was to evaluate the volume status of NS patients by using different methods and to investigate the utility of bioelectrical impedance analysis (BIA) in children with NS.

METHODS

The hydration status of 19 patients with NS (before treatment of NS and at remission) and 25 healthy controls was assessed by multifrequency BIA, serum N-terminal-pro-brain natriuretic peptide (NT-proBNP) levels, inferior vena cava (IVC) diameter, left atrium diameter (LAD) and vasoactive hormones.

RESULTS

Renin, aldosterone levels, IVC diameter and LAD were not statistically different between the groups. NT-proBNP values were statistically higher in the attack period compared to remission and the control group (p=0.005 for each). Total body water (TBW), overhydration (OH) and extracellular water (ECW) estimated by the BIA measurement in the attack group was significantly higher than that of the remission group and controls. There were no significant correlations among volume indicators in group I and group II. However, significant correlations were observed between NT-proBNP and TBW/BSA (p=0.008), ECW/BSA (p=0.003) and ECW/ICW (p=0.023) in the healthy group. TBW was found to be higher in patients with NS in association with increased ECW but without any change in ICW. NT-proBNP values were higher in patients during acute attack than during remission.

CONCLUSIONS

Our findings support the lack of hypovolaemia in NS during acute attack. In addition, BIA is an easy-to-perform method for use in routine clinical practice to determine hydration status in patients with NS.

Finding covert fluid: methods for detecting volume overload in children on dialysis

BACKGROUND

Lung ultrasound is a novel technique for detecting generalized fluid overload in children and adults with end-stage renal disease (ESRD). Echocardiography and bioimpedance spectroscopy are established methods, albeit variably adopted in clinical practice. We compared the practicality and accuracy of lung ultrasound with current objective techniques for detecting fluid overload in children with ESRD.

METHODS

A prospective observational study was performed to compare lung ultrasound B-lines, echocardiographic measurement of inferior vena cava parameters and bioimpedance spectroscopy in the assessment of fluid overload in children with ESRD on dialysis. The utility of each technique in predicting fluid overload, based on short-term weight gain, was assessed. Multiple linear regression models to predict fluid overload by weight were explored.

RESULTS

A total of 22 fluid assessments were performed in 13 children (8 on peritoneal dialysis, 5 on haemodialysis) with a median age of 4.0 (range 0.8-14.0) years. A significant linear correlation was observed between the number of B-lines detected by lung ultrasound and fluid overload by weight (r = 0.57, p = 0.005). A non-significant positive linear correlation was observed between fluid overload by weight and bioimpedance spectroscopy (r = 0.43, p = 0.2), systolic blood pressure (r = 0.19, p = 0.4) and physical examination measurements (r = 0.19, p = 0.4), while a non-significant negative linear relationship was found between the inferior vena cava collapsibility index and fluid overload by weight (r = -0.24, p = 0.3). In multiple linear regression models, a combination of three fluid parameters, namely lung ultrasound B-lines, clinical examination and systolic blood pressure, best predicted fluid overload (R ²  = 0.46, p = 0.05).

CONCLUSIONS

Lung ultrasound may be superior to echocardiographic methods and bioimpedance spectroscopy in detecting volume overload in children with ESRD. Given the practicality and sensitivity of this new technique, it can be adopted alongside clinical examination and blood pressure in the routine assessment of fluid status in children with ESRD.

Hypertension in children with end-stage renal disease

This review summarizes current data on the epidemiology, pathophysiology, and treatment of hypertension (HTN) in children with end-stage renal disease (ESRD). Worldwide prevalence of ESRD ranges from 5.0 to 84.4 per million age-related population. HTN is present in 27-79% of children with ESRD, depending on the modality of renal replacement therapy and the exact definition of hypertension. Ambulatory BP monitoring has been recommended for the detection of HTN and evaluation of treatment effectiveness. HTN in dialyzed patients is mostly related to hypervolemia, sodium overload, activation of the renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system, impaired nitric oxide synthesis, reduced vitamin D levels, and effects of microRNA. In children undergoing chronic dialysis therapy, important factors include optimization of renal replacement therapy and preservation of residual renal function, allowing reduction of volume- and sodium-overload, along with appropriate drug treatment, particularly with calcium channel blockers, RAAS inhibitors, and loop diuretics.

Interdialytic weight gain in oligoanuric children and adolescents on chronic hemodialysis

BACKGROUND

Little is known about the clinical impact of interdialytic weight gain (IDWG) on oligoanuric children undergoing chronic hemodialysis (HD).

METHODS

We retrospectively assessed IDWG, left ventricular mass index (LVMI) and its changes (ΔLVMI), pre-HD systolic and diastolic blood pressure (DBP), residual urine output, Kt/V, the frequency of intradialytic symptoms, normalized protein catabolic rate, and the 3-month change in the dry weight of 16 hemodialyzed oligoanuric patients with a median age of 14.8 years (range 5.0-17.9).

RESULTS

There was a significant correlation between IDWG and median LVMI (r 0.55, p = 0.026), which was 27.3 g/m(2.7) (22.5-37.6) in the patients with a median IDWG of <4 %, and 44.3 g/m(2.7) (28.2-68.7) in those with a median IDWG of >4 % (p = 0.003). None of the four patients with an IDWG of <4 % showed left ventricular hypertrophy, compared with 10 of the 12 patients (83.3 %) with an IDWG of >4 % (p = 0.003); the former also had a better median ΔLVMI (-33.5 % vs -13.0 %; p = 0.02) and a lower median DBP sds (0.24 vs 1.72, p = 0.04).

CONCLUSIONS

There is a significant correlation between IDWG and LVMI in pediatric oligoanuric patients on chronic HD: those with an IDWG of >4 % are at a higher risk of left ventricular hypertrophy.

The interdialytic weight gain: a simple marker of left ventricular hypertrophy in children on chronic haemodialysis

Despite multiple advances in haemodialysis (HD) technology over the years, the morbidity and mortality of HD patients remain unacceptably high. Cardiovascular disease is the most common cause of death, and left ventricular hypertrophy (LVH), seen in two-thirds of children on dialysis, is a significant contributor. The importance of volume control is increasingly recognized by nephrologists and now considered to be as important as urea kinetics, both in the day-to-day management and the long-term outcome of dialysis patients. The results published by Paglialonga et al. ( 10.1007/s00467-014-3005-2 ) in this issue of Pediatric Nephrology clearly demonstrate that there is a significant correlation between interdialytic weight gain (IDWG) and LVH in oligoanuric children on chronic HD and that children with an IDWG of >4 % are at high risk of LVH. One common practice to achieve euvolaemia is to prescribe very high ultrafiltration rates. However, both volume overload and aggressive fluid removal can induce circulatory stress and multi-organ injury. In adults, ultrafiltration rates of >1.24 % body weight per hour, even if well tolerated, are associated with a significant increase in mortality. Nephrologists should be aware of the risk of a high ultrafiltration rate, especially if tolerance is obtained by a positive dialysate-to-plasma sodium gradient. Haemodiafiltration, which allows for higher ultrafiltration rates with greater intradialytic haemodynamic stability, or more frequent and longer dialysis sessions allow for safe and effective fluid removal.

Assessment and management of hypertension in patients on dialysis

Hypertension is common, difficult to diagnose, and poorly controlled among patients with ESRD. However, controversy surrounds the diagnosis and treatment of hypertension. Here, we describe the diagnosis, epidemiology, and management of hypertension in dialysis patients, and examine the data sparking debate over appropriate methods for diagnosing and treating hypertension. Furthermore, we consider the issues uniquely related to hypertension in pediatric dialysis patients. Future clinical trials designed to clarify the controversial results discussed here should lead to the implementation of diagnostic and therapeutic techniques that improve long-term cardiovascular outcomes in patients with ESRD.

Whole-body single-frequency bioimpedance analysis in pediatric hemodialysis patients

BACKGROUND

We hypothesized that the percent change in resistance (%RΔ) from bioimpedance analysis (BIA) measurements during hemodialysis (HD) can provide information on pediatric HD patients' hydration status.

METHODS

Whole-body single-frequency BIA measurements were obtained before HD, each hour on HD, and after HD during two HD sessions. Pre-and post-HD weights, blood pressures, Crit-Line® measurements, and intradialytic symptoms were collected on the day of the BIA measurements.

RESULTS

One hundred and thirty BIA measurements were obtained from 14 HD patients. The group was 43 % girls, and the mean age was 13.2 ± 4.4 years. Percent change in resistance was 13.5 ± 10.8 % at the end of HD; %RΔ correlated with percent body weight change (%BWΔ) following HD (r = -0.83, P < 0.01), as well as with percent blood volume change (%BVΔ) (r = -0.79, P < 0.01). The %RΔ was similar between patients with and without hypertension immediately before HD and was greater in those with intradialytic symptoms (19.1 ± 7.7 %) than in those without (9.9 ± 11.2 %) (P = 0.02). Patients with left ventricular hypertrophy (LVH) had lower %RΔ (7.2 ± 9.7 %) than those without (19.5 ± 7.7 %) (P = 0.03). Left ventricular mass index (LVMI) also correlated strongly with %RΔ (r = -0.79, P = 0.004) and %BWΔ (r = 0.82, P = 0.002).

CONCLUSIONS

Our study showed that %RΔ strongly correlates with %BWΔ and %BVΔ and that %RΔ also correlated with intradialytic symptoms and LVMI.

ABC transporters as differentiation markers in glioblastoma cells

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumour, characterized by a high aggressivity, a huge heterogeneity attending a hierarchical model and resistance to therapy. Drug resistance has been correlated with the presence of the ABC efflux transporters which are able to exclude drugs for the cellular cytoplasm. In the nucleus of the GBM, initiating cells (ICs) can self-renew and give rise to cancer stem cells, which differ to the side population cells and the different cellular subtypes that form the mass around them. The ICs do not express or express ATP binding cassette (ABC) at very low levels, but this expression may increase with the differentiation process. We suggest that the differentiation process may be responsible of chemoresistance of the GBM cells. We compared three ABC transporters expression: ABCA1, MRP4 and MRP5, in the ICs obtained from 9 patients with GBM and their respective differentiated GBM cells. We show an overexpression of the three ABC transporters in the differentiated GBM cells in comparison to ICs.

IMPLICATIONS OF THE HYPOTHESIS

The blockade of these ABC transporters could help to improve the drug effectivity and thus reduce the tumour growth and prevent the tumour recurrence.

Hydration measurement by bioimpedance spectroscopy and blood pressure management in children on hemodialysis

BACKGROUND

Hypertension is frequent in chronic hemodialyzed patients and usually treated by reducing extracellular fluid. Probing dry weight only based on a clinical evaluation may be hazardous, especially in case of volume independent hypertension.

METHODS

We performed a 1-year retrospective study in three pediatric centers to define the relation between blood pressure (BP) and hydration status, assessed by whole-body bioimpedance spectroscopy (BIS). We analyzed 463 concomitant measurements of BP, relative overhydration (rel.OH), and plasma sodium (Napl) in 23 children (mean age 13.9 ± 5.1 years).

RESULTS

Pre-dialytic under-hydration (rel.OH < -7%) was present in 5.4% of the sessions, out of which 24% showed hypertension. Normohydration (rel.OH -7 - +7%) was observed in 62.4% of the sessions, 45.3% of them revealed hypertension. Moderate OH (rel.OH +7 - +15%) was present in 21% of the sessions, 47.4% of them showed normal BP. In 11.2% of the sessions, severe overhydration (rel.OH > +15%) was assessed, however, the majority (73%) showed normal BP. Patient-specific Napl setpoint could not be described. Mean dialysate sodium concentration was higher than mean Napl.

CONCLUSIONS

Hypertension is not always related to overhydration. Therefore, BIS should restrict the practice of "probing dry weight" in hypertensive children. Moreover, sodium dialytic balance needs to be considered to improve BP management.

Differentiating factors between erythropoiesis-stimulating agents: an update to selection for anaemia of chronic kidney disease

Erythropoiesis-stimulating agents (ESAs) have become a hallmark of anaemia therapy in patients with chronic kidney disease (CKD). Although different ESAs are available for the treatment of renal anaemia, each nephrologist should select a single ESA for an individual patient. Epoetin alfa and epoetin beta have been used 1-3 times weekly but extended-interval dosing up to every 4 weeks is also effective in a substantial majority of CKD patients. However, the epoetin dose necessary to achieve or maintain target haemoglobin (Hb) levels increases substantially as the dosing interval increases. Subcutaneous administration of short-acting ESAs is more effective than the intravenous route of administration. Darbepoetin alfa and the continuous erythropoietin receptor activator (CERA) have been developed as a treatment for anaemia with extended administration intervals (every 2 weeks and every 4 weeks, respectively). Dose requirements for these long-acting ESAs are independent of the route of administration. Patents of short-acting ESAs have expired, which has opened the field for biosimilars. Epoetin biosimilars approved by the European Medicines Agency (EMA) or the US Food and Drug Administration (FDA) have been shown to have a comparable efficacy and safety profile to their originators. An alarming increase in pure red cell aplasia (PRCA) in Thailand with follow-on epoetins manufactured in Asia (but also those manufactured in Latin America) indicates that stringent country-specific approval and pharmacovigilance protocols for ESAs manufactured in non-North American and non-EU European countries are urgently needed. Two PRCA cases occurring with subcutaneous HX575 (one certain, one likely) indicate that chances of inducing a more immunogenic product are unpredictable, even with a biosimilar epoetin approved under the EMA biosimilar approval pathway. Phase III clinical trials with peginesatide, a pegylated synthetic peptide-based ESA without any homology to erythropoietin raised safety concerns in non-dialysis CKD patients but not in dialysis patients.