Accuracy of Bioimpedance Spectroscopy in the Detection of Hydration Changes in Patients on Hemodialysis.

OBJECTIVES: The body composition monitor (BCM) is a bioimpedance spectroscopy device, specifically developed for patients on hemodialysis (HD) to improve ultrafiltration (UF) programming, based on an objective assessment of the degree of overhydration (OH) at the start of HD. However, its acceptance in clinical practice remains limited because of concerns about the accuracy at the individual level. The aim of this study is to examine the performance of the BCM and to identify means of improvement. METHODS: Precision of the OH estimate was assessed by 6 consecutive measurements in 24 patients on HD. Accuracy was examined in 45 patients, by comparing the change in OH (ΔOH) during HD with UF volume. Accuracy was considered acceptable if the volume error in individual patients was ≤0.5 L. RESULTS: The OH estimate had an analytical precision of 1.0 ± 0.4%. The correlation between UF volume and ΔOH was moderate (Slope = 0.66, R2 = 0.44, P < .001) and indicated underestimation of UF volume, in particular for high UF volumes. Accuracy at individual level was highly variable. A volume error >0.5 L occurred in 44% of patients. Accuracy improved over the course of HD, with a decrease in total error range from 2.3 L in the first hour to 1.1 L in the final hour of HD. CONCLUSIONS: The accuracy of BCM volume change estimates is highly variable and below requirements of daily practice. Improvement may be achieved by a switch to an end-of-HD measurement.

[Calciphylaxis, a life-threatening condition in dialysis patients]. / Calcifylaxie, levensbedreigende huidaandoening bij nierdialyse.

BACKGROUND: Calcification can be seen vascular, peritoneal and also subcutaneous. Subcutaneous calcifications are seen in calciphylaxis, which is a rare but life-threatening condition with painful skin lesions and varying stages of skin necrosis, mostly described in patients on dialysis. CASE DESCRIPTION: A 65-year old man presented at the emergency room with complaints of abdominal pain. He had a long history of chronic kidney disease, currently on hemodialysis after previous peritonitis from peritoneal dialysis. Physical examination shows painful plate-like areas of indurated skin on the abdomen with possible central spots of necrosis, suspicious for calciphylaxis. CT-scan showed calcifications on multiple sides. Unfortunately it was already in an advanced stage. He died a few days after hospitalization. CONCLUSION: Recognition of calciphylaxis at an early stage is important to prevent and reduce mortality by elimination of risk factors, prevention of infection, pain relief, increasing frequency and length of dialysis, and administration of sodium thiosulfate.

COVID-19-related mortality in kidney transplant and haemodialysis patients: a comparative, prospective registry-based study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has exposed haemodialysis (HD) patients and kidney transplant (KT) recipients to an unprecedented life-threatening infectious disease, raising concerns about kidney replacement therapy (KRT) strategy during the pandemic. This study investigated the association of the type of KRT with COVID-19 severity, adjusting for differences in individual characteristics. METHODS: Data on KT recipients and HD patients diagnosed with COVID-19 between 1 February 2020 and 1 December 2020 were retrieved from the European Renal Association COVID-19 Database. Cox regression models adjusted for age, sex, frailty and comorbidities were used to estimate hazard ratios (HRs) for 28-day mortality risk in all patients and in the subsets that were tested because of symptoms. RESULTS: A total of 1670 patients (496 functional KT and 1174 HD) were included; 16.9% of KT and 23.9% of HD patients died within 28 days of presentation. The unadjusted 28-day mortality risk was 33% lower in KT recipients compared with HD patients {HR 0.67 [95% confidence interval (CI) 0.52-0.85]}. In a fully adjusted model, the risk was 78% higher in KT recipients [HR 1.78 (95% CI 1.22-2.61)] compared with HD patients. This association was similar in patients tested because of symptoms [fully adjusted model HR 2.00 (95% CI 1.31-3.06)]. This risk was dramatically increased during the first post-transplant year. Results were similar for other endpoints (e.g. hospitalization, intensive care unit admission and mortality >28 days) and across subgroups. CONCLUSIONS: KT recipients had a greater risk of a more severe course of COVID-19 compared with HD patients, therefore they require specific infection mitigation strategies.

Impact of diffusion, ultrafiltration, and posture on total body electrical resistance in patients on hemodialysis.

Monitoring of hydration in patients on hemodialysis (HD) by currently available bioelectrical impedance analysis (BIA) methods is hampered by limited accuracy. This may be caused by changes in total body electrical resistance (TBER) that are induced by processes other than ultrafiltration (UF). To identify these sources of error, we examined the impact of UF, diffusion, and postural change (PC), separately. Extracellular TBER (TBERe) was measured by bioimpedance spectroscopy every 30 min in 23 patients on HD, for 2 h during diffusion-only (DO), followed by 2-h UF-only (UFO). The impact of PC from upright to semi-recumbent position was assessed by a 2-h TBERe measurement on the day after HD. TBERe increased by 23.5 ± 12.4 Ω (P < 0.001) during DO and by 40.0 ± 16.2 Ω (P < 0.001) during UFO. PC, evaluated on a separate day, was associated with an increase in TBERe of 27.6 ± 26.0 Ω (P < 0.001). TBERe changes during DO were mainly attributed to PC and to a lesser extent to electrolyte exchange. Extrapolation of the data to a conventional 4-h HD session indicates that about 32% of the total increase in TBERe is not related to UF. In conclusion, a significant part of the increase in TBER during HD is not related to UF but can be attributed to other processes such as the effects of PC and diffusion-related electrolyte exchange. These factors have to be taken into account when TBER-guided UF is considered.NEW & NOTEWORTHY Current BIA methods have limited accuracy in patients on HD. This may be related to the incorrect assumption that all changes in total body electrical resistance (TBER) are caused by changes in body water volumes. The present study indicates that two-thirds of the change in TBER during a conventional 4-h HD session can be attributed to fluid extraction, and that the remaining part is caused by other processes such as postural change and electrolyte exchange. This may cause volume prediction errors when not recognized.

The Clinical Course of Minimal Change Nephrotic Syndrome With Onset in Adulthood or Late Adolescence: A Case Series.

BACKGROUND: Few studies have examined the treatment and outcome of adult-onset minimal change nephrotic syndrome (MCNS). We retrospectively studied 125 patients who had MCNS with onset in either adulthood or late adolescence. Presenting characteristics, duration of initial treatment and response to treatment, relapse patterns, complications, and long-term outcome were studied. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Patients with new-onset nephrotic syndrome 16 years or older and a histologic diagnosis of MCNS in 1985 to 2011 were identified from pathology records of 10 participating centers. OUTCOMES: Partial and complete remission, treatment resistance, relapse, complications, renal survival. RESULTS: Corticosteroids were given as initial treatment in 105 (84%) patients. After 16 weeks of corticosteroid treatment, 92 (88%) of these patients had reached remission. Median time to remission was 4 (IQR, 2-7) weeks. 7 (6%) patients initially received cyclophosphamide with or without corticosteroids, and all attained remission after a median of 4 (IQR, 3-11) weeks. 13 (10%) patients reached remission without immunosuppressive treatment. One or more relapses were observed in 57 (54%) patients who received initial corticosteroid treatment. Second-line cyclophosphamide resulted in stable remission in 57% of patients with relapsing MCNS. Acute kidney injury was observed in 50 (40%) patients. Recovery of kidney function occurred almost without exception. Arterial or venous thrombosis occurred in 11 (9%) patients. At the last follow-up, 113 (90%) patients were in remission and had preserved kidney function. 3 patients with steroid-resistant MCNS progressed to end-stage renal disease, which was associated with focal segmental glomerulosclerosis lesions on repeat biopsy. LIMITATIONS: Retrospective design, variable treatment protocols. CONCLUSIONS: The large majority of patients who had MCNS with onset in adulthood or late adolescence were treated with corticosteroids and reached remission, but many had relapses. Cyclophosphamide resulted in stable remission in many patients with relapses. Significant morbidity was observed due to acute kidney injury and other complications. Progression to end-stage renal disease occurred in a few patients and was explained by focal segmental glomerulosclerosis.

Assessment of calcium balance in patients on hemodialysis, based on ionized calcium and parathyroid hormone responses.

BACKGROUND: Identification of the underlying causes of secondary hyperparathyroidism (SHPT) in individual patients on hemodialysis (HD) is hampered by the lack of clinically reliable information on calcium balance. The aim of this study was to assess calcium balance during HD sessions with a method that is applicable in day-to-day practice. METHODS: Plasma ionized calcium (pCa2+) and parathyroid hormone (PTH) were measured at the beginning and end of HD to evaluate calcium fluxes in 23 patients on a dialysate calcium (DCa) concentration of 1.25 mmol/L. RESULTS: HD with a DCa of 1.25 mmol/L caused a decrease in pCa2+ from 1.15 ± 0.01 mmol/L to 1.09 ± 0.01 mmol/L (p<0.0001) and increased plasma PTH from 26.7 ± 1.8 pmol/L to 37.0 ± 2.9 pmol/L (p<0.0001). The changes in pCa2+ were inversely related to the predialysis pCa2+ levels (R2 = 0.86, p<0.001). Patients with a predialysis pCa2+ >1.06 mmol/L had a calcium efflux, whereas those with a predialysis pCa2+ <1.06 mmol/L had a calcium influx during HD. CONCLUSION: The results suggest that measurement of pCa2+ and PTH at the beginning and the end of HD provides useful information about calcium fluxes in individual patients. Further validation of this approach is warranted.

Epidemiology of contrast material-induced nephropathy in the era of hydration.

PURPOSE: To evaluate the incidence of contrast material-induced nephropathy (CIN) in patients with an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m(2) who received intravenous contrast media and underwent treatment in accordance with current guidelines and to determine risk factors associated with CIN. MATERIALS AND METHODS: The research ethics committee waived the requirement for informed consent for this prospective cohort study. All nonhospitalized patients with an eGFR of less than 60 mL/min/1.73 m(2) were seen at a special outpatient clinic. Patients were stratified for the risk of CIN. They were classified as having high or low risk for CIN on the basis of absolute glomerular filtration rate (Modification of Diet in Renal Disease formula result multiplied by body surface area divided by 1.73 m(2)) and the presence of risk factors. Patients at high risk were hydrated with 1000 mL of isotonic saline before and after contrast material exposure. Serum creatinine level was measured 3-5 days later, and CIN was defined as an increase of 25% of more from the baseline level. Risk factors were recorded and compared between patients with CIN and those without CIN by using forward stepwise multiple logistic regression analysis. RESULTS: A total of 944 procedures in 747 patients were evaluated. Mean age was 71.3 years ± 10 (standard deviation), and 42.9% of patients were female. In 511 procedures (54.1%), patients were hydrated. CIN developed after 23 procedures (2.4%). No patient needed hemodialysis treatment. Heart failure (odds ratio, 3.0), body mass index (BMI) (odds ratio, 0.9), and repeated contrast material administration (odds ratio, 2.8) were found to be independent predictors of CIN. CONCLUSION: Heart failure, low BMI, and repeated contrast material administration were identified as risk factors for CIN under the current treatment strategy. The low incidence of CIN supports the use of hydration as a preventive measure in patients at high risk for CIN.