Preservation of residual kidney function in hemodialysis patients: reviving an old concept

Twice against thrice-weekly hemodialysis (TATH): a multicenter nonrandomized trial

BACKGROUND

The optimal frequency of maintenance hemodialysis remains a subject of debate. In many countries, twice-weekly hemodialysis is still commonly practiced. This trial aimed to compare the outcomes of patients undergoing twice-weekly versus thrice-weekly hemodialysis.

METHODS

This prospective, multicenter, nonrandomized trial included incident adult patients, with chronic kidney disease stage 5, initiating hemodialysis between January 2018 and August 2021. Patients were allocated to either a twice-weekly or thrice-weekly regimen, and monitored at 1, 3, 6, 12 and 24 months. This trial was terminated before reaching the required sample size due to the COVID-19 pandemic and economic factors. Recruitment achieved 25% of the projected number. Missing baseline factors were imputed using multiple imputation algorithms, then entered in a logistic regression model to estimate propensity scores. The primary outcome was two-year survival analyzed using a Cox regression survival model adjusted for propensity scores and baseline residual urine output. Secondary outcomes included hospitalization rates, uncontrolled hypertension and cumulative erythropoietin dose at two years, analyzed using regression models adjusted for propensity scores and baseline residual urine output. All analyses were conducted on an intention-to-treat basis.

RESULTS

A total of 132 patients on thrice-weekly hemodialysis and 71 on twice-weekly hemodialysis were included. The mean age was 67 ± 15 years and the median eGFR at dialysis initiation was 6 (4,8) mL/min/1.73 m2. At one year, patients in the twice-weekly group had greater residual urine output. At two years, there was no significant difference in survival (HR = 0.84; 95% CI: 0.37, 1.90), hospitalization rates (P = 0.515) or uncontrolled hypertension (P = 0.442). The twice-weekly group showed a trend toward higher erythropoietin requirements (P = 0.08). Serum potassium levels and the number of antihypertensive medications were greater in the twice-weekly group.

CONCLUSIONS

Patients on twice-weekly hemodialysis showed comparable overall survival at two years to those on thrice-weekly hemodialysis. While a twice-weekly regimen may be a viable option during the first year of dialysis, especially in low-resource settings, it carries potential risks that necessitate careful monitoring after the first year.

TRIAL REGISTRATION

The trial was registered on ClinicalTrials.gov on January 16, 2018 (Identifier NCT03415776).

Expanded Hemodialysis with Theranova Dialyzer and Residual Kidney Function in Patients Starting Long-Term Hemodialysis: A Randomized Controlled Trial

Background

Expanded hemodialysis using a medium cutoff dialyzer improves the clearance of middle-molecular toxins compared with conventional hemodialysis. This study evaluated the effect of expanded hemodialysis on preserving residual kidney function in patients starting treatment with long-term hemodialysis.

Methods

Patients who initiated long-term hemodialysis were randomized to receive dialysis with either a Theranova 400 (Baxter) or a high-flux dialyzer with a similar surface area over 12 months. The primary outcome was a change in GFR over 12 months, as determined by the mean of urea and creatinine clearance. The secondary outcome was a change in 24-hour urine volume, middle molecules, and kidney injury markers.

Results

A total of 80 patients on hemodialysis (mean age [SD]: 63 [12] years; male: 52 [65%]) underwent randomization. Over 12 months, the Theranova group demonstrated a significantly smaller decrease in GFR than the high-flux group (least squares mean difference of change [95% confidence interval], −1.4 [−2.4 to −0.5] ml/min per 1.73 m2). Theranova maintained greater 24-hour urine volume until 9 months, not at 12 months, compared with the high-flux dialyzer. The reduction ratio for κ/λ free light chains, TNF-α, and growth differentiation factor-15 was higher in the Theranova group than in the high-flux group. The increase in the kidney injury marker, IGF-binding protein 7, was attenuated in the Theranova group. Hospitalization rate and mortality did not differ between the two groups.

Conclusions

This trial suggests that expanded hemodialysis using the Theranova dialyzer slowed decline in residual kidney function compared with a high-flux dialyzer in patients starting treatment with long-term hemodialysis.

Incremental Hemodialysis: Review of Clinical Trials Focused on Patients Undergoing Once-Weekly Hemodialysis

Background/objectives: The implementation of appropriate hemodialysis treatment in the transition from end-stage kidney disease to reduced frequency schedules represents a major challenge. The aim of our work is to report only treatment protocols that used once-weekly hemodialysis. Methods: The benefits and risks of 1WHD were explored in this systematic review. A search of MEDLINE, Scopus, and the Cochrane Central Register was conducted to identify publications relating to once-weekly hemodialysis trials performed between June 1981 and December 2024 and assess clinical impact, duration, safety, and mortality. Items, including age, causes of chronic kidney disease (CKD), creatinine levels, Blood Urea Nitrogen and GFR values, diuresis, nutritional supplementation, drop-out, survival, clinical benefit or drawbacks, and data from eventual control groups relating to higher frequency weekly HD sessions were included. Outcome at the end of a 1WHD regimen was represented by death or transition to twice/thrice-weekly HD rhythms. Results: A total of 1238 articles focused on IHD were included in the review, and 1226 trials were excluded as they referred either to twice-weekly hemodialysis (2WHD) schedules or failed to meet eligibility criteria, whilst another two were excluded based on incomplete outcome or patient recruitment issues. A total of eight articles comprising 254 patients undergoing 1WHD schedules were ultimately identified and evaluated. Only three studies focused on a comparison with a 1WHD schedule, whilst 107 referred to thrice-weekly HD (3WHD) and 15 2WHD). This choice demonstrated the possibility of slowing down the progression of CKD in the patients studied. Daily amino acid supplementation also proved to be beneficial. However, the milestone on which the 1WHD protocol is based is a low-protein diet. Conclusions: 1WHD has been shown to be safe and may result in improved clinical outcomes, particularly in appropriately selected patients. Large-scale randomized controlled trials should be carried out to confirm these potential advantages. However, the standard recruitment techniques applied tended to prevent suitably selected patients from transitioning into less frequent and potentially long-lasting 1WHD schedules.

Comparing residual kidney function equations based on β2-microglobulin in Chinese patients undergoing continuous ambulatory peritoneal dialysis

BACKGROUND

Few studies have evaluated the predictive capability of equations for residual kidney function (RKF) in patients undergoing peritoneal dialysis (PD). Moreover, the applicability of each equation remains unclear. Therefore, we aimed to evaluate the performances of the estimated RKF (eRKF) equations of Shafi, Steubl, and Jaques in Chinese patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

METHODS

This was a retrospective study. We enrolled patients who underwent CAPD and RKF measurements (via 24-h urine collection) in our hospital between November 2021 and May 2022. Using the measured RKF (mRKF) as the reference, we derived the bias, precision and accuracy of each equation.

RESULTS

We enrolled 174 participants. The mean β2-microglobulin and median mRKF were 29.00 ± 8.69 mg/L and 2.94 (1.26, 4.65) mL/min/1.73 m2, respectively. The Steubl equation had the least bias (MD [95% confidence interval, CI]: -0.52 [-0.77 to -0.38]), higher precision (interquartile range: 1.43 [1.16, 1.76]), and highest accuracy (83%). It also had a high diagnostic accuracy for identifying patients with an mRKF of > 2.5 mL/min/1.73 m2, area under the curve of 0.936 95% CI [0.903-0.970], p < 0.001), cut-off value of 1.80 mL/min/1.73 m2, specificity of 0.895, and sensitivity of 0.847.

CONCLUSION

Although no equation was fully accurate, the Steubl equation identified patients suitable for an incremental PD prescription more accurately than the Shafi and Jaques versions. It may be useful for monitoring the RKF of Chinese patients undergoing CAPD who are unable to reliably collect urine.

Copeptin associates with major adverse cardiovascular events in patients on maintenance hemodialysis

BACKGROUND

End-stage renal disease (ESRD) necessitating hemodialysis pose substantial cardiovascular risks, with cardiovascular disease (CVD) as a leading cause of mortality. Biomarkers like copeptin have emerged as potential indicators of cardiovascular stress and prognosis in CKD populations.

OBJECTIVE

This study aimed to assess the prognostic value of copeptin in predicting major adverse cardiovascular events (MACEs) among hemodialysis patients, alongside traditional cardiac biomarkers.

METHODS

ESRD patients undergoing maintenance hemodialysis were enrolled. Copeptin levels were measured, and patients were followed for MACEs, defined as cardiovascular deaths, myocardial infarction, stroke, or heart failure-related hospitalizations. Cox proportional-hazards models were used to evaluate the association between copeptin and outcomes, adjusting for relevant covariates.

RESULTS

Among 351 patients followed for a median of 22.7 months, elevated copeptin levels were significantly associated with an increased risk of MACEs (HR 1.519, 95 % CI 1.140 to 2.023; p = 0.00425). Copeptin demonstrated predictive capability across multiple statistical tests (Log-rank p = 0.024; Gehan p < 0.001; Tarone-Ware p < 0.001; Peto-Peto p = 0.027), although significance was attenuated in pairwise comparisons post-adjustment for multiple testing. Combining copeptin with NT-proBNP or hs-cTnT further enhanced risk stratification for MACEs.

CONCLUSION

Elevated copeptin levels independently predict adverse cardiovascular outcomes in hemodialysis patients. Integrating copeptin with traditional cardiac biomarkers may refine risk stratification and guide personalized therapeutic strategies in this high-risk population.

Nutritional outcomes between different techniques of intradialytic amino acid replacement: a randomized controlled trial

Background

Amino acid (AA) depletion during dialysis deteriorates the protein-energy status of haemodialysis (HD) patients. This study aimed to determine whether intradialytic amino acid (IDAA) replacement by continuous infusion versus acute load could provide better nutritional outcomes.

Methods

HD patients with mild protein-energy wasting, defined as a serum albumin level of 3.5-3.9 mg/dl despite 7-point subjective global assessment in category A or a malnutrition inflammation score ≤5, were randomly assigned to receive IDAA by continuous infusion or acute load for 3 months. In continuous infusion (n = 24), 50% glucose followed by 7.2% branched-chain enriched AA solution were instilled in the first 15 minutes after HD initiation with high-flux dialyser through the end of the session. Similar parenteral nutrition compositions containing the same total amount of glucose and AA were rapidly added into the venous drip chamber within the last hour of HD in the acute load group (n = 24). The primary outcome was the change in serum albumin level. Secondary outcomes were changes in muscle parameters and plasma as well as dialysate AA concentrations.

Results

The mean age of patients was 68.9 ± 12.7 years and the average body mass index was 22.8 ± 4.4 kg/m2 with 45.8% being men. After 3 months, serum albumin levels were significantly elevated in continuous infusion (P = .001) whereas it was unchanged in the acute load (P = .13). Despite comparable energy and protein intake, total body muscle mass was also increased in the continuous infusion group at 3 months (P = .03) compared with no significant change in the acute load group (P = .45). The amount of AA loss into the dialysate was similar between the two groups (P = .17). At post-dialysis, most plasma essential and non-essential AA levels were significantly lower in patients receiving continuous infusion than acute load, while branched-chain AA concentrations including leucine (P = .61) and valine (P = .09) were comparable between the two groups. Despite enhancing muscle mass in continuous infusion, handgrip strength and gait speed were unaltered in both techniques of IDAA replacement.

Conclusions

IDAA using continuous infusion appears to be superior to acute load in terms of serum albumin and muscle mass improvement. The impact of IDAA on hard clinical outcomes may require larger scale with a longer period of study (TCTR20230401003).

Once-per-week haemodialysis in a financial crisis: Predictors of interdialytic weight gain

BACKGROUND

Several countries are experiencing challenges in maintaining standard haemodialysis services for people with kidney failure.

OBJECTIVE

This study aimed to investigate the health profile of people receiving haemodialysis and to identify factors associated with interdialytic weight gain.

DESIGN

A cross-sectional study.

PARTICIPANTS

A total of 166 adults with kidney failure and receiving haemodialysis for at least 3 months were included.

MEASUREMENTS

A structured chart audit form collected, demographic and haemodialysis treatment characteristics, recent biochemical and haematological results, and prescribed treatment regimens from clinical records. Data were analysed descriptively. Odds ratios (OR) were calculated to identify independent risk factors for interdialytic weight gain.

RESULTS

Mean age was 52 years (SD = 12.5), over half were male (60.2%, n = 100), and most were receiving 4 h of haemodialysis once per week (87.3%, n = 145). Approximately half (51.8%, n = 86) had an interdialytic weight gain >2%. Being female (OR = 3.39; 95% CI, 1.51-7.61), increased comorbidities (OR = 1.50; 95% CI, 1.22-1.84) and having BMI outside of the normal range (overweight/obese [OR = 8.49; 95% CI, 3.58-20.13] or underweight [OR = 4.61; 95% CI, 1.39-15.31]) were independent risk factors for increased interdialytic weight gain.

CONCLUSION

Most patients were receiving 4 h of haemodialysis once per week although only modest alterations in potassium, phosphate, and fluid status were observed. Understanding the patient profile and predictors of interdialytic weight gain will inform the development of self-management interventions to optimise clinician support.

Redefining the concept of residual renal function with kidney sodium MRI: a pilot study

BACKGROUND

The concept of residual kidney function (RKF) is exclusively based upon urine volume and small solute clearance, making RKF challenging to assess in clinical practice. The aim of this study was to test the technical feasibility of obtaining usable sodium magnetic resonance imaging (23Na-MRI) kidney images in hemodialysis (HD) participants.

METHODS

We conducted an exploratory prospective study to quantify the cortico-medullary sodium gradient in 17 healthy volunteers and 21 HD participants. Participants fasted for 8 h prior to their study visit. Urine samples were collected to measure urinary osmolarity, before MRI. Proton and sodium pictures were merged; regions of interest were delineated for the medulla and cortex when feasible. In cases where cortex could not be identified, we considered the corticomedullary gradient (CMG) to be no longer present, resulting in a medulla-to-cortex ratio of 1.

RESULTS

Median (interquartile range) fasting medulla-to-cortex ratio was significantly higher 1.56 (1.5-1.61) in healthy volunteers compared with HD patients 1.22 (1.13-1.3), P < .0001. Medulla to cortex ratio and median urinary osmolarity were correlated (r = 0.87, P < .0001) in the whole population. We found a significant association between HD vintage and medulla-to-cortex ratio, whereas we did not find any association with urine volume. Sodium signal intensity distribution within healthy kidney describes two different peaks relating to well defined cortex and medulla, whereas HD participants displays only a single peak indicative of the markedly lower sodium concentration.

LIMITATIONS

This study is only exploratory, with a modest number of patients.

CONCLUSIONS

The application of kidney 23Na-MRI to the study of RKF in patients receiving maintenance HD is practical and provides a previously unavailable ability to interrogate the function of remnant tubular function.Clinical Trial Registration: NCT05014178.

Twice Weekly versus Thrice Weekly Hemodialysis-A Pilot Cross-Over Equivalence Trial

Key Points

The 2015 Kidney Disease Outcomes Quality Initiative Guideline Update increased the contribution of residual kidney function, shortening the time required for twice weekly hemodialysis. No study had yet assessed the feasibility of prescribing twice weekly hemodialysis according to the updated guideline. Twice weekly hemodialysis prescribed using the updated guideline maintained quality of life and controlled fluid gain, potassium, and uremic solutes.

Background

The 2015 Update of the Kidney Disease Outcomes Quality Initiative (KDOQI) Guideline for Hemodialysis Adequacy increased the contribution of residual kidney function in calculating standard Kt/Vurea (stdKt/Vurea). However, no study has assessed the effect of prescribing twice weekly hemodialysis according to this guideline on patients' quality of life or uremic solute levels.

Methods

Twenty six hemodialysis patients with average residual urea clearance (Kru) 4.7±1.8 ml/min and hemodialysis vintage of 12±15 months (range 2 months to 4.9 years) underwent a cross-over trial comparing four weeks of twice weekly hemodialysis and four weeks of thrice weekly hemodialysis. Twice weekly hemodialysis was prescribed to achieve stdKt/Vurea 2.2 incorporating Kru using the 2015 KDOQI Guideline. Thrice weekly hemodialysis was prescribed to achieve spKt/Vurea 1.3 regardless of Kru. Quality of life and plasma levels of secreted uremic solutes and β 2 microglobulin were assessed at the end of each period.

Results

Equivalence testing between twice and thrice weekly hemodialysis based on the Kidney Disease Quality of Life instrument (primary analysis) was inconclusive. Symptoms as assessed by the secondary outcomes Dialysis Symptom Index and Post-Dialysis Recovery Time were not worse with twice weekly hemodialysis. StdKt/Vurea was adequate during twice weekly hemodialysis (2.7±0.5), and ultrafiltration rate and plasma potassium were controlled with minimally longer treatment times (twice weekly: 195±20 versus thrice weekly: 191±17 minutes). Plasma levels of the secreted solutes and β 2 microglobulin were not higher with twice weekly than thrice weekly hemodialysis.

Conclusions

Twice weekly hemodialysis can be prescribed using the higher contribution assigned to Kru by the 2015 KDOQI Guideline. With twice weekly hemodialysis, quality of life was unchanged, and the continuous function of the residual kidneys controlled fluid gain and plasma levels of potassium and uremic solutes without substantially longer treatment times.

Clinical Trial registration number:

NCT03874117 .

Residual Kidney Function in Hemodialysis: Its Importance and Contribution to Improved Patient Outcomes

Individuals afflicted with advanced kidney dysfunction who require dialysis for medical management exhibit different degrees of native kidney function, called residual kidney function (RKF), ranging from nil to appreciable levels. The primary focus of this manuscript is to delve into the concept of RKF, a pivotal yet under-represented topic in nephrology. To begin, we unpack the definition and intrinsic nature of RKF. We then juxtapose the efficiency of RKF against that of hemodialysis in preserving homeostatic equilibrium and facilitating physiological functions. Given the complex interplay of RKF and overall patient health, we shed light on the extent of its influence on patient outcomes, particularly in those living with advanced kidney dysfunction and on dialysis. This manuscript subsequently presents methodologies and measures to assess RKF, concluding with the potential benefits of targeted interventions aimed at preserving RKF.

Carbon dioxide automated digital subtraction angiography for endovascular arteriovenous fistulas creation

Recent literature shows how residual renal function (RKF), defined as the urinary clearance of urea and creatinine, is associated with a lower mortality risk in HD patients. The use of non-nephrotoxic contrast media during radiological procedure, may be useful for preservation of RKF in patients with chronic kidney disease not yet in haemodialysis. We describe the case of a 51-year-old male suffering from chronic kidney disease from 2018, due to a right nephrectomy for an adenocarcinoma, who was considered for an endovascular arteriovenous fistula (endoAVF) creation (WavelinQ endoAVF System, Becton Dickinson, Franklin Lakes, New Jersey, US), using Carbon Dioxide as contrast media instead of conventional iodinated ones, with optimal results. CO2 DSA permits to well recognize the patency of target vein, its connection to the perforator vein and finally the endoAVF creation without requiring supplemental iodate contrast medium. We propose, CO2 automated digital subtraction angiography (DSA) as a safer technique that could be substitutive of the standard iodinated ones, in the creation of endo AVF.

Phosphate kinetic modeling as an estimate of daily ingested phosphate in hemodialysis patients with or without residual kidney function

BACKGROUND AND AIM

Daugirdas suggested a 2-pool phosphate kinetic model based on his previously established urea kinetic model. The current study aims to assess the level of agreement between the modeled daily ingested phosphorus (DIP) values and the routine method of dietary recall calculations in hemodialysis patients.

METHOD

The study was conducted on 100 hemodialysis patients; 50 were anuric, and the others had residual kidney function (RKF). The level of correlation and agreement between the dietary calculated and modeled DIP were assessed in both study groups.

RESULTS

A statistically significant positive correlation existed between the calculated and modeled DIP (r = 0.79 for the anuric group, r = 0.84 for the RKF group, p < 0.001). There was a significant level of agreement between calculated and modeled DIP in RKF patients only.

CONCLUSION

These findings suggest that phosphate modeling can estimate phosphate intake in RKF patients and be cost-effective in their management.

Residual Kidney Function and Cause-Specific Mortality Among Incident Hemodialysis Patients

Introduction

The survival benefit of residual kidney function (RKF) in patients on hemodialysis is presumably due to enhanced fluid management and solute clearance. However, data are lacking on the association of renal urea clearance (CLurea) with specific causes of death.

Methods

We conducted a longitudinal cohort study of 39,623 adults initiating thrice-weekly in-center hemodialysis from 2007 to 2011 and had data on renal CLurea and urine volume. Multivariable cause-specific proportional hazards model was used to examine the associations between baseline RKF and cause-specific mortality, including sudden cardiac death (SCD), non-SCD cardiovascular death (CVD), and non-CVD. Restricted cubic splines were fitted for change in RKF over 6 months after initiating hemodialysis.

Results

Among 39,623 patients with data on baseline renal CLurea and urine volume, there was a significant trend toward a higher mortality risk across lower RKF levels, irrespective of cause of death in a case-mix adjustment model (Ptrend < 0.05). Adjustment for ultrafiltration rate (UFR) slightly attenuated the association between low renal CLurea and high cause-specific mortality, whereas adjustment for highest potassium did not have substantial effect. Among 12,169 patients with data on change in RKF, a 6-month decline in renal CLurea showed graded associations with SCD, non-SCD CVD, and non-CVD risk, whereas the graded associations between faster 6-month decline in urine output and higher death risk were clear only for SCD and non-CVD.

Conclusion

Lower RKF and loss of RKF were associated with higher cause-specific mortality among patients initiating thrice-weekly in-center hemodialysis.

Diuretic-resistant heart failure and the role of ultrafiltration: A proposed protocol

Acute heart failure (HF) decompensation generally manifests with signs and symptoms of congestion that strongly predict poor poor patient outcome. Loop diuretics are the cornerstone of therapy to counteract fluid overload and are widely used for acute management and chronic stabilization of HF. However, a diminished response to loop diuretics is a common problem, affecting the patient's clinical course and potentially prolonging hospitalization. Diuretic resistance is defined as failure to decongest despite appropriate and escalating loop diuretic therapy. We propose a protocol for the management of diuretic resistance. The initial approach should include an assessment of causes of pseudo-diuretic resistance. Adjustments to loop diuretic therapy, such as increasing doses and frequency of administration and sequential nephron blockade, may be successful. For hospitalized patients with progressive disease there are more invasive methods for fluid removal. Switching from oral to intravenous loop diuretics is essential to avoid variable absorption and for symptomatic relief. Extracorporeal ultrafiltration is also an option since this technique is highly effective at removing plasma fluid from blood. While extracorporeal ultrafiltration is an invasive solution, peritoneal dialysis is a home-based, intermittent therapeutic option that can enable efficient management of fluid overload, preventing HF-related hospital admission, and improving quality of life. As a last resort for fluid removal, a peritoneal dialysis regimen should fully exploit its decongestive properties and should be tailored to the patient's characteristics and clinical needs.

Gut Microbiota Interventions to Retain Residual Kidney Function

Residual kidney function for patients with chronic kidney disease (CKD) is associated with better quality of life and outcome; thus, strategies should be implemented to preserve kidney function. Among the multiple causes that promote kidney damage, gut dysbiosis due to increased uremic toxin production and endotoxemia need attention. Several strategies have been proposed to modulate the gut microbiota in these patients, and diet has gained increasing attention in recent years since it is the primary driver of gut dysbiosis. In addition, medications and faecal transplantation may be valid strategies. Modifying gut microbiota composition may mitigate chronic kidney damage and preserve residual kidney function. Although various studies have shown the influential role of diet in modulating gut microbiota composition, the effects of this modulation on residual kidney function remain limited. This review discusses the role of gut microbiota metabolism on residual kidney function and vice versa and how we could preserve the residual kidney function by modulating the gut microbiota balance.

Association between anemia-related biomarkers and the adequacy of peritoneal dialysis in Chinese patients with chronic kidney disease

Objectives: The study aimed to examine the association of three anemia-related biomarkers with the adequacy of peritoneal dialysis (PD) in patients with chronic kidney disease (CKD). Methods: This study included 127 PD patients. The total Kt/V urea (Kt/V) was calculated according to the Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines. All patients were classified into two groups based on Kt/V, viz., adequate (Kt/V ≥1.7) and inadequate (Kt/V <1.7) groups. Effect sizes are expressed as odds ratios (ORs) and 95% confidence interval (CI). Results: After adjusting for age, gender, hypertension, diabetes, and PD duration, 20 g/L increment in hemoglobin (Hgb) was observed to significantly reduce the risk of inadequate PD by 19% (OR; 95% CI; P: 0.81; 0.70 to 0.95; 0.009), 5 g/L increment in the mean corpuscular hemoglobin concentration (MCHC) by 7% (0.93; 0.88 to 0.98; 0.009), and 5% increment in transferrin saturation (TS) by 23% (0.77; 0.64 to 0.94; 0.012). The gender-specific nomogram model was constructed by incorporating three significant anemia-related biomarkers and convenient influencing factors, and the prediction accuracy was good (concordance index (C-index): 0.686 for men and 0.825 for women). Conclusion: Our findings indicate that the deterioration of three anemia-related biomarkers (Hgb, MCHC, and TS) can precipitate the development of inadequate PD in Chinese patients with CKD.

Fibroblast growth factor-23 and cardiovascular disease among prevalent hemodialysis patients focusing on residual kidney function

Background

In patients undergoing incident hemodialysis, increased fibroblast growth factor-23 (FGF-23) levels are associated with the development of cardiovascular disease (CVD), but the influence of residual kidney function (RFK) on this association is unclear. This study aimed to investigate the association between FGF-23 levels, RKF, and CVD in patients undergoing prevalent hemodialysis.

Methods

This cross-sectional and longitudinal observational study included 296 patients undergoing maintenance hemodialysis for at least three months who were followed up for a median of 44 months. RKF was defined as 24-h urine output >200 mL, left ventricular (LV) diastolic dysfunction as E/E' >15 on echocardiographic parameters. CVD was defined as hospitalization or emergency room visits due to cardiovascular causes, such as angina, myocardial infarction, or congestive heart failure.

Results

The median intact FGF-23 (iFGF-23) level was 423.8 pg/mL (interquartile range, 171-1,443). Patients with an FGF-23 level > 423.8 pg/mL significantly had a lower proportion of RKF (39.2% vs. 60.1%, P < 0.001) and a higher proportion of LV diastolic dysfunction (54. 1% vs. 29.1%, P < 0.001) than those with an iFGF-23 level ≤ 423.8 pg/mL. The odds ratio (OR) for LV diastolic dysfunction was significantly higher in patients with RFK (OR per one-unit increase in the natural log-transformed iFGF-23 levels, 1.80; 95% confidence interval [CI]: 1.11-2.93) than in patients without RKF (OR per one-unit increase in the natural log-transformed iFGF-23 levels: 1.42; 95% CI: 1.01-1.99) in multivariate analysis (p < 0.001). During the follow-up period, 55 patients experienced CVD. The hazard ratio (HR) for CVD development was also significantly higher in patients with RKF (HR per one-unit increase in the natural log-transformed iFGF-23 levels, 2.64; 95% CI: 1.29-5.40) than those without RKF (HR per one-unit increase in the natural log-transformed iFGF-23 levels: 1.44; 95% CI: 1.04-1.99) in multivariate analysis (p = 0.05).

Conclusions

Increased iFGF-23 levels were associated with LV diastolic dysfunction and CVD development in patients undergoing prevalent hemodialysis; however, the loss of RKF attenuated the magnitude of these associations. Therefore, in these patients, RKF strongly influenced the detrimental role of iFGF-23 in the development of CVD.

Efficacy and Safety of the Use of SGLT2 Inhibitors in Patients on Incremental Hemodialysis: Maximizing Residual Renal Function, Is There a Role for SGLT2 Inhibitors?

SGLT-2i are the new standard of care for diabetic kidney disease (DKD), but previous studies have not included patients on kidney replacement therapy (KRT). Due to their high risk of cardiovascular, renal complications, and mortality, these patients would benefit the most from this therapy. Residual kidney function (RKF) conveys a survival benefit and cardiovascular health among hemodialysis (HD) patients, especially those on incremental hemodialysis (iHD). We retrospectively describe the safety and efficacy of SGLT2i regarding RKF preservation in seven diabetic patients with different clinical backgrounds who underwent iHD (one or two sessions per week) during a 12-month follow-up. All patients preserved RKF, measured as residual kidney urea clearance (KrU) in 24 h after the introduction of SGLT2i. KrU levels improved significantly from 4.91 ± 1.14 mL/min to 7.28 ± 1.68 mL/min at 12 months (p = 0.028). Pre-hemodialysis blood pressure improved 9.95% in mean systolic blood pressure (SBP) (p = 0.015) and 10.95% in mean diastolic blood pressure (DBP) (p = 0.041); as a result, antihypertensive medication was modified. Improvements in blood uric acid, hemoglobin A1c, urine albumin/creatinine ratio (UACR), and 24 h proteinuria were also significant. Regarding side effects, two patients developed uncomplicated urinary tract infections that were resolved. No other complications were reported. The use of SGLT2i in our sample of DKD patients starting iHD on a 1-2 weekly regimen appears to be safe and effective in preserving RKF.

Management of Cardiovascular Diseases in Chronic Hemodialysis Patients

Hemodialysis (HD) is the main treatment modality for patients with end-stage kidney disease. Cardiovascular diseases (CVD) are highly prevalent in HD patients and are the leading cause of death in this population, with the mortality from CVD approximately 20 times higher than that of the general population. Traditional and non-traditional cardiovascular risk factors accelerate progression of CVD and exacerbate the prognosis in HD patients. This review provides a brief overview of the characteristics of CVD in HD patients, and a description of advances in its management.

Residual Renal Phosphate Clearance in Patients Receiving Hemodialysis or Hemodiafiltration

OBJECTIVES

Substantial levels of residual renal clearance and urine output may occur in patients treated with hemodialysis or hemodiafiltration. However, the relationships among residual renal urea, creatinine, and phosphate clearances, respectively, and between clearances and urine volume have not been well described.

METHODS

We performed a prospective, cross-sectional study which enrolled hemodialysis and hemodiafiltration patients with a urine volume of >100 mL/day, in whom at least 2 residual renal clearances were obtained over a 6-month observation period. Urine was collected for 24 hours prior to the midweek treatment session and concentrations of urea, creatinine, and phosphate were measured.

RESULTS

Thirty-eight patients (24 men, 14 women) with a mean age of 70.4 ± 12.4 (SD) years were included in this analysis. All patients were dialyzed 3 times per week with mean treatment duration of 243 ± 7.89 minutes. Twenty patients were undergoing hemodiafiltration and 18 patients high-flux hemodialysis. In total, 102 dialysis sessions, of which 52 were hemodiafiltration, and urine collections were analyzed. Mean urine volume was 457 ± 254 mL per 24 hours. Residual renal clearance rates of urea (Kr Urea), creatinine (Kr Cr), and phosphate (Kr Phos) were 1.60 ± 0.979, 4.69 ± 3.79, and 1.98 ± 1.36 mL/minute, respectively. Mean ratios of Kr Cr/Kr Urea, Kr Phos/Kr Urea, and Kr Phos/Kr Cr were 2.83 ± 1.21, 1.23 ± 0.387, and 0.477 ± 0.185, respectively. There was a modest correlation between Kr Phos and daily urine volume (r = 0.605, P = .001).

CONCLUSIONS

In maintenance hemodialysis and hemodiafiltration patients, residual renal phosphate clearance is approximately 23% higher than residual renal urea clearance. Urine volume is a modestly accurate surrogate for estimating residual renal phosphate clearance, but only when urine volume is <300 mL/day.

Focusing on Phosphorus Loads: From Healthy People to Chronic Kidney Disease

Phosphorus is an essential micromineral with a key role in cellular metabolism and tissue structure. Serum phosphorus is maintained in a homeostatic range by the intestines, bones, and kidneys. This process is coordinated by the endocrine system through the highly integrated actions of several hormones, including FGF23, PTH, Klotho, and 1,25D. The excretion kinetics of the kidney after diet phosphorus load or the serum phosphorus kinetics during hemodialysis support that there is a "pool" for temporary phosphorus storage, leading to the maintenance of stable serum phosphorus levels. Phosphorus overload refers to a state where the phosphorus load is higher than is physiologically necessary. It can be caused by a persistently high-phosphorus diet, renal function decline, bone disease, insufficient dialysis, and inappropriate medications, and includes but is not limited to hyperphosphatemia. Serum phosphorus is still the most commonly used indicator of phosphorus overload. Trending phosphorus levels to see if they are chronically elevated is recommended instead of a single test when judging phosphorus overload. Future studies are needed to validate the prognostic role of a new marker or markers of phosphorus overload.

Catheter-Related Bloodstream Infection in Hemodialysis Patient due to Atlantibacter hermannii

Atlantibacter hermannii, previously known as Escherichia hermannii, is a rare causative agent of human infections. Several reports testify that the most frequently infected patients are immunosuppressed, especially those undergoing hemodialysis. A 34-year-old man with an end-stage renal disease complained of chills, fever, and general fatigue at the end of a regular hemodialysis session. The echocardiographic examination showed vegetation located on the dialysis catheter in the right atrium. Empirical therapy was initiated with intravenous gentamicin, and after the isolation of the agent, the treatment was continued with intravenous imipenem/cilastatin. The blood cultures and the tip of the replaced catheter were positive for A. hermannii, identified by Vitek 2 Compact. Verification of the automated identification was performed using 16S sequencing. The 16S sequence product was used to query the NCBI bacterial database and revealed 99.75% identity to that of A. hermannii strain CIP 103176 16S ribosomal RNA in the NCBI GenBank database. The antimicrobial susceptibility results revealed resistance to aminopenicillins and susceptibility to all other tested antimicrobials. To our knowledge, this is the first report of catheter-related vegetation with echocardiographic confirmation and the successful eradication of A. hermannii infection in a patient undergoing hemodialysis with imipenem/cilastatin.

Factors associated with low-compliance bladder in end-stage renal disease patients and development of a clinical prediction model for urodynamic evaluation: the DUDi score

OBJECTIVES

To investigate factors associated with low-compliance bladders (LCB) in pretransplant patients with end-stage renal disease (ESRD) and develop a clinical prediction model for urodynamic studies.

METHODS

This study was a prospective cohort study. Patients with ESRD on the renal transplantation waiting list were recruited and underwent the urodynamic study. Demographics data, predictor factors related to the bladder compliance such as underlying disease of the lower urinary tract disease (LUTD), duration of urine < 250 mL/day, type and duration of renal replacement therapy (RRT), urine volume per day and urodynamic study information were collected. Univariable and multivariable logistic regression models were used to assess the independence of explanatory factors, then we developed the clinical prediction model.

RESULTS

One hundred fifty-two patients participated in the study: 94 patients in the normal bladder group and 58 patients in LCB group. Demographic data were not significantly different between the two groups, except diabetes. Cystometric capacity, detrusor pressure, compliance were significantly different. From the univariate analysis, DM status, duration of RRT, and passing < 100 mL of urine per day were related to LCB. We named the prediction model, the DUDi score based on the predictors (Duration of RRT, Urine volume/day, Diabetes). Higher scores predicted a higher risk of low-compliance bladder [P value = 0.464 according to the Hosmer-Lemeshow test, and the AUC was 0.87 (95% CI 0.81-0.92)].

CONCLUSIONS

Our clinical prediction model is easy to use and provides a high predictive value that is appropriate for patients who have no known LUTD to identify low-compliance bladder. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION FOR PROSPECTIVELY REGISTERED TRIALS: This study was approved by the Thai Clinical Trials Registry Committee on 09 February 2021. The TCTR identification number is TCTR20210209006.

Serum irisin level is higher in peritoneal dialysis than in hemodialysis

BACKGROUND

Previous studies have proved that irisin is related to the development of chronic kidney disease. In this study, we aimed to compare serum irisin level in patients treated with peritoneal dialysis (PD) and hemodialysis (HD).

METHODS

Two hundred and fifty-two dialysis patients (146 PD patients and 106 HD patients) were included in the study. Levels of serum irisin and other parameters were compared between the two groups' patients.

RESULTS

There were higher serum irisin levels in PD patients than those in HD patients [113.10 (106.15 ~ 119.15) ng/ml vs. 45.72(21.67 ~ 79.71) ng/ml, P < 0.001]. Moreover, body fat mass, percent body fat, serum calcium, high-density lipoprotein, low-density lipoprotein, carbon dioxide combining power (CO₂CP) and residual renal function were higher in patients on PD than that in those on HD, whereas levels of lean body mass, systolic blood pressure, albumin, serum uric acid, potassium, and phosphorus（It should be "were" replace are) are higher in HD patients in comparison to PD patients. Dialysis modality (PD/HD), serum CO₂CP level, lean body mass, and percent body fat independently positively correlated with natural logarithm of irisin (lnirisin) by multivariate linear regression analysis.

CONCLUSIONS

In this study, we prove that serum irisin level is significantly higher in patients treated with peritoneal dialysis than that with hemodialysis. As well as, increasing skeletal muscle mass and fat body percent, and correcting metabolic acidosis may increase serum irisin levels.

Nurse-based educational interventions in patients with peritoneal dialysis: A systematic review and meta-analysis

Background

Peritoneal dialysis (PD) is a major renal replacement therapy modality for patients with end-stage kidney disease (ESKD) worldwide. As poor self-care of PD patients could lead to serious complications, including peritonitis, exit-site infection, technique failure, and death; several nurse-based educational interventions have been introduced. However, these interventions varied and have been supported by small-scale studies so the effectiveness of nurse-based educational interventions on clinical outcomes of PD patients has been inconclusive.

Objectives

To evaluate the effectiveness of nurse-based education interventions in PD patients.

Design

A systematic review and meta-analysis of Randomized Controlled Trials (RCTs).

Methods

We performed a systematic search using PubMed, Embase, and CENTRAL up to December 31, 2021. Selection criteria included Randomized Controlled Trials (RCTs) relevant to nurse-based education interventions in ESKD patients with PD in the English language. The meta-analyses were conducted using a random-effects model to evaluate the summary outcomes of peritonitis, PD-related infection, mortality, transfer to hemodialysis, and quality of life (QoL).

Results

From 9,816 potential studies, 71 theme-related abstracts were selected for further full-text articles screening against eligibility criteria. As a result, eleven studies (1,506 PD patients in seven countries) were included in our systematic review. Of eleven studies, eight studies (1,363 PD patients in five countries) were included in the meta-analysis. Sleep QoL in the intervention group was statistically significantly higher than control (mean difference = 12.76, 95% confidence intervals 5.26-20.27). There was no difference between intervention and control groups on peritonitis, PD-related infection, HD transfer, and overall QoL.

Conclusions

Nurse-based educational interventions could help reduce some PD complications, of which only the sleep QoL showed statistically significant improvement. High-quality evidence on the nurse-based educational interventions was limited and more RCTs are needed to provide more robust outcomes.

Tweetable abstract

Nurse-based educational interventions showed promising sleep quality improvement and potential peritonitis risk reduction among PD patients.

Twice-Weekly Hemodialysis With Adjuvant Pharmacotherapy and Transition to Thrice-Weekly Hemodialysis: A Pilot Study

RATIONALE & OBJECTIVE

Thrice-weekly hemodialysis (HD) is the most common treatment modality for kidney failure in the United States. We conducted a pilot study to assess the feasibility and safety of incremental-start HD in patients beginning maintenance HD.

STUDY DESIGN

Pilot study.

SETTING & PARTICIPANTS

Adults with estimated glomerular filtration rate (eGFR) ≥5 mL/min/1.73 m² and urine volume ≥500 mL/d beginning maintenance HD at 14 outpatient dialysis units.

EXPOSURE

Randomized allocation (1:1 ratio) to twice-weekly HD and adjuvant pharmacologic therapy for 6 weeks followed by thrice-weekly HD (incremental HD group) or thrice-weekly HD (conventional HD group).

OUTCOME

The primary outcome was feasibility. Secondary outcomes included changes in urine volume and solute clearance.

RESULTS

Of 77 patients invited to participate, 51 consented to do so, representing 66% of eligible patients. We randomized 23 patients to the incremental HD group and 25 patients to the conventional HD group. Protocol-based loop diuretics, sodium bicarbonate, and patiromer were prescribed to 100%, 39%, and 17% of patients on twice-weekly HD, respectively. At a mean follow-up of 281.9 days, participant adherence was 96% to the HD schedule (22 of 23 and 24 of 25 in the incremental and conventional groups, respectively) and 100% in both groups to serial timed urine collection. The incidence rate ratio for all-cause hospitalization was 0.31 (95% CI, 0.08-1.17); and 7 deaths were recorded (1 in the incremental and 6 in the conventional group). At week 24, the incremental HD group had lower declines in urine volume (a difference of 51.0 [95% CI, -0.7 to 102.8] percentage points) and in the averaged urea and creatinine clearances (a difference of 57.9 [95% CI, -22.6 to 138.4] percentage points).

LIMITATIONS

Small sample size, time-limited twice-weekly HD.

CONCLUSIONS

It is feasible to enroll patients beginning maintenance HD into a randomized study of incremental-start HD with adjuvant pharmacotherapy who adhere to the study protocol during follow-up. Larger multicenter clinical trials are indicated to determine the efficacy and safety of incremental HD with longer twice-weekly HD periods.

FUNDING

Funding was provided by Vifor Inc.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov, identifier NCT03740048.

Can residual kidney function affect quality of life and cognitive function in hemodialysis patients?

BACKGROUND

Residual kidney function (RKF) may provide many benefits to patients on permanent renal replacement therapy that are reflected in better control of biochemical parameters. In hemodialysis patients, quality of life (QOL) and cognitive function are often impaired. This study aimed to assess the predictors of RKF and its impact on QOL and cognitive function in chronic hemodialysis patients.

PATIENTS AND METHODS

The study involved seventy-eight patients suffering from end-stage renal disease on regular hemodialysis. The patients were divided into two groups according to the presence or absence of RKF (24-hour urine volume ≥ 100 ml). Beside basic laboratory investigations, all patients were subjected to Kidney Disease Quality of Life-Short Form (KDQOL-SF) version 1.3 for assessing the quality of life and Montreal cognitive assessment (MoCA) score for assessing cognitive function.

RESULTS

There was a significantly higher score for KDQOL domains and MoCA score in patients with RKF compared to patients without RKF. There was a significant positive correlation between RKF and both of MoCA score and the physical composite score (PCS) of QOL. Moreover, there were statistically significant positive correlations between the MoCA score and both PCS and mental composite score (MCS). On multivariate analysis, hemodialysis duration was the only predictor for RKF; whereas age was a significant predictor for PCS; and MoCA score could be significantly predicted by the measured RKF and patients' age.

CONCLUSION

HD patients with maintained RKF had better QOL and cognitive function. The duration of HD and the age of the patients were found to be related to RKF and PCS in this study. RKF was associated with the cognitive performance of hemodialysis patients.

The rationale for the need to study sodium-glucose co-transport 2 inhibitor usage in peritoneal dialysis patients

The wave of kidney and heart outcome trials, showing multiple potential benefits for sodium-glucose co-transport 2 (SGLT2) inhibitors, have excluded patients with an estimated glomerular filtration rate below 25 ml/min/1.73 m2. However, dialysis patients are at the highest risk of cardiovascular disease and would benefit most from effective cardioprotective therapies. There is emerging evidence from experimental studies and post hoc analyses of randomised clinical trials that SGLT2 inhibitors are well tolerated and may also be effective in preventing cardiovascular and mortality outcomes in patients with severe chronic kidney disease, including patients receiving dialysis. As such, extending the usage of SGLT2 inhibitors to dialysis patients could provide a major advancement in their care. Peritoneal dialysis (PD) patients have an additional unmet need for effective pharmacotherapy to preserve their residual kidney function (RKF), with its associated mortality benefits, and for treatment options that help reduce the risk of transfer to haemodialysis. Experimental data suggest that SGLT2 inhibitors, via various mechanisms, may preserve RKF and protect the peritoneal membrane. There is sound physiological rationale and an urgent clinical need to execute robust randomised control trials to study the use of SGLT2 inhibitors in PD patients to answer important questions of relevance to patients and healthcare systems.

Incremental Hemodialysis: What We Know so Far

Traditionally, patients that develop progressive chronic kidney disease in need of kidney replacement therapy are prescribed thrice weekly in-center hemodialysis sessions at the beginning of therapy. This empiric prescription is based on historic trials that were comprised of mostly prevalent patients. Incremental hemodialysis is the process of performing <3 sessions of dialysis per week or limiting dialysis dose by duration at the initial onset of treatment to provide a more gradual transition, mimicking the progressive nature of kidney disease. Adding clearance contributions from residual kidney function is the standard of care with peritoneal dialysis but has not routinely been employed with hemodialysis. Accounting for residual kidney function accompanied by improvement in adjuvant pharmacotherapy, such as newer potassium binding agents and dietary modification, can augment dialytic clearances and allow for an incremental approach. Utilizing incremental dialysis has been associated with both preserving residual kidney function as well as improving patient quality of life. Barriers to this approach include concerns regarding patient acceptance of dialysis prescription changes, adherence to therapy, and provider factors that would require a restructuring of the current thrice weekly hemodialysis rubric. Candidacy for incremental therapy has shown the best outcomes when urea clearances exceed 3 mL/min and urine volumes are >500 mL/day, although these measures have been deemed conservative. A significant amount of retrospective and registry data has been supportive of initiating incremental hemodialysis and several pilot studies have shown the feasibility of implementing such an approach. Larger, randomized control trials are needed to fully evaluate safety and efficacy to allow for more widespread acceptance of this patient-centered approach to chronic kidney disease.

Estimated Glomerular Filtration Rate in Chronic Kidney Disease: A Critical Review of Estimate-Based Predictions of Individual Outcomes in Kidney Disease

Chronic kidney disease (CKD) is generally regarded as a final common pathway of several renal diseases, often leading to end-stage kidney disease (ESKD) and a need for renal replacement therapy. Estimated GFR (eGFR) has been used to predict this outcome recognizing its robust association with renal disease progression and the eventual need for dialysis in large, mainly cross-sectional epidemiological studies. However, GFR is implicitly limited as follows: (1) GFR reflects only one of the many physiological functions of the kidney; (2) it is dependent on several non-renal factors; (3) it has intrinsic variability that is a function of dietary intake, fluid and cardiovascular status, and blood pressure especially with impaired autoregulation or medication use; (4) it has been shown to change with age with a unique non-linear pattern; and (5) eGFR may not correlate with GFR in certain conditions and disease states. Yet, many clinicians, especially our non-nephrologist colleagues, tend to regard eGFR obtained from a simple laboratory test as both a valid reflection of renal function and a reliable diagnostic tool in establishing the diagnosis of CKD. What is the validity of these beliefs? This review will critically reassess the limitations of such single-focused attention, with a particular focus on inter-individual variability. What does science actually tell us about the usefulness of eGFR in diagnosing CKD?

Comparison between peritoneal dialysis and hemodialysis on kidney function recovery in incident kidney failure: A nationwide cohort study

BACKGROUND

Patients with kidney failure who start dialysis have a chance of kidney function recovery. Whether the initial dialysis modality affects the possibility of recovery is not fully understood.

METHODS

We included patients diagnosed with kidney failure requiring dialysis during 2001-2013 from the Taiwan National Health Insurance Research Database. We excluded diabetic and elderly patients. Kidney function recovery was defined as not receiving dialysis therapy for longer than 3 months. The primary outcome was kidney function recovery, and the secondary outcome was all-cause mortality during a 3-year follow up.

RESULTS

A total of 12,619 patients was eligible for analysis, with 981 received PD and 11,638 received HD. Total 620 patients had kidney function recovery during a 3-year follow up, which represented 4.9% of the entire cohort. After propensity score matching, the PD groups were more likely to experience kidney function recovery (subdistribution hazard ratio [SHR]: 1.64, 95% confidence interval [CI]: 1.19-2.25). The risk of all-cause mortality between groups did not significantly differ (hazard ratio [HR]: 1.23, 95% CI: 0.89-1.70).

CONCLUSION

The study found that in nonelderly, nondiabetic patients who received inadequate predialysis nephrology care before kidney failure, PD is associated with a higher chance of kidney function recovery.

Choices in hemodialysis therapies: variants, personalized therapy and application of evidence-based medicine

The extent of removal of the uremic toxins in hemodialysis (HD) therapies depends primarily on the dialysis membrane characteristics and the solute transport mechanisms involved. While designation of ‘flux’ of membranes as well toxicity of compounds that need to be targeted for removal remain unresolved issues, the relative role, efficiency and utilization of solute removal principles to optimize HD treatment are better delineated. Through the combination and intensity of diffusive and convective removal forces, levels of concentrations of a broad spectrum of uremic toxins can be lowered significantly and successfully. Extended clinical experience as well as data from several clinical trials attest to the benefits of convection-based HD treatment modalities. However, the mode of delivery of HD can further enhance the effectiveness of therapies. Other than treatment time, frequency and location that offer clinical benefits and increase patient well-being, treatment- and patient-specific criteria may be tailored for the therapy delivered: electrolytic composition, dialysate buffer and concentration and choice of anticoagulating agent are crucial for dialysis tolerance and efficacy. Evidence-based medicine (EBM) relies on three tenets, i.e. clinical expertise (i.e. doctor), patient-centered values (i.e. patient) and relevant scientific evidence (i.e. science), that have deviated from their initial aim and summarized to scientific evidence, leading to tyranny of randomized controlled trials. One must recognize that practice patterns as shown by Dialysis Outcomes and Practice Patterns Study and personalization of HD care are the main driving force for improving outcomes. Based on a combination of the three pillars of EBM, and particularly on bedside patient–clinician interaction, we summarize what we have learned over the last 6 decades in terms of best practices to improve outcomes in HD patients. Management of initiation of dialysis, vascular access, preservation of kidney function, selection of biocompatible dialysers and use of dialysis fluids of high microbiological purity to restrict inflammation are just some of the approaches where clinical experience is vital in the absence of definitive scientific evidence. Further, HD adequacy needs to be considered as a broad and multitarget approach covering not just the dose of dialysis provided, but meeting individual patient needs (e.g. fluid volume, acid–base, blood pressure, bone disease metabolism control) through regular assessment—and adjustment—of a series of indicators of treatment efficiency. Finally, in whichever way new technologies (i.e. artificial intelligence, connected health) are embraced in the future to improve the delivery of dialysis, the human dimension of the patient–doctor interaction is irreplaceable. Kidney medicine should remain ‘an art’ and will never be just ‘a science’.

Novel Protein to Phosphorous Ratio Score Predicts Mortality in Hemodialysis Patients

OBJECTIVE

Lowering serum phosphorus in people on hemodialysis may improve their survival. However, prior studies have shown that restricting dietary protein intake, a major source of phosphorus, is associated with higher mortality. We hypothesized that a novel metric that incorporates both these values commensurately can improve survival prediction.

METHODS

We used serum phosphorous and normalized protein catabolic rate (nPCR), a surrogate of dietary protein intake, to form a new metric R that was used to examine the associations with mortality in 63,016 people on hemodialysis (HD) of one year after treatment initiation. Survival models were adjusted for case-mix, malnutrition-inflammation cachexia syndrome (MICS), and residual kidney function (RKF).

RESULTS

Individuals treated with hemodialysis were divided into five groups in accordance with R value. Group 1 included sick individuals with high phosphorous and low nPCR. Group 5 included individuals with low phosphorous and high nPCR. After 1-year follow-up, survival difference between the groups reflected R value, where an increase in R was associated with improved survival. The association of R with mortality was strengthened by adjustment in demographic variables and attenuated after adjustment to MICS. Mortality associations in accordance with R were not influenced by residual kidney function (RKF).

CONCLUSION

The novel protein to phosphorus ratio score R predicts mortality in people on dialysis, probably reflecting both nutrition and inflammation state independent of RKF. The metric enables better phosphorus monitoring, although adequate dietary protein intake is ensured and may improve the prediction of outcomes in the clinical setting.

Toward an individualized determination of dialysis adequacy: a narrative review with special emphasis on incremental hemodialysis

INTRODUCTION

The search for the 'perfect' renal replacement therapy has been paralleled by the search for the perfect biomarkers for assessing dialysis adequacy. Three main families of markers have been assessed: small molecules (prototype: urea); middle molecules (prototype β2-microglobulin); comprehensive and nutritional markers (prototype of the simplified assessment, albumin levels; composite indexes as malnutrition-inflammation score). After an era of standardization of dialysis treatment, personalized dialysis schedules are increasingly proposed, challenging the dogma of thrice-weekly hemodialysis.

AREAS COVERED

In this review, we describe the advantages and limitations of the approaches mentioned above, focusing on the open questions regarding personalized schedules and incremental hemodialysis.

EXPERT OPINION

In the era of personalized dialysis, the assessment of dialysis adequacy should be likewise personalized, due to the limits of 'one size fits all' approaches. We have tried to summarize some of the relevant issues regarding the determination of dialysis adequacy, attempting to adapt them to an elderly, highly comorbidity population, which would probably benefit from tailor-made dialysis prescriptions. While no single biomarker allows precisely tailoring the dialysis dose, we suggest using a combination of clinical and biological markers to prescribe dialysis according to comorbidity, life expectancy, residual kidney function, and small and medium-size molecule depuration.

Association of Plasma Uremic Solute Levels with Residual Kidney Function in Children on Peritoneal Dialysis

BACKGROUND AND OBJECTIVES

Residual native kidney function confers health benefits in patients on dialysis. It can facilitate control of extracellular volume and inorganic ion concentrations. Residual kidney function can also limit the accumulation of uremic solutes. This study assessed whether lower plasma concentrations of uremic solutes were associated with residual kidney function in pediatric patients on peritoneal dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Samples were analyzed from 29 pediatric patients on peritoneal dialysis, including 13 without residual kidney function and ten with residual kidney function. Metabolomic analysis by untargeted mass spectrometry compared plasma solute levels in patients with and without residual kidney function. Dialytic and residual clearances of selected solutes were also measured by assays using chemical standards.

RESULTS

Metabolomic analysis showed that plasma levels of 256 uremic solutes in patients with residual kidney function averaged 64% (interquartile range, 51%-81%) of the values in patients without residual kidney function who had similar total Kt/V_urea. The plasma levels were significantly lower for 59 of the 256 solutes in the patients with residual kidney function and significantly higher for none. Assays using chemical standards showed that residual kidney function provides a higher portion of the total clearance for nonurea solutes than it does for urea.

CONCLUSIONS

Concentrations of many uremic solutes are lower in patients on peritoneal dialysis with residual kidney function than in those without residual kidney function receiving similar treatment as assessed by Kt/V_urea.

Hemodialysis (HD) dose and ultrafiltration rate are associated with survival in pediatric and adolescent patients on chronic HD-a large observational study with follow-up to young adult age

BACKGROUND

Hemodialysis (HD) dose targets and ultrafiltration rate (UFR) limits for pediatric patients on chronic HD are not known and are derived from adults (spKt/V>1.4 and <13 ml/kg/h). We aimed to characterize how delivered HD dose and UFR are associated with survival in a large cohort of patients who started HD in childhood.

METHODS

Retrospective analysis on a cohort of patients <30 years, on chronic HD since childhood (<19 years), having received thrice-weekly HD 2004-2016 in outpatient DaVita centers.

OUTCOME

Survival while remaining on HD.

PREDICTORS

(I) primary analysis: mean delivered dialysis dose stratified as spKt/V ≤1.4/1.4-1.6/>1.6 (Kaplan-Meier analysis), (II) secondary analyses: UFR and alternative dialysis adequacy measures [eKt/V, body-surface normalized Kt/BSA] on continuous scale (Weibull regression model).

RESULTS

A total of 1780 patients were included (age at the start of HD: 0-12y: n=321, >12-18y: n=1459; median spKt/V=1.55, eKt/V=1.31, Kt/BSA=31.2 L/m², UFR=10.6 mL/kg/h). (I) spKt/V<1.4 was associated with lower survival compared to spKt/V>1.4-1.6 (P<0.001, log-rank test), and spKt/V>1.6 (P<0.001), with 10-year survival of 69.3% (59.4-80.9%) versus 83.0% (76.8-89.8%) and 84.0% (79.6-88.5%), respectively. (II) Kt/BSA was a better predictor of survival than spKt/V or eKt/V. UFR was additionally associated with survival (P<0.001), with increased mortality <10/>18 mL/kg/h. Associations did not alter significantly following adjustment for demographic characteristics (age, etiology of kidney disease, and ethnicity).

CONCLUSIONS

Our results suggest usefulness of targeting Kt/BSA>30 L/m² for best long-term outcomes, corresponding to spKt/V>1.4 (>12 years) and >1.6 (<12 years). In contrast to adults, higher UFR of 10-18 ml/kg/h was not associated with greater mortality in this population.

Patiromer in a Patient with Severe Hyperkalemia on Incremental Hemodialysis with 1 Session per Week: A Case Report and Literature Review

Hyperkalemia is common in patients with ESRD, undergoing hemodialysis (HD), and is associated with an increase in hospitalization and mortality. Residual kidney function in long-term dialysis patients is associated with lower morbidity and mortality in HD patients. Although the 2015 National Kidney Foundation-Kidney Disease Outcomes Quality Initiate (NKD-KDOQI) guidelines allow the reduction in the weekly HD dose for patients with a residual kidney urea clearance (Kur) >3 mL/min/1.73 m², very few centers adjust the dialysis dose based on these criteria. In our center, the pattern of incremental hemodialysis (iHD) with once-a-week schedule (1 HD/W) has been an option for a group of patients showing very good results. This pattern is maintained as long as residual diuresis is >1,000 mL/24 h, Kur is >4 mL/min, and there is no presence of edema or volume overload, as well as no analytical parameters persistently outside the advisable range (serum phosphorus >6 mg/dL or potassium [K⁺] >6.5 mmol/L). Management of hyperkalemia in HD patients includes reduction of dietary intake, dosing of medications that contribute to hyperkalemia, and use of cation-exchange resins such as calcium or sodium polystyrene sulfonate. Two newer potassium binders, patiromer sorbitex calcium and sodium zirconium cyclosilicate, have been safely used for potassium imbalance treatment in patients with ESRD in HD with a conventional regimen of thrice weekly, but has not yet been studied in 1 HD/W schedules. We present the case of a 76-year-old woman in iHD (1 HD/W) treated with patiromer for severe HK and describe her clinical characteristics and outcomes. In addition, we review the corresponding literature. Based on these data, it can be anticipated that the use of patiromer may overcome the risk of hyperkalemia in patients with incident ESRD treated with less-frequent HD regimens.

Efficacy and safety of oral tolvaptan in patients undergoing hemodialysis: a Phase 2, double-blind, randomized, placebo-controlled trial

BACKGROUND

Loop diuretics are used to manage fluid retention in patients with end-stage kidney disease undergoing hemodialysis (HD). This randomized, double-blind, placebo-controlled, Phase 2 trial evaluated the efficacy and safety of tolvaptan, a vasopressin V2 receptor antagonist, in Japanese HD patients.

METHODS

A total of 124 patients (24-h urine volume ≥500 mL) on thrice-weekly HD were randomized to receive oral tolvaptan 15 mg/day (n = 40), tolvaptan 30 mg/day (n = 40) or placebo (n = 44) for 24 weeks. Efficacy endpoints were change from baseline in 24-h urine volume, total fluid removal by HD per week and interdialytic weight gain (IDWG). Safety was assessed via the incidence of treatment-emergent adverse events (TEAEs).

RESULTS

At treatment end, the difference (95% confidence interval) from the placebo group in the mean change from baseline in 24-h urine volume was significant in the tolvaptan 15 mg {429.1 mL [95% confidence interval (CI) 231.0, 627.2]; P < 0.0001} and 30 mg [371.6 mL (95% CI 144.1, 599.2); P = 0.0017] groups. The mean changes from baseline in total fluid removal by HD and IDWG were not significantly different in the tolvaptan groups versus the placebo group. Although the proportion of patients with TEAEs was lower in the placebo group (77.3%) than in the tolvaptan groups (92.3%), tolvaptan was safe and well-tolerated during the study period.

CONCLUSIONS

Tolvaptan significantly sustained diuretic action for 24 weeks in HD patients but did not reduce total fluid removal by HD per week and IDWG to the same extent.

CENTRAL NERVOUS SYSTEM RESPONSE TO CHRONIC KIDNEY DISEASE

Due to the aging of the human population, the prevalence of chronic diseases such as chronic kidney disease (CKD) is increasing every year. Chronic kidney disease is a general term that refers to heterogeneous disorders that affect kidney structure and function. Decrease in glomerular filtration can be defined as chronic and progressive deterioration in fluid-solute balance, metabolic and endocrine functions of the kidney. CKD often affects the elderly. With the advancement of age, some structural and functional changes occur in the kidneys. Therefore, the number of patients suffering from mild and moderate CKD is expected to increase in the future.CKD leads to the deep metabolic and hemodynamic changes that damage other organs, such as the heart and brain. CNS abnormalities and cognitive deficits progress with the severity of CBS and occurs mostly among hemodialysis patients. It also has great socio-economic effects on individuals. Since symptoms of CKD are not often found in patients, early recognition of risk factors is the main point. For this reason, it is necessary to identify possible protective and preventive treatments to be applied in at-risk groups and to examine these mechanisms for the treatment of the disease. This review provides available information on the relevant mechanisms.

Protection of Residual Renal Function and Nutritional Treatment: First Step Strategy for Reduction of Uremic Toxins in End-Stage Kidney Disease Patients

The retention of uremic toxins and their pathological effects occurs in the advanced phases of chronic kidney disease (CKD), mainly in stage 5, when the implementation of conventional thrice-weekly hemodialysis is the prevalent and life-saving treatment. However, the start of hemodialysis is associated with both an acceleration of the loss of residual kidney function (RKF) and the shift to an increased intake of proteins, which are precursors of uremic toxins. In this phase, hemodialysis treatment is the only way to remove toxins from the body, but it can be largely inefficient in the case of high molecular weight and/or protein-bound molecules. Instead, even very low levels of RKF are crucial for uremic toxins excretion, which in most cases are protein-derived waste products generated by the intestinal microbiota. Protection of RKF can be obtained even in patients with end-stage kidney disease (ESKD) by a gradual and soft shift to kidney replacement therapy (KRT), for example by combining a once-a-week hemodialysis program with a low or very low-protein diet on the extra-dialysis days. This approach could represent a tailored strategy aimed at limiting the retention of both inorganic and organic toxins. In this paper, we discuss the combination of upstream (i.e., reduced production) and downstream (i.e., increased removal) strategies to reduce the concentration of uremic toxins in patients with ESKD during the transition phase from pure conservative management to full hemodialysis treatment.

Paraoxonase 1 concerning dyslipidaemia, cardiovascular diseases, and mortality in haemodialysis patients

Paraoxonase 1 (PON1) is known for preventing atherosclerosis through lipid-modifying features, antioxidant activity, anti-inflammatory, anti-apoptosis, anti-thrombosis, and anti-adhesion properties. Uremic patients requiring haemodialysis (HD) are especially prone to atherosclerosis and its complications. We analysed the PON1 gene (PON1) polymorphisms and serum PON1 (paraoxonase) activity concerning dyslipidaemia and related cardiovascular diseases and mortality to show how they associate under uremic conditions modified by maintenance HD treatment. The rs662 AA + AG (OR 1.76, 95%CI 1.10-2.80, P = 0.018), rs854560 TT (OR 1.48, 95%CI 1.04-2.11, P = 0.031), and rs854560 AT + TT (OR 1.28, 95%CI 1.01-1.63, P = 0.040) contributed to the prevalence of atherogenic dyslipidaemia diagnosed by the triglyceride (TG)/HDL-cholesterol ratio ≥ 3.8. The normalized serum PON1 activity positively correlated with atherogenic dyslipidaemia (ẞ 0.67 ± 0.25, P = 0.008). The PON1 rs854560 allele T was involved in the higher prevalence of ischemic cerebral stroke (OR 1.38, 1.02-1.85, P = 0.034). The PON1 rs705379 TT genotype contributed to cardiovascular (HR 1.27, 95% CI 1.03-1.57, P = 0.025) and cardiac (HR 1.34, 95% CI 1.05-1.71, P = 0.018) mortality. All P-values were obtained in multiple regression analyses, including clinical variables. Multifaceted associations of PON1 with dyslipidaemia, ischemic cerebral stroke, and cardiovascular mortality in HD patients provide arguments for the consideration of PON1 and its protein product as therapeutic targets in the prevention of atherosclerosis and its complications in uremic patients.

The Nitty-Gritties of Kt/Vurea Calculations in Hemodialysis and Peritoneal Dialysis

In advanced Chronic Kidney Disease, patients require renal replacement therapy (dialysis or transplantation) for clearance of toxins, electrolyte and acid-base balance and removal of excess fluid. Dialysis adequacy should be taken into consideration in the adjustment of the dialysis prescription. Kt/Vurea is one method of measuring dialysis adequacy that is commonly used in clinical practice. Different formulae for calculating Kt/V are available. The appropriate Kt/V formula to be used depends on the clinical scenario, as well as parameters such as gender and size of patient, frequency of dialysis, mode of dialysis (ie hemodialysis vs, peritoneal dialysis), inter-dialysis weight gain, clinical symptoms, complications (fluid overload, hyperkalemia, intolerance to dialysis, etc), and residual kidney function. Nutrition parameters including serum protein and albumin levels, vitamin B12 and β2-microglobulin levels should be factored into the assessment of dialysis adequacy. In this review, we have described how Kt/Vurea is calculated in hemodialysis and peritoneal dialysis with examples. We reviewed the available literature by searching for papers related to calculating Kt/Vurea, single pool Kt/V, double pool Kt/V, weekly Kt/V, standard Kt/V, surface area normalized Kt/V, and various equations commonly practiced in clinical practice. We found several original articles, some review articles along with detailed information from manufacturers of different dialyzers published on their websites or as package inserts. Understanding the different equations available for calculating Kt/Vurea and the application of these results in the clinical setting is important for refining patient care and for designing clinical studies.

Nonsteroidal anti-inflammatory drugs in end-stage kidney disease: dangerous or underutilized?

Introduction: Nonsteroidal anti-inflammatory drugs (NSAIDs) are a popular class of analgesic and anti-inflammatory medications, but their use is often avoided in end-stage kidney disease (ESKD) patients due to their reputation for nephrotoxic side effects. This removes a useful agent from the analgesic arsenal, even as ESKD patients suffer from proportionally more severe chronic pain than the general population as well as from a large reliance on opioid medications. Areas Covered: This paper reviews the current literature to comprehensively define the pharmacologic mechanisms and adverse effects of NSAIDs and reassesses the viability of their use in ESKD patients. Expert opinion: The evidence directly examining the impact of NSAIDs on long-term outcomes in ESKD is limited. Further study quantifying the risk of NSAID use - especially in dialysis-dependent patients - is warranted. Given the difficulty in achieving adequate pain control in ESKD patients, limited use of NSAIDs in these patients may yet be justified.

Diagnostic performance of pulmonary ultrasonography and a clinical score for the evaluation of fluid overload in haemodialysis patients

INTRODUCTION

There is no feasible benchmark in daily routine to estimate the hydration status of haemodialysis patients, which is essential to their management.

OBJECTIVE

We performed a study in haemodialysis patients to assess the diagnostic performance of pulmonary ultrasound and clinical examination for the evaluation of fluid overload using transthoracic echocardiography as a gold standard.

METHODS

Thirty-one patients receiving chronic haemodialysis patients were included. Evaluation of hydration status was assessed weekly before haemodialysis sessions using clinical and Echo Comet Score from pulmonary ultrasound and transthoracic echocardiography (reference method).

RESULTS

Five patients had a transthoracic echocardiography overload. Compared with transthoracic echocardiography, the diagnostic performance of the clinical overload score has a sensitivity of 100%, a specificity of 77%, a positive predictive value of 50% and a negative predictive value of 100% with a κ of 0.79. Only orthopnoea (P=0.008), jugular turgor (P=0.005) and hepatic-jugular reflux (P=0.008) were significantly associated with transthoracic echocardiography overload diagnosis. The diagnostic performance of Echo Comet Score by pulmonary ultrasound has a sensitivity of 80%, a specificity of 58%, a positive predictive value of 26% and a negative predictive value of 94%. Ten patients (32.3%) had an increase of extravascular pulmonary water without evidence of transthoracic echocardiography or clinical overload.

CONCLUSIONS

Our clinical score has a convincing diagnostic performance compared to transthoracic echocardiography and could be easily used in daily clinical routine to adjust dry weight. The evaluation of the overload using pulmonary ultrasound seems poorly correlated with the overload evaluated by transthoracic echocardiography. Extravascular pulmonary water undetected by clinical examination and transthoracic echocardiography remains a parameter that requires further investigation.

Novel conservative management of chronic kidney disease via dialysis-free interventions

PURPOSE OF REVIEW

In advanced chronic kidney disease (CKD) patients with progressive uremia, dialysis has traditionally been the dominant treatment paradigm. However, there is increasing interest in conservative and preservative management of kidney function as alternative patient-centered treatment approaches in this population.

RECENT FINDINGS

The primary objectives of conservative nondialytic management include optimization of quality of life and treating symptoms of end-stage renal disease (ESRD). Dietetic-nutritional therapy can be a cornerstone in the conservative management of CKD by reducing glomerular hyperfiltration, uremic toxin generation, metabolic acidosis, and phosphorus burden. Given the high symptom burden of advanced CKD patients, routine symptom assessment using validated tools should be an integral component of their treatment. As dialysis has variable effects in ameliorating symptoms, palliative care may be needed to manage symptoms such as pain, fatigue/lethargy, anorexia, and anxiety/depression. There are also emerging treatments that utilize intestinal (e.g., diarrhea induction, colonic dialysis, oral sorbents, gut microbiota modulation) and dermatologic pathways (e.g., perspiration reduction) to reduce uremic toxin burden.

SUMMARY

As dialysis may not confer better survival nor improved patient-centered outcomes in certain patients, conservative management is a viable treatment option in the advanced CKD population.

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.