Kidney function and daily emtricitabine/tenofovir disoproxil fumarate pre-exposure prophylaxis against HIV: results from the real-life multicentric demonstrative project PrEP Brazil

Background

Pre-Exposure Prophylaxis (PrEP) has demonstrated efficacy in the reduction of sexually transmitted HIV infections. The prolonged use of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) co-formulation (TDF/FTC), however, may result in augmented risk of renal toxicity. We aimed to evaluate changes in the estimated Glomerular Filtration Rate (eGFR) in a real-world population setting of participants enrolled in PrEP Brazil, a 48-week prospective, open-label, demonstration study to assess the feasibility of daily oral TDF/FTC used by men who have sex with men and transgender women at high-risk of HIV infection, all over 18 years old.

Methods

Kidney function was assessed by serial measurement of serum creatinine and eGFR with the Modification of Diet in Renal Disease Study (MDRD) formula on weeks 4, 12, 24, 36 and 48. Adherence to PrEP was assessed by dosing TDF concentration in dried blood spots at weeks 4 and 48, measured by liquid chromatography-mass spectrometry or mass spectrometry.

Results

Of 392 participants completing the 48-week follow-up protocol with TDF blood detectable levels and eGFR measures, 43.1% were young adults, of Caucasian ethnic background (57.9%), with BMI below 30 kg/m², without arterial hypertension. At screening, median eGFR was 93.0 mL/min/1.73 m². At week 4 follow-up, 90 (23% of the study population) participants presented reductions in eGFR greater than 10 mL/min/1.73 m² as compared to baseline eGFR, some as large as 59 mL/min/1.73 m², but with no clinical outcomes (adverse events and renal adverse events) severe enough to demand TDF/FTC discontinuation. A negative relationship was observed between TDF blood levels and eGFR at weeks 4 (r = − 0.005; p < 0.01) and 48 (r = − 0.006; p < 0.01).

Conclusions

These results suggest that the renal function profile in individuals on TDF/FTC may be assessed on week 4 and then only annually, allowing a more flexible medical follow-up in primary care centers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12981-022-00437-4.

Can we cure diabetic kidney disease? Present and future perspectives from a nephrologist's point of view

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease (CKD) worldwide, contributing to a great burden across a variety of patient-reported and clinical outcomes. New interventions for DKD management have been established in recent years, unleashing a novel paradigm, in which kidney-dedicated trials yield informative and robust data to guide optimal clinical management. After unprecedented results from groundbreaking randomized controlled trials were released, a new scenario of evidence-based recommendations has evolved for the management of diabetic patients with CKD. The current guidelines place great emphasis on multidimensional and interdisciplinary approaches, but the challenges of implementation are just starting and will be pivotal to optimize clinical results and to understand the new threshold for residual risk in DKD. We thereby provide an updated review on recent advances in DKD management based on new guideline recommendations, summarizing recent evidence while projecting the landscape for innovative ongoing initiatives in the field. Specifically, we review current insights on the natural history, epidemiology, pathogenesis, and therapeutics of DKD, mapping the new scientific information into the recently released Kidney Disease - Improving Global Outcomes Guidelines translating results from major novel randomized controlled trials to the clinical practice. Additionally, we approach the landscape of new therapeutics in the field, summarizing ongoing phase IIb and III trials focused on DKD. Finally, reflecting on the past and looking into the future, we highlight unmet needs in the current DKD management based on real-world evidence and offer a nephrologist's perspective into the challenge of fostering continuous improvement on clinical and patient-reported outcomes for individuals living with DKD.

Sex Differences in Kidney Transplantation: Austria and the United States, 1978–2018

Background

Systematic analyses about sex differences in wait-listing and kidney transplantation after dialysis initiation are scarce. We aimed at identifying sex-specific disparities along the path of kidney disease treatment, comparing two countries with distinctive health care systems, the US and Austria, over time.

Methods

We analyzed subjects who initiated dialysis from 1979–2018, in observational cohort studies from the US and Austria. We used Cox regression to model male-to-female cause-specific hazard ratios (csHRs, 95% confidence intervals) for transitions along the consecutive states dialysis initiation, wait-listing, kidney transplantation and death, adjusted for age and stratified by country and decade of dialysis initiation.

Results

Among 3,053,206 US and 36,608 Austrian patients starting dialysis, men had higher chances to enter the wait-list, which however decreased over time [male-to-female csHRs for wait-listing, 1978–1987: US 1.94 (1.71, 2.20), AUT 1.61 (1.20, 2.17); 2008–2018: US 1.35 (1.32, 1.38), AUT 1.11 (0.94, 1.32)]. Once wait-listed, the advantage of the men became smaller, but persisted in the US [male-to-female csHR for transplantation after wait-listing, 2008–2018: 1.08 (1.05, 1.11)]. The greatest disparity between men and women occurred in older age groups in both countries [male-to-female csHR for wait-listing after dialysis, adjusted to 75% age quantile, 2008–2018: US 1.83 (1.74, 1.92), AUT 1.48 (1.02, 2.13)]. Male-to-female csHRs for death were close to one, but higher after transplantation than after dialysis.

Conclusions

We found evidence for sex disparities in both countries. Historically, men in the US and Austria had 90%, respectively, 60% higher chances of being wait-listed for kidney transplantation, although these gaps decreased over time. Efforts should be continued to render kidney transplantation equally accessible for both sexes, especially for older women.

Comparative metabolomic study of high-flux hemodialysis and high volume online hemodiafiltration in the removal of uremic toxins using 1H NMR spectroscopy

Uremic toxins (UTs) accumulate in the circulation of patients with chronic kidney disease (CKD). High volume hemodiafiltration (HDF) improves clearance of low and medium molecular weight UTs compared to HD. The present study is a post-hoc analysis comparing the metabolomic profile in serum from patients under high flux HD (hf-HD) and HDF in HDFIT, a multicentric randomized controlled trial (RCTs). Per protocol, serum samples were collected pre- and post- dialysis treatments at randomization (baseline) and at the end of the follow up (6 months) and stored in a biorepository. Random (pre- and post-dialysis) samples from nine patients in study arm were selected at baseline and at the end of the follow up. To compare the samples, 26 possibly matching metabolites were identified by a t-test among the four groups using ¹H nuclear magnetic resonance (NMR). To evaluate the comparison between the modalities is a single treatment session, the clearance rates (CRs) of each metabolite were calculated based on pre-dialysis and post-dialysis samples. In addition, to evaluate to effect of UT removal during the trial follow up period, the pre-dialysis metabolite concentrations at the baseline and at 6 months were compared among the two arms of the study. There was no significant difference between in the single session CRs of metabolites when hf-HD and HDF were compared. On the other hand, the comparison between baseline and 6-month (long-term evolution) led to the identification of 16 metabolites that differentiated the hf-HD and the HDF evolutions. Most of these 16 metabolites are involved in several important metabolic pathways, such as metabolism of phenylalanine and biosynthesis of phenylalanine, tyrosine, and tryptophan, which are related to UTs and cardiovascular disease development. Although no difference was observed between hf-HD and HDF samples before and after a single session, concentrations of CKD-relevant metabolites and associated pathologies were stable in the HDF samples, but not in the hf-HD samples, over the six-month period, suggesting that HDF enhances long-term stability.

Routinely measured cardiac troponin I and N-terminal pro-B-type natriuretic peptide as predictors of mortality in haemodialysis patients

Aims

Cardiac troponin (cTn) and B‐type natriuretic peptide (BNP) are elevated in haemodialysis (HD) patients, and this elevation is associated with HD‐induced myocardial stunning/myocardial strain. However, studies using data from the international Dialysis Outcomes and Practice Patterns Study (DOPPS) have shown that these cardiac biomarkers are measured in <2% of HD patients in real‐world practice. This study aimed to examine whether routinely measured N‐terminal pro‐BNP (NT‐proBNP) and cTnI (contemporary assay) are more appropriate than clinical models for reclassifying the risk of HD patients who have the highest risk of death.

Methods and results

Pre‐dialysis levels of cTnI and NT‐proBNP at study enrolment were measured in 1152 HD patients (Japan DOPPS Phase 5). The patients were prospectively followed for 3 years. Cox regression was used to test the associations of cardiac biomarkers with all‐cause mortality, adjusting for potential confounders. Subgroup analyses were performed to assess potential effect modification of clinical characteristics, such as age, systolic blood pressure, HD vintage, diabetes mellitus, coronary artery disease, and a history of congestive heart failure. At baseline, 337 (29%) patients had elevated cTnI (99th percentile of a healthy population: >0.04 ng/mL) with a median (inter‐quartile range) level of 0.020 (0.005–0.041) ng/mL, and 1140 (99%) patients had elevated NT‐proBNP (cut‐off for heart failure: >125 pg/mL) with a median level of 3658 (1689–9356) pg/mL. There were 167 deaths during a median follow‐up of 2.8 (2.2–2.8) years. Higher levels of both cardiac biomarkers were incrementally associated with mortality after adjustment for potential confounders. Even after adjustment for alternative cardiac biomarkers, the overall P value for the association was <0.01 for both biomarkers. However, the prognostic significance of NT‐proBNP was moderately diminished when cTnI was added to the model. The hazard ratios of mortality for cTnI > 0.04 ng/mL (vs. cTnI < 0.006 ng/mL) and NT‐proBNP > 8000 pg/mL (vs. NT‐proBNP < 2000 pg/mL) were 2.56 (95% confidence interval: 1.37–4.81) and 1.90 (95% confidence interval: 0.95–3.79), respectively. Subgroup analyses showed that the associations of both cardiac biomarkers with mortality were generally consistent between stratified groups.

Conclusions

Routinely measured NT‐proBNP and cTnI levels are strongly associated with mortality among prevalent HD patients. These associations remain robust, even after adjustment for alternative biomarkers, suggesting that cTnI and NT‐proBNP have identical prognostic significance and may reflect different pathological aspects of cardiac abnormalities.

Assessing the impact of screening, early identification and intervention programmes for chronic kidney disease: protocol for a scoping review

INTRODUCTION

Chronic kidney disease (CKD) is a major threat to public health, especially in low-income and lower middle-income countries, where resources for treating patients with advanced CKD are scarce. Although early CKD identification and intervention hold promise for reducing the burden of CKD and risk factors, it remains unclear if an uniform strategy can be applicable across all income groups. The aim of this scoping review is to synthesise available evidence on early CKD identification programmes in all world regions and income groups. The study will also identify efforts that have been made to use interventions and implementation of early identification programmes for CKD across countries and income groups.

METHODS AND ANALYSIS

This review will be guided by the methodological framework for conducting scoping studies developed by Arksey and O'Malley. Empirical (Medline, Embase, Cochrane Library, CINAHL, ISI Web of Science and PsycINFO) and grey literature references will be searched to identify studies on CKD screening, early identification and interventions across all populations. Two reviewers will independently screen references in consecutive stages of title/abstract screening and then full-text screening. We will use a general descriptive overview, tabular summaries and content analysis on extracted data.

ETHICS AND DISSEMINATION

The findings from our planned scoping review will enable us to identify items in early identification programmes that can be used in developing screening toolkits for CKD. We will disseminate our findings using traditional approaches that include open-access peer-reviewed publication, scientific presentations and a white paper (call to action) report. Ethical approval will not be required for this scoping review as the data will be extracted from already published studies.

The global impact of the Coronavirus 2019 pandemic on in-centre haemodialysis services: an International Society of Nephrology -Dialysis Outcomes Practice Patterns Study survey

Introduction

To assess the impact of the COVID-19 pandemic impact on hemodialysis (HD) centers, The Dialysis Outcomes and Practice Patterns Study and ISN collaborated on a web-survey of centers.

Methods

A combined approach of random sampling and open invitation was used between March 2020 and March 2021. Responses were obtained from 412 centers in 78 countries and all 10 ISN regions.

Results

In 8 regions, rates of SARS-CoV-2 infection were <20% in most centers, but in North East Asia (NE Asia) and Newly Independent States and Russia (NIS & Russia), rates were ≥20% and ≥30%, respectively. Mortality was ≥10% in most centers in 8 regions, although lower in North America and Caribbean (N America & Caribbean) and NE Asia. Diagnostic testing was not available in 33%, 37%, and 61% of centers in Latin America, Africa, and East and Central Europe, respectively. Surgical masks were widely available, but severe shortages of particulate-air filter masks were reported in Latin America (18%) and Africa (30%). Rates of infection in staff ranged from 0% in 90% of centers in NE Asia to ≥50% in 63% of centers in the Middle East and 68% of centers in NIS & Russia. In most centers, <10% of staff died, but in Africa and South Asia (S Asia), 2% and 6% of centers reported ≥50% mortality, respectively.

Conclusion

There has been wide global variation in SARS-CoV-2 infection rates among HD patients and staff, personal protective equipment (PPE) availability, and testing, and the ways in which services have been redesigned in response to the pandemic.

How common is hyperkalaemia? A systematic review and meta-analysis of the prevalence and incidence of hyperkalaemia reported in observational studies

Background

The prevalence and incidence of hyperkalaemia, a potassium abnormality that can potentially have life-threatening consequences, are unclear.

Methods

The objective was to provide the most comprehensive overview of the epidemiology of hyperkalaemia to date within the general population, across different continents, in different healthcare settings and within pre-specified subgroups. Embase and MEDLINE were searched from database inception to 2 February 2021 using the Ovid SP platform. Relevant congress proceedings from 2018 to 2020 were also reviewed for inclusion. There was no language constraint applied. Observational studies from any time period and language reporting prevalence or incidence of hyperkalaemia within both adult and paediatric populations. Four investigators independently screened abstracts and assessed study quality of those meeting the pre-determined inclusion/exclusion criteria. Data extraction was conducted by the lead author with oversight from the senior author and data were pooled using a random-effects model. The measures assessed were the prevalence and incidence of hyperkalaemia. Prevalence was reported as a percentage, whilst incidence was reported as the rate per 100 person years.

Results

In total, 542 articles were included from an initial search of 14 112 articles. Across all adult studies, we report a prevalence of hyperkalaemia (by any definition/threshold) of 6.3% [95% confidence interval (CI): 5.8–6.8%], with an incidence of hyperkalaemia in the adult population of 2.8 (2.3–3.3) cases per 100 person years. Prevalence within the general population was 1.3% (1.0–1.8%), whilst incidence was 0.4 (0.2–0.8) cases per 100 person years. There was a variation by sex with a prevalence of 6.3% (4.9–8.0%) in males and 5.1% (4.0–6.6%) in females. Prevalence also varied according to the definition/threshold of hyperkalaemia used: >5 mmol/L—8.0% (7.2–8.9), ≥5.5 mmol/L—5.9% (3.5–10.0) and ≥6.0 mmol/L—1.0% (0.8–1.4); hyperkalaemia (by any definition/threshold) was highest amongst patients with end-stage kidney disease (21.5%; 18.3–25.3), kidney transplant patients (21.8%; 16.1–29.5) and patients with acute kidney injury (24.3%; 19.3–30.7).

Conclusions

This novel review provides a comprehensive and valuable resource on the prevalence and incidence of hyperkalaemia to better inform clinicians, healthcare providers and health policy makers on the burden of hyperkalaemia across different healthcare settings, patient populations and continents.

Potential Surrogate Outcomes for Kidney Failure in Advanced CKD: Evaluation of Power and Predictive Ability in CKDopps

Rationale & Objective

Potential surrogate end points for kidney failure have been proposed in chronic kidney disease (CKD); however, they must be evaluated to ensure accurate, powerful, and harmonized research, particularly among patients with advanced CKD. The aim of the current study was to investigate the power and predictive ability of surrogate kidney failure end points in a population with moderate-to-advanced CKD.

Study Design

Analysis of longitudinal data of a large multinational CKD observational study (Chronic Kidney Disease Outcomes and Practice Patterns Study).

Setting & Participants

CKD stage 3-5 patients from Brazil, France, Germany, and the United States.

Outcomes

Reaching an estimated glomerular filtration rate (eGFR) < 15 mL/min/1.73 m² or eGFR decline of ≥40%, and composite end points of these individual end points.

Analytical Approach

Each end point was used as a time-varying indicator in the Cox model to predict the time to kidney replacement therapy (KRT; dialysis or transplant) and was compared by the number of events and prediction accuracy.

Results

8,211 patients had a median baseline eGFR of 27 mL/min/1.73 m² (interquartile range, 21-36 mL/min/1.73 m²) and 1,448 KRT events over a median follow-up of 2.7 years (interquartile range, 1.2-3.0 years). Among CKD stage 4 patients, the eGFR < 15 mL/min/1.73 m² end point had higher prognostic ability than 40% eGFR decline, but the end points were similar for CKD stage 3 patients. The combination of eGFR < 15 mL/min/1.73 m² and 40% eGFR decline had the highest prognostic ability for predicting KRT, regardless of the CKD stage. Including KRT in the composite can increase the number of events and, therefore, the power.

Limitations

Variable visit frequency resulted in variable eGFR measurement frequency.

Conclusions

The composite end point can be useful for CKD progression studies among patients with advanced CKD. Harmonized use of this approach has the potential to accelerate the translation of new discoveries to clinical practice by identifying risk factors and treatments for kidney failure.

Sex-Specific Differences in Mortality and Incident Dialysis in the Chronic Kidney Disease Outcomes and Practice Patterns Study

Introduction

More men than women start kidney replacement therapy (KRT) although the prevalence of chronic kidney disease (CKD) is higher in women than men. We therefore aimed at analyzing sex-specific differences in clinical outcomes among 8237 individuals with CKD in stages 3 to 5 from Brazil, France, Germany, and the United States participating in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps).

Methods

Fine and Gray models, evaluating the effect of sex on time to events, were adjusted for age, Black race (model A); plus diabetes, cardiovascular disease, albuminuria (model B); plus estimated glomerular filtration rate (eGFR) slope during the first 12 months after enrollment and first eGFR after enrollment (model C).

Results

There were more men than women at baseline (58% vs. 42%), men were younger than women, and men had higher eGFR (28.9 ± 11.5 vs. 27.0 ± 10.8 ml/min per 1.73 m²). Over a median follow-up of 2.7 and 2.5 years for men and women, respectively, the crude dialysis initiation and pre-emptive transplantation rates were higher in men whereas that of pre-KRT death was more similar. The adjusted subdistribution hazard ratios (SHRs) between men versus women for dialysis were 1.51 (1.27–1.80) (model A), 1.32 (1.10–1.59) (model B), and 1.50 (1.25–1.80) (model C); for pre-KRT death, were 1.25 (1.02–1.54) (model A), 1.14 (0.92–1.40) (model B), and 1.15 (0.93–1.42) (model C); for transplantation, were 1.31 (0.73–2.36) (model A), 1.44 (0.76–2.74) (model B), and 1.53 (0.79–2.94) (model C).

Conclusion

Men had a higher probability of commencing dialysis before death, unexplained by CKD progression alone. Although the causal mechanisms are uncertain, this finding helps interpret the preponderance of men in the dialysis population.

Effectiveness and Tolerance of Renin-Angiotensin System Inhibitors With Aging in Chronic Kidney Disease

OBJECTIVES

Renin-angiotensin system inhibitors (RASi) are recommended for slowing chronic kidney disease (CKD) progression to kidney failure. Their effectiveness and tolerance as patients age remain uncertain because older patients have often been excluded from clinical trials.

DESIGN

CKD-REIN cohort study.

SETTING AND PARTICIPANTS

We studied 2762 patients with CKD stages 3 and 4 and a clinical indication for RASi enrolled between 2013 and 2016 in 40 nephrology clinics nationally representative in France.

METHODS

The primary outcome was the occurrence of kidney failure or death. The secondary outcomes were the occurrence of cardiovascular events and hospitalizations with acute kidney injury (AKI) or hyperkalemia. A propensity score analysis was performed. We used Cox models to estimate hazard ratios (HRs) for each outcome associated with RASi prescription and tested interactions with age.

RESULTS

Patients' mean age was 67 years, including 841 (30%) aged 75 years and older; 2178 (79%) were prescribed RASi's. During a median follow-up of 4.6 years, 33% of patients reached kidney failure or died. RASi prescription was associated with a lower risk of kidney failure or death (HR 0.79, 95% CI 0.66, 0.95), an association not modified by age (P for interaction = .72). It was not significantly associated with cardiovascular events. During the first 3 years of follow-up, 14% of patients were hospitalized with AKI or hyperkalemia, but risk was not higher among those prescribed RASi's (HR 0.75, 95% CI 0.55-1.02) and age did not modify its effect (P for interaction = .28).

CONCLUSIONS AND IMPLICATIONS

This study shows that aging does not appear to modify either RASi's beneficial effects on major CKD outcomes or their potential adverse effects.

Nephrologists’ Perspectives on Gender Disparities in CKD and Dialysis

Introduction

Globally, there are more women with chronic kidney disease (CKD), yet they comprise only 40% of patients receiving kidney replacement therapy by dialysis. We aimed to describe the perspectives of nephrologists on gender disparities in access to care and outcomes in CKD and dialysis.

Methods

We conducted semistructured interviews with 51 nephrologists (28, 55% women) from 22 countries from October 2019 to April 2020. Transcripts were analyzed thematically.

Results

We identified 6 themes. Related to women were primary commitment to caregiving (with subthemes of coordinating care, taking charge of health management, deprioritizing own health, centrality of family in decision-making); vigilance and self-reliance (diligence and conscientiousness, stoicism and tolerating symptoms, avoiding burden on family, isolation and coping alone); and stereotyping, stigma, and judgment (body image, dismissed as anxiety, shame and embarrassment, weakness and frailty). Related to men was protecting masculinity (safeguarding the provider role, clinging to control, self-regard, and entitled). Decisional power and ownership included men’s dominance in decision-making and women’s analytical approach in treatment decisions. Inequities compounded by social disadvantage (financial and transport barriers, without social security, limited literacy, entrenched discrimination, vulnerability) were barriers to care for women, particularly in socioeconomically disadvantaged communities.

Conclusion

Nephrologists perceived that women with CKD faced many challenges in accessing care related to social norms and roles of caregiving responsibilities, disempowerment, lack of support, stereotyping by clinicians, and entrenched social and economic disadvantage. Addressing power differences, challenging systemic patriarchy, and managing unconscious bias may help to improve equitable care and outcomes for all people with CKD.

Management of Blood Pressure in Patients With Chronic Kidney Disease Not Receiving Dialysis: Synopsis of the 2021 KDIGO Clinical Practice Guideline

DESCRIPTION

The Kidney Disease: Improving Global Outcomes (KDIGO) 2021 clinical practice guideline for the management of blood pressure (BP) in patients with chronic kidney disease (CKD) not receiving dialysis is an update of the KDIGO 2012 guideline on the same topic and reflects new evidence on the risks and benefits of BP-lowering therapy among patients with CKD. It is intended to support shared decision making by health care professionals working with patients with CKD worldwide. This article is a synopsis of the full guideline.

METHODS

The KDIGO leadership commissioned 2 co-chairs to convene an international Work Group of researchers and clinicians. After a Controversies Conference in September 2017, the Work Group defined the scope of the evidence review, which was undertaken by an evidence review team between October 2017 and April 2020. Evidence reviews were done according to the Cochrane Handbook. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach was used to guide the development of the recommendations and rate the strength and quality of the evidence. Practice points were included to provide guidance when evidence was insufficient to make a graded recommendation. The guideline was revised after public consultation between January and March 2020.

RECOMMENDATIONS

The updated guideline comprises 11 recommendations and 20 practice points. This synopsis summarizes key recommendations pertinent to the diagnosis and management of high BP in adults with CKD, excluding those receiving kidney replacement therapy. In particular, the synopsis focuses on recommendations for standardized BP measurement and a target systolic BP of less than 120 mm Hg, because these recommendations differ from some other guidelines.

Abstract 52: KDIGO (Kidney Disease: Improving Global Outcomes) Guideline Update On The Management Of Blood Pressure In Chronic Kidney Disease: What’s New And What’s Different From Other Guidelines

Introduction: In 2012, KDIGO released a guideline on BP management in CKD not receiving dialysis. The emergence of new trials and meta-analyses coupled with wider recognition of the importance of standardized BP measurement protocols have prompted a call to update the 2012 guideline. This summary will outline the changes to the prior recommendations and highlight similarities to guidelines from ACC/AHA and ESC/ESH.

Methods: A systematic review was undertaken to formally assess the following issues: 1) BP measurement; 2) lifestyle interventions; BP management in 3) patients with CKD, with and without diabetes, 4) kidney transplant recipients, and 5) children with CKD.

Results: A total of 6863 citations were screened. Of these, 290 RCTs, 14 observational studies, and 35 systematic reviews were included in the evidence review. A major addition to the KDIGO 2021 guideline is a chapter devoted to BP measurement. KDIGO recommends the use of standardized office BP over routine BP. Out-of-office measurements (ABPM, HBPM) can be used to complement standardized readings. This emphasis on standardized office BP measurement is similar to recommendations from ACC/AHA and ESC/ESH. A systolic BP target of <120 mm Hg is suggested; however, the guidance emphasizes that the target is only applicable when BP is measured using standardized office protocols. RASi are the preferred agents for adults with CKD with increased albuminuria. For lifestyle interventions, dietary sodium intake should be limited to <2 g/day, and ≥150 minutes/week of physical activity is recommended. A BP target of <130/80 mm Hg and use of CCB or ARB are preferred in kidney transplant recipients. BP in children with CKD should be guided by 24-hour MAP using ambulatory monitoring, targeting ≤50th percentile for age, sex, and height. Similar to ACC/AHA and ESC/ESH guidelines, KDIGO also encourages shared-decision making between patients and clinicians in the individualization of BP therapy.

Conclusions: KDIGO has revised its guideline for BP management in CKD based on a rigorous development process and emerging new evidence underscoring the importance of standardized office BP measurement and a lower systolic BP target of <120 mm Hg for achieving potential cardiovascular, kidney, and mortality benefits.

Commentary on the KDIGO 2021 Clinical Practice Guideline for the Management of Blood Pressure in CKD

PURPOSE OF REVIEW

To summarize and explain the new guideline on blood pressure (BP) management in chronic kidney disease (CKD) published by Kidney Disease: Improving Global Outcomes (KDIGO), an independent global nonprofit organization which develops and implements evidence-based clinical practice guidelines in kidney disease. KDIGO issued its first clinical practice guideline for the Management of Blood Pressure (BP) in Chronic Kidney Disease (CKD) for patients not receiving dialysis in 2012 and now updated the guideline in 2021.

RECENT FINDINGS

Recommendations in this update were developed based on systematic literature reviews and appraisal of the quality of the evidence and strength of recommendation following the "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) approach. The updated guideline includes five chapters covering BP measurement techniques, lifestyle interventions for lowering BP, and management of BP in three target populations, namely adults (with and without diabetes), kidney transplant recipients, and children. A dedicated chapter on BP measurement emphasizing standardized preparation and measurement protocols for office BP measurement is a new addition, following protocols used in large randomized trials of BP targets with pivotal clinical outcomes. Based on the available evidence, and in particular in the CKD subgroup of the SPRINT trial, the 2021 guideline suggests a systolic BP target of <120 mm Hg, based on standardized measurements, for most individuals with CKD not receiving dialysis, with the exception of kidney transplant recipients and children. This recommendation is strictly contingent on the measurement of BP using standardized office readings and not routine office readings.

The Environmental Role of Hydration in Kidney Health and Disease

Clinical Background: Hydration status, which is influenced by environment and self-behavior is associated with kidney health and disease. Epidemiology: Lack of safe water, sanitation, and high temperatures are environmental issues that affect a significant part of the worldwide population. Occupational factors that discourage proper hydration, as well as low water intake in favorable environment conditions, are also highly prevalent. As a consequence, inadequate water intake can lead to several kidney problems ranging from uncomplicated urinary tract infections to kidney stones, acute kidney injury, and chronic disorders with high mortality rates. Challenges: Increasing water intake is an individual effort when self-behavior is the main reason for inadequate hydration status. When the environment is an obstacle, it might require complex changes in a concerted multidisciplinary effort from employers, health authorities, researchers, and governments. Prevention and Treatment: Strategies can be implemented at global, local, and individual levels. Global efforts include actions to decrease poverty and climate change consequences, while increasing access to safe water and sanitation. Local actions can improve working conditions and access to water and toilets to workers. At an individual level, self-monitoring through regular observation of thirst sensation, acute weight loss, urine frequency, and urine color are recommended tools to monitor hydration status.

Uremia and Inadequate Oxygen Supply Induce Eryptosis and Intracellular Hypoxia in Red Blood Cells

BACKGROUND/AIMS

Chronic kidney disease is frequently accompanied by anemia, hypoxemia, and hypoxia. It has become clear that the impaired erythropoietin production and altered iron homeostasis are not the sole causes of renal anemia. Eryptosis is a process of red blood cells (RBC) death, like apoptosis of nucleated cells, characterized by Ca²⁺ influx and phosphatidylserine (PS) exposure to the outer RBC membrane leaflet. Eryptosis can be induced by uremic toxins and occurs before senescence, thus shortening RBC lifespan and aggravating renal anemia. We aimed to assess eryptosis and intracellular oxygen levels of RBC from hemodialysis patients (HD-RBC) and their response to hypoxia, uremia, and uremic toxins uptake inhibition.

METHODS

Using flow cytometry, RBC from healthy individuals (CON-RBC) and HD-RBC were subjected to PS (Annexin-V), intracellular Ca²⁺ (Fluo-3/AM) and intracellular oxygen (Hypoxia Green) measurements, at baseline and after incubation with uremic serum and/or hypoxia (5% O₂), with or without ketoprofen. Baseline levels of uremic toxins were quantified in serum and cytosol by high performance liquid chromatography.

RESULTS

Here, we show that HD-RBC have less intracellular oxygen and that it is further decreased post-HD. Also, incubation in 5% O₂ and uremia triggered eryptosis in vitro by exposing PS. Hypoxia itself increased the PS exposure in HD-RBC and CON-RBC, and the addition of uremic serum aggravated it. Furthermore, inhibition of the organic anion transporter 2 with ketoprofen reverted eryptosis and restored the levels of intracellular oxygen. Cytosolic levels of the uremic toxins pCS and IAA were decreased after dialysis.

CONCLUSION

These findings suggest the participation of uremic toxins and hypoxia in the process of eryptosis and intracellular oxygenation.

Serum Biomarkers of Iron Stores Are Associated with Increased Risk of All-Cause Mortality and Cardiovascular Events in Nondialysis CKD Patients, with or without Anemia

BACKGROUND

Approximately 30%-45% of patients with nondialysis CKD have iron deficiency. Iron therapy in CKD has focused primarily on supporting erythropoiesis. In patients with or without anemia, there has not been a comprehensive approach to estimating the association between serum biomarkers of iron stores, and mortality and cardiovascular event risks.

METHODS

The study included 5145 patients from Brazil, France, the United States, and Germany enrolled in the Chronic Kidney Disease Outcomes and Practice Patterns Study, with first available transferrin saturation (TSAT) and ferritin levels as exposure variables. We used Cox models to estimate hazard ratios (HRs) for all-cause mortality and major adverse cardiovascular events (MACE), with progressive adjustment for potentially confounding variables. We also used linear spline models to further evaluate functional forms of the exposure-outcome associations.

RESULTS

Compared with patients with a TSAT of 26%-35%, those with a TSAT ≤15% had the highest adjusted risks for all-cause mortality and MACE. Spline analysis found the lowest risk at TSAT 40% for all-cause mortality and MACE. Risk of all-cause mortality, but not MACE, was also elevated at TSAT ≥46%. Effect estimates were similar after adjustment for hemoglobin. For ferritin, no directional associations were apparent, except for elevated all-cause mortality at ferritin ≥300 ng/ml.

CONCLUSIONS

Iron deficiency, as captured by TSAT, is associated with higher risk of all-cause mortality and MACE in patients with nondialysis CKD, with or without anemia. Interventional studies evaluating the effect on clinical outcomes of iron supplementation and therapies for alternative targets are needed to better inform strategies for administering exogenous iron.

Hyperkalemia excursions are associated with an increased risk of mortality and hospitalizations in hemodialysis patients

BACKGROUND

Hyperkalemia is common among hemodialysis (HD) patients and has been associated with adverse clinical outcomes. Previous studies considered a single serum potassium (K) measurement or time-averaged values, but serum K excursions out of the target range may be more reflective of true hyperkalemia events. We assessed whether hyperkalemia excursions lead to an elevated risk of adverse clinical outcomes.

METHODS

Using data from 21 countries in Phases 4-6 (2009-18) of the Dialysis Outcomes and Practice Patterns Study (DOPPS), we investigated the associations between peak serum K level, measured monthly predialysis, over a 4-month period ('peak K') and clinical outcomes over the subsequent 4 months using Cox regression, adjusted for potential confounders.

RESULTS

The analysis included 62 070 patients contributing a median of 3 (interquartile range 2-6) 4-month periods. The prevalence of hyperkalemia based on peak K was 58% for >5.0, 30% for >5.5 and 12% for >6.0 mEq/L. The all-cause mortality hazard ratio for peak K (reference ≤5.0 mEq/L) was 1.15 [95% confidence interval (CI) 1.09, 1.21] for 5.1-5.5 mEq/L, 1.19 (1.12, 1.26) for 5.6-6.0 mEq/L and 1.33 (1.23, 1.43) for >6.0 mEq/L. Results were qualitatively consistent when analyzing hospitalizations and a cardiovascular composite outcome.

CONCLUSIONS

Among HD patients, we identified a lower K threshold (peak K 5.1-5.5 mEq/L) than previously reported for increased risk of hospitalization and mortality, with the implication that a greater proportion (>50%) of the HD population may be at risk. A reassessment of hyperkalemia severity ranges is needed, as well as an exploration of new strategies for effective management of chronic hyperkalemia.

Scope and heterogeneity of outcomes reported in randomized trials in patients receiving peritoneal dialysis

BACKGROUND

Randomized trials can provide evidence to inform decision-making but this may be limited if the outcomes of importance to patients and clinicians are omitted or reported inconsistently. We aimed to assess the scope and heterogeneity of outcomes reported in trials in peritoneal dialysis (PD).

METHODS

We searched the Cochrane Kidney and Transplant Specialized Register for randomized trials in PD. We extracted all reported outcome domains and measurements and analyzed their frequency and characteristics.

RESULTS

From 128 reports of 120 included trials, 80 different outcome domains were reported. Overall, 39 (49%) domains were surrogate, 23 (29%) patient-reported and 18 (22%) clinical. The five most commonly reported domains were PD-related infection [59 (49%) trials], dialysis solute clearance [51 (42%)], kidney function [45 (38%)], protein metabolism [44 (37%)] and inflammatory markers/oxidative stress [42 (35%)]. Quality of life was reported infrequently (4% of trials). Only 14 (12%) trials included a patient-reported outcome as a primary outcome. The median number of outcome measures (defined as a different measurement, aggregation and metric) was 22 (interquartile range 13-37) per trial. PD-related infection was the most frequently reported clinical outcome as well as the most frequently stated primary outcome. A total of 383 different measures for infection were used, with 66 used more than once.

CONCLUSIONS

Trials in PD include important clinical outcomes such as infection, but these are measured and reported inconsistently. Patient-reported outcomes are infrequently reported and nearly half of the domains were surrogate. Standardized outcomes for PD trials are required to improve efficiency and relevance.