Discontinuation of RAAS Inhibition in Children with Advanced CKD

Role of hypertension in progression of pediatric CKD

Hypertension is frequent in children with chronic kidney disease (CKD). Its prevalence varies according to CKD stage and cause. It is relatively uncommon in children with congenital kidney disease, while acquired kidney disease is associated with a higher prevalence of hypertension. Studies in children with CKD utilizing ambulatory blood pressure monitoring also showed a high prevalence of masked hypertension. Uncontrolled and longstanding hypertension in children is associated with progression of CKD. Aggressive treatment of high blood pressure should be an essential part of care to delay CKD progression in children.

Hyperkalemia in pediatric chronic kidney disease

BACKGROUND

While hyperkalemia is well described in adult chronic kidney disease (CKD), large studies evaluating potassium trends and risk factors for hyperkalemia in pediatric CKD are lacking. This study aimed to characterize hyperkalemia prevalence and risk factors in pediatric CKD.

METHODS

Cross-sectional analysis of Chronic Kidney Disease in Children (CKiD) study data evaluated median potassium levels and percentage of visits with hyperkalemia (K ≥5.5 mmoL/L) in relation to demographics, CKD stage, etiology, proteinuria, and acid-base status. Multiple logistic regression was used to identify risk factors for hyperkalemia.

RESULTS

One thousand and fifty CKiD participants with 5183 visits were included (mean age 13.1 years, 62.7% male, 32.9% self-identifying as African American or Hispanic). A percentage of 76.6% had non-glomerular disease, 18.7% had CKD stage 4/5, 25.8% had low CO2, and 54.2% were receiving ACEi/ARB therapy. Unadjusted analysis identified a median serum potassium level of 4.5 mmol/L (IQR 4.1-5.0, p <0.001) and hyperkalemia in 6.6% of participants with CKD stage 4/5. Hyperkalemia was present in 14.3% of visits with CKD stage 4/5 and glomerular disease. Hyperkalemia was associated with low CO2 (OR 7.72, 95%CI 3.05-19.54), CKD stage 4/5 (OR 9.17, 95%CI 4.02-20.89), and use of ACEi/ARB therapy (OR 2.14, 95%CI 1.36-3.37). Those with non-glomerular disease were less frequently hyperkalemic (OR 0.52, 95%CI 0.34-0.80). Age, sex, and race/ethnicity were not associated with hyperkalemia.

CONCLUSIONS

Hyperkalemia was observed more frequently in children with advanced stage CKD, glomerular disease, low CO2, and ACEi/ARB use. These data can help clinicians identify high-risk patients who may benefit from earlier initiation of potassium-lowering therapies. A higher resolution version of the Graphical abstract is available as Supplementary information.

Renin angiotensin aldosterone inhibitors in the treatment of proteinuria in children with congenital anomalies of the kidney and urinary tract: more evidence needed

INTRODUCTION

Congenital anomalies of the kidney and urinary tract (CAKUT) can be associated with proteinuria, possibly leading to a decline in kidney function. The aim of this review is to evaluate evidence on the efficacy of renin-angiotensin-aldosterone system inhibitors (RAASi) in children affected by CAKUT with proteinuria or chronic kidney disease (CKD).

AREAS COVERED

We conducted a bibliographic search between 1 December 2022 and 20 February 2023, including randomized controlled trials, case-control studies, observational studies, meta-analyses, and systematic reviews dealing with the efficacy of RAASi in reducing proteinuria and slowing the decline of kidney function in children.

EXPERT OPINION

RAASi are effective in reducing proteinuria and slowing CKD progression in many renal conditions; however, the efficacy of these drugs in patients affected by CAKUT with proteinuria is still unknown. While waiting for more evidence, when facing a child with CAKUT with isolated proteinuria or with proteinuria and CKD, a 6-12-month trial with RAASi with gradual increase to the maximal tolerated dose should be considered. If no improvement of proteinuria is obtained, the RAASi should be discontinued.

Case report: Withdrawal of angiotensin-converting enzyme inhibitors in children with advanced chronic kidney disease and rapidly declining kidney function

Background

It is not known whether withdrawal of angiotensin-converting enzyme inhibitors (ACEIs) in children with advanced chronic kidney disease (CKD) is beneficial similar to adults. We report a case series of children with advanced CKD whose ACEIs were stopped.

Methods

In the last 5 years, we stopped ACEIs in seven consecutive children on ACEI therapy with rapidly declining CKD stage 4-5. The median age was 12.5 years (range 6.8-17.6); the median estimated glomerular filtration rate (eGFR) at stopping ACEIs was 12.5 ml/min/1.73 m² (range 8.8-19.9).

Results

Six to twelve months after stopping ACEIs, the eGFR increased in five children (71%). The median absolute increase of eGFR was 5.0 ml/min/1.73 m² (range -2.3 to +20.0) and relative increase of eGFR was 30% (range -34 to +99). The median follow-up after stopping ACEIs was 2.7 (range 0.5-5.0) years, either until the start of dialysis (n = 5) or until the last follow-up without dialysis (n = 2).

Conclusions

This case series showed that withdrawal of ACEIs in children with CKD stage 4-5 and rapidly declining kidney function may lead to an increase in eGFR.

Urinary DKK3 as a biomarker for short-term kidney function decline in children with chronic kidney disease: an observational cohort study

BACKGROUND

Childhood-onset chronic kidney disease is a progressive condition that can have a major effect on life expectancy and quality. We evaluated the usefulness of the kidney tubular cell stress marker urinary Dickkopf-related protein 3 (DKK3) in determining the short-term risk of chronic kidney disease progression in children and identifying those who will benefit from specific nephroprotective interventions.

METHODS

In this observational cohort study, we assessed the association between urinary DKK3 and the combined kidney endpoint (ie, the composite of 50% reduction of the estimated glomerular filtration rate [eGFR] or progression to end-stage kidney disease) or the risk of kidney replacement therapy (ie, dialysis or transplantation), and the interaction of the combined kidney endpoint with intensified blood pressure reduction in the randomised controlled ESCAPE trial. Moreover, urinary DKK3 and eGFR were quantified in children aged 3-18 years with chronic kidney disease and urine samples available enrolled in the prospective multicentre ESCAPE (NCT00221845; derivation cohort) and 4C (NCT01046448; validation cohort) studies at baseline and at 6-monthly follow-up visits. Analyses were adjusted for age, sex, hypertension, systolic blood pressure SD score (SDS), BMI SDS, albuminuria, and eGFR.

FINDINGS

659 children were included in the analysis (231 from ESCAPE and 428 from 4C), with 1173 half-year blocks in ESCAPE and 2762 in 4C. In both cohorts, urinary DKK3 above the median (ie, >1689 pg/mg creatinine) was associated with significantly greater 6-month eGFR decline than with urinary DKK3 at or below the median (-5·6% [95% CI -8·6 to -2·7] vs 1·0% [-1·9 to 3·9], p<0·0001, in ESCAPE; -6·2% [-7·3 to -5·0] vs -1·5% [-2·9 to -0·1], p<0·0001, in 4C), independently of diagnosis, eGFR, and albuminuria. In ESCAPE, the beneficial effect of intensified blood pressure control was limited to children with urinary DKK3 higher than 1689 pg/mg creatinine, in terms of the combined kidney endpoint (HR 0·27 [95% CI 0·14 to 0·55], p=0·0003, number needed to treat 4·0 [95% CI 3·7 to 4·4] vs 250·0 [66·9 to ∞]) and the need for kidney replacement therapy (HR 0·33 [0·13 to 0·85], p=0·021, number needed to treat 6·7 [6·1 to 7·2] vs 31·0 [27·4 to 35·9]). In 4C, inhibition of the renin-angiotensin-aldosterone system resulted in significantly lower urinary DKK3 concentrations (least-squares mean 12 235 pg/mg creatinine [95% CI 10 036 to 14 433] in patients not on angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers vs 6861 pg/mg creatinine [5616 to 8106] in those taking angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers, p<0·0001).

INTERPRETATION

Urinary DKK3 indicates short-term risk of declining kidney function in children with chronic kidney disease and might allow a personalised medicine approach by identifying those who benefit from pharmacological nephroprotection, such as intensified blood pressure lowering.

FUNDING

None.

Refining Kidney Survival in 383 Genetically Characterized Patients With Nephronophthisis

Introduction

Nephronophthisis (NPH) comprises a group of rare disorders accounting for up to 10% of end-stage kidney disease (ESKD) in children. Prediction of kidney prognosis poses a major challenge. We assessed differences in kidney survival, impact of variant type, and the association of clinical characteristics with declining kidney function.

Methods

Data was obtained from 3 independent sources, namely the network for early onset cystic kidney diseases clinical registry (n = 105), an online survey sent out to the European Reference Network for Rare Kidney Diseases (n = 60), and a literature search (n = 218).

Results

A total of 383 individuals were available for analysis: 116 NPHP1, 101 NPHP3, 81 NPHP4 and 85 NPHP11/TMEM67 patients. Kidney survival differed between the 4 cohorts with a highly variable median age at onset of ESKD as follows: NPHP3, 4.0 years (interquartile range 0.3–12.0); NPHP1, 13.5 years (interquartile range 10.5–16.5); NPHP4, 16.0 years (interquartile range 11.0–25.0); and NPHP11/TMEM67, 19.0 years (interquartile range 8.7–28.0). Kidney survival was significantly associated with the underlying variant type for NPHP1, NPHP3, and NPHP4. Multivariate analysis for the NPHP1 cohort revealed growth retardation (hazard ratio 3.5) and angiotensin-converting enzyme inhibitor (ACEI) treatment (hazard ratio 2.8) as 2 independent factors associated with an earlier onset of ESKD, whereas arterial hypertension was linked to an accelerated glomerular filtration rate (GFR) decline.

Conclusion

The presented data will enable clinicians to better estimate kidney prognosis of distinct patients with NPH and thereby allow personalized counseling.

Glomerular Biomechanical Stress and Lipid Mediators during Cellular Changes Leading to Chronic Kidney Disease

Hyperfiltration is an important underlying cause of glomerular dysfunction associated with several systemic and intrinsic glomerular conditions leading to chronic kidney disease (CKD). These include obesity, diabetes, hypertension, focal segmental glomerulosclerosis (FSGS), congenital abnormalities and reduced renal mass (low nephron number). Hyperfiltration-associated biomechanical forces directly impact the cell membrane, generating tensile and fluid flow shear stresses in multiple segments of the nephron. Ongoing research suggests these biomechanical forces as the initial mediators of hyperfiltration-induced deterioration of podocyte structure and function leading to their detachment and irreplaceable loss from the glomerular filtration barrier. Membrane lipid-derived polyunsaturated fatty acids (PUFA) and their metabolites are potent transducers of biomechanical stress from the cell surface to intracellular compartments. Omega-6 and ω-3 long-chain PUFA from membrane phospholipids generate many versatile and autacoid oxylipins that modulate pro-inflammatory as well as anti-inflammatory autocrine and paracrine signaling. We advance the idea that lipid signaling molecules, related enzymes, metabolites and receptors are not just mediators of cellular stress but also potential targets for developing novel interventions. With the growing emphasis on lifestyle changes for wellness, dietary fatty acids are potential adjunct-therapeutics to minimize/treat hyperfiltration-induced progressive glomerular damage and CKD.

L-type calcium channel blocker use and proteinuria among children with chronic kidney diseases

BACKGROUND

Hypertension is common among children with chronic kidney disease (CKD), and dihydropyridine calcium channel blockers (dhCCBs) are frequently used as treatment. The impact of dhCCBs on proteinuria in children with CKD is unclear.

METHODS

Data from 722 participants in the Chronic Kidney Disease in Children (CKiD) longitudinal cohort with a median age of 12 years were used to assess the association between dhCCBs and log transformed urine protein/creatinine levels as well as blood pressure control measured at annual visits. Angiotensin-converting enzyme inhibitor (ACEi) and angiotensin receptor blocker (ARB) use was evaluated as an effect measure modifier.

RESULTS

Individuals using dhCCBs had 18.8% higher urine protein/creatinine levels compared to those with no history of dhCCB or ACEi and ARB use. Among individuals using ACEi and ARB therapy concomitantly, dhCCB use was not associated with an increase in proteinuria. Those using dhCCBs had higher systolic and diastolic blood pressures.

CONCLUSIONS

Use of dhCCBs in children with CKD and hypertension is associated with higher levels of proteinuria and was not found to be associated with improved blood pressure control.

When should we start and stop ACEi/ARB in paediatric chronic kidney disease?

Renin-angiotensin-aldosterone inhibitors (RAASi) are the mainstay therapy in both adult and paediatric chronic kidney disease (CKD). RAASi slow down the progression of kidney failure by optimization of blood pressure and reduction of proteinuria. Despite recommendations from published guidelines in adults, the evidence related to the use of RAASi is surprisingly scarce in children. Moreover, their role in advanced CKD remains controversial. Without much guidance from the literature, paediatric nephrologists may discontinue RAASi in patients with advanced CKD due to apparent worsening of kidney function, hyperkalaemia and hypotension. Current data suggest that this strategy may in fact lead to a more rapid decline in kidney function. The optimal approach in this clinical scenario is still not well defined and there are varying practices worldwide. We will in this review describe the existing evidence on the use of RAASi in CKD with particular focus on paediatric data. We will also address the use of RAASi in advanced CKD and discuss the potential benefits and harms. At the end, we will suggest a practical approach for the use of RAASi in children with CKD based on current state of knowledge.

Cardiovascular disease in childhood and adolescence: Lessons from children with chronic kidney disease

Children suffering from chronic kidney disease (CKD) have the apparent highest risk for the development of cardiovascular disease (CVD) at a young age. While symptoms of CVD are characteristically absent in childhood and adolescence, remodelling of the myocardium, medium and large-sized arteries and of the microcirculation is clinically significant and can be assessed with non-invasive technology. Kidney disease and its progression are the driver of CVD, mediated by an unparalleled accumulation of risk factors converging on several comorbid conditions including hypertension, anaemia, dyslipidaemia, disturbed mineral metabolism and chronic persistent inflammation. Large prospective paediatric cohorts studies have provided valuable insights into the pathogenesis and the progression of CKD-induced cardiovascular comorbidity and have characterised the cardiovascular phenotype in young patients. They have also provided the rationale for close monitoring of risk factors and have defined therapeutic targets. Recently discovered new biomarkers could help identify the individual risk for CVD. Prevention of CVD by aggressive therapy of modifiable risk factors is essential to enable long-term survival of young patients with CKD.

Renin-angiotensin system blockade in patients with chronic kidney disease: benefits, problems in everyday clinical use, and open questions for advanced renal dysfunction

Management of hypertension and albuminuria are considered among the primary goals of treatment to slow the progression of chronic kidney disease (CKD). Renin-angiotensin system (RAS) blockers, i.e., angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) are the main drugs to achieve these goals. Seminal studies have showed that RAS blockers present significant renoprotective effects in CKD patients with very high albuminuria. In post hoc analyses of such trials, these renoprotective effects appeared more robust in patients with more advanced CKD. However, randomized trials specifically addressing whether RAS blockers should be initiated or maintained in patients with advanced CKD are scarce and do not include subjects with normoalbuminuria, thus, many clinicians are unconvinced for the beneficial effects of RAS blockade in these patients. Further, the fear of hyperkalemia or acute renal decline is another factor due to which RAS blockers are usually underprescribed and are easily discontinued in patients with more advanced CKD; i.e., those in Stages 4 and 5. This review summarizes evidence from the literature regarding the use of RAS blockers in patients with advanced CKD.

Clinical Management of Children with a Congenital Solitary Functioning Kidney: Overview and Recommendations

CONTEXT

A congenital solitary functioning kidney (cSFK) is a common developmental defect that predisposes to hypertension and chronic kidney disease (CKD) as a consequence of hyperfiltration. Every urologist takes care of patients with a cSFK, since some will need lifelong urological care or will come with clinical problems or questions to an adult urologist later in life.

OBJECTIVE

We aim to provide clear recommendations for the initial clinical management and follow-up of children with a cSFK.

EVIDENCE ACQUISITION

PubMed and EMBASE were searched to identify relevant publications, which were combined with guidelines on related topics and expert opinion.

EVIDENCE SYNTHESIS

Initially, cSFK diagnosis should be confirmed and risk factors for kidney injury should be identified using ultrasound. Although more research into early predictors of kidney injury is needed, additional congenital anomalies of the kidney or urinary tract and absence of compensatory kidney hypertrophy have repeatedly been associated with a worse prognosis. The role of voiding cystourethrography and antibiotic prophylaxis remains controversial, and is complicated by the exclusion of children with a cSFK from studies. A yearly follow-up for signs of kidney injury is recommended for children with a cSFK. As masked hypertension is prevalent, annual ambulatory blood pressure measurement should be considered. During puberty, an increasing incidence of kidney injury is seen, indicating that long-term follow-up is necessary. If signs of kidney injury are present, angiotensin converting enzyme inhibitors are the first-line drugs of choice.

CONCLUSIONS

This overview points to the urological and medical clinical aspects and long-term care guidance for children with a cSFK, who are at risk of hypertension and CKD. Monitoring for signs of kidney injury is therefore recommended throughout life. Large, prospective studies with long-term follow-up of clearly defined cohorts are still needed to facilitate more risk-based and individualized clinical management.

PATIENT SUMMARY

Many children are born with only one functioning kidney, which could lead to kidney injury later in life. Therefore, a kidney ultrasound is made soon after birth, and other investigations may be needed as well. Urologists taking care of patients with a solitary functioning kidney should realize the long-term clinical aspects, which might need medical management.

Acute kidney injury in children with chronic kidney disease is associated with faster decline in kidney function

BACKGROUND

This study aimed to investigate the association of acute kidney injury (AKI) with change in estimated glomerular filtration rate (eGFR) in children with advanced chronic kidney disease (CKD).

METHODS

Single centre, retrospective longitudinal study including all prevalent children aged 1-18 years with nondialysis CKD stages 3-5. Variables associated with CKD were analysed for their potential effect on annualised eGFR change (ΔGFR/year) following multiple regression analysis. Composite end-point including 25% reduction in eGFR or progression to kidney replacement therapy was evaluated.

RESULTS

Of 147 children, 116 had at least 1-year follow-up in a dedicated CKD clinic with mean age 7.3 ± 4.9 years with 91 (78.4%) and 77 (66.4%) with 2- and 3-year follow-up respectively. Mean eGFR at baseline was 29.8 ± 11.9 ml/min/1.73 m² with 79 (68%) boys and 82 (71%) with congenital abnormalities of kidneys and urinary tract (CAKUT). Thirty-nine (33.6%) had at least one episode of AKI. Mean ΔGFR/year for all patients was - 1.08 ± 5.64 ml/min/1.73 m² but reduced significantly from 2.03 ± 5.82 to - 3.99 ± 5.78 ml/min/1.73 m² from youngest to oldest age tertiles (P < 0.001). There was a significant difference in primary kidney disease (PKD) (77% versus 59%, with CAKUT, P = 0.048) but no difference in AKI incidence (37% versus 31%, P = 0.85) between age tertiles. Multiple regression analysis identified age (β = - 0.53, P < 0.001) and AKI (β = - 3.2, P = 0.001) as independent predictors of ΔGFR/year. 48.7% versus 22.1% with and without AKI reached composite end-point (P = 0.01).

CONCLUSIONS

We report AKI in established CKD as a predictor of accelerated kidney disease progression and highlight this as an additional modifiable risk factor to reduce progression of kidney dysfunction. Graphical abstract.

Strategies for Optimizing Growth in Children With Chronic Kidney Disease

Growth failure is a hallmark in children with chronic kidney disease (CKD). Therefore, early diagnosis and adequate management of growth failure is of utmost importance in these patients. The risk of severe growth retardation is the higher the younger the child is, which places an additional burden on patients and their families and hampers the psychosocial integration of these children. Careful monitoring of growth, and effective interventions are mandatory to prevent and treat growth failure in children with CKD at all ages and all stages of kidney failure. Early intervention is critical, as all therapeutic interventions are much more effective if they are started prior to the initiation of dialysis. Prevention and treatment of growth failure focuses on: (i) preservation of renal function, e.g., normalization of blood pressure and proteinuria by use of inhibitors of the renin-angiotensin aldosterone system, (ii) adequate energy intake, including tube feeding or gastrostomy in case of persisting malnutrition, (iii) substitution of water and electrolytes, especially in children with renal malformation, (iv) correction of metabolic acidosis, (v) control of parathyroid hormone levels within the CKD-dependent target range, (vi) use of recombinant human growth hormone in cases of persistent growth failure, and, (vii) early/preemptive kidney transplantation using steroid-minimizing immunosuppressive protocols in children with end-stage CKD. This review discusses these measures based on recent guidelines.