Treatment outcome of late steroid-resistant nephrotic syndrome: a study by the Midwest Pediatric Nephrology Consortium

Rates of idiopathic childhood nephrotic syndrome relapse are lower during the COVID-19 pandemic

BACKGROUND

Infections are thought to be primarily responsible for triggering relapse in children with steroid-sensitive nephrotic syndrome (NS). The COVID-19 pandemic promoted physical distancing, facial mask wearing, and greater attention to infection-prevention measures resulting in decreased transmission of infections. We hypothesized there would also be a decreased rate of NS relapse during this period.

METHODS

We conducted a single-center retrospective chart review of children with steroid-sensitive NS. Demographics, rate of relapses, and rate of hospitalizations were collected for a baseline pre-pandemic period (BPP) and for the social distancing period during the pandemic (SDP).

RESULTS

One hundred twenty-two children with primary steroid-sensitive NS were identified and 109 were followed for the duration of the study period. The paired rate of relapse per subject per year was significantly lower during the SDP (0.6 relapses per subject per year ± 1 SD) compared to the BPP (1.0 relapses per subject per year ± 0.9 SD), P < 0.01. A subgroup of 32 subjects who were newly diagnosed with NS during the BPP similarly had significantly fewer relapses during the SDP (0.8 ± 1 SD) than during the BPP (1.4 ± 1 SD), P = 0.01.

CONCLUSIONS

Our results support the hypothesis of lower rates of NS relapse and hospitalizations during social distancing for all subjects in our cohort and a subgroup of those newly diagnosed. Lower relapse rates were likely attributable to decreased transmission of infections and greater attention to infection prevention. A higher resolution version of the Graphical abstract is available as Supplementary information.

Adult survivors of idiopathic childhood onset nephrotic syndrome

Like many pediatric chronic health conditions, idiopathic childhood onset nephrotic syndrome (iCONS) and late effects of iCONS medical management may continue to impact the affected population in adulthood. Approximately 15% of adult survivors of steroid-sensitive iCONS continue to relapse. Long-term kidney health is associated with steroid response patterns as well as pathology findings of FSGS, tubulointerstitial fibrosis, tubular atrophy, and global glomerulosclerosis. Long-term cardiovascular disease burden is largely unknown in adult survivors, but risk factors starting in childhood, including hypertension, dyslipidemia, and obesity, are common in iCONS. Reproductive health concerns, including azo-/oligospermia and successful pregnancies, are largely related to prior exposure to cytotoxic therapies. Additional investigations are needed to complete the assessment and initiate the mitigation of the late effects of treatment-sensitive and treatment-resistant iCONS.

Long-Term Outcome of Secondary Steroid-Resistant Nephrotic Syndrome in Chinese Children

Introduction

Secondary steroid-resistant nephrotic syndrome (SRNS) refers to the condition when patients with initial steroid-sensitive nephrotic syndrome develop steroid resistance in subsequent relapses. Long-term outcomes of secondary SRNS in children are uncertain.

Methods

This was a single-center retrospective study of 56 children with secondary SRNS between 2006 and 2016. The survival curve was estimated using the Kaplan-Meier method. Independent risk factors for end-stage renal disease (ESRD) were determined using Cox proportional hazards model.

Results

The median time from nephrotic syndrome onset to secondary SRNS was 7.8 months. Biopsy results at diagnosis secondary SRNS showed that 64.3% of cases were minimal change disease (MCD). No remission was observed in seven (12.5%) patients within the first year. The mean follow-up time was 7.8 ± 3.2 years. Eight patients were clinically cured, one died before ESRD, 10 reached ESRD, and 75.0% (3 of 4) of patients recurred post-transplantation. The 10-year ESRD-free survival rate was 85.8%. No response to intensified immunosuppression (IIS) in the first year was the independent predictor for ESRD. Repeat biopsies were performed in 20 cases, revealing that the reclassification from MCD to mesangial hypercellularity and focal segmental glomerulosclerosis (FSGS) in two when secondary steroid resistance appeared, from MCD and mesangial hypercellularity to FSGS in seven who developed multidrug resistance, and from FSGS to MCD and mesangial hypercellularity in two with favorable outcomes.

Conclusions

The long-term outcome in children with secondary SRNS was heterogeneous, and no response to IIS in the first year was the independent predictor for ESRD. In patients with repeat biopsy, changes in histological appearance to FSGS were associated with multidrug resistance.

Case Report: Novel Dietary Supplementation Associated With Kidney Recovery and Reduction in Proteinuria in a Dialysis Dependent Patient Secondary to Steroid Resistant Minimal Change Disease

Minimal change disease (MCD) is the most common cause of nephrotic syndrome worldwide. For decades, the foundation of the treatment has been corticosteroids. However, relapse rate is high and up to 40% of patients develop frequent relapsing/steroid dependent course and one third become steroid resistant. This requires treatment with repeated courses of corticosteroids, and second and third line immunomodulators increasing the incidence of drug related adverse effects. More recently, there have been reports of a very small subset of Nephrotic Syndrome (NS) patients who are initially steroid sensitive and later become secondarily steroid resistant. The disease course in this small subset is often protracted leading ultimately to end stage kidney disease requiring dialysis or kidney transplantation. Unfortunately, patients with this disease course do not do well post transplantation because 80% of them will develop disease recurrence that will ultimately lead to graft failure. Few approaches have been tried over many years to reduce the frequency of relapses, and steroid dependence and there is absolutely no therapeutic intervention for patients who develop secondary steroid resistance. Nonetheless, their therapeutic index is low, evidencing the need of a safer complementary treatment. Several hypotheses, including an oxidative stress-mediated mechanism, and immune dysregulation have been proposed to date to explain the underlying mechanism of Minimal Change Disease (MCD) but its specific etiology remains elusive. Here, we report a case of a 54-year-old man with steroid and cyclosporine resistant MCD. The patient rapidly progressed to end stage kidney disease requiring initiation of chronic dialysis. Intradialytic parenteral nutrition (IDPN), albumin infusion along with a proprietary dietary supplement, as part of the supportive therapy, led to kidney function recovery and complete remission of MCD without relapses.

Podocytopathies

Podocytopathies are kidney diseases in which direct or indirect podocyte injury drives proteinuria or nephrotic syndrome. In children and young adults, genetic variants in >50 podocyte-expressed genes, syndromal non-podocyte-specific genes and phenocopies with other underlying genetic abnormalities cause podocytopathies associated with steroid-resistant nephrotic syndrome or severe proteinuria. A variety of genetic variants likely contribute to disease development. Among genes with non-Mendelian inheritance, variants in APOL1 have the largest effect size. In addition to genetic variants, environmental triggers such as immune-related, infection-related, toxic and haemodynamic factors and obesity are also important causes of podocyte injury and frequently combine to cause various degrees of proteinuria in children and adults. Typical manifestations on kidney biopsy are minimal change lesions and focal segmental glomerulosclerosis lesions. Standard treatment for primary podocytopathies manifesting with focal segmental glomerulosclerosis lesions includes glucocorticoids and other immunosuppressive drugs; individuals not responding with a resolution of proteinuria have a poor renal prognosis. Renin-angiotensin system antagonists help to control proteinuria and slow the progression of fibrosis. Symptomatic management may include the use of diuretics, statins, infection prophylaxis and anticoagulation. This Primer discusses a shift in paradigm from patient stratification based on kidney biopsy findings towards personalized management based on clinical, morphological and genetic data as well as pathophysiological understanding.

CureGN Study Rationale, Design, and Methods: Establishing a Large Prospective Observational Study of Glomerular Disease

RATIONALE & OBJECTIVES

Glomerular diseases, including minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, and immunoglobulin A (IgA) nephropathy, share clinical presentations, yet result from multiple biological mechanisms. Challenges to identifying underlying mechanisms, biomarkers, and new therapies include the rarity of each diagnosis and slow progression, often requiring decades to measure the effectiveness of interventions to prevent end-stage kidney disease (ESKD) or death.

STUDY DESIGN

Multicenter prospective cohort study.

SETTING & PARTICIPANTS

Cure Glomerulonephropathy (CureGN) will enroll 2,400 children and adults with minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy (including IgA vasculitis) and a first diagnostic kidney biopsy within 5 years. Patients with ESKD and those with secondary causes of glomerular disease are excluded.

EXPOSURES

Clinical data, including medical history, medications, family history, and patient-reported outcomes, are obtained, along with a digital archive of kidney biopsy images and blood and urine specimens at study visits aligned with clinical care 1 to 4 times per year.

OUTCOMES

Patients are followed up for changes in estimated glomerular filtration rate, disease activity, ESKD, and death and for nonrenal complications of disease and treatment, including infection, malignancy, cardiovascular, and thromboembolic events.

ANALYTICAL APPROACH

The study design supports multiple longitudinal analyses leveraging the diverse data domains of CureGN and its ancillary program. At 2,400 patients and an average of 2 years' initial follow-up, CureGN has 80% power to detect an HR of 1.4 to 1.9 for proteinuria remission and a mean difference of 2.1 to 3.0mL/min/1.73m² in estimated glomerular filtration rate per year.

LIMITATIONS

Current follow-up can only detect large differences in ESKD and death outcomes.

CONCLUSIONS

Study infrastructure will support a broad range of scientific approaches to identify mechanistically distinct subgroups, identify accurate biomarkers of disease activity and progression, delineate disease-specific treatment targets, and inform future therapeutic trials. CureGN is expected to be among the largest prospective studies of children and adults with glomerular disease, with a broad goal to lessen disease burden and improve outcomes.

Improving the evidence for the management of childhood nephrotic syndrome

Management of idiopathic nephrotic syndrome in children is based on a series of clinical trials. The trial by Sinha and colleagues in this issue is 1 of many needed to improve the evidence base for induction and maintenance therapies in this population. While key questions remain about identifying the appropriate therapy for each patient, clinical trials provide an opportunity to extend evidence-based practice that minimizes toxicity and optimizes patient health.

Efficacy and Safety of Cyclosporine versus Tacrolimus in Steroid and Cyclophosphamide Resistant Nephrotic Syndrome: A Prospective Study

Calcineurin inhibitors (CNIs) are the preferred drugs for treatment of childhood steroid-resistant nephrotic syndrome (SRNS) who are also resistant to cyclophosphamide (CYC). Although few studies have shown a benefit of one over the other, efficacy and safety of either CNIs (tacrolimus [TAC] or cyclosporine [CSA]) in this special population remained to be assessed in long-term studies. Forty-five children with SRNS who were also resistant to CYC (CYC-SRNS) from January 2006 to June 2011, were included in the study. Patients were treated with CNI either TAC or CSA based on 1:1 allocations and were prospectively observed. Patients who were nonresponsive to CNIs had been treated with mycophenolate mofetil. Outcomes were measured in terms of remission of NS, adverse effects of drugs, and progression of disease. After 6 months of treatment, 16/23 (69.5%) patients on CSA achieved remission and 18/22 (81.8%) on TAC achieved remission (P = 0.3). The side effects hypertrichosis, and gum hyperplasia were significantly less in TAC group as compared to CSA group (P < 0.001). The 1-, 2-, 3-, 4-, and 5-year estimated renal survival (doubling of serum creatinine as event) in CSA group was 96%, 91%, 85%, 54%, and 33% and in TAC group was 96%, 95%, 90%, 89%, and 79%, respectively (P = 0.02). Although TAC and CSA are equally efficacious, TAC has significantly less side effects. The long-term outcome of renal function was significantly better in patients who were treated with TAC as compared to CSA.

Mycophenolate mofetil is inferior to tacrolimus in sustaining remission in children with idiopathic steroid-resistant nephrotic syndrome

Studies of nephrotic syndrome show that substitution of calcineurin inhibitors by mycophenolate mofetil (MMF) enables sustained remission and corticosteroid sparing and avoids therapy associated adverse effects. However, controlled studies in patients with steroid resistance are lacking. Here we examined the effect of switching from therapy with tacrolimus to MMF on disease course in an open-label, one-to-one randomized, controlled trial on children (one to 18 years old), recently diagnosed with steroid-resistant nephrotic syndrome, at a referral center in India. Following six months of therapy with tacrolimus, patients with complete or partial remission were randomly assigned such that 29 received MMF while 31 received tacrolimus along with tapering prednisolone on alternate days for 12 months. On intention-to-treat analyses, the proportion of patients with a favorable outcome (sustained remission, infrequent relapses) at one year was significantly lower (44.8%) in the MMF group than in the tacrolimus group (90.3%). The incidence of relapses was significantly higher for patients treated with MMF than tacrolimus (mean difference: 1.05 relapses per person-year). While there was no difference in the proportion of patients with sustained remission, the risk of recurrence of steroid resistance was significantly higher for patients receiving MMF compared to tacrolimus (mean difference: 20.7%). Compared to tacrolimus, patients receiving MMF had a significantly (71%) lower likelihood of a favorable outcome and significantly increased risk of treatment failure (frequent relapses, steroid resistance). Thus, replacing tacrolimus with MMF after six months of tacrolimus therapy for steroid-resistant nephrotic syndrome in children is associated with significant risk of frequent relapses or recurrence of resistance. These findings have implications for guiding the duration of therapy with tacrolimus for steroid-resistant nephrotic syndrome.

Long-term Outcomes of Childhood Onset Nephrotic Syndrome

There are limited studies on long-term outcomes of childhood onset nephrotic syndrome (NS). A majority of children with NS have steroid-sensitive nephrotic syndrome (SSNS). Steroid-resistant nephrotic syndrome (SRNS) is associated with a high risk of developing end-stage renal disease. Biomarkers and analysis of genetic mutations may provide new information for prognosis in SRNS. Frequently relapsing and steroid-dependent NS is associated with long-term complications, including dyslipidemia, cataracts, osteoporosis and fractures, obesity, impaired growth, and infertility. Long-term complications of SSNS are likely to be under-recognized. There remain many gaps in our knowledge of long-term outcomes of childhood NS, and further study is indicated.

Childhood nephrotic syndrome in the 21st century: What's new?

Childhood nephrotic syndrome is a condition managed by general paediatricians and paediatric nephrologists. Whether treating a first presentation or a relapse, the clinician requires expertise in order to minimise the risk of serious complications and optimise long-term care. Indeed, many children suffer a difficult relapsing course in their disease, warranting consideration of second-line therapies. The last two decades have witnessed a growing knowledge of the condition and increased complexity of diagnostic and therapeutic options, which poses a challenge for the general paediatrician, given the condition's relative rarity in daily practice. This review aims to familiarise the reader with some of the most important recent developments and particularly to provide an insight into what management options are available and when it may be appropriate to seek advice from a nephrologist.

[Treatment of idiopathic nephrotic syndrome in children]

The annual incidence of the nephrotic syndrome has been estimated to be 1-3 per 100,000 children<16 year of age. In children, the most common cause of nephrotic syndrome is idiopathic nephrotic syndrome (INS). INS is defined by the presence of proteinuria and hypoalbuminemia and by definition is a primary disease. Renal biopsy study shows non-specific histological abnormalities of the kidney including minimal changes, focal and segmental glomerular sclerosis, and diffuse mesangial proliferation. Steroid therapy is applied in all cases of INS. Renal biopsy is usually not indicated before starting corticosteroid therapy. The majority of patients (80-90%) are steroid-responsive. Children with INS who do not achieve a complete remission with corticosteroid therapy commonly present focal and segmental glomerular sclerosis and require treatment with calcineurin inhibitors (cyclosporine or tacrolimus), mycophenolate mofetil or rituximab, plus renin-angiotensin system blockade. In this article we review the recent accepted recommendations for the treatment of children with INS.

Late steroid resistance in childhood nephrotic syndrome: do we now know more than 40 years ago?

The formation of steroid resistance in children with nephrotic syndrome (NS) who were initially steroid responsive was described decades ago but has not been studied in sufficient depth. Except for the International Study of Kidney Disease in Children, conducted more than three decades ago, when only cyclophosphamide was available as a second-line agent in steroid-resistant NS, only a handful of small studies have addressed the problem of late steroid resistance (LSR) over the past 40 years. Epidemiology and risk factors for the formation of LSR and differences in outcomes when compared with initial steroid resistance still remain unknown. While multiple second-line treatment choices (calcineurin inhibitors, mycophenolate mofetil, rituximab) exist today, therapeutic approaches to the patients with LSR remain empirical, as no evidence-based data have become available. In the current issue of Pediatric Nephrology, Straatmann et al. report retrospective data on the treatment outcomes for 29 pediatric NS patients with LSR from eight participating centers of the Midwest Pediatric Research Consortium. The authors describe a current pattern of second-line agents used in their cohort and show that the majority of patients (66 %) achieved complete or partial remission after a period of observation for 85 ± 47 months. The authors also describe the data on renal histology. While these data represent an important step forward in our understanding of LSR, further work is needed before firm clinical recommendations can be made. Large-scale prospective studies are required to answer important questions about the epidemiology, genetics and outcomes in late steroid-resistant NS, explore the role of medication adherence and develop evidence-based practice guidelines.