Remission of Proteinuria May Protect against Progression to Chronic Kidney Disease in Pediatric-Onset IgA Nephropathy

IPNA clinical practice recommendations for the diagnosis and management of children with IgA nephropathy and IgA vasculitis nephritis

IgA nephropathy and IgA vasculitis with nephritis, albeit rare, represent two relatively frequent glomerular conditions in childhood. Compared to adults, pediatric IgA nephropathy has a more acute presentation, most frequently with synpharyngitic macrohematuria and histologically with more intense inflammation and less intense chronic damage. Management of these conditions is controversial and supported by little high-quality evidence. The paucity of evidence is due to the disease heterogeneity, its inter-ethnic variability, and the difficulty of extrapolating data from adult studies due to the peculiarities of the condition in children. IgA vasculitis with nephritis is a kidney manifestation of a systemic disorder, typical of the pediatric age, in which both the diagnosis of kidney involvement and its management are poorly defined, and an interdisciplinary approach is crucial. Both conditions can have a profound and long-lasting impact on kidney function and the global health of affected children. The International Pediatric Nephrology Association has therefore convened a diverse international group of experts from different disciplines to provide guidance on the recommended management of these conditions in children and to establish common definitions and define priorities for future high-quality, evidence-based collaborative studies for the benefit of children.

Differences of clinicopathological characteristics and outcomes of IgA nephropathy patients with and without nephrotic syndrome

PURPOSE

To evaluate the differences in clinicopathological features and outcomes of IgA nephropathy (IgAN) patients with and without nephrotic syndrome.

METHODS

In this retrospective cohort study, IgAN patients from January 2006 to December 2011 in the First Affiliated Hospital of Sun Yat-sen University were enrolled and followed up to Dec 31, 2013. Logistic and Cox regression were conducted to evaluate the associated factors of nephrotic syndrome (NS) and its relation with outcomes of creatinine doubling and progression to end-stage kidney disease (ESKD).

RESULTS

A total of 1413 patients with IgAN were enrolled in this study, 57 (4.0%) of whom exhibited NS. Meanwhile, 13 (22.8%) of NS IgAN patients had minimal change disease (MCD). Logistic regression showed that more presence of hypertension, less glomerular sclerosis, less tubular atrophy/interstitial fibrosis, and lower density of IgA deposition in mesangial region were significantly associated with NS IgAN that were independent of age and gender. In addition, a total of 921 patients (890 with non-NS IgAN and 31 with NS IgAN) were followed up to Dec 31, 2013. After adjusting for age, sex, baseline estimated glomerular rate, hypertension and hemoglobin, no significant difference was observed in outcomes of serum creatinine doubling and ESKD between patients with or without NS IgAN.

CONCLUSIONS

Prevalence of NS IgAN patients was 4.0%, and 22.8% of them had MCD. Patients with NS IgAN had more severe clinical but less severe pathological features. However, outcomes of serum creatinine doubling and ESKD were not significantly different between patients with or without NS IgAN.

IgAN Across the Age Spectrum: The Pediatric Perspective

IgA nephropathy (IgAN) presents with different expressions and natural histories across ages. The direct comparison of incidence and progression of IgAN in children and adults is difficult due to different policies for performing kidney biopsy in different ages and countries. In the past decade the focus has been on assessing the individual risk profile at kidney biopsy or after 1 year of follow-up in children and adults. This would help avoid overtreatment and unnecessary drug exposure in benign cases of IgAN, and promptly initiate an aggressive therapy in progressive ones. This issue is particularly relevant in children. This review addresses some recent insights into the similarities and differences of IgAN across the age spectrum, with a particular focus on the prognostic predictors of progression in children and in adults, aiming at offering some critical elements useful for treatment choices for IgAN across ages.

Clinical Practice Guideline: Microhematuria in Children and Young Adults

BACKGROUND

Occult blood in the urine, or microhematuria, is a common finding (about 10%) in children and young adults. It is often of brief duration and therefore harmless. In persistent microhematuria, acanthocytes in the urine are a frequently unrecognized early marker of glomerular kidney disease. The purpose of this guideline is to promote the early detection of kidney disease in children and young adults with practical, evidence-based recommendations.

METHODS

A systematic search for pertinent publications up to January 2023 was conducted in Pubmed, the Cochrane Database, and Livivo. 474 publications were retrieved, summarized in terms of method and content, and classified by Oxford (2011) evidence level.

RESULTS

Approximately 1% of children and young adults have undiagnosed chronic kidney disease. Microhematuria is an early warning sign. A timely nephrological evaluation is indicated if microhematuria persists for 3 to 6 months, if ≥ 5% acanthocytes are detectable in the urine, and if there is also proteinuria, hypertension, or impaired renal function. Ultrasonography of the kidneys and urinary tract is the imaging method of choice; cystoscopy should be avoided. For patients with glomerular microhematuria, molecular genetic testing is recommended. Renal biopsy is recommended in case of florid glomerular diseases, after the determination of various laboratory param eters and clinical findings, including molecular genet ic testing especially in children.

CONCLUSION

In the absence of a guideline until now, findings have often been incorrectly assessed, leading either to an inadequate work-up or to excessive diagnostics. As a result, in approximately 30% of young patients, valuable opportunities for early treatment to protect the kidneys have been missed.

Childhood-onset IgA nephropathy: is long-term recovery possible?

BACKGROUND

IgA nephropathy (IgAN) is the most common glomerulonephritis worldwide. While studies have primarily focused on identifying risk factors for disease progression, very few data exist on the likelihood of achieving complete recovery from the disease.

METHODS

We conducted a single-center retrospective study on all consecutive patients with biopsy-proven IgAN diagnosed between 1986 and 2018 in our pediatric center. Biopsies were classified according to the MEST-C Oxford classification score. "Complete clinical remission" was defined as the absence of proteinuria, hematuria, and hypertension in patients with normal kidney function who had been off therapy for more than 2 years.

RESULTS

Overall, 153 patients with age at onset of 10.6 ± 4 years were enrolled in the study. Of these, 41 achieved "complete clinical remission." The estimated probability of complete clinical remission at 10 years was 43% (95%CI 33-54). However, seven patients relapsed within 10 years. Multivariable analysis showed that higher age at onset (HR 0.89, 95%CI 0.80-0.98, p = 0.017) and segmental glomerulosclerosis lesions (HR 0.28, 95%CI 0.10-0.79, p = 0.017) decreased significantly the chances of achieving complete clinical remission. Immunosuppressive therapy was not significantly associated with clinical outcomes.

CONCLUSIONS

Approximately one-third of patients with pediatric-onset IgAN achieve prolonged remission, in particular, very young children at disease onset without sclerotic glomerular lesions. Longer term follow-up is needed to assess if these patients have achieved permanent remission.

Review on epidemiology, disease burden, and treatment patterns of IgA nephropathy in select APAC countries

BACKGROUND

Immunoglobulin type A (IgA) nephropathy is the most common primary glomerulonephritis (GN) worldwide with higher rates in East and Pacific Asia compared to North America and Europe. Despite high reported prevalence of IgAN in these countries, the overall disease prevalence across Asia is not available. Treatment patterns of IgAN patients across Asian countries have also not been summarized. The aim of this study was to review and summarize evidence on IgA nephropathy prevalence, treatment patterns, and humanistic and economic burden in mainland China, Taiwan, South Korea, Japan, and Australia.

METHODS

A targeted literature review was conducted in PubMed and local databases in China (including Taiwan), South Korea, Japan, and Australia between January 2010-December 2021. Website literature searches were conducted using Google Scholar and Baidu.

RESULTS

Sixty-nine publications and 3 clinical guidelines were included. Incidence ranged from 0 to 10.7 per 100 000 people per year in Australia, Japan, and Taiwan, and ranged from 6.3 to 24.70% among patients who underwent renal biopsy in mainland China. Prevalence and diagnosis rates ranged from 0 to 72.1% in mainland China, South Korea, Taiwan, Japan, and Australia. Mortality rates in mainland China, South Korea, and Japan varied widely. The top 3 commonly used therapies were angiotensin-converting enzyme inhibitor/angiotensin receptor blockers (0.9-99.6%), corticosteroids (3.5-100%), and immunosuppressants (1.6-85.5%) in Japan, mainland China, and South Korea. Patient quality of life was measured by different tools, and annual hospitalization costs ranged from $1 284.73 to $2 252.12 (2015-2018) in China.

CONCLUSIONS

The prevalence of IgA nephropathy among the general population in select countries/regions is not commonly available, despite evidence from studies and clinical guidelines. In addition, it is observed across geographic regions that heterogeneity exists in prevalence rates, and large variations exist in treatment patterns. There is need to fill in these gaps to understand the contributing factors behind the differences through population-based, multi-center, and real-world studies.

Prognostic factors of IgA nephropathy presenting with mild proteinuria at the time of diagnosis (a multicenter cohort study)

BACKGROUND

Clinical factors affecting renal prognosis in patients with immunoglobulin A nephropathy (IgAN) and low urinary protein excretion (U-Prot) remain unclear. This study evaluated such factors in patients with clinical grade I (CG-I) IgAN with U-Prot < 0.5 g/day.

METHODS

This secondary analysis of a previous retrospective study included 394 patients with CG-I IgAN. The primary outcome was the first occurrence of a 1.5-fold increase in serum creatinine levels from baseline. Factors related to renal prognosis were examined using univariate and multivariate Cox regression analyses. CG-I was divided into C-Grade Ia (CG-Ia) (n = 330) with baseline eGFR ≥ 60 ml/min/1.73 m², and C-Grade Ib (CG-Ib) (n = 64) with baseline eGFR < 60 ml/min/1.73 m². Outcome incidence was compared between conservative and aggressive therapy (corticosteroids and/or tonsillectomy) groups.

RESULTS

Overall outcome incidence was significantly higher in CG-Ib than in CG-Ia; the cumulative incidence was significantly higher in CG-Ib (hazard ratio, 9.67; 95% confidence interval, 2.90-32.23). Older age, higher IgA levels, eGFR < 60 mL/min/1.73 m², lower eGFR at baseline were independent prognostic factors for CG-I. Older age, lower eGFR, higher IgA levels at baseline, and U-Prot remission at 1-year post-diagnosis were independent prognostic factors for CG-Ib. Aggressive therapy tended to suppress the cumulative outcome incidence compared with conservative therapy in CG-Ib (p = 0.087).

CONCLUSION

An eGFR < 60 mL/min/1.73 m² is a significant predictor of renal prognosis in patients with IgAN and U-Prot < 0.5 g/day.

Nephropathy in a Child with Severe Recessive Dystrophic Epidermolysis Bullosa Treated with Cyclophosphamide: A Case Report

Long-term inflammation and recurrent skin infection in recessive dystrophic epidermolysis bullosa (RDEB) are associated with the presence of immunoglobulin A (IgA)-containing immune complexes in the glomerulus. Only eight pediatric RDEB cases with IgA nephropathy (IgAN) have been documented in English-language literature. Most RDEB patients with IgAN progress to kidney failure within 5 years of diagnosis, indicating that these patients may require more intensive early treatment compared to those with primary IgAN. However, diagnosing IgAN in RDEB cases with severe cutaneous manifestations can be challenging. Herein, we report a rare case of nephropathy in an 11-year-old boy with severe RDEB and a frameshift mutation on the COL7A1 gene, which may manifest as kidney disorders. He presented with persistent hematuria and progressing proteinuria. A presumptive IgAN diagnosis was based on clinical features and increased IgA serum levels, as kidney biopsy was refused by his parents. Nephrotic-range proteinuria persisted despite initial steroid and lisinopril treatment. Monthly intravenous cyclophosphamide (IV CPA; 500 mg/m2) led to proteinuria remission and preservation of kidney function for 2 years posttreatment. We conclude that COL7A1 mutations may result in extracutaneous manifestations, including kidney disorders. The association between IgA-containing immune complex deposits in the glomerulus and recurrent skin infection in RDEB may indicate IgAN, particularly when kidney biopsy is infeasible due to severe skin manifestations. In our case, positive results with IV CPA suggest further investigation is needed to explore its potential role in non-rapidly progressing IgAN in children with RDEB.

Efficacy and safety of leflunomide combined with corticosteroids for the treatment of IgA nephropathy: a Meta-analysis of randomized controlled trials

OBJECTIVE

We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy and safety of leflunomide combined with corticosteroids, compared with corticosteroids alone, for IgA nephropathy.

MATERIALS AND METHODS

Studies were retrieved by searching of PubMed, Embase, Cochrane's Library, China National Knowledge Infrastructure (CNKI), and Wanfang databases on 11 October 2021. A random-effect model incorporating the heterogeneity was used to pool the results. The efficacy outcomes included the complete remission rate of proteinuria, overall response rate (the combined rates of patients with complete and partial remission of proteinuria), changes of urine protein excretion (UPE), serum creatinine (SCr), and estimated glomerular infiltrating rate (eGFR).

RESULTS

Nineteen studies were included. Patients receiving the combined therapy had a higher complete remission rate (relative risk [RR]: 1.29, 95% CI: 1.08-1.55, p = 0.006; I2 = 0%) and overall response rate (RR: 1.18, 95% CI: 1.10-1.26, p < 0.001, I2 = 0%) compared to patients who received CS alone. Besides, combined therapy was associated with significantly reduced levels of UPE (mean difference [MD]: -0.30 g/24h, 95% CI: -0.43 to -0.16, p < 0.001; I2 = 34%) and SCr (MD: -7.55 mmol/L, 95% CI: -11.06 to -4.04, p < 0.001; I2 = 34%), and increased level of eGFR (MD: 6.51 mL/min/1.73 m2, 95% CI: 4.06-8.97, p < 0.001; I2 = 0%). The incidence of adverse events was not significantly different.

CONCLUSIONS

Combined treatment with leflunomide and corticosteroids was more effective than corticosteroids alone for patients with IgA nephropathy.

Management of IgA Nephropathy in Pediatric Patients

The onset of IgA nephritis in childhood and adolescence often develops into chronic glomerulonephritis with declining renal function. Although these long-term consequences are known, there is still a lack of evidence-based treatment recommendations in this age group. We report data from 22 pediatric patients who were biopsied to confirm the diagnosis of IgAN at our clinical center. 14 of them were treated with corticosteroids according to the recommendations for IgA nephritis vasculitis of the German Society of Pediatric Nephrology (GPN). Improvement was achieved in the majority of all cases, with a significant reduction in proteinuria five months after initiation of therapy. Our data suggest that treatment regimens for acute IgA nephritis and IgA vasculitis nephritis may be unified and are discussed in the context of current studies.

An evaluation of the roles of hematuria and uric acid in defining the prognosis of patients with IgA nephropathy

In recent years, many significant advances have been made in determining which clinical manifestations and pathologic lesions can provide prognostic information for patients with IgA nephropathy (IgAN). However, some important questions remain, including the long-term consequences of hematuria, both macroscopic (MH) and microscopic (mH), in patients with IgAN. The importance of distinguishing patients who have a single episode of MH of long duration from those with recurrent episodes of short duration and the prognostic importance of the episodes of acute kidney injury (AKI) that sometimes accompany episodic MH will be discussed. Studies that have evaluated the mechanisms that may be responsible for recurrent MH and the toxic effects of red blood cells (RBCs), or their constituents, on kidney tubules will also be addressed. In the last section, I will review the evidence that hyperuricemia (HU) may be a significant independent risk factor for progressive kidney disease in patients with IgAN.

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