Effectiveness of Mycophenolate Mofetil Among Patients With Progressive IgA Nephropathy: A Randomized Clinical Trial

Immunosuppressive treatment results in patients with primary IgA nephropathy in Turkiye; the data from TSN-GOLD working group

BACKGROUND

Immunoglobulin A (IgA) nephropathy (IgAN) treatment consists of maximal supportive care and, for high-risk individuals, immunosuppressive treatment (IST). There are conflicting results regarding IST. Therefore, we aimed to investigate IST results among IgAN patients in Turkiye.

METHOD

The data of 1656 IgAN patients in the Primary Glomerular Diseases Study of the Turkish Society of Nephrology Glomerular Diseases Study Group were analyzed. A total of 408 primary IgAN patients treated with IST (65.4% male, mean age 38.4 ± 12.5 years, follow-up 30 (3-218) months) were included and divided into two groups according to treatment protocols (isolated corticosteroid [CS] 70.6% and combined IST 29.4%). Treatment responses, associated factors were analyzed.

RESULTS

Remission (66.7% partial, 33.7% complete) was achieved in 74.7% of patients. Baseline systolic blood pressure, mean arterial pressure, and proteinuria levels were lower in responsives. Remission was achieved at significantly higher rates in the CS group (78% vs. 66.7%, p = 0.016). Partial remission was the prominent remission type. The remission rate was significantly higher among patients with segmental sclerosis compared to those without (60.4% vs. 49%, p = 0.047). In the multivariate analysis, MEST-C S1 (HR 1.43, 95% CI 1.08-1.89, p = 0.013), MEST-C T1 (HR 0.68, 95% CI 0.51-0.91, p = 0.008) and combined IST (HR 0.66, 95% CI 0.49-0.91, p = 0.009) were found to be significant regarding remission.

CONCLUSION

CS can significantly improve remission in high-risk Turkish IgAN patients, despite the reliance on non-quantitative endpoints for favorable renal outcomes. Key predictors of remission include baseline proteinuria and specific histological markers. It is crucial to carefully weigh the risks and benefits of immunosuppressive therapy for these patients.

Drug repurposing for glomerular diseases: an underutilized resource

Drug repurposing in glomerular disease can deliver opportunities for steroid-free regimens, enable personalized multi-target options for resistant or relapsing disease and enhance treatment options for understudied populations (for example, children) and in resource-limited settings. Identification of drug-repurposing candidates can be data driven, which utilizes existing data on disease pathobiology, drug features and clinical outcomes, or experimental, which involves high-throughput drug screens. Information from databases of approved drugs, clinical trials and PubMed registries suggests that at least 96 drugs on the market cover 49 targets with immunosuppressive potential that could be candidates for drug repurposing in glomerular disease. Furthermore, evidence to support drug repurposing is available for 191 immune drug target-glomerular disease pairs. Non-immunological drug repurposing includes strategies to reduce haemodynamic overload, podocyte injury and kidney fibrosis. Recommended strategies to expand drug-repurposing capacity in glomerular disease include enriching drug databases with glomeruli-specific information, enhancing the accessibility of primary clinical trial data, biomarker discovery to improve participant selection into clinical trials and improve surrogate outcomes and initiatives to reduce patent, regulatory and organizational hurdles.

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.

Low dose glucocorticoids, mycophenolate mofetil and hydroxychloroquine in IgA nephropathy, an update of current clinical trials

This mini-review explores glucocorticoids, mycophenolate mofetil (MMF), and hydroxychloroquine (HCQ) in IgA nephropathy (IgAN). It discusses conflicting findings from pivotal trials like TESTING and STOP-IgAN regarding glucocorticoid efficacy, emphasizing reduced-dose protocols as potentially safer options. MMF's effectiveness varies among populations, demonstrating promise in Chinese cohorts but yielding inconclusive results elsewhere. HCQ shows potential in reducing proteinuria, with ongoing trials investigating its long-term benefits.

Contemporary review of IgA nephropathy

IgA nephropathy (IgAN) is considered the most common primary glomerulonephritis worldwide with a predilection for Asian-Pacific populations and relative rarity in those of African descent. Perhaps 20%-50% of patients progress to kidney failure. The pathogenesis is incompletely understood. Mesangial deposition of immune complexes containing galactose-deficient IgA1 complexed with anti-glycan IgG or IgA antibodies results in mesangial cell activation and proliferation, inflammatory cell recruitment, complement activation, and podocyte damage. Diagnosis requires a biopsy interpreted by the Oxford criteria. Additional pathologic features include podocytopathy, thrombotic microangiopathy, and C4d staining. Biomarkers predicting adverse outcomes include proteinuria, reduced GFR, hypertension, and pathology. Acceptable surrogate endpoints for therapeutic trials include ongoing proteinuria and rate of eGFR decline. The significance of persisting hematuria remains uncertain. The mainstay of therapy is supportive, consisting of lifestyle modifications, renin-angiotensin inhibition (if hypertensive or proteinuric), sodium-glucose-transporter 2 inhibition (if GFR reduced or proteinuric), and endothelin-receptor antagonism (if proteinuric). Immunosuppression should be considered for those at high risk after maximal supportive care. Corticosteroids are controversial with the most positive results observed in Chinese. They carry a high risk of serious side effects. Similarly, mycophenolate may be most effective in Chinese. Other immunosuppressants are of uncertain benefit. Tonsillectomy appears efficacious in Japanese. Active areas of investigation include B-cell inhibition with agents targeting the survival factors BAFF and APRIL and complement inhibition with agents targeting the alternate pathway (Factors B and D), the lectin pathway (MASP-2), and the common pathway (C3 and C5). Hopefully soon, the who and the how of immunosuppression will be clarified, and kidney failure can be forestalled.

Navigating Adult-Onset IgA Vasculitis-Associated Nephritis

PURPOSE OF REVIEW

IgA vasculitis (IgAV), formerly Henoch-Schonlein purpura, is the most common systemic vasculitis in childhood. In adults, however, this condition is poorly understood, yet associated with more severe disease and poorer outcomes. This necessitates the need for early diagnosis and management.

SCOPE OF REVIEW

We describe the pathophysiology, clinical manifestations, and diagnosis of IgAV in adults. Poor outcomes are often due to the high frequency of glomerulonephritis in IgAV-IgA vasculitis-associated nephritis (IgAVN). We hence also aim to summarize the latest clinical data regarding treatment strategies in IgAVN. The diagnosis and differentiation in histology between IgAVN and IgA nephropathy (IgAN) remain a challenge. Review of treatment therapies: Pathological mechanisms between IgAVN and IgAN appear to be consistent between the two, and data from IgAN are often extrapolated to IgAVN. The role of various immunosuppression therapies remains controversial, and in this review, we will discuss immunosuppression use and highlight evidence surrounding emerging and promising novel therapies in IgAVN/IgAN. Our aim for this review is to guide future treatment strategies and direct future studies.

Pemphigoid diseases in patients with end-stage kidney diseases: pathogenesis and treatment

Background

Pemphigoid diseases constitute a group of autoimmune blistering disorders characterized by subepithelial blistering. The association between pemphigoid diseases and both end-stage kidney disease (ESKD) and its treatment is notable. However, there is limited evidence about the management of pemphigoid diseases in patients with ESKD. This systematic review compiled case reports and relevant studies, summarized the underlying mechanisms of pemphigoid diseases in patients with ESKD, and summarized the efficacy of various therapies.

Methods

A systematic search of PubMed and Embase was performed for articles published between 1982 to June 2, 2024.

Results

Fifty-three case reports and eight relevant studies were included. Triggers for pemphigoids in patients with ESKD included materials used to treat ESKD, immune dysregulation of patients with ESKD, and rejection of renal allograft. Treatment for these patients included removing triggers, as well as administering of corticosteroids, mycophenolate mofetil (MMF), tetracyclines, rituximab, methotrexate, dapsone, azathioprine, cyclosporine, intravenous immunoglobin (IVIG), plasmapheresis, and Janus kinase inhibitors.

Conclusion

Removing triggers is the most effective strategy. Despite their suboptimal efficacy, corticosteroids remain the most commonly used agents in this patient population. MMF, tetracyclines, and rituximab are less used but with benefits. There are significant adverse effects associated with methotrexate treatment. Other treatment may also be beneficial and require further investigation. These findings may enable clinicians to optimize the therapeutic approach for these patients.

Immunosuppressive therapy for IgA nephropathy in children

BACKGROUND

IgA nephropathy (IgAN) is the most common cause of primary glomerulonephritis. It is a heterogeneous disease with different presentations and high morbidity. Thirty per cent of adults and 20% of children (followed into adulthood) will have a 50% decline in kidney function or develop kidney failure after 10 years.

OBJECTIVES

To determine the benefits and harms of immunosuppressive therapy for the treatment of IgAN in children.

SEARCH METHODS

We contacted the Information Specialist and searched the Cochrane Kidney and Transplant Register of Studies up to 03 October 2023 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and non-randomised studies of interventions (NRSIs) investigating the treatment of IgAN in children with immunosuppressive therapies compared to placebo, no treatment, supportive care, standard therapy (Japanese protocol), other immunosuppressive therapies or non-immunosuppressive therapies.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the risk of bias. Random effects meta-analyses were used to summarise estimates of treatment effects. Treatment effects were expressed as risk ratios (RR) and 95% confidence intervals (CI) for dichotomous outcomes, and the mean difference (MD) and 95% CI for continuous outcomes. The risk of bias was assessed using the Cochrane risk of bias tool for RCTs and the ROBIN-I tool for NRSIs. The certainty of the evidence was assessed using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE).

MAIN RESULTS

This review included 13 studies with 686 participants. Ten RCTs included 334 children and 191 adults, and three NRSIs included 151 participants, all children. Most participants had mild kidney disease. The risk of bias was unclear for most of the domains relating to allocation concealment, blinding of participants, personnel, and outcome assessment. In children with IgAN, it is uncertain if corticosteroid (steroid) therapy, compared to placebo reduces proteinuria (1 study, 64 children and young adults: RR 0.47, 95% CI 0.13 to 1.72; low certainty evidence) or the decline in estimated glomerular filtration rate (eGFR) (1 study, 64 children and young adults: RR 0.47, 95% CI 0.09 to 2.39; low certainty evidence). It is uncertain if steroids reduce proteinuria compared to supportive care (2 studies, 61 children: RR 0.04, 95% CI -0.83 to 0.72; low certainty evidence). Adverse events associated with steroid therapy were not assessed due to heterogeneity in steroid protocols, including dose and duration, and lack of systematic assessment for adverse events in the included studies. Azathioprine, mycophenolate mofetil, mizoribine, or cyclophosphamide alone or in combination with steroid therapy had uncertain effects on improving proteinuria or preventing eGFR decline in children with IgAN. Fish oil, vitamin E and tonsillectomy had uncertain effects on improving proteinuria or preventing eGFR decline. Effects of other immunosuppressive therapies, secondary outcomes and adverse events were not assessed due to insufficient data.

AUTHORS' CONCLUSIONS

There is a lack of high-quality evidence to guide the management of IgAN in children. There is no evidence to indicate that steroids, other immunosuppressive therapies, or tonsillectomy, when added to optimal supportive care, prevent a decline in eGFR or proteinuria in children with IgAN. Available studies were few, with small numbers, low-quality evidence, high or uncertain risk of bias, did not systematically assess harms associated with treatment, or report net benefits or harms. Severe cases and atypical presentations of IgAN were not included in the reviewed studies, and our findings cannot be generalised to these situations.

Immunosuppressant Agents as Add-On Therapy Failed to Improve the Outcome of Immunoglobulin A Nephropathy with Crescent Score C1

INTRODUCTION

The renoprotective benefits of adding immunosuppressant therapy to corticosteroid (CS) treatment for immunoglobulin A nephropathy (IgAN) patients with less than 25% crescent formation (C1) remain uncertain, warranting further research.

METHODS

A retrospective study was conducted on IgAN patients with crescent C1 lesions confirmed by renal biopsy at Xinqiao Hospital between May 1, 2017, and May 1, 2020. Patients were stratified into either the CS treatment group or the CS combined with an additional immunosuppressant therapy group. Follow-up assessments were conducted within 24 months. Propensity score analysis was used to match patients receiving CS and CS + immunosuppressant drug treatment in a 1:1 ratio. Primary outcomes included changes in estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR). Subgroup analyses were performed to evaluate the benefits of different populations. Composite endpoint outcomes comprised a 30% eGFR decrease, end-stage kidney disease (ESKD) necessitating dialysis or transplant, or kidney disease-related mortality. Adverse events were also compared between the two groups.

RESULTS

296 IgAN patients with C1 lesions were included in the analysis. Baseline characteristics indicated that IgAN patients in the CS + immunosuppressant group exhibited poorer renal function and higher UACR levels. Propensity score analysis effectively minimized the influence of baseline clinical characteristics, including age, serum creatinine, initial eGFR, UACR, and 24-h proteinuria. Both treatment groups demonstrated continuous eGFR improvement and significant UACR reduction during follow-up, especially at 6 months. However, no significant differences in eGFR and UACR reduction rates were observed between the two groups throughout the entire follow-up period, both before and after matching. Subgroup analysis revealed improved eGFR in both treatment groups, notably among patients with an initial eGFR below 90 mL/min/1.73 m2. Conversely, IgAN patients with C1 lesions and a cellular crescent ratio exceeding 50% treated with CS and immunosuppressant therapy experienced a significant improvement in renal function and a decline in urinary protein creatinine ratio. Composite endpoint outcomes did not significantly differ between the two groups, while the incidence of adverse events was comparable.

CONCLUSION

Our findings suggest that the addition of immunosuppressant therapy to corticosteroid monotherapy did not confer significant therapeutic advantages in patients with C1 lesions compared to CS monotherapy, although some specific patient populations appeared to derive modest benefits from this combined approach.

Primary IgA Nephropathy: New Insights and Emerging Therapies

Primary IgA nephropathy (IgAN) is a common glomerular disorder defined by predominant mesangial IgA deposition. Once thought to follow a progressive course in 10-20% of those diagnosed, emerging evidence now suggests most will progress to kidney failure over their lifetimes. Although the lack of safe and effective treatments to impede disease progression continues to present a challenge, the landscape of IgAN has dramatically evolved over the last 2 years. Driven by fundamental changes to accepted end points for IgAN clinical trials as well as fascinating new insights into the pathophysiology of IgAN, a swathe of novel and repurposed therapies are currently being evaluated. Already, two novel drugs, targeted-release formulation budesonide and sparsentan, have received conditional approvals for the treatment of IgAN, with sodium glucose co-transporter 2 inhibitors establishing themselves as further options. Soon to join this ensemble are likely to be treatments that modulate the complement system and B-cell activity; several are currently undergoing clinical trials in IgAN with promising interim results. In this review, we provide an overview of evolving epidemiological insights, disease mechanisms, emerging therapies, and contemporary challenges surrounding the management of IgAN.

New therapies for immunoglobulin A nephropathy: what's the standard of care in 2023?

PURPOSE OF REVIEW

As the most common primary glomerulonephritis, immunoglobulin A (IgA) nephropathy (IgAN) is an important cause of kidney failure and mortality. Until recently, therapeutic options were limited. Fortunately, there have been numerous recent clinical trials demonstrating efficacy of new therapies in slowing chronic kidney disease (CKD) progression at varying stages of disease.

RECENT FINDINGS

The TESTING trial has provided high-quality evidence for slowing estimated glomerular filtration rate (eGFR) decline with a reduced-dose glucocorticoid regimen, while demonstrating an improved safety profile. Targeted-release budesonide represents a well tolerated therapy for reducing eGFR decline. Mycophenolate mofetil may reduce CKD progression in some populations, while hydroxychloroquine is efficacious in reducing proteinuria. Sodium-glucose cotransporter (SGLT2) inhibitors and sparsentan are effective therapies for CKD due to IgAN, but should not be used in lieu of disease-modifying immunosuppressive therapy. Many new therapies are approaching readiness for clinical use.

SUMMARY

Numerous therapeutic options now exist and include disease-modifying and nephroprotective drugs. Identifying the right treatment for the right patient is now the clinical challenge and, with new drugs on the horizon, represents the primary unmet research need in this rapidly-developing field.

Drugs in Development to Treat IgA Nephropathy

IgA nephropathy is a common glomerulonephritis consequent to the autoimmune response to aberrant glycosylated immunoglobulin (Ig) A antibodies. Although it has historically been considered a benign disease, it has since become clear that a substantial percentage of patients reach end-stage kidney failure over the years. Several therapeutic attempts have been proposed, with systemic steroids being the most prevalent, albeit burdened by possible serious adverse events. Thanks to the more in-depth knowledge of the pathogenesis of IgA nephropathy, new treatment targets have been identified and new drugs developed. In this narrative review, we summarise the molecules under clinical development for the treatment of IgA nephropathy. As a search strategy, we used PubMed, Google, ClinicalTrials.gov and abstracts from recent international congresses. TRF budesonide and sparsentan are the two molecules at a more advanced stage, just entering the market. Other promising agents are undergoing phase III clinical development. These include anti-APRIL and anti-BLyS/BAFF antibodies and some complement inhibitors. Other new possible strategies include spleen tyrosine kinase inhibitors, anti-CD40 ligands and anti-CD38 antibodies. In an era increasingly characterised by 'personalised medicine' and 'precision therapy' approaches and considering that the potential therapeutic armamentarium for IgA nephropathy will be very broad in the near future, the identification of biomarkers capable of helping the nephrologist to select the right drug for the right patient should be the focus of future studies.

Histological reappraisal of IgA nephropathy: the role of glomerular pattern of injury and mesangial complement deposition

BACKGROUND

There is a clear need to refine the histological assessment in IgA Nephropathy (IgAN). We sought to investigate the clinical significance of the light microscopy (LM) pattern of glomerular injury and of the intensity of mesangial C3 staining in IgAN.

METHODS

We conducted a retrospective, observational study that included all patients with biopsy-proven primary IgAN that had at least 12 months of follow-up. The LM pattern of glomerular injury was reevaluated based on a modified HAAS classification. Mesangial C3 deposition by immunofluorescence (IF) staining was scored semi-quantitatively. The study primary composite endpoint was defined as doubling of serum creatinine or ESRD (dialysis, renal transplant or eGFR < 15 ml/min). The secondary study endpoint was eGFR decline per year.

RESULTS

This cohort included 214 patients with IgAN (mean age, 41.4 ± 12.6 years), with a mean eGFR and median 24-h proteinuria of 55.2 ± 31.5 ml/min/1.73m2 and 1.5 g/day (IQR:0.8-3.25), respectively. The most frequent LM pattern was the mesangioproliferative (37.4%), followed by the sclerotic (22.5%) and proliferative/necrotizing patterns (21.4%). Regarding the IF findings, mild-moderate and intense mesangial C3 staining was present in 30.6% and 61.1% of patients, respectively. Those with sclerosing and crescentic patterns had the worst renal survival (5-year renal survival of 48.8% and 42.9%) and the highest rate of eGFR change/year (-2.32 ml/min/y and - 2.16 ml/min/y, respectively) compared to those with other glomerular patterns of injury. In addition, those with intense C3 staining reached the composite endpoint more frequently compared to those without intense C3 staining (35.5% vs. 21.4%, p = 0.04). After multivariate adjustment, patients with crescentic and sclerosing patterns had a 3.6-fold and 2.1-fold higher risk for the composite endpoint compared to those with mesangioproliferative pattern, while an intense mesangial C3 deposition being also associated with a worse renal outcome (HR, 3.33; 95%CI, 1.21-9.2).

CONCLUSIONS

We have shown that the LM pattern of glomerular injury and the intensity of mesangial C3 deposition might stratify more accurately the renal outcome in patients with IgAN.

Biologics and Non-Biologics Immunosuppressive Treatments for IgA Nephropathy in Both Adults and Children

Immunoglobulin A nephropathy represents the most prevalent cause of glomerulonephritis worldwide and may lead to renal failure in a relevant number of cases in both paediatric and adult subjects. Although their pathogenesis is still largely unclear, evidence of immune abnormalities provides the background for the use of immunosuppressive drugs, such as corticosteroids, calcineurin inhibitors, and antiproliferative and alkylating agents. Unfortunately, these treatments fail to achieve a sustained remission in a significant percentage of affected patients and are burdened by significant toxicities. Recent developments of new biologics, including anti-BAFF/APRIL inhibitors and molecules targeting complement components, offered the opportunity to selectively target immune cell subsets or activation pathways, leading to more effective and safer hypothesis-driven treatments. However, studies testing new biologic agents in IgAN should also consider paediatric populations to address the unique needs of children and close the therapeutic gap between adult and paediatric care.

Points of view in nephrology: personalized management of IgA nephropathy, beyond KDIGO

IgA nephropathy is the most common primary glomerulonephritis worldwide, and an important cause of kidney failure, as 20-40% of patients progress to renal replacement therapy 20-30 years after diagnosis. Its clinical presentation ranges from isolated microscopic hematuria to nephrotic syndrome, and even to a rapidly progressive course. Ethnicity and epigenetics play a key role in its clinical aggressiveness. Selection of patients at risk needing immunosuppressive treatment is a challenge for the nephrologist. Some active and chronic kidney lesions detected on kidney biopsy have been demonstrated to have prognostic value according to the Oxford Classification of IgA nephropathy, later validated by numerous studies. However, KDIGO 2021 guidelines still consider persistent proteinuria > 1 g/24 h to be the most relevant risk factor for the progression of IgA nephropathy and the only one requiring immunosuppressive treatment. KDIGO guidelines have proposed a therapeutic algorithm, but many patients present peculiar characteristics that are not addressed by the current guidelines, pointing to the need for alternative approaches. In these cases, a tailored approach to each patient should be followed in which clinical, histological, laboratory, social and ethical aspects must be considered. In this manuscript we present three cases of IgA nephropathy from different countries, highlighting many of the aspects encountered in clinical practice that illustrate an individualized approach to the treatment of these patients.

Secular Trend in GFR Decline in Non-Dialysis CKD Based on Observational Data From Standard of Care Arms of Trials

RATIONALE & OBJECTIVE

The standard of care (SoC) group of randomized controlled trials (RCTs) is a useful setting to explore the secular trends in kidney disease progression because implementation of best clinical practices is pursued for all patients enrolled in trials. This meta-analysis evaluated the secular trend in the change of glomerular filtration rate (GFR) decline in the SoC arm of RCTs in chronic kidney disease (CKD) published in the last 30 years.

STUDY DESIGN

Systematic review and meta-analysis of the SoC arms of RCTs analyzed as an observational study.

SETTING & STUDY POPULATIONS

Adult patients with CKD enrolled in the SoC arm of RCTs.

SELECTION CRITERIA FOR STUDIES

Phase 3 RCTs evaluating GFR decline as an outcome in SoC arms.

DATA EXTRACTION

Two independent reviewers evaluated RCTs for eligibility and extracted relevant data.

ANALYTICAL APPROACH

The mean of GFR declines extracted in the SoC arm of selected RCTs were pooled by using a random effects model. Meta-regression analyses were performed to identify factors that may explain heterogeneity.

RESULTS

The SoC arms from 92 RCTs were included in the meta-analysis with a total of 32,202 patients. The overall mean GFR decline was-4.00 (95% CI, -4.55 to-3.44) mL/min/1.73m2 per year in the SoC arms with a high level of heterogeneity (I2, 98.4% [95% CI, 98.2-98.5], P<0.001). Meta-regression analysis showed an association between publication year (β estimate, 0.09 [95% CI, 0.032-0.148], P=0.003) and reduction in GFR over time. When evaluating publication decade categorically, GFR decline was-5.44 (95% CI, -7.15 to-3.73), -3.92 (95% CI, -4.82 to-3.02), and -3.20 (95% CI, -3.75 to -2.64) mL/min/1.73m2 per year during 1991-2000, 2001-2010, and 2011-2023, respectively. Using meta-regression, the heterogeneity of GFR decline was mainly explained by age and proteinuria.

LIMITATIONS

Different methods assessing GFR in selected trials and observational design of the study.

CONCLUSIONS

In the last 3 decades, GFR decline has decreased over time in patients enrolled in RCTs who received the standard of care.

TRIAL REGISTRATION

Registered at PROSPERO with record number CRD42022357704.

PLAIN-LANGUAGE SUMMARY

This study evaluated the secular trend in the change in glomerular filtration rate (GFR) decline in the placebo arms of randomized controlled trials (RCTs) that were studying approaches to protect the kidneys in the setting of chronic kidney disease. The placebo groups of RCTs are useful for examining whether the rate of progression of kidney disease has changed over time. We found an improvement in the slope of change in GFR over time. These findings suggest that adherence to standards of kidney care as implemented in clinical trials may be associated with improved clinical outcomes, and these data may inform the design of future RCTs in nephrology.

Immunoglobulin A glomerulonephropathy: A review

In this editorial, we comment on the article by Meng et al published in the World Journal of Clinical Cases. We comprehensively review immunoglobulin A nephropathy (IgAN), including epidemiology, clinical presentation, diagnosis, and management. IgAN, also known as Berger's disease, is the most frequent type of primary glomerulonephritis (GN) globally. It is mostly found among the Asian population. The presentation can be variable, from microscopic hematuria to a rapidly progressive GN. Around 50% of patients present with single or recurring episodes of gross hematuria. An upper respiratory infection and tonsillitis often precede these episodes. Around 30% of patients present microscopic hematuria with or without proteinuria, usually detected on routine examination. The diagnosis relies on having a renal biopsy for pathology and immunofluorescence microscopy. We focus on risk stratification and management of IgAN. We provide a review of all the landmark studies to date. According to the 2021 KDIGO (kidney disease: Improving Global Outcomes) guidelines, patients with non-variant form IgAN are first treated conservatively for three to six months. This approach consists of adequate blood pressure control, reduction of proteinuria with renin-angiotensin system blockade, treatment of dyslipidemia, and lifestyle modifications (weight loss, exercise, smoking cessation, and dietary sodium restrictions). Following three to six months of conservative therapy, patients are further classified as high or low risk for disease progression. High-risk patients have proteinuria ≥ 1 g/d or < 1 g/d with significant microscopic hematuria and active inflammation on kidney biopsy. Some experts consider proteinuria ≥ 2 g/d to be very high risk. Patients with high and very high-risk profiles are treated with immunosuppressive therapy. A proteinuria level of < 1 g/d and stable/improved renal function indicates a good treatment response for patients on immunosuppressive therapy.

Metabolomics study reveals blood biomarkers for early diagnosis of chronic kidney disease and IgA nephropathy: A retrospective cross-sectional study

BACKGROUND AND AIMS

Chronic kidney disease (CKD) causes low quality of life and alarming morbidity and mortality. The crucial to retard CKD progression is to diagnose early for timely treatment. IgA nephropathy (IgAN) is a typical CKD and the most common glomerulonephritis. Both CKD and IgAN lack accurate and sensitive blood biomarkers for early diagnosis. Here we report the potential of plasma biomarkers for early diagnosis of CKD and IgAN.

MATERIALS AND METHODS

Plasma levels of metabolites derived from tryptophan were quantified with an LC-MS/MS-based metabolomics for two cohorts. Based on the predictive probability of each metabolite, multivariate models including logistic regression and random forest were used to establish the early diagnostic biomarkers for CKD and IgAN.

RESULTS

The plasma melatonin diagnosed early CKD (stages Ⅰ-Ⅱ) with an accuracy exceeding 95%, and a panel of melatonin and tryptophan achieved a remarkable 100% accuracy in diagnosing early CKD. Furthermore, indole-3-lactic acid had an excellent ability to distinguish IgAN among CKD patients. Based on the CKD screening and IgAN diagnosis primarily contributed by melatonin and indole-3-lactic acid, early IgAN could be diagnosed with an accuracy of over 85%.

CONCLUSIONS

This study provides promising plasma biomarkers for early diagnosis of CKD and IgAN.

Crescent calculator: A webtool enabling objective decision-making for assessment of IgA nephropathy immune activity throughout the disease course

IgA nephropathy (IgAN) is an immune-mediated glomerulonephritis, posing a challenge for the long-term management. It is crucial to monitor the disease's activity over the disease course. Crescent lesions have been known as an active lesion associated with immune activity. We aimed to develop the Crescent Calculator to aid clinicians in making timely and well-informed decisions throughout the long-term disease course, such as renal biopsies and immunosuppressive therapy. 1,761 patients with biopsy-proven IgAN were recruited from four medical centers in Zhejiang Province, China. 16.9% presented crescent lesions. UPCR, URBC, eGFR and C4 were independently associated with the crescent lesions. By incorporating these variables, the Crescent Calculator was constructed to estimate the likelihood of crescent lesions. The predictor achieved AUC values of over 0.82 in two independent testing datasets. In addition, to fulfill varied clinical needs, multiple classification modes were established. The Crescent Calculator was developed to estimate the risk of crescent lesions for patients with IgAN, assisting clinicians in making timely, objective, and well-informed decisions regarding the need for renal biopsies and more appropriate use of immunosuppressive therapy in patients with IgAN.

An Update on Current Therapeutic Options in IgA Nephropathy

Immunoglobulin A nephropathy (IgAN) remains the leading cause of primary glomerular disease worldwide. Outcomes are poor with high rates of progressive chronic kidney disease and kidney failure, which contributes to global healthcare costs. Although this disease entity has been described, there were no disease-specific treatments until recently, with the current standard of care focusing on optimal supportive measures including lifestyle modifications and optimization of the renin-angiotensin-aldosterone blockade. However, with significant advances in the understanding of the pathogenesis of IgAN in the past decade, and the acceptance of surrogate outcomes for accelerated drug approval, there have been many new investigational agents tested to target this disease. As these agents become available, we envision a multi-pronged treatment strategy that simultaneously targets the consequences of ongoing nephron loss, stopping any glomerular inflammation, inhibiting pro-fibrotic signals in the glomerulus and tubulo-interstitium, and inhibiting the production of pathogenic IgA molecules. This review is an update on a previous review published in 2021, and we aim to summarize the developments and updates in therapeutic strategies in IgAN and highlight the promising discoveries that are likely to add to our armamentarium.

Use of corticosteroids in Norwegian patients with immunoglobulin a nephropathy progressing to end-stage kidney disease: a retrospective cohort study

BACKGROUND

Despite several clinical trials, the use of corticosteroid therapy for treating immunoglobulin A nephropathy (IgAN) remains controversial. We aimed to describe the use of corticosteroid therapy combined with supportive therapy in Norwegian patients with IgAN who had progressed to end-stage kidney disease.

METHODS

We conducted a retrospective cohort study using data from the Norwegian Renal Registry. Overall, 143 patients with primary IgAN who progressed to end-stage kidney disease were divided into two groups: the corticosteroid group, who had been treated with corticosteroids and supportive therapy, and the non-corticosteroid group, which had underwent only supportive therapy. The kidney function, time to end-stage kidney disease, and adverse effects were described. The observation period lasted from the diagnostic kidney biopsy until the initiation of kidney replacement therapy.

RESULTS

Of the 143 included patients, 103 underwent supportive therapy alone, and 40 were treated with corticosteroids. Most patients (94%) were treated with renin-angiotensin-system blockade, and all patients reached end-stage kidney disease after a median of 5 years (interquartile range; 2-9 years). Time from diagnosis until end-stage kidney disease was similar in the two study groups (p = 0.98). During 6 months of corticosteroid therapy, median eGFR declined from 21 (interquartile range; 13-46) mL/min/1.73 m2 to 20 (interquartile range; 12-40) mL/min/1.73 m2, and median proteinuria decreased from 5.5 g/24 h to 3.0 g/24 h. Most patients (87.5%) treated with corticosteroids reported adverse events. In our linear regression analysis investigating the time to ESKD, we found that age (β = -0.079, p = 0.008) and proteinuria at diagnosis (β = -0.50, p = 0.01) exhibited statistically significant associations with a delay in the progression to ESKD.

CONCLUSIONS

In this cohort of Norwegian patients with IgAN, corticosteroid therapy did not affect the time from diagnosis until end-stage kidney disease among a cohort of patients who all reached end-stage kidney disease. The treatment was also associated with adverse effects.

Treatment of Patients with IgA Nephropathy: Evaluation of the Safety and Efficacy of Mycophenolate Mofetil

INTRODUCTION AND AIM

Immunoglobulin A nephropathy (IgAN), characterized by aberrant IgA immune complex deposition, is the most prevalent primary glomerular disease and the main cause of end-stage renal disease, causing a significant physical and psychological burden on people worldwide. Conventional therapeutic approaches, such as renin-angiotensin-aldosterone system inhibitors and corticosteroids, may not achieve sufficient effectiveness and may produce major side events in the past. The previous data in Asian populations indicated that mycophenolate mofetil (MMF) might significantly advance the development of a new therapy strategy for IgAN. The effectiveness and safety of MMF in patients with IgAN will be investigated in this study.

METHODS

A literature search was conducted on June 30th, 2023, by searching the following databases: PubMed and the Cochrane Library according to predefined criteria. To investigate the renoprotective benefits and safety of MMF, statistical analyses were performed using Cochrane's Review Manager Version 5.3.

RESULTS

The meta-analysis included nine randomized controlled studies that fulfilled the inclusion criterion. In the Asian population, the results revealed a substantial difference in remission rates between the MMF group and the control group (OR: 2.53, 95% CI: 1.02, 6.30, P = 0.05). MMF can increase the rate of decrease in proteinuria in IgAN patients when compared with controls in Asians (OR: 7.34, 95% CI: 2.69, 20.08, P = 0.0001), and MMF can reduce the urinary protein in patients with IgAN in Asians (WMD: -0.61, 95% CI: -1.15, -0.08, P = 0.02). Interestingly, these studies on Asians were conducted in China. However, the differences in remission rate, rate of decrease in proteinuria, and urinary protein reduction between the MMF group and control group were not found in overall populations and in the Caucasian population. The differences in complete remission rate, partial remission rate, serum creatinine (SCr) doubling rate, rate of 50% increase in SCr, and rate of need for renal replacement treatment between the MMF group and control group were not found in Asians, Caucasians, and overall populations. The difference in the rate of side effects between the MMF group and the control group was not found.

CONCLUSION

MMF protects renal function and is a safe medication for treating Chinese IgAN patients. MMF might significantly advance the development of a new therapy strategy for IgAN in the Chinese population.

Treatment of IgA Nephropathy: A Rapidly Evolving Field

The pivotal event in the pathophysiology of IgA nephropathy is the binding of circulating IgA-containing immune complexes to mesangial cells, with secondary glomerular and tubulointerstitial inflammation and fibrosis. The paramount difficulty in the management of IgA nephropathy is the heterogeneity in its clinical presentation and prognosis, requiring an individualized treatment approach. Goal-directed supportive care remains the bedrock of therapy for all patients, regardless of risk of progression. Sodium-glucose transporter 2 inhibitors and sparsentan should be integral to contemporary supportive care, particularly in patients with chronic kidney damage. Pending the development of reliable biomarkers, it remains a challenge to identify patients prone to progression due to active disease and most likely to derive a net benefit from immunosuppression. The use of clinical parameters, including the degree of proteinuria, the presence of persistent microscopic hematuria, and the rate of eGFR loss, combined with the mesangial hypercellularity, endocapillary hypercellularity, segmental glomerulosclerosis, tubular atrophy/interstitial fibrosis, crescents score, is currently the best approach. Systemic glucocorticoids are indicated in high-risk patients, but the beneficial effects wane after withdrawal and come at the price of substantial treatment-associated toxicity. Therapies with direct effect on disease pathogenesis are increasingly becoming available. While targeted-release budesonide has garnered the most attention, anti-B-cell strategies and selective complement inhibition will most likely prove their added value. We propose a comprehensive approach that tackles the different targets in the pathophysiology of IgA nephropathy according to their relevance in the individual patient.

Efficacy of prednisone combined with mycophenolate mofetil for immunoglobulin A nephropathy with moderate-to-severe renal dysfunction

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is a common form of chronic glomerulonephritis. Currently, IgAN is one of the main causes of chronic renal failure in China; its prognosis varies greatly between patients, with renal function at the time of diagnosis and prognosis being strongly correlated. Mycophenolate mofetil (MMF) is a drug with a good immunomodulatory effect and is commonly used clinically. However, its effects in IgAN have not yet been clearly demonstrated. Therefore, herein, we retrospectively compared the effectiveness and safety of prednisone alone or combined with MMF for the treatment of primary IgAN with moderate-to-severe renal impairment.

AIM

To evaluate the effectiveness and safety of prednisone and MMF in treating IgAN with moderate-to-severe renal dysfunction.

METHODS

Between January 2011 and December 2020, 200 patients with moderate-to-severe IgAN were included in this study, all of whom were admitted to Wuxi People's Hospital affiliated with Nanjing Medical University. All patients underwent a renal puncture biopsy, which revealed primary IgAN with a glomerular filtration rate (GFR) of 30-60 mL/min. The patients were divided into a glucocorticoid therapy group (GTG) and an immunosuppressive therapy group (ITG) according to the different treatment regimens, with 100 patients in each group. Based on general treatments, such as angiotensin-converting enzyme inhibitors/ angiotensin receptor blockers, patients in the GTG were administered prednisone 0.5-0.8 mg/ (kg·d-1) for 4-8 wk, which was reduced by 5 mg every two weeks until the maintenance(30 mg/d) dose was reached and maintained for 12 mo. In the ITG, MMF was administered at 1.0 g/d for 6-12 mo, followed by a maintenance dosage of 0.5 g/d for 12 mo. Age, sex, blood pressure, 24-h urinary egg white measurement, serum creatinine (Scr), blood uric acid, blood albumin, blood potassium (K), hemoglobin, GFR, alanine aminotransferase, total cholesterol (T-CHO), fasting blood glucose, and body mass index were recorded. The 24-h urinary protein, Scr, and GFR levels were recorded 3, 6, 9, and 12 mo after treatment. Follow-up data were also collected.

RESULTS

No discernible differences existed between the two groups in terms of age, sex, blood pressure, creatinine, 24-h urinary protein level, GFR, or other biochemical indicators at the time of enrollment. Both regimens significantly reduced the 24-h urinary protein quantitation and stabilized renal function. Nine months after treatment, the 24-h urinary protein and Scr of the ITG decreased more significantly than those of the GTG. By the 12th month of treatment, the 24-h urinary protein and Scr in both groups continued to decrease compared to those by the 9th month. In addition, the overall response rate in the ITG was significantly higher than that in the GTG. The occurrence of side effects did not vary significantly between the two regimens; however, endpoint events were significantly more common in the GTG than in the ITG. The follow-up time for the GTG was noticeably lower than that for the ITG.

CONCLUSION

Prednisone combined with MMF was effective for the treatment of IgAN with moderate-to-severe renal dysfunction.

Clinical Practice Patterns in IgA Nephropathy: A Global Questionnaire-Based Survey

Introduction

IgA nephropathy (IgAN) displays ethnic differences in disease phenotype. We aimed to examine how this common disease is managed worldwide.

Methods

An online 2-step questionnaire-based survey was conducted among nephrologists globally focusing on various management strategies used in IgAN.

Results

A total of 422 nephrologists responded to the initial survey and 339 to the follow-up survey. Of the nephrologists, 13.7% do not get MEST-C scores in biopsy reports; 97.2% of nephrologists use renin-angiotensin-aldosterone system (RAAS) blockade with angiotensin-converting-enzyme inhibitors (ACEi) / angiotensin receptor blockers (ARB) as initial treatment. Other supportive treatments commonly employed are fish oil (43.6%) and sodium-glucose co-transporter-2 (SGLT2) inhibitors (48.6%) with regional differences. Immunosuppression is generally (92.4%) initiated when proteinuria >1 g/d persists for ≥3 months.Main considerations for initiating immunosuppression are level of proteinuria (87.9%), estimated glomerular filtration rate (eGFR) decline (78.7%), lack of response to RAAS blockade (57.6%) and MEST-C score (64.9%). Corticosteroids (89.1%) are universally used as first-line immunosuppression; mycophenolate mofetil is commonly used in resistant patients (49.3%). Only 30.4% nephrologist enroll patients with persistent proteinuria >1 g/d in clinical trials. Nephrologists in Europe (63.6%), North America (56.5%), and Australia (63.6%) are more likely to do so compared to South America (31.3%) and Asia (17.2%). Only 8.1% nephrologists in lower-middle income countries (LMICs) enroll patients in clinical trials, though 40% of them are aware of such trials in their nations.

Conclusion

Although most nephrologists agree on common parameters to assess clinical severity of IgAN, use of RAAS blockade, and blood pressure control, there is heterogeneity in use of other supportive therapies and initiation of immunosuppression. There is reluctance to enroll patients in clinical trials with novel treatments, principally in LMICs.

IgA nephropathy

IgA nephropathy (IgAN), the most prevalent primary glomerulonephritis worldwide, carries a considerable lifetime risk of kidney failure. Clinical manifestations of IgAN vary from asymptomatic with microscopic or intermittent macroscopic haematuria and stable kidney function to rapidly progressive glomerulonephritis. IgAN has been proposed to develop through a 'four-hit' process, commencing with overproduction and increased systemic presence of poorly O-glycosylated galactose-deficient IgA1 (Gd-IgA1), followed by recognition of Gd-IgA1 by antiglycan autoantibodies, aggregation of Gd-IgA1 and formation of polymeric IgA1 immune complexes and, lastly, deposition of these immune complexes in the glomerular mesangium, leading to kidney inflammation and scarring. IgAN can only be diagnosed by kidney biopsy. Extensive, optimized supportive care is the mainstay of therapy for patients with IgAN. For those at high risk of disease progression, the 2021 KDIGO Clinical Practice Guideline suggests considering a 6-month course of systemic corticosteroid therapy; however, the efficacy of systemic steroid treatment is under debate and serious adverse effects are common. Advances in understanding the pathophysiology of IgAN have led to clinical trials of novel targeted therapies with acceptable safety profiles, including SGLT2 inhibitors, endothelin receptor blockers, targeted-release budesonide, B cell proliferation and differentiation inhibitors, as well as blockade of complement components.

IgA nephropathy in adults-treatment standard

Immunoglobulin A nephropathy (IgAN) is the most common primary form of glomerular disease worldwide and carries a high lifetime risk of kidney failure. The underlying pathogenesis of IgAN has been characterized to a sub-molecular level; immune complexes containing specific O-glycoforms of IgA1 are central. Kidney biopsy remains the gold-standard diagnostic test for IgAN and histological features (i.e. MEST-C score) have also been shown to independently predict outcome. Proteinuria and blood pressure are the main modifiable risk factors for disease progression. No IgAN-specific biomarker has yet been validated for diagnosis, prognosis or tracking response to therapy. There has been a recent resurgence of investigation into IgAN treatments. Optimized supportive care with lifestyle interventions and non-immunomodulatory drugs remains the backbone of IgAN management. The menu of available reno-protective medications is rapidly expanding beyond blockade of the renin-angiotensin-aldosterone system to include sodium-glucose cotransporter 2 and endothelin type A receptor antagonism. Systemic immunosuppression can further improve kidney outcomes, although recent randomized controlled trials have raised concerns regarding infectious and metabolic toxicity from systemic corticosteroids. Studies evaluating more refined approaches to immunomodulation in IgAN are ongoing: drugs targeting the mucosal immune compartment, B-cell promoting cytokines and the complement cascade are particularly promising. We review the current standards of treatment and discuss novel developments in pathophysiology, diagnosis, outcome prediction and management of IgAN.

Clinicopathological Features and Outcomes of IgA Nephropathy with Serum Antineutrophil Cytoplasmic Autoantibody Positivity

INTRODUCTION

IgA nephropathy (IgAN) with serum antineutrophil cytoplasmic autoantibody (ANCA) positivity is uncommon. This study analyzed the clinicopathologic features and prognosis of IgAN patients with serum ANCA positivity.

METHODS

2,864 IgAN patients were tested for ANCA by the indirect immunofluorescence assay and chemiluminescence immunoassay. Patients with serum ANCA positivity (n = 85) were identified, and their clinical, pathological, and prognostic characteristics were analyzed. They were compared with ANCA-negative IgAN patients (n = 170) and ANCA-associated systemic vasculitis (AAV) with renal involvement patients (n = 85) selected randomly.

RESULTS

2.97% (85/2,864) of IgAN were ANCA positive, and 4 patients were diagnosed as having crescentic IgAN with ANCA positivity. The clinicopathological characteristics of ANCA-positive IgAN patients were comparable to ANCA-negative IgAN patients, but they had higher antinuclear antibody (ANA)-positive rates, lower levels of renal interstitial inflammation, and fewer immune depositions than ANCA-negative IgAN patients. Compared with AAV patients, ANCA-positive IgAN patients were younger and had fewer extrarenal manifestations, milder renal damage, and more immune complex depositions. The renal outcomes were similar between IgAN patients with and without ANCA positivity. Multivariate Cox analysis revealed that in IgAN patients with ANCA positivity, male, ANA positivity, higher serum creatinine and proteinuria, and more severe renal tubular atrophy/interstitial fibrosis were risk factors for adverse renal outcomes.

CONCLUSION

The clinical, pathological features and prognosis of ANCA-positive IgAN patients were similar to those of ANCA-negative IgAN patients except for higher ANA-positive rate, milder renal inflammation, and fewer immune depositions. ANA positivity was an independent risk factor for adverse renal outcomes in ANCA-positive IgAN patients.

Immunosuppression versus Supportive Care on Kidney Outcomes in IgA Nephropathy in the Real-World Setting

BACKGROUND

The efficacy of immunosuppression in the management of immunoglobulin A (IgA) nephropathy remains highly controversial. The study was conducted to assess the effect of immunosuppression, compared with supportive care, in the real-world setting of IgA nephropathy.

METHODS

A cohort of 3946 patients with IgA nephropathy, including 1973 new users of immunosuppressive agents and 1973 propensity score-matched recipients of supportive care, in a nationwide register data from January 2019 to May 2022 in China was analyzed. The primary outcome was a composite of 40% eGFR decrease of the baseline, kidney failure, and all-cause mortality. A Cox proportional hazard model was used to estimate the effects of immunosuppression on the composite outcomes and its components in the propensity score-matched cohort.

RESULTS

Among 3946 individuals (mean [SD] age 36 [10] years, mean [SD] eGFR 85 [28] ml/min per 1.73 m 2 , and mean [SD] proteinuria 1.4 [1.7] g/24 hours), 396 primary composite outcome events were observed, of which 156 (8%) were in the immunosuppression group and 240 (12%) in the supportive care group. Compared with supportive care, immunosuppression treatment was associated with 40% lower risk of the primary outcome events (adjusted hazard ratio, 0.60; 95% confidence interval, 0.48 to 0.75). Comparable effect size was observed for glucocorticoid monotherapy and mycophenolate mofetil alone. In the prespecified subgroup analysis, the treatment effects of immunosuppression were consistent across ages, sexes, levels of proteinuria, and values of eGFR at baseline. Serious adverse events were more frequent in the immunosuppression group compared with the supportive care group.

CONCLUSIONS

Immunosuppressive therapy, compared with supportive care, was associated with a 40% lower risk of clinically important kidney outcomes in patients with IgA nephropathy.

Novel agents for treating IgA nephropathy

PURPOSE OF REVIEW

In the past, the treatment of IgA nephropathy (IgAN), which is the most common glomerulonephritis worldwide, mostly relied on blockade of the renin-angiotensin system as a central component of so-called supportive therapy as well as on high-dose systemic corticosteroid therapy.

RECENT FINDINGS

The supportive treatment arm has been expanded by the addition of sodium-glucose cotransporter-2 inhibitors, hydroxychloroquine, and, most recently, endothelin A receptor blockers. Treatment with high-dose systemic corticosteroids has become more controversial, with some studies observing no benefit and others documenting the protection of kidney function. However, all recent studies on systemic corticosteroids consistently found significant toxicity. An important novel approach to IgAN, therefore, is therapy with a targeted release formulation of budesonide with preferential release in the distal small intestine, given the mounting evidence for a gut-kidney axis in the pathophysiology of IgAN. In addition, emerging new therapeutic options include a variety of complement inhibitors as well as agents targeting B-cell proliferation and differentiation.

SUMMARY

In recent years, IgAN has become the focus of a considerable number of clinical studies that will significantly advance the development of new therapy strategies.

Knowledge Translation in Glomerulonephritis: Successes in Translational Research From the Bench to Bedside

Purpose of review

Glomerulonephritis refers to a rare group of diseases characterized by glomerular inflammation, which collectively are a common cause of kidney failure. Until recently, there was a lack of high-quality clinical trials to inform the care of patients with glomerulonephritides. We identified examples of successful translational research spanning from basic science to clinical applications, and highlight gaps in implementation science.

Sources of information

The focus of our review was derived from discussions between health care professionals, researchers, and patient partners. We also performed literature searches pertaining to the treatment of glomerulonephritis in PubMed and Google Scholar.

Methods

Examples of successful knowledge translation were generated through review of new evidence in the past 5 years and by iterative discussions by the authors. We then conducted a narrative review of several themes related to knowledge translation in glomerulonephritis. This was complemented by an interview with a patient partner to provide an example of a patient's perspective living with glomerulonephritis.

Key findings

We summarized selected recent advances in glomerulonephritis and its knowledge translation in the following domains: (1) identification of auto-antibodies in membranous nephropathy and minimal change disease; (2) clinical trials of novel targeted therapies for IgA nephropathy and lupus nephritis, which have led to approval of new treatments; (3) developments in research networks and clinical trials in glomerulonephritis; (4) recognition of the importance in developing standardized patient reported outcome measures in clinical trials; and (5) barriers in knowledge translation including access to medication.

Limitations

A systematic search of the literature and formal assessment of quality of evidence were beyond the scope of this review.

Comparative effectiveness and safety for the treatments despite optimized renin-angiotensin system blockade among IgA nephropathy patients at high-risk of disease progression: A network meta-analysis of randomized controlled trials

OBJECTIVE

Approximately 20-40% of IgA nephropathy patients would develop end-stage renal disease, for whom safety concerns remained a major setback when using conventional pharmaceutical treatments. Evidence is lacking for optimal selection of effective and safe pharmaceuticals to slow the disease progression. To compare the effectiveness and safety profile of different treatments despite optimized RAS blockade for IgA nephropathy patients at high-risk of disease progression.

STUDY DESIGN

PubMed, ScienceDirect and Web of science databases published from 1990 to March 18th, 2023 without language restriction. Immunosuppressant and cortico-steroid treatments were considered as two independent regimens.

RESULTS

Fifteen trials with 1,983 participants were evaluated for the occurrence of five outcomes. For ESRD, dapagliflozin was superior to placebo (RR: 0.30; 95% CI 0.11, 0.80), immunosuppressant (RR:0.14; 95% CI 0.02,0.81) and RAS (RR:0.10; 95% CI 0.01,0.69). Glucocorticoid was superior to placebo (RR: 0.71; 95%CI 0.52,0.99). For clinical remission, immunosuppressant was superior to placebo (RR: 2.71; 95%CI 1.16, 6.31) and RAS monotherapy (RR: 2.87; 95%CI 1.60, 5.17). For 50% reduction in 24 h proteinuria or UPCR, immunosuppressant was superior to placebo (RR: 2.71; 95%CI 1.16, 6.31) and RAS monotherapy (RR: 2.40; 95%CI 1.04, 5.55). For SAE, dapagliflozin was superior to glucocorticoid (RR: 0.22; 95%CI 0.09, 0.54), whereas glucocorticoid was inferior to placebo (RR: 2.91; 95%CI 1.39, 6.07). Cluster ranking showed dapagliflozin appeared to have the lowest SAE risk and the best comparative therapeutic efficacy in preventing ESRD.

CONCLUSIONS

The current findings highlighted dapagliflozin was a promising pharmaceutical treatment alternative to achieve optimal outcomes for IgA nephropathy patients at high risk of disease progression.

REGISTRATION

PROSPERO CRD42022374418.

IgA Nephropathy: Current Treatment and New Insights

IgA Nephropathy (IgAN) is the most common cause of primary glomerulonephritis worldwide. Despite the histopathologic hallmark of mesangial IgA deposition, IgAN is a heterogenous autoimmune disease not only in terms of clinical presentation but also in long-term disease progression. The pathogenesis of the disease is complex and includes the generation of circulating IgA immune complexes with chemical and biological characteristics that favor mesangial deposition and reaction to mesangial under-glycosylated IgA1 accumulation, which leads to tissue injury with glomerulosclerosis and interstitial fibrosis. Patients with proteinuria over 1 g, hypertension, and impaired renal function at diagnosis are considered to be at high risk for disease progression and end-stage kidney disease (ESKD). Glucocorticoids have been the mainstay of treatment for these patients for years, but without long-term benefit for renal function and accompanied by several adverse events. A better understanding of the pathophysiology of IgAN in recent years has led to the development of several new therapeutic agents. In this review, we summarize the current therapeutic approach for patients with IgAN as well as all novel investigational agents.

The Development of a Comprehensive Clinicopathologic Registry for Glomerular Diseases Using Natural Language Processing

Background

Glomerulonephritis (GN) represents a common cause of chronic kidney disease, and treatment to slow or prevent progression of GN is associated with significant morbidity. Large patient registries have improved the understanding of risk stratification, treatment selection, and definitions of treatment response in GN, but can be resource-intensive, with incomplete patient capture.

Objective

To describe the creation of a comprehensive clinicopathologic registry for all patients undergoing kidney biopsy in Manitoba, using natural language processing software for data extraction from pathology reports, as well as to describe cohort characteristics and outcomes.

Design

Retrospective population-based cohort study.

Setting

Tertiary care center in the province of Manitoba.

Patients

All patients undergoing a kidney biopsy in the province of Manitoba from 2002 to 2019.

Measurements

Descriptive statistics are presented for the most common glomerular diseases, along with outcomes of kidney failure and mortality for the individual diseases.

Methods

Data from native kidney biopsy reports from January 2002 to December 2019 were extracted into a structured database using a natural language processing algorithm employing regular expressions. The pathology database was then linked with population-level clinical, laboratory, and medication data, creating a comprehensive clinicopathologic registry. Kaplan-Meier curves and Cox models were constructed to assess the relationship between type of GN and outcomes of kidney failure and mortality.

Results

Of 2421 available biopsies, 2103 individuals were linked to administrative data, of which 1292 had a common glomerular disease. The incidence of yearly biopsies increased almost 3-fold over the study period. Among common glomerular diseases, immunoglobulin A (IgA) nephropathy was the most common (28.6%), whereas infection-related GN had the highest proportions of kidney failure (70.3%) and all-cause mortality (42.3%). Predictors of kidney failure included urine albumin-to-creatinine ratio at the time of biopsy (adjusted hazard ratio [HR] = 1.43, 95% confidence interval [CI] = 1.24-1.65), whereas predictors of mortality included age at the time of biopsy (adjusted HR = 1.05, 95% CI = 1.04-1.06) and infection-related GN (adjusted HR = 1.85, 95% CI = 1.14-2.99, compared with the reference category of IgA nephropathy).

Limitations

Retrospective, single-center study with a relatively small number of biopsies.

Conclusions

Creation of a comprehensive glomerular diseases registry is feasible and can be facilitated through the use of novel data extraction methods. This registry will facilitate further epidemiological research in GN.

IgA nephropathy: a review of existing and emerging therapies

IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide. Recently, there have been multiple advances in the understanding of IgAN pathophysiology and therapeutic options. Despite the advent of new treatment options, individual risk stratification of the disease course and choosing the best treatment strategy for the patient remains challenging. A multitude of clinical trials is ongoing, opening multiple opportunities for enrollment. In this brief review we discuss the current approach to the management of IgAN and highlight the ongoing clinical trials.