A Systematic Literature Review of the Epidemiology, Health-Related Quality of Life Impact, and Economic Burden of Immunoglobulin A Nephropathy

HDAC9-mediated deacetylation of CALML6 promotes excessive proliferation of glomerular mesangial cells in IgA nephropathy

PURPOSE

This study seeks to investigate the fundamental molecular processes through which histone deacetylase 9 (HDAC9) governs the proliferation of glomerular mesangial cells in the context of immunoglobulin A nephropathy (IgAN) and to identify novel targets for clinical research on IgAN.

METHODS

Data from high-throughput RNA sequencing for IgAN were procured from the Gene Expression Omnibus database to assess the expression profiles and clinical diagnostic significance of histone deacetylase family proteins (HDACs). Blood samples from 20 IgAN patients were employed in RT-qPCR analysis, and the spearman linear regression method was utilized to analyze the clinical correlation. The proliferation of glomerular mesangial cells (GMCs) under the influence of HDAC9 was examined using the 5-ethynyl-2'-deoxyuridine (EdU) assay. Proteins interacting with HDAC9 were predicted utilizing the STRING database. Immunoprecipitation and protein immunoblotting employing anti-acetylated lysine antibodies were conducted to determine the acetylation status of calmodulin-like protein 6 (CALML6).

RESULTS

Analysis of the GSE141295 dataset revealed a significant upregulation of HDAC9 expression in IgAN and the results of RT-qPCR demonstrated a substantial increase in HDAC9 expression in IgAN patients. Receiver operating characteristic (ROC) analysis indicated that the area under the curve (AUC) value for HDAC9 were 0.845 and Spearman correlation analysis showed that HDAC9 expression was positively correlated with blood levels of blood urea nitrogen (BUN) and serum creatinine (Crea). The EdU cell proliferation assay indicated that HDAC9 facilitated the excessive proliferation of GMCs. The STRING database and recovery experiments identified CALML6 as a downstream effector of HDAC9 in controlling abnormal GMC multiplication. Co-immunoprecipitation assays demonstrated that HDAC9 modulates CALML6 expression through acetylation modification.

CONCLUSION

HDAC9 is markedly upregulated in IgAN, and it mediates the excessive proliferation of GMCs by regulating the deacetylation of CALML6.

Long-Term Results from an Open-Label Extension Study of Atacicept for the Treatment of IgA Nephropathy

Key Points

Participants who completed a 36-week double-blind study of atacicept were eligible for a 60-week, open-label extension study. Atacicept 96-week treatment resulted in sustained reductions in galactose-deficient IgA1, hematuria, and urine protein-creatinine ratio. The slope of the eGFR was similar to that observed in the general population without kidney disease.

Background

B-cell activating factor (BAFF) and A proliferation-inducing ligand (APRIL) play key roles in the pathogenesis of IgA nephropathy. Atacicept is a novel fully humanized fusion protein, self-administered at home by subcutaneous injection, that binds and inhibits BAFF and APRIL. By inhibiting BAFF and APRIL, atacicept targets the underlying B-cell–mediated pathogenesis driving disease progression. This study evaluated the long-term efficacy and safety of atacicept in patients with IgA nephropathy over 96 weeks.

Methods

Participants with IgA nephropathy who received atacicept (25, 75, or 150 mg) or placebo in a 36-week phase 2b, randomized, blinded trial were enrolled in an open-label extension study and received atacicept 150 mg for an additional 60 weeks. Key efficacy outcomes were changes in galactose-deficient IgA1 (Gd-IgA1), percentage of participants with hematuria, urine protein-creatinine ratio (UPCR), and eGFR over 96 weeks. Long-term safety data were also evaluated.

Results

There were 113 participants (67 [59%] male; 46 [41%] female) who ranged in age from 18 to 67 years who received ≥1 atacicept dose. Over 96 weeks, safety data demonstrated that atacicept was generally well tolerated. There were also sustained reductions (mean±SEM) in Gd-IgA1 (−66%±2%), percentage of participants with hematuria (−75%; 95% confidence intervals, −87 to −59; in participants with baseline hematuria), and UPCR (−52%±5%). The mean annualized slope of eGFR was −0.6±0.5 ml/min per 1.73 m2 through 96 weeks.

Conclusions

Atacicept was well tolerated over the duration of the study. Atacicept treatment reduced Gd-IgA1, hematuria, and UPCR with stabilization of eGFR through 96 weeks.

Clinical Trial registry name and registration number:

Atacicept in Subjects with IgA Nephropathy (ORIGIN 2), NCT04716231 .

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The humanistic burden of immunoglobulin A nephropathy on patients and care-partners in the United States

PURPOSE

This cross-sectional survey study quantified the humanistic burden of immunoglobulin A nephropathy (IgAN), in terms of physical and mental health-related quality of life (HRQoL) and work productivity, among adults with primary IgAN and their care-partners.

METHODS

HRQoL was assessed (01/31/22 - 05/31/23) with validated tools including the KDQoL-36 (with SF-12), GAD-7 (anxiety), PHQ-9 (depression), and WPAI: SHP (work productivity). Participant characteristics and total/domain scores were summarized; selected outcomes were compared to an external, kidney disease-free cohort.

RESULTS

117 adults with IgAN and their care-partner pairs, and one adult without a care-partner, were included. The mean ages of patients and care-partners were 38.0 (SD: 8.6) and 40.2 (11.8) years, respectively; 55.9% and 43.6% were female. Mean physical and mental SF-12 scores for patients were 46.7 (SD: 8.0) and 41.9 (9.2), respectively, and 50.7 (7.3) and 43.7 (10.24) for care-partners. Both SF-12 components for patients, and the mental component for care-givers, were significantly worse compared to the US general population. Among patients, 27.1% had moderate/severe anxiety and 49.2% reported at least moderate depression. Compared to external controls, patients experienced significantly higher severity of anxiety (6.6 vs. 5.4) and depression (8.1 vs. 6.6; both p < 0.0001). Among care-partners, 13.7% experienced moderate anxiety and 37.8% experienced moderate/moderately-severe depression. Among employed individuals, both groups reported IgAN-related absenteeism (8.8-9.4%), presenteeism (25.1-25.9%), and overall work impairment (30.4-30.5%).

CONCLUSION

US adults with IgAN and their care partners experience impairments to mental and physical HRQoL and heightened levels of depression and anxiety, underscoring the need for effective IgAN therapies and care-partner support.

Healthcare of patients with immunoglobulin A nephropathy through a retrospective observational study of Italian administrative data

Background

Immunoglobulin A nephropathy (IgAN) is a rare disease poorly described in real-world settings. This observational retrospective study aimed to assess the direct healthcare burden of new IgAN patients on the Italian National Healthcare Service (SSN).

Methods

From the Fondazione Ricerca e Salute's database (administrative healthcare data of ~5.5 million inhabitants/year), inpatients with new potential in-hospital biopsy-verified IgAN from 2016 to 2019 were identified. Dispensations of IgAN-recommended and other drugs, kidney replacement therapies (KRT), hospital and emergency department (ED) admissions, local outpatient specialist care, and related direct costs were assessed throughout a 3-year follow-up.

Results

New IgAN patients (n = 292) were identified (incidence/year: 1.25/100 000 inhabitants); 64% of patients were male; the median age was 41 (27; 57) years. Annual consumption of most healthcare resources decreased from Year 1 to 3: from 90% to 84% of patients received ≥1 IgAN-recommended drug; from 100% (due to selection criteria) to 15% of patients underwent overnight hospitalizations; from 8% to 3% patients underwent day hospitalizations; from 31% to 21% patients underwent ≥1 ED access; from 87% to 85% patients received local outpatient specialist services. Of all patients, 2-4% were treated with KRT, and ~91% received other drugs. The per capita mean total annual cost was €7441 in Year 1 (hospitalizations accounting for 73% due to selection criteria), €3497 in Year 2, and €3243 in Year 3 (drugs accounting for 51%, mostly attributable to other drugs).

Conclusion

This real-world study shows a substantial direct healthcare burden for new IgAN patients arising from IgAN-specific care and comorbidities.

Clinical and Humanistic Burden of IgA Nephropathy in Adult Patients: A Global Real-World Survey

Key Points

IgA nephropathy (IgAN) exerts a significant humanistic burden on patients. Quality of life is impaired in patients with IgAN. Progression of disease in IgAN, especially proteinuria and GFR loss, are associated with the burden of disease.

Background

IgA nephropathy (IgAN) is a chronic, progressive kidney disease in which proteinuria, reduced eGFR, pain, and fatigue are common. How symptoms interact and affect patient quality of life (QoL) in real-world practice is poorly studied. This study investigated how patient and physician symptom perceptions differ and how proteinuria and eGFR correlate with pain, fatigue, and QoL in adult patients with IgAN.

Methods

Data were drawn from the Adelphi IgAN Disease Specific Program, a cross-sectional survey of physicians and their biopsy confirmed patients with IgAN in China, France, Germany, Italy, Spain, the United Kingdom, the United States, and Japan from June to October 2021. Physicians provided demographics and clinical characteristics, including pain and fatigue severity. The same patients completed a self-completion form containing questions on symptom severity, the EQ-5D-5L, Kidney Disease QoL, and Work Productivity and Activity Impairment questionnaires. Symptom scores were grouped by severity, and patients were grouped by proteinuria and eGFR. Analysis of variance, chi-squared, or Fisher exact tests were performed as appropriate and Dunn multiple comparisons with Bonferroni adjustment for pair-wise comparisons.

Results

Overall, 1515 patients were included (mean [SD] age: 43 [15] years, 60% [n =903] male, 70% [n =1020/1459] diagnosed >1 year ago). Pain was reported by 46% (n =374) of physicians and 47% (n =384) of patients and fatigue by 65% (n =530) of physicians and 76% (n =620) of patients. Both pain and fatigue increased with increased proteinuria and reduced eGFR (all P < 0.001). Finally, patients with increased proteinuria and reduced eGFR experienced worse (P < 0.05) QoL and work productivity across all measures (except work absenteeism).

Conclusions

Patients with higher proteinuria and lower eGFR face higher symptom burden and reduced QoL compared to their counterparts. Physicians underestimated fatigue levels faced by patients. To improve QoL, more effective treatments are needed to prevent high proteinuria and preserve eGFR.

Estimation of Health State Utility Values for Immunoglobulin A Nephropathy: A Time Trade-Off Analysis

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is a rare progressive disease that can lead to kidney failure. The current study aimed to estimate health state utility values for IgAN from a UK societal perspective.

METHODS

We used the time trade-off (TTO) method to derive utility values for various health states in IgAN, defined based on chronic kidney disease (CKD) stage, proteinuria, dialysis, and nephrotic syndrome (CKD stages 1-4, proteinuria < 1 g/day vs ≥ 1 g/day; CKD stage 5, dialysis vs non-dialysis). We developed health state vignettes to describe typical symptoms and quality-of-life impairments of IgAN. Eligible participants from the UK general public completed a computer-assisted telephone interview. Estimated TTO utility values were reviewed against visual analogue scale (VAS)-derived values.

RESULTS

In total, 200 participants were included in the study (mean age, 48.9 years; female, 59.0%). Mean (standard deviation [SD]) utility values were 0.84 (0.17) and 0.71 (0.23) for CKD stage 1/2 with proteinuria < 1 g/day and with proteinuria ≥ 1 g/day, respectively; 0.68 (0.23) and 0.61 (0.25) for CKD stage 3; and 0.55 (0.26) and 0.49 (0.27) for CKD stage 4. Mean (SD) utility of CKD stage 5 with and without dialysis was 0.38 (0.30) and 0.42 (0.28), respectively. The mean (SD) utility value of nephrotic syndrome was 0.43 (0.33).

CONCLUSIONS

Our results indicated that various IgAN health states are associated with impaired health status, with substantial utility decrements related to disease progression, elevated proteinuria, and nephrotic syndrome.

Long-term renal survival in patients with IgA nephropathy: a systematic review

The management strategy for IgA nephropathy (IgAN), has undergone constant improvements since the disease entity was first described 50 years ago. However, it is still unknown how these changes affected the long-term renal survival of IgAN patients. We systematically evaluate changes in IgAN renal survival by searching PubMed, Embase, and the Cochrane Library Database of Systematic Reviews from inception to 19 May 2024. We included a large sample of 103076 IgAN cases from 158 studies. Renal survival rates were 94.16% (95% CI: 94.02% to 94.31%), 88.68% (95% CI: 88.48% to 88.87%), and 78.13% (95% CI: 77.82% to 78.43%) at three, five, and ten-year, respectively. Over the past few decades, there haven't been any sound changes in the 3-year and 5-year renal survival rates. The kidney survival rate in developed countries is higher than in developing countries. Researchers consistently show that while proteinuria < 1.0 g/24 h, renal survival rates increase dramatically. In IgAN, long-term renal survival fluctuated rather than continuously improving over time. Our system review's findings indicate that supportive care-the most important recommendation for managing IgAN has shown promising results. The long-term outcomes of IgAN could be significantly improved by the latest developed treatment options.

The Relationship between Vascular Biomarkers (Serum Endocan and Endothelin-1), NT-proBNP, and Renal Function in Chronic Kidney Disease, IgA Nephropathy: A Cross-Sectional Study

IgA nephropathy (IgAN) is the most common primary glomerular disease. Endothelin-1 (ET-1) is one of the strongest vasoconstrictor materials in the blood. The N-terminal prohormone of brain natriuretic peptide (NT-proBNP) is associated with renal function and poor outcomes in chronic kidney disease (CKD). Serum endocan is a biomarker associated with proinflammatory cytokines, and the increase in the serum level plays a critical role in inflammatory, proliferative, and neovascularization processes and is associated with poor cardiovascular outcomes in patients with CKD too. Identifying high-risk patients using biomarkers could help to optimize their treatment. Ninety patients with biopsy-confirmed IgAN were included in the study (50 males/40 females, mean age: 54.9 ± 14.4 years). Serum endocan, ET-1, and NT-proBNP were measured by enzyme-linked immunosorbent assay kits. Echocardiography was performed, and carotid-femoral pulse wave velocity (cfPWV) was measured by SphygmoCor in this cross-sectional study. Patients were divided into two groups based on serum endocan median level (cut-off: 44 ug/L). There was significantly higher aorta systolic blood pressure (SBPao) (p = 0.013), NT-proBNP (p = 0.028), albumin/creatinine ratio (p = 0.036), and uric acid (p = 0.045) in the case of the higher endocan group compared to the lower. There was also significantly higher SBPao (p = 0.037) and NT-proBNP (p = 0.038) in the case of higher endothelin-1 (ET-1) levels compared to the lower (cut-off: 231 pg/mL) group by the two-sample t-test. Then, we divided the patients into two groups based on the eGFR (CKD 1-2 vs. CKD 3-5). The levels of serum endocan, NT-proBNP, cfPWV, SBPao, left ventricular mass index (LVMI), uric acid, and albuminuria were significantly higher in the CKD 3-5 group compared to the CKD 1-2 group. The serum endocan and NT-proBNP levels were significantly higher in the diastolic dysfunction group (p = 0.047, p = 0.015). There was a significant increase in serum endocan levels (CKD 1 vs. CKD 5; p = 0.008) with decreasing renal function. In IgAN, vascular biomarkers (endocan, ET-1) may play a role in endothelial dysfunction through vascular damage and elevation of SBPao. Serum endocan, ET-1, and NT-proBNP biomarkers may help to identify IgAN patients at high risk.

IgA Nephropathy: Epidemiology and Disease Risk Across the World

Despite decades of research, our knowledge of the global epidemiology of IgA nephropathy remains limited. Much of what we know about IgA nephropathy incidence comes from biopsy registry studies that are subject to bias related to differences in screening programs, referral patterns, and access to healthcare. Fewer epidemiologic studies used an appropriate data infrastructure that includes a well-defined source population. Nonetheless, all these studies show considerable geographic variation in disease incidence with an increase from west to east and south to north across Eurasia. This pattern is partly explained by the distribution of genetic risk alleles in individuals of European and East Asian ancestry. Although historically thought to be an indolent disease, recent long-term follow-up studies have demonstrated an exceptionally high lifetime risk of kidney failure. The International IgA Nephropathy Prediction Tool, derived and validated in multiple ethnically diverse cohorts, has improved our ability to identify patients at high risk of progression who may benefit from therapies being tested in clinical trials. The earlier identification of high-risk patients, evaluation of novel risk factors, and accurate assessment of global disease burden require high-quality regional data infrastructures and broad collaborative efforts to ensure the impact of new treatments is maximized.

Therapy of IgA nephropathy: time for a paradigm change

Immunoglobulin A nephropathy (IgAN) often has a poor outcome, with many patients reaching kidney failure within their lifetime. Therefore, the primary goal for the treatment of IgAN should be to reduce nephron loss from the moment of diagnosis. To achieve this, IgAN must be recognized and treated as both a chronic kidney disease and an immunological disease. Agents that have received US Food and Drug Administration and European Medicines Agency approval for the treatment of IgAN include modified-release/targeted-release formulation budesonide (Nefecon) and sparsentan, a selective dual endothelin-A and angiotensin II receptor type 1 antagonist. Other agents, including selective endothelin receptor antagonists, selective or combined APRIL and BAFF antagonists, and a vast array of complement inhibitors are being investigated for the treatment of IgAN. Furthermore, treatment combinations are also being studied, including sodium-glucose cotransporter-2 inhibitors with endothelin receptor antagonists. Due to the complexity of IgAN, combination treatment, rather than a single-agent approach, may provide maximum benefit. With the number of treatments for IgAN likely to increase, combinations allowing safe and effective treatment to halt progression to kidney failure seem within grasp. While trials evaluating combinations are ongoing, more are needed to pave the way for a comprehensive IgAN treatment strategy. Furthermore, an approach to IgAN treatment in which agents are combined early to achieve rapid induction of remission and prevent unnecessary and irreversible nephron loss is required. Following remission, treatments may be adjusted and stripped back as necessary in the maintenance phase with close monitoring. This review discusses the current status of IgAN treatment and explores future strategies to improve outcomes for patients with IgAN.

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.

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.

Development of a Conceptual Model for the Patient Experience of Immunoglobulin A Nephropathy (IgAN): A Qualitative Literature Review

INTRODUCTION

Immunoglobulin A nephropathy (IgAN) is a kidney disorder that can lead to progressive kidney disease. Currently, there lacks a comprehensive overview of the symptoms and impacts experienced by those living with IgAN that would help inform the selection or development of fit-for-purpose clinical outcome assessments (COA) to be used in clinical trials. The aim of this study was to develop a conceptual model of the adult and pediatric patient experience of IgAN, including disease signs and symptoms, treatment side effects, and impact on functioning and well-being.

METHODS

This study comprised a systematic review and thematic analysis of qualitative studies with adults and children diagnosed with IgAN. Data sources were identified through an electronic database search of journal articles (MEDLINE, Embase, PsycINFO; June 2021), hand-searching of conference proceedings, patient advocacy group websites, and gray literature. Non-English articles were excluded. Identified data (patient/caregiver quotes, author summaries, and interpretations of patient experiences) were extracted from articles. Extracted data were qualitatively analyzed, aided by ATLAS.ti v7. Codes were applied to data; concepts (i.e., symptoms) were identified, named, and refined. A conceptual model was developed by grouping related concepts into domains.

RESULTS

In total, five sources were identified for analysis: two journal articles, two online anthologies of patient stories, and one patient organization-sponsored "Voice of the Patient" meeting report. Conceptual model symptom domains included swelling/puffiness (edema), pain/aches/discomfort, fatigue, weight gain, sleep problems, urinary problems, and gastrointestinal problems. Impact domains included emotional/psychological well-being, physical functioning/activities of daily living, social functioning, work/school, and relationships.

CONCLUSIONS

Secondary analysis of published qualitative literature permitted development of a novel conceptual model depicting the patient experience of IgAN; however, its depth is limited by a lack of available literature. Further qualitative research is recommended to refine and/or confirm the concepts and domains, determine any relationships between them, and explore the outcomes that are most meaningful to patients. The refined model will provide a useful tool to inform the selection, development, and/or amendment of COAs for use in future IgAN clinical trials.

Kidney Failure Attributed to Focal Segmental Glomerulosclerosis: A USRDS Retrospective Cohort Study of Epidemiology, Treatment Modalities, and Economic Burden

Rationale & Objective

This study describes the epidemiology, characteristics, and clinical outcomes of patients with focal segmental glomerulosclerosis (FSGS)-attributed kidney failure in the US Renal Data System (USRDS) during 2008-2018, and health care resource utilization and costs among those with Medicare-linked data.

Study Design

This was a retrospective cohort study.

Setting & Population

Patients with FSGS-attributed kidney failure in the USRDS were enrolled in the study.

Outcomes

The outcomes were as follows: Prevalence and incidence, clinical and demographic characteristics, time to kidney transplant or death, health care resource utilization, and direct health care costs.

Analytical Approach

Patients with FSGS as the primary cause of kidney failure were followed from USRDS registration (index date) until death or data end. Prevalence and incidence were calculated per 1,000,000 US persons. Patient characteristics at index and treatment modalities during follow-up were described. Time to kidney transplant or death was assessed with Kaplan-Meier and competing risk analyses. Health care resource utilization and costs were reported among patients with 1 year Medicare Part A+B coverage postindex, including (Medicare Coverage subgroup) or excluding (1-year Medicare Coverage subgroup) those who died.

Results

The FSGS cohort and Medicare Coverage and 1-year Medicare Coverage subgroups included 25,699, 6,340, and 5,575 patients, respectively. Mean annual period prevalence and incidence rates of FSGS-attributed kidney failure were 87.6 and 7.5 per 1,000,000 US persons, respectively. Initial treatment for most patients was in-center hemodialysis (72.1%), whereas 7.3% received kidney transplant. Accounting for competing risk of death, year 1 and 5 kidney transplant rates were 15% and 34%, respectively. In the Medicare Coverage and 1-year Medicare Coverage subgroups, 76.6% and 74.2% required inpatient admission, 69.9% and 67.3% visited the emergency room, and mean monthly health care costs were $6,752 and $5,575 in the year postindex, respectively.

Limitations

Drug costs may be underestimated because Medicare Part D coverage was not required; kidney acquisition costs were not available.

Conclusions

FSGS-attributed kidney failure is associated with substantial clinical and economic burden, prompting the need for novel therapies for FSGS to delay kidney failure.

Kidney Failure Attributed to Immunoglobulin A Nephropathy: A USRDS Retrospective Cohort Study of Epidemiology, Treatment Modalities, and Economic Burden

Rationale & Objective

This study describes the epidemiology, characteristics, and outcomes of patients with immunoglobulin A nephropathy (IgAN)-attributed kidney failure in the US Renal Data System (USRDS) from 2008 to 2018, including health care resource utilization and costs among patients with Medicare-linked data.

Study Design

Retrospective cohort study.

Setting & Population

Patients with IgAN-attributed kidney failure in the USRDS.

Outcomes

Prevalence/incidence, clinical/demographic characteristics, time to kidney transplant, and health care resource utilization and costs.

Analytical Approach

Patients with IgAN as primary cause of kidney failure (IgAN cohort) were followed from USRDS registration (index date) until data end/death. Prevalence/incidence were calculated per 1,000,000 US persons. Demographic and clinical characteristics at index and treatment modality during follow-up were summarized. Time from index to kidney transplant was assessed using Kaplan-Meier and competing risk analyses. Health care resource utilization and health care costs were reported among patients with 1 year Medicare Part A+B coverage postindex, including or excluding those who died (Medicare Coverage and 1-year Medicare Coverage subgroups, respectively).

Results

The IgAN cohort, Medicare Coverage, and 1-year Medicare Coverage subgroups included 10,101, 1,696, and 1,510 patients, respectively. Mean annual period prevalence and incidence of IgAN-attributed kidney failure were 39.3 and 2.9 per 1,000,000 US persons, respectively. Initial treatment was in-center hemodialysis (63.1%) or kidney transplant (15.1%). Year 1 and 5 kidney transplant rates were 5% and 17%, respectively, accounting for competing risk of death. In the Medicare Coverage and 1-year Medicare Coverage subgroups, 74.4% and 72.3%, respectively, required inpatient admission, 67.3% and 64.4%, respectively, visited the emergency room, and mean total health care costs were $6,293 (SD: $6,934) and $5,284 ($3,455), respectively, per-patient-per-month in the year postindex.

Limitations

Drug costs may be underestimated as Medicare Part D coverage was not required; kidney acquisition costs were unavailable.

Conclusions

IgAN-attributed kidney failure is associated with substantial clinical and economic burdens. Novel therapies for IgAN that delay kidney failure are needed.

Practical Considerations for the Use of Sparsentan in the Treatment of Patients with IgAN in Clinical Practice

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. It is characterized by the mesangial deposition of IgA-containing immune complexes, triggering damage to the glomerular filtration barrier that is amplified by the tandem action of endothelin-1 and angiotensin II at their receptors. Proteinuria and progressive glomerular damage cause loss of kidney function in up to 50% of patients within 10-20 years. The risk of progression is strongly associated with persistent proteinuria (>0.75-1 g/day). Current standard of care involves interventions to decrease proteinuria and control blood pressure. Immunosuppressive agents, used in selected patients at high risk for progression, can be associated with significant side effects. Sparsentan, a novel non-immunosuppressive single-molecule Dual Endothelin Angiotensin Receptor Antagonist (DEARA), received FDA accelerated approval based on interim results from the PROTECT trial, which demonstrated that sparsentan-treated patients achieved a significantly greater reduction in proteinuria from baseline versus the active control irbesartan and that sparsentan was generally safe and well tolerated. Sparsentan is the first non-immunosuppressive treatment to be FDA-approved for the reduction of proteinuria in adults with IgAN at high risk of disease progression. We provide practical guidance for the clinical use of sparsentan in adults with IgAN.

A PRoliferation-Inducing Ligand (APRIL) in the Pathogenesis of Immunoglobulin A Nephropathy: A Review of the Evidence

A PRoliferation-Inducing Ligand (APRIL), the thirteenth member of the tumor necrosis factor superfamily, plays a key role in the regulation of activated B cells, the survival of long-lived plasma cells, and immunoglobulin (Ig) isotype class switching. Several lines of evidence have implicated APRIL in the pathogenesis of IgA nephropathy (IgAN). Globally, IgAN is the most common primary glomerulonephritis, and it can progress to end-stage kidney disease; yet, disease-modifying treatments for this condition have historically been lacking. The preliminary data in ongoing clinical trials indicate that APRIL inhibition can reduce proteinuria and slow the rate of kidney disease progression by acting at an upstream level in IgAN pathogenesis. In this review, we examine what is known about the physiologic roles of APRIL and evaluate the experimental and epidemiological evidence describing how these normal biologic processes are thought to be subverted in IgAN. The weight of the preclinical, clinical, and genetic data supporting a key role for APRIL in IgAN has galvanized pharmacologic research, and several anti-APRIL drug candidates have now entered clinical development for IgAN. Herein, we present an overview of the clinical results to date. Finally, we explore where more research and evidence are needed to transform potential therapies into clinical benefits for patients with IgAN.

Exploring the pathogenesis and treatment of IgA nephropathy based on epigenetics

IgA nephropathy is the most common primary glomerulonephritis worldwide. However, its exact cause remains unclear, with known genetic factors explaining only 11% of the variation. Recently, researchers have turned their attention to epigenetic abnormalities in immune-related diseases, recognizing their significance in IgA nephropathy's development and progression. This emerging field has revolutionized our understanding of epigenetics in IgA nephropathy research. Though in its early stages, studying IgA nephropathy's epigenetics holds promise for unraveling its pathogenesis and identifying new biomarkers and therapies. This review aims to comprehensively analyze epigenetics' role in IgA nephropathy's development and suggest avenues for potential therapeutic interventions. In the future, assessing and modulating epigenetics may become integral in diagnosing, tailoring treatments and assessing prognoses for IgA nephropathy.

Clinicopathological Characteristics of Adult IgA Nephropathy in the United States

Introduction

IgA nephropathy (IgAN) is a progressive autoimmune kidney disease and a leading cause of glomerular disease that can result in kidney failure (KF). The median age at diagnosis is 35 to 37 years and approximately 50% of patients will progress to KF within 20 years. We aimed to enhance the understanding of renal histology and chronic kidney disease (CKD) stage at the time of IgAN diagnosis using a large real-world biopsy cohort.

Methods

This retrospective cohort study evaluated biopsy data and clinical characteristics from adult patients within the US who were diagnosed with IgAN between January 1, 2016 to May 31, 2020. Descriptive statistics were summarized and relationship(s) between each Oxford Classification (MEST-C) component score with 24-hour proteinuria or CKD stage were examined using regression analysis.

Results

A total of 4375 patients (mean age 47.7 years, 62.7% male) met eligibility criteria. Mild to moderate mesangial hypercellularity (47.3%), segmental sclerosis (65.0%), tubular atrophy ≥25% (57.4%), and crescents (18.5%) were identified; and 74.6% of patients were at CKD stage ≥3. Proteinuria ≥1 g/d was associated with higher MEST-C scores, and the odds of mesangial hypercellularity, segmental sclerosis, tubular atrophy, and crescents increased with CKD stage.

Conclusion

Most patients with IgAN in our US cohort were diagnosed at CKD stage ≥3 and had high MEST-C scores and proteinuria that are suggestive of significant disease burden at the time of kidney biopsy. Strategies are required to raise awareness and promote earlier detection of asymptomatic urinary abnormalities before extensive irreversible kidney damage has occurred.

Humanistic and Economic Burden of IgA Nephropathy: Systematic Literature Reviews and Narrative Synthesis

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is a progressive inflammatory kidney disease requiring long-term treatment to reduce the risk of progression to kidney failure. Here, we present two systematic literature reviews (SLRs) to identify and summarize literature reporting the humanistic and economic burden of IgAN.

METHODS

Electronic literature databases (Ovid Embase, PubMed, and Cochrane) were searched for relevant literature on 29 November 2021, supplemented with gray literature searches. Studies reporting any health-related quality of life (HRQoL) or health state utility outcomes in IgAN patients were included in the humanistic impact SLR, and studies reporting the costs and healthcare resource utilization associated with or economic models of IgAN disease management were included in the economic burden SLR. Narrative synthesis was used to discuss the heterogeneous studies included in the SLRs. Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and Cochrane guidelines were followed, and all included studies were assessed for risk of bias using the Center for Evidence-Based Management tool for Critical Appraisal of a Survey or the Drummond Checklist.

RESULTS

A total of 876 and 1122 references were identified from electronic and gray literature searches for humanistic and economic burden, respectively. Three studies reporting humanistic impact and five studies reporting economic burden met criteria for inclusion in these SLRs. The included humanistic studies reported patient preferences in the USA and China, HRQoL for patients with IgAN in Poland, and impact of exercise on HRQoL for patients with IgAN in China. The five economic studies reported costs of IgAN treatment in Canada, Italy, and China, along with two economic models from Japan.

DISCUSSION

Current literature suggests IgAN is associated with substantial humanistic and economic burdens. However, these SLRs demonstrate the paucity of research conducted to specifically describe the humanistic or economic burden of IgAN and highlight the need for further research.

Impact of Proteinuria and Kidney Function Decline on Health Care Costs and Resource Utilization in Adults With IgA Nephropathy in the United States: A Retrospective Analysis

Rationale & Objective

Among patients with IgA nephropathy (IgAN), proteinuria and decline in kidney function may be associated with increased economic burden. This study aimed to provide current information on the epidemiology and economic burden of IgAN in the United States.

Study Design

Retrospective cohort study.

Setting & Study Population

Overall, 9,984 patients in the Optum's Market Clarity database identified by the presence of at least 2 natural language processing-derived IgAN signs and disease and symptoms terms; 813 with linked claims data included in a health care resource utilization/cost subcohort.

Predictor

High-risk proteinuria (≥1 g/d), chronic kidney disease (CKD) stage.

Outcomes

Standardized prevalence, health care resource utilization, costs.

Analytical Approach

Descriptive statistics for categorical and continuous variables. Direct standardization for prevalence estimation. Generalized linear models for health care resource utilization/costs, reported as per-patient-per-month (PPPM) costs in 2020 US dollars.

Results

The estimated standardized US prevalence of IgAN (2016-2020) was 329.0 per 1,000,000 persons. High-risk proteinuria (≥1 vs <1 g/d) was associated with a higher mean PPPM number of outpatient visits (3.49 vs 1.74; P = 0.01) and pharmacy claims (3.79 vs 2.41; P = 0.01), contributing to higher mean total costs PPPM ($3,732 vs $1,457; P = 0.01). Furthermore, higher CKD stage was also associated with higher health care resource utilization (number of outpatient visits PPPM, number of pharmacy claims PPPM, proportion of patients with inpatient visits and emergency department visits; P < 0.001) and mean total cost PPPM (from $2,111 CKD stage 1 to $10,703 CKD stage 5/kidney failure; P < 0.001).

Limitations

Generalizability outside of the catchment group for the database, missing data/errors inherent in retrospective database studies, relatively small sample size, use of Optum Market Clarity standardized pricing algorithms, exclusion of out-of-pocket costs.

Conclusions

Health care resource utilization and costs were higher for IgAN patients with high-risk proteinuria and worsening kidney function. Treatments that reduce proteinuria and slow CKD disease progression may reduce the economic burden associated with IgAN.

Plain-Language Summary

Immunoglobulin A nephropathy (IgAN) is a rare kidney disease. Over time, the kidneys may leak protein into the urine (proteinuria). IgAN can lead to kidney failure. Because IgAN is rare, it is hard to know how many people have it. This study used electronic health records to estimate the number of patients with IgAN in the United States, describe the characteristics of patients, and understand their treatments and the costs. The number of patients with IgAN increased between 2016 and 2020. The researchers think this is because doctors learned more about IgAN. Patients with severe disease used more health care resources and had higher costs. The authors believe treatments that slow kidney damage may reduce the cost of treating IgAN.

Secondary immunoglobulin A nephropathy with gross hematuria leading to rapidly progressive glomerulonephritis following severe acute respiratory syndrome coronavirus 2 vaccination: a case report

BACKGROUND

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been followed by many reports of the development and relapse of autoimmune diseases associated with SARS-CoV-2 vaccination. Some of these reports have involved relapse or onset of immunoglobulin A (IgA) nephropathy following SARS-CoV-2 vaccination. Here, we report on a patient with IgA nephropathy who presented with gross hematuria and rapidly progressive glomerulonephritis following SARS-CoV-2 vaccination.

CASE PRESENTATION

A 63-year-old male patient with a history of habitual tonsillitis underwent bilateral tonsillectomy. He had a history of alcoholic cirrhosis of the liver and microscopic hematuria and proteinuria were indicated during a health checkup 2 years before hospital admission. He developed hematuria after the SARS-CoV-2 vaccination, which led to rapidly progressive glomerulonephritis, for which he was hospitalized. A renal biopsy led to the diagnosis of IgA nephropathy. Although pulse steroid therapy during his condition resulted in hepatic encephalopathy, three courses combined with mizoribine improved his renal function.

CONCLUSION

SARS-CoV-2 mRNA vaccines activate T cells, which are involved in the pathophysiology of IgA nephropathy. Therefore, this case suggests that the exacerbation of IgA nephropathy by the vaccine favors the vasculitis aspect of the disease.

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.

Global Incidence of IgA Nephropathy by Race and Ethnicity: A Systematic Review

Key Points

In 16 studies conducted abroad, IgA nephropathy incidence varied from 0.06 in South Africa to 4.2 per 100,000 in Japan. Globally, the incidence of IgA nephropathy seemed higher in Asians than in non-Asians and higher in male patients than in female patients. Five studies conducted in the United States found no consistent difference in incidence between Black patients and White patients.

Background

The reported incidence of IgA nephropathy varies widely across studies and may vary on the basis of race/ethnicity. This study systematically reviewed the incidence of IgA nephropathy in the United States and other countries and explored variability on the basis of the racial/ethnic composition and other demographic characteristics of different populations.

Methods

This was a systematic review. Studies were eligible for inclusion if they contained data collected from January 1, 1974, to December 31, 2021, and reported IgA nephropathy incidence at a population level (i.e. , cases of IgA nephropathy per 100,000 population).

Results

Five US and 16 international studies were included; three of the US studies reported the race-specific incidence of IgA nephropathy. In the United States, the reported incidence of IgA nephropathy ranged from 0.39 per 100,000 in Tennessee to 1.4 per 100,000 in Minnesota; internationally, IgA nephropathy ranged from 0.06 per 100,000 in South Africa to 4.2 per 100,000 in Japan. Findings regarding the incidence of IgA nephropathy in the United States by race were inconsistent: One study found a higher incidence among White patients compared with Black patients, one study found a lower incidence in White patients, and one study found no difference. Globally, the incidence of IgA nephropathy seemed to be higher in Asian than in non-Asian populations and higher in male patients than in female patients.

Conclusions

Reported incidence of IgA nephropathy varies widely; there is no consensus regarding the relationship between race and IgA nephropathy. Incidence rates seemed to be higher in Asians than non-Asians and in male patients than female patients. We recommend that future studies should report IgA nephropathy incidence rates by race/ethnicity and account for the demographic characteristics of the background population.

The Role of Two Heart Biomarkers in IgA Nephropathy

Cardiovascular mortality is a leading cause of death in chronic kidney disease (CKD), as is IgA nephropathy (IgAN). The purpose of this study is to find different biomarkers to estimate the outcome of the disease, which is significantly influenced by the changes in vessels (characterized by arterial stiffness) and the heart. In our cross-sectional study, 90 patients with IgAN were examined. The N-terminal prohormone of brain natriuretic peptide (NT-proBNP) was measured as a heart failure biomarker by an automated immonoassay method, while the carboxy-terminal telopeptide of collagen type I (CITP) as a fibrosis marker was determined using ELISA kits. Arterial stiffness was determined by measuring carotid-femoral pulse wave velocity (cfPWV). Renal function and routine echocardiography examinations were performed as well. Based on eGFR, patients were separated into two categories, CKD 1-2 and CKD 3-5. There were significantly higher NT-proBNP (p = 0.035), cfPWV (p = 0.004), and central aortic systolic pressure (p = 0.037), but not CITP, in the CKD 3-5 group. Both biomarker positivities were significantly higher in the CKD 3-5 group (p = 0.035) compared to the CKD 1-2 group. The central aortic systolic pressure was significantly higher in the diastolic dysfunction group (p = 0.034), while the systolic blood pressure was not. eGFR and hemoglobin levels showed a strong negative correlation, while left ventricular mass index (LVMI), aortic pulse pressure, central aortic systolic pressure, and cfPWV showed a positive correlation with NT-proBNP. cfPWV, aortic pulse pressure, and LVMI showed a strong positive correlation with CITP. Only eGFR was an independent predictor of NT-proBNP by linear regression analysis. NT-proBNP and CITP biomarkers may help to identify IgAN patients at high risk for subclinical heart failure and further atherosclerotic disease.

IgA Nephropathy: the Lectin Pathway and Implications for Targeted Therapy

Many patients with IgA nephropathy (IgAN) progress to end-stage kidney disease even with optimal supportive care. An improved understanding of the pathophysiology of IgAN in recent years has led to the investigation of targeted therapies with acceptable tolerability that may address the underlying causes of IgAN or the pathogenesis of kidney injury. The complement system - particularly the lectin and alternative pathways of complement - have emerged as key mediators of kidney injury in IgAN and possible targets for investigational therapy. This review will focus on the lectin pathway. Examination of kidney biopsies has consistently shown glomerular deposition of mannan-binding lectin (one of six pattern-recognition molecules that activate the lectin pathway) together with IgA1 in up to 50% of patients with IgAN. Glomerular deposition of pattern-recognition molecules for the lectin pathway is associated with more severe glomerular damage and more severe proteinuria and hematuria. Emerging research suggests that the lectin pathway may also contribute to tubulointerstitial fibrosis in IgAN, and that collectin-11 is a key mediator of this association. This review summarizes the growing scientific and clinical evidence supporting the role of the lectin pathway in IgAN and examines the possible therapeutic role of lectin pathway inhibition for these patients.

IgA Nephropathy Patient Baseline Characteristics in the Sparsentan PROTECT Study

Introduction

Sparsentan is a novel single-molecule dual endothelin angiotensin receptor antagonist with hemodynamic and anti-inflammatory properties and is not an immunosuppressant. The ongoing phase 3 PROTECT trial examines sparsentan in adults with IgA nephropathy (IgAN).

Methods

The PROTECT trial (NCT03762850) is a multicenter, international, randomized, double-blind, parallel-group, active-controlled study. The efficacy and safety of sparsentan versus the active control irbesartan is being evaluated in adults with biopsy-proven IgAN and proteinuria ≥1.0 g/d despite maximized treatment with an angiotensin-converting enzyme inhibitor (ACEi) and/or angiotensin receptor blocker (ARB) for at least 12 weeks. Blinded and aggregated baseline characteristics are reported descriptively and compared to contemporary phase 3 trials with patients with IgAN.

Results

The primary analysis population includes 404 patients who were randomized and received study drug (median age, 46 years). Enrolled patients were from Europe (53%), Asia Pacific (27%), and North America (20%). Baseline median urinary protein excretion was 1.8 g/d. The range of estimated glomerular filtration rate (eGFR) was broad with the largest proportion of patients (35%) in chronic kidney disease (CKD) stage 3B. Before transitioning to study medication, mean systolic/diastolic blood pressure was 129/82 mm Hg, with the majority of patients (63.4%) receiving the maximum labeled ACEi or ARB dose. Patients in Asian versus non-Asian regions included a higher percentage of females, had lower blood pressures, and included lower proportions of patients with a history of hypertension and baseline antihypertensive treatment.

Conclusions

Patient enrollment in PROTECT, with differing racial backgrounds and across CKD stages, will allow for important characterization of the treatment effect of sparsentan in patients with IgAN with proteinuria at high risk of kidney failure.

Histological Features of IgA Nephropathy in Pediatrics and the Magnitude of the Disease in Saudi Children

Objectives

This review addresses the microscopic features of immunoglobulin A nephropathy (IgA nephropathy), its prognostic variables in children, and measures to which extent these features and variables differ from adults. Furthermore, it describes the extent of this disease process among children in Saudi Arabia and the rest of the Arab countries and compares it with the data from the West and the Far East.

Method

All the original work described the histological features of pediatric IgA nephropathy, and studies involved in developing the prognostic classification of IgA nephropathy, Oxford Classification, were reviewed. Moreover, the studies describing the crescent prevalence and outcome in pediatric IgA nephropathy in addition to thrombotic microangiopathy association were studied. National studies describing the prevalence of pediatric IgA nephropathy and pediatric crescentic glomerulonephritis were tracked with an overview of the regional data from the rest of the Arab world.

Results

IgA nephropathy in children showed more glomerular proliferative changes and less glomerular vascular and tubule-interstitial chronic injury compared to adults. The reference study that described the association between thrombotic microangiopathy and IgA nephropathy did not include the pediatric age group. Moreover, it was found that the data from the Middle East was not encountered in developing the original and updated IgA nephropathy Oxford Classification. Furthermore, the prevalence of IgA nephropathy in children is described in the regional literature, but its histological features were not well detailed. Finally, the percentage of crescentic glomerulonephritis (GN) due to IgA nephropathy is less in our country compared to the West and concords with the Far East findings.

Conclusion

A well-designed regional study addressing IgA nephropathy in Middle East children with a focus on histological features, association with crescent, and thrombotic microangiopathy and challenging the validity of the updated IgA nephropathy Oxford Classification is recommended.

COVID-19 and glomerular diseases

COVID (Coronavirus disease)-19 is a systemic disease and the kidney is one of the target organs of infection. Kidney injury is common and can occur in up to 40% of patients. Several glomerular diseases have been reported in association with COVID-19. Some are likely related to COVID-19 whereas many are likely coincidental. Glomerular diseases that are frequently reported in COVID-19 and have a plausible mechanistic explanation, are likely to be related to COVID-19. On the other hand, glomerular diseases that are seldom reported and have no known plausible mechanism, are likely to be unrelated. Collapsing glomerulopathy (CG) is by far the most prevalent. Its association with COVID-19, resembling human immunodeficiency virus (HIV) and CG, led to the newly proposed term “COVID-19 associated nephropathy” or “COVAN”. High-risk APOL1 genotypes are the major risk factor in COVAN patients. Podocytopathy, membranous nephropathy, pauci-immune crescentic glomerulonephritis, and thrombotic microangiopathy are also reported. In kidney allografts, CG remains the most common glomerular pathology. Patients typically present with acute kidney injury (AKI) or abnormal urinary findings at the time of or shortly after COVID-19 diagnosis. Treatment of glomerular disease in COVID-19 patients is challenging. Providers should cautiously consider balancing risks and benefit of immunosuppression, particularly in patients with active diseases. Short-term outcomes vary but generally remain poor with high morbidity and mortality. Future study of long-term outcomes is needed to improve our understanding of glomerular disease associated with COVID-19.