Changing prevalence of glomerular diseases in Korean adults: a review of 20 years of experience

Changes in the spectrum of biopsy-proven renal diseases over 11 years: a single-center study in China

BACKGROUND

There have been some shifts in the frequency and distribution of biopsy-proven renal diseases in China over recent years. The aim of the study was to investigate the changing spectrum of renal diseases from the view of kidney biopsy data in a single center of China.

METHODS AND RESULTS

A total of 10,996 cases of native renal biopsies from patients aged ≥15 years old in Huashan Hospital, Fudan University, between 2008 and 2018 were analyzed retrospectively. The results showed that primary glomerular nephropathy (PGN) remained the most common biopsy-proven renal disease (69.42% of total), with IgA nephropathy (IgAN) accounting for 44.40% of PGN, membranous nephropathy (MN) for 28.55%, minimal change disease (MCD) for 13.26% and focal segmental glomerulosclerosis (FSGS) for 8.00%. During the study period, the proportion of MN in PGN appeared an increasing tendency, while that of IgAN and MCD remained stable and that of FSGS showed a decline. Secondary glomerular nephropathy (SGN) constituted 21.54% of total cases, among which the leading two diseases were lupus nephritis (LN) and Henoch-Schonlein purpura nephritis (HSN) which accounted for 41.08% and 19.11% respectively.

CONCLUSIONS

The 11-year retrospective study revealed that PGN was the predominant histologic diagnosis among patients undergoing renal biopsy and the most frequent type of PGN remained to be IgAN, followed by MN which increased dramatically.

Are children with IgA nephropathy different from adult patients?

BACKGROUND

Previously, several studies have indicated that pediatric IgA nephropathy (IgAN) might be different from adult IgAN, and treatment strategies might be also different between pediatric IgAN and adult IgAN.

METHODS

We analyzed two prospective cohorts established by pediatric and adult nephrologists, respectively. A comprehensive analysis was performed investigating the difference in clinical and pathological characteristics, treatment, and prognosis between children and adults with IgAN.

RESULTS

A total of 1015 children and 1911 adults with IgAN were eligible for analysis. More frequent gross hematuria (88% vs. 20%, p < 0.0001) and higher proteinuria (1.8 vs. 1.3 g/d, p < 0.0001) were seen in children compared to adults. In comparison, the estimated glomerular filtration rate (eGFR) was lower in adults (80.4 vs. 163 ml/min/1.73 m2, p < 0.0001). Hypertension was more prevalent in adult patients. Pathologically, a higher proportion of M1 was revealed (62% vs. 39%, p < 0.0001) in children than in adults. S1 (62% vs. 28%, p < 0.0001) and T1-2 (34% vs. 8%, p < 0.0001) were more frequent in adults. Adjusted by proteinuria, eGFR, and hypertension, children were more likely to be treated with glucocorticoids than adults (87% vs. 45%, p < 0.0001). After propensity score matching, in IgAN with proteinuria > 1 g/d, children treated with steroids were 1.87 (95% CI 1.16-3.02, p = 0.01) times more likely to reach complete remission of proteinuria compared with adults treated with steroids.

CONCLUSIONS

Children present significantly differently from adults with IgAN in clinical and pathological manifestations and disease progression. Steroid response might be better in children.

Demographic distribution analysis of different glomerular diseases in Southwest China from 2008 to 2022

BACKGROUND

Environmental and lifestyle factors play an etiological role in the pathogenesis of different glomerular diseases. Thus, exploring the epidemic characteristics of renal disease in different nationalities and regions is important.

MATERIALS AND METHODS

Patients who underwent renal biopsy from October 2008 to October 2022 were included. The proportion and change tendency of glomerular diseases and the differences between the sexes and different ages and races were analyzed.

RESULTS

There were 15,146 cases of glomerular diseases (98.5%), involving 7538 males (49.8%) and 7608 females (50.2%). The mean age was 37.0 years (range 0-80 years). The proportion of membranous nephropathy (MN) and diabetic nephropathy (DN) showed an increased trend. The most common primary glomerulonephritis (PGN) was IgA nephropathy (IgAN, 44.6%), followed by minimal-change disease (MCD, 24.3%) and MN (15.4%). Lupus nephritis (LN, 30%) accounted for the largest proportion of SGNs, followed by Henoch-Schonlein purpura nephritis (HSPN, 20.9%) and DN (19.8%). Compared with adults aged 18-60 years old, MCD and HSPN were more common in children and MN and DN in elderly individuals, statistically significant differences. Additionally, the sex and age distribution of PGN and SGN between the Tibetan and Han populations differed significantly, whereby LN was higher in the Han population and HSPN in the Tibetan population.

CONCLUSION

The distribution of glomerular diseases showed age, sex and race differences. This research will be beneficial for providing epidemiological evidence for clinical diagnosis, disease prevention and public health decision-making.

Efficacy of tacrolimus monotherapy in primary membranous nephropathy

Objective

The aim of this study was to observe the remission of primary membranous nephropathy (PMN) and evaluate the efficacy of tacrolimus (TAC) monotherapy for PMN in comparison with TAC combined with a low-dose glucocorticoid (GC) protocol (TAC + GC).

Methods

This was tested in a prospective monocentric observational trial of 70 patients with PMN, of whom 34 received TAC (0.05-0.075 mg/kg/day) or 36 received TAC (0.05-0.075 mg/kg/day) and GC (0.3-0.5 mg/kg/day of prednisone).

Results

At 3, 6, 9, and 12 months of treatment, the effective rates in the TAC group and the TAC + GC group were similar (P > 0.05). The urinary protein quantification was reduced in patients under both therapeutic protocols, and the differences in the proteinuria quantification at 3, 6, 9, and 12 months of treatment were not statistically significant between the two groups (P > 0.05). The overall incidence of adverse reactions in the TAC group was lower than that in the TAC + GC group (23.5% < 36.1%), and the difference was statistically significant (P < 0.05).

Conclusion

TAC monotherapy for PMN could effectively reduce urinary protein quantification and increase serum albumin levels. Compared with TAC + GC, TAC monotherapy for PMN had no difference in efficacy and fewer incidences of adverse reactions.

Characteristics and Challenges of Providing Acupuncture and Chinese Herbal Medicine in Oncology Treatment: Report of Survey Data and Experience of Five Unique Clinical Settings

Acupuncture is an integrative therapy with strong evidence to support its use in the oncology setting, yet barriers exist for implementation into conventional medical clinics. Though acupuncture is recommended in clinical practice guidelines for oncology, there is little data in the literature showing how acupuncture and other related therapies, including herbal medicine are successfully implemented in some oncology clinics, while others experience barriers to care. To characterize the current use of acupuncture (ACU) and herbal medicine (HM) in oncology clinics, we collected general demographic and usage data from 5 example clinics. In addition, to better understand the barriers faced by ACU and HM clinics in implementing acupuncture as a treatment modality, a survey was deployed to 2320 members of the Society for Integrative Oncology. This article examines the characteristics of oncology settings around the world, and shares data from the survey on the use of these therapies in the field of oncology. The primary barrier to acupuncture care, as reported by providers, was cost. With just under 70% of the oncologists reporting it as the most important obstacle. Additional barriers to implementation included concerns about competency and training, accessibility and safety of herbal medicine during treatment. Though acupuncture is being incorporated into more conventional oncology settings, organized strategies for implementation involving payers and policymakers is needed.

Spontaneous Remission of Minimal Change Disease in a Colon Cancer Patient: A Case Report

Introduction

Minimal change disease (MCD) is most often primary but may occur secondary to other systemic diseases such as malignancy. In secondary MCD, spontaneous remission of nephrotic syndrome after the treatment of related diseases without steroid therapy is rare.

Case Presentation

A 78-year-old man visited the outpatient clinic with foamy urine and generalized edema that had persisted for 2 months. The patient had nephrotic syndrome. Before a kidney biopsy, he underwent several tests to determine the secondary cause of the nephrotic syndrome. The serum CEA was slightly elevated, and colon cancer was detected in the sigmoid colon. MCD was diagnosed from a kidney biopsy. He immediately underwent surgery for colon cancer. Complete remission of the MCD was achieved within 2 weeks after surgery.

Conclusion

Here, we report a rare case of a patient with secondary MCD who successfully achieved spontaneous remission after colon cancer surgery.

Changes in spectrum of biopsy-proven kidney diseases within decade: an analysis based on 10 199 cases from South China

PURPOSE

To assess the regional epidemiological trends of kidney diseases over time in the South China using renal biopsy-proven cases.

METHODS

This retrospective observational cohort study was conducted at the Institute of Nephrology, Second Xiangya Hospital of Central South University, and encompasses all patients diagnosed with kidney disease via biopsy from 2012 to 2021.

RESULTS

The study sample consisted of 10 199 native kidneys, with a male-to-female ratio of 0.91:1 and an average age of 38.74 (±14.53) years. Primary glomerular nephropathy, systemic glomerular nephropathy (SGN), tubulointerstitial disease, and hereditary renal diseases accounted for 66.92 (6825)%, 24.49 (2498)%, 8.06 (822)%, and 0.53 (54)%, respectively. The leading pathologies of primary glomerular nephropathy remained the IgA nephropathy. The frequencies of IgA nephropathy and membranous nephropathy increased significantly, whereas the frequencies of minimal change disease and focal segmental glomerulosclerosis decreased (P < .001) between 2017 and 2021 than in the years 2012 and 2016. An earlier onset of membranous nephropathy was observed in the age group of 45-59 years compared to previous studies. The leading pathologies of SGN were found to be lupus nephritis (758 cases, 30.45%) and hypertension nephropathy (527 cases, 21.17%). The frequencies of hypertension nephropathy and diabetic nephropathy increased between 2017 and 2021 compared to 2012 and 2016 (P < .001), gradually becoming the leading pathological types of SGN. In elderly patients diagnosed with nephrotic syndrome, the frequencies of amyloidosis significantly increased (P < .01).

CONCLUSION

Our study may provide insights for kidney disease prevention and public health strategies. What is already known on this topic The pathological spectrum of kidney diseases has undergone significant transformations in the past decade, driven by the escalating incidence of chronic diseases. Although there are studies exploring the renal biopsy findings from various regions in China which present both similarities and differences in epidemiology, few large-scale reports from the South China in recent decades were published. What this study adds Our findings reveal the following key observations: (i) increased proportion of middle-aged patients leading to the increasing average age at the time of biopsy；(ii) the frequencies of IgA nephropathy and membranous nephropathy (MN) increased significantly, whereas the frequencies of minimal change disease and focal segmental glomerulosclerosis decreased (P < .001) between 2017 and 2021 than in the years 2012 and 2016; (iii) earlier onset of MN in the age group of 45-59 years old was found in our study; and (iv) a higher frequency of hypertension nephropathy and DN presented over time, and frequency of amyloidosis increased in elderly patients diagnosed with NS. How this study might affect research, practice, or policy This single-center yet a large-scale study of the kidney disease spectrum in South China may provide a reference point for the diagnosis, treatment, and prevention of chronic kidney disease.

Spectrum and Distribution of Biopsy-proven Kidney Diseases: A 12-year Survey of a Single Center in Iran

Data about the prevalence of biopsy-proven kidney diseases in Iran are rare, and none of the previous studies used electron microscopy for diagnosis. This study aimed to analyze the prevalence of biopsy-proven kidney diseases in Iran's primary referral center. To the best of our knowledge, this is the most extensive study carried out in Iran. Reports of kidney biopsy samples from patients referred to our center in 2007-2018 were reviewed for demographic data, clinical presentation, and final diagnosis. Statistical analyses were performed. Among the 3455 samples received, 2975 were analyzed. Nephrotic syndrome (39%) was the most common cause of biopsy, followed by subnephrotic proteinuria (18%), hematuria in association with proteinuria (15%), renal failure (9%), isolated hematuria (6%), and lupus nephritis (LN) (4%). The most common diagnoses were membranous glomerulonephritis (17.9%), focal segmental glomerulosclerosis (FSGS) (15.9%), LN (13.7%), minimal histopathological findings (unsampled FSGS vs. minimal change disease, 12.1%), Immunoglobin A nephropathy (IgAN) (6.5%) and Alport syndrome (6.1%). NS and proteinuria were the most common indications for a kidney biopsy. IgAN and LN were the most common causes of primary and secondary glomerulonephritis, presenting with hematuria and proteinuria, respectively. Although membranous glomerulonephritis was the most common disease, it has been replaced by FSGS in recent years.

The frequency of sarcopenia has increased in patients with glomerulonephritis

AIM

Sarcopenia is defined as the loss of muscle mass and muscle strength, and its frequency increases in kidney patients. However, sarcopenia frequency in patients with glomerulonephritis is unknown. The present study aimed to investigate the frequency of sarcopenia in patients with glomerulonephritis and compare the results with the healthy population for the first time in the literature.

PATIENTS AND METHODS

A total of 110 participants, including 70 patients previously diagnosed with glomerulonephritis and 40 healthy individuals, were included in the study. The diagnosis of sarcopenia was made based on the EWSGOP 2 Criteria.

RESULTS

The mean age of the glomerulonephritis patients group was 39.3 ± 1.5. In the anthropometric measurements of the patients, walking speed was low in 50 patients (71.4%), muscle strength was decreased in 44 patients (62.9%), and sarcopenia was detected in 10 patients (14.3%) according to the EWGSOP 2 Criteria. Considering the anthropometric measurements of the control group, sarcopenia was not detected in any of the subjects according to the EWGSOP 2 Criteria.

CONCLUSION

The result of the present study revealed that the rate of sarcopenia was significantly higher in glomerulonephritis patients compared to the healthy population and that sarcopenia can also be observed even in middle age in this population. We think it would be beneficial for clinicians treating glomerulonephritis to be more careful regarding sarcopenia and keep these parameters in mind during treatment.

Risk of CKD Following Detection of Microscopic Hematuria: A Retrospective Cohort Study

RATIONALE & OBJECTIVE

Microscopic hematuria is an uncertain risk factor for chronic kidney disease (CKD). We investigated the association between persistent or single episodes of microscopic hematuria and the development of incident CKD, overall and separately among men and women.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

A total of 232,220 Korean adults without CKD at baseline who underwent repeated regular health examinations at Kangbuk Samsung Health Study formed the study cohort.

EXPOSURE

Microscopic hematuria was defined by≥5 red blood cells per high-power field. Participants were categorized into 1 of 4 groups according to the presence of hematuria at 2 consecutive examinations: (1) no hematuria at both examinations (reference group); (2) hematuria followed by no hematuria (regressed hematuria group); (3) no hematuria followed by hematuria (developed hematuria group); and (4) hematuria at both examinations (persistent hematuria group).

OUTCOME

CKD was defined as an estimated glomerular filtration rate<60mL/min/1.73m² or proteinuria (1+or more on dipstick examination).

ANALYTICAL APPROACH

Semiparametric proportional hazards models were used to estimate hazard ratios.

RESULTS

During a 4.8-year median follow-up period, 2,392 participants developed CKD. Multivariable-adjusted hazard ratios for incident CKD, comparing the regressed, developed, and persistent hematuria groups to the no-hematuria group were 1.85 (95% CI, 1.35-2.53), 3.18 (95% CI, 2.54-3.98), and 5.23 (95% CI, 4.15-6.59), respectively. The association between persistent hematuria and incident CKD was stronger in men than women (P for interaction<0.001), although a statistically significant association was observed in both sexes.

LIMITATIONS

Lack of albuminuria and inability to consider specific glomerular diseases.

CONCLUSIONS

Men and women with microscopic hematuria, especially persistent hematuria, may be at increased risk of CKD.

Prevalence and Pattern of Glomerulonephritis: An Experience of Two Tertiary Centers in Malaysia

The prevalence of glomerulonephritis (GN), especially membranous GN (MGN), changes from time to time. This change may be due to genetic predisposition, environmental factors race, age, and indications for a renal biopsy. This study was conducted to evaluate the distribution and changing patterns of GN by further assessing the prevalence of MGN. A 1000, 123 biopsies were performed from January 2012 to October 2019 in Hospital Serdang and Hospital Kuala Lumpur. Electron microscopy, immunohistochemistry, and clinical presentations were used to differentiate primary and secondary MGN, from which 611 and 457 primary and secondary subjects were diagnosed with primary and secondary GN, respectively. Primary MGN accounts for 13% of all the primary GN, while lupus nephritis (LN) accounts for 44.2% of all secondary GN followed by diabetes mellitus (25.6%). The proportions of primary and secondary MGN were 64.8% and 35.2%, respectively, with a male-to-female ratio of 1:1.1 in favor of females. The renal biopsy obtained from the registry of two prominent hospitals in Malaysia provided valuable prevalence and demonstrated changes in the prevalence of GN in Malaysia. Notwithstanding, immunoglobulin A nephropathy and LN remain the most common causes of primary and secondary GN in Malaysia.

IgA Nephropathy: Pleiotropic impact of Epstein-Barr virus infection on immunopathogenesis and racial incidence of the disease

IgA nephropathy (IgAN) is an autoimmune disease in which poorly galactosylated IgA1 is the antigen recognized by naturally occurring anti-glycan antibodies, leading to formation of nephritogenic circulating immune complexes. Incidence of IgAN displays geographical and racial disparity: common in Europe, North America, Australia, and east Asia, uncommon in African Americans, many Asian and South American countries, Australian Aborigines, and rare in central Africa. In analyses of sera and cells from White IgAN patients, healthy controls, and African Americans, IgAN patients exhibited substantial enrichment for IgA-expressing B cells infected with Epstein-Barr virus (EBV), leading to enhanced production of poorly galactosylated IgA1. Disparities in incidence of IgAN may reflect a previously disregarded difference in the maturation of the IgA system as related to the timing of EBV infection. Compared with populations with higher incidences of IgAN, African Americans, African Blacks, and Australian Aborigines are more frequently infected with EBV during the first 1-2 years of life at the time of naturally occurring IgA deficiency when IgA cells are less numerous than in late childhood or adolescence. Therefore, in very young children EBV enters "non-IgA" cells. Ensuing immune responses prevent infection of IgA B cells during later exposure to EBV at older ages. Our data implicate EBV-infected cells as the source of poorly galactosylated IgA1 in circulating immune complexes and glomerular deposits in patients with IgAN. Thus, temporal differences in EBV primo-infection as related to naturally delayed maturation of the IgA system may contribute to geographic and racial variations in incidence of IgAN.

Molecular signatures of intrarenal complement receptors C3AR1 and C5AR1 correlate with renal outcome in human lupus nephritis

OBJECTIVE

Lupus nephritis is one of the most common and serious complications of systemic lupus erythematosus (SLE). Lupus nephritis is a major cause of kidney failure in patients with SLE, attributed to increased morbidity and mortality. The in situ deposition of intrarenal immune complexes promotes the accumulation of inflammatory cells and causes kidney injury.

METHODS

We here extracted transcriptome array datasets for expression of complement molecules in human lupus nephritis. Furthermore, we performed gene set enrichment analysis to identify molecular signatures associated with follow-up kidney function in lupus nephritis.

RESULTS

Within the glomerular compartment, intrarenal mRNA expression levels of C3AR1 (p=0.0333) and C5AR1 (p=0.0167) correlated with treatment success reflected by kidney function recovery specifically in class III lupus nephritis, while no such association was observed in class II or class IV lupus nephritis. Interestingly, mRNA expression levels of either glomerular C3AR1 or C5AR1 resulted in identical gene set and signalling pathways enrichments in human lupus nephritis, including interferon signalling and signalling by interleukins. Direct comparison of C3AR1 and C5AR1 confirmed a strong association between glomerular mRNA expression levels of both complement receptors (r=0.8955, p<0.0001).

CONCLUSIONS

This study provides additional insights into signalling pathways associated with intrarenal synthesis of complement components in lupus nephritis that might be also affected by targeted therapy of the complement system. These results require confirmation but may contribute to a personalised treatment approach in distinct classes of human lupus nephritis.

Epidemiological characteristics and pathological changes of primary glomerular diseases

Objective

By analyzing the pathological characteristics and clinical data of renal biopsy in our hospital in the past 20 years, to further understand the epidemic characteristics and pathological changes of primary glomerular disease, and to provide regional data for the big data of kidney disease in my country.

Methods

A retrospective analysis of 9448 patients with primary glomerular disease who were hospitalized in our hospital from January 1, 2000 to December 31, 2019, aged 18 years or older, and undergoing renal biopsy. Divided every 5 years into a group, a total of 4 groups (first group 2000.1.1–2004.12.31, second groups 2005.1.1–2009.12.31; third groups 2010.1.1–2014.12.31, fourth groups 2015.1.1–2019.12.31).

Results

① There were more males than females, and male: female vs 1.53:1. The proportion of men in the past five years has increased compared with the previous 15 years. ② Mostly middle-aged, with a median age of 41.39 years old. The age is increasing over time. There are differences between the four groups, P <0.001; ③ The most common clinical manifestations are nephrotic syndrome, followed by chronic glomerulonephritis. Occult glomerulonephritis, the proportion of patients with nephrotic syndrome increases over time, first to fourth group (40.08%< 42.64% < 47.08%< 53.69%); ④ The most common pathology type from 2000 to 2009 was mesangial proliferative glomerulonephritis. IgA nephropathy was the most common type from 2010 to 2014, but the proportion of membranous nephropathy increased year by year, and it became the most common pathological type from 2015 to 2019; ⑤ The clinical and pathological manifestations of different genders are different, but there is no statistical difference.

Conclusion

In the past 20 years, the primary glomerular disease is mainly middle-aged. There are more men than women. The most common type of clinical manifestation is nephrotic syndrome. The pathological type is mesangial proliferative glomerulonephritis. Over time, the average age is increasing, and the proportion of patients with renal syndrome is increasing. IgA nephropathy is the most common pathological type from 2010 to 2014, and membranous nephropathy has become the main pathological type in the past 5 years.

Clinical and histopathological analyses of kidney biopsies in a single center for 7 years

Kidney biopsy is the most important tool for diagnosing kidney disease and can be helpful in determining treatment and prognosis. Pathological spectra vary by country, region, race, sex, and age. We are the first to investigate the pathological spectrum of biopsy-proven kidney disease in Gyeongnam province of South Korea. We retrospectively analyzed 631 patients who underwent a kidney biopsy between 2013 and 2019 at Gyeongsang National University Hospital. The mean age of the 631 patients was 51.5 ± 18.1 years, and 361 patients (57.2%) were male. The mean estimated glomerular filtration rate by serum creatinine (Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]) was 68.0 ± 45.7 mL/min/1.73 m2. The mean systolic blood pressure was higher in 2017, 2018, and 2019 than in 2013 (P = .002). Hypertension (47.4%) was the most common comorbid disease, followed by diabetes (18.2%) and dyslipidemia (10.9%). Common clinical syndromes at the time of biopsy were renal insufficiency (42.0%) and nephrotic syndrome (33.9%). The prevalence of primary and secondary glomerular disease and tubulointerstitial disease were 71.4%, 16.9%, and 5.4%, respectively. Immunoglobulin A nephropathy was the most common primary glomerular disease (34.9%). Diabetic nephropathy was the most common secondary glomerular disease, followed by lupus nephritis. Tubulointerstitial disease was underestimated, as in other reports. Our data can be a useful reference for diagnosing kidney disease and understanding the patients in our province.

Changes in the spectrum of kidney diseases: a survey of 2803 patients from 2010 to 2018 at a single center in southeastern China

Primary glomerular disease was the leading cause of chronic kidney disease (CKD) in China; however, changes in the economy and environment introduce variations in the spectrum of kidney diseases. This study aimed to analyze renal biopsy data to inform disease prevention and public health interventions. In this retrospective cohort study, data from 2,803 consecutive renal biopsies conducted at our center between January 2010 and December 2018 were analyzed. The sample was disaggregated by age and the date of biopsy to facilitate analysis. Primary glomerulonephritis (PGN) is the most frequent (81.84%) finding, followed by secondary glomerulonephritis (SGN; 15.38%), tubulointerstitial nephritis (15.38%), and others (1.57%). IgA nephropathy (IgAN), idiopathic membranous nephropathy (iMN), and minimal change disease were the primary causes of PGN. Among PGN cases, the incidence of iMN arose, especially among those aged ≥ 60 years old, during the observation period. Contrary to the case of iMN, the proportion of IgAN in PGN trended downward, continuously, and at length. Moreover, IgAN mainly affected those aged 25–44 years old and less so those aged ≥ 60 years old. Lupus nephritis, Henoch–Schönlein purpura nephritis, and diabetic nephropathy (DN) were key causes of SGN. A ratio reversal between infectious disease and chronic disease dramatically changed SGN patterns. In the past year, the incidence of hepatitis B–related nephritis has constantly declined; however, the proportion of DN among SGN had steadily increased. The incidence of iMN significantly increased during these years. Among SGN cases, the proportion of DN has increased.

Proximity to petrochemical industrial parks and risk of chronic glomerulonephritis

This study determined whether individuals residing near petrochemical industrial parks (PIPs) have a higher risk of chronic glomerulonephritis (CGN). We performed population-based 1:4 case-control study by using Taiwan's National Health Insurance Research Database from 2000 to 2016. The subjects were aged 20-65 years, residing in western Taiwan, and did not have a history of any renal or urinary system disease in 2000. The case cohort included those who had at least three outpatient visits or one hospitalization between 2001 and 2016 with codes for CGN as per International Classification of Diseases (ICD)-Ninth and Tenth Revisions. Controls were randomly sampled age-, sex-, and urbanization-matched individuals without renal and urinary system diseases. Petrochemical exposure was evaluated by the distance to the nearest PIP of the residential township, and petrochemical exposure probability was examined considering the monthly prevailing wind direction. Conditional logistic regression was used to determine the association between petrochemical exposure and CGN risk. A total of 320,935 subjects were included in the final analysis (64,187 cases and 256,748 controls). After adjustment for potential confounders, living in townships within a 3-km radius of PIPs was associated with a higher risk of CGN (adjusted odds ratio [aOR] = 1.32, 95% confidence interval [CI] = 1.28-1.37). Compared with townships more than 20 km away from PIPs, those within 10 km of PIPs were associated with significantly increased risks of CGN in a dose-dependent manner. When prevailing wind was considered, townships with high exposure probability were associated with a significantly increased risk of CGN. We found that those residing near PIPs or with high petrochemical exposure probability had a higher risk of CGN. These findings highlight the need for monitoring environmental nephrotoxic substances and the renal health of residents living near PIPs.

External validation of the International Prediction Tool in Korean patients with immunoglobulin A nephropathy

Background

The International IgA Nephropathy Prediction Tool (International IgA Nephropathy Prediction Tool) has been recently developed to estimate the progression risk of immunoglobulin A nephropathy (IgAN). This study aimed to evaluate the clinical performance of this prediction tool in a large IgAN cohort in Korea.

Methods

The study cohort was comprised of 2,064 patients with biopsy-proven IgAN from four medical centers between March 2012 and September 2021. We calculated the predicted risk for each patient. The primary outcome was occurrence of a 50% decline in estimated glomerular filtration rate (eGFR) from the time of biopsy or end-stage kidney disease. The model performance was evaluated for discrimination, calibration, and reclassification. We also constructed and tested an additional model with a new coefficient for the Korean race.

Results

During a median follow-up period of 3.8 years (interquartile range, 1.8–6.6 years), 363 patients developed the primary outcome. The two prediction models exhibited good discrimination power, with a C-statistic of 0.81. The two models generally underestimated the risk of the primary outcome, with lesser underestimation for the model with race. The model with race showed better performance in reclassification compared to the model without race (net reclassification index, 0.13). The updated model with the Korean coefficient showed good agreement between predicted risk and observed outcome.

Conclusion

In Korean IgAN patients, International IgA Nephropathy Prediction Tool had good discrimination power but underestimated the risk of progression. The updated model with the Korean coefficient showed acceptable calibration and warrants external validation.

Trends of primary glomerular disease in Turkey: TSN-GOLD registry report

BACKGROUND

Although several renal biopsy registry reports have been published worldwide, there are no data on primary glomerular disease trends in Turkey.

METHODS

Three thousand eight-hundred fifty-eight native kidney biopsy records were assessed in the Turkish Society of Nephrology Primary Glomerulopathy Working Group (TSN-GOLD) Registry. Secondary disease and transplant biopsies were not recorded in the registry. These records were divided into four periods, before 2009, 2009 to 2013, 2013-2017, and 2017-current.

RESULTS

A total of 3858 patients (43.6% female, 6.8% elderly) were examined. Nephrotic syndrome was the most common biopsy indication in all periods (58.6%, 53%, 44.1%, 51.6%, respectively). In the whole cohort, IgA nephropathy (IgAN) (25.7%) was the most common PGN with male predominance (62.7%), and IgAN frequency steadily increased through the periods (× 2 = 198, p < 0.001). MGN was the most common nephropathy in the elderly (> 65 years), and there was no trend in this age group. An increasing trend was seen in the frequency of overweight patients (× 2 = 37, p < 0.0001). Although the biopsy rate performed with interventional radiology gradually increased, the mean glomeruli count in the samples did not change over the periods.

CONCLUSIONS

In Turkey, IgAN is the most common primary glomerulonephritis, and the frequency of this is increasing.

Glomerular Diseases in the Colombian Caribbean: Data from the Colombian Nephropathy Registry (NEFRORED®)

Our study aimed to describe the glomerular diseases, both primary glomerular disease (PGD) and secondary glomerular disease (SGD) in the Colombian Caribbean based on the first regional Colombian Nephropathy Registry (NEFRORED®). A descriptive and retrospective study of adult patients with glomerular diseases from the Colombian Caribbean region was made. All diagnoses by renal biopsy with light microscopy and immunofluorescence obtained between January 2008 and June 2018 were recorded. Eight hundred and seventy-one renal biopsies were obtained. The main clinical indication for biopsy was nephritic syndrome (36%). SGD was more frequent than PGD (55% vs. 45%). Within SGD group, lupus nephritis (LN) was the most frequent etiology (83%). Within PGD group, membranous nephropathy (33%) and focal segmental glomerulosclerosis (FSGS) (19%) were the most common glomerular diseases. At a 24-month follow-up, the patients with FSGS and paraproteinemia-mediated glomerular disease had the worst renal survival prognosis. This is the first Colombian Nephropathy Registry in a Caribbean population, demonstrating a high predominance of SGD due to LN.

Clinical and pathologic analysis of kidney damage in patients with nephrotic syndrome in the Republic of Srpska

Background / Aim: Nephrotic syndrome (NS) is a clinical syndrome characterised by massive proteinuria > 3.5 g in 24 h urine, hypoalbuminaemia, hyperlipidaemia and oedema. Aim of this study was to determine the aetiology and frequency of kidney diseases that occur as the cause of NS in adults in the Republic of Srpska and the progression of renal insufficiency, disease outcomes and efficacy of applied therapy. Methods: The retrospective study included patients aged 18 to 80 hospitalised between 2014 and 2018 due to clinically and laboratory-manifested NS. In patients with suspected primary glomerular disease, a kidney biopsy with immunofluorescent dyeing was performed. The first examination involved hospital admission and the next check-up six months after the first hospitalisation. Basic clinical parameters were followed: creatinine, clearance creatinine, albumin, total protein, cholesterol, total protein in 24 h urine and microscopy of urine during the first hospitalisation and repeated same laboratory findings on control. The progression of kidney failure during this period was assessed, as well as the efficacy of immunosuppressive therapy. Results: In primary NS category membranous glomerulonephritis (MGN) was present at 40.7 % of patients, followed by focal segmental glomerulosclerosis (FSGS) 21.7 %, membranoproliferative glomerulonephritis (MPGN) 11.9 % and IgA glomerulonephritis (IgAN) 11.9 %. Nephroangiosclerosis was verified as the most common cause of secondary NS with 28.8 % and lupus nephritis 21.2 %, followed by ANCA-associated GN (11.5 %) and diabetic nephropathy (11.5 %). Thirty-four patients (21 %) died during the follow-up. Thirty-four patients (18.6 %) progressed to end stage renal disease during the five-year follow-up. Conclusion: The pathology of kidney disease in older patients is often very complex; therefore, a kidney biopsy should be conducted at an early stage of kidney disease for the purpose of obtaining an accurate diagnosis, determining appropriate treatment and thus improving the prognosis of the patient.

Association between the progression of immunoglobulin A nephropathy and a controlled status of hypertension in the first year after diagnosis

BACKGROUND/AIMS

Hypertension is considered a risk factor in immunoglobulin A nephropathy (IgAN). However, after IgAN diagnosis, the relationship between early blood pressure control and renal prognosis remains unclear. This study aimed to analyze the association between the prognosis of IgAN patients and a controlled status of hypertension within the first year of IgAN diagnosis.

METHODS

We retrospectively analyzed 2,945 patients diagnosed with IgAN by renal biopsy. The patients were divided into 'normal,' 'new-onset,' 'well-controlled,' and 'poorly-controlled' groups using blood pressure data from two consecutive measurements performed within a year. The Kaplan-Meier survival analysis and Cox proportional-hazards regression model were used to survey the independent association between recovery from hypertension and the risk of IgAN progression. The primary endpoint was IgAN progression defined as the initiation of dialysis or kidney transplantation.

RESULTS

Before IgAN diagnosis, 1,239 patients (42.1%) had been diagnosed with hypertension. In the fully adjusted Cox proportional-hazards models, the risk of IgAN progression increased by approximately 1.7-fold for the prevalence of hypertension. In the subgroup analyses, the 'well-controlled' group showed a statistically significant risk of IgAN progression (hazard ratio [HR], 3.19; 95% confidence interval [CI], 1.103 to 9.245; p = 0.032). Moreover, the 'new-onset' and 'poorly-controlled' groups had an increased risk of IgAN progression compared to the 'normal' group (HR, 2.58; 95% CI, 1.016 to 6.545; p = 0.046 and HR, 3.85;95% CI, 1.541 to 9.603; p = 0.004, respectively).

CONCLUSION

Although hypertension was well-controlled in the first year after IgAN diagnosis, it remained a risk factor for IgAN progression.

Chinese medicinal herbs for idiopathic membranous nephropathy in adults with nephrotic syndrome: A systematic review of effectiveness and safety

ABSTRACT

To assess the benefits and harms of Chinese medicinal herbs formulae for the treatment of idiopathic membranous nephropathy in adult patients with primary nephrotic syndrome.Only randomized controlled trials were included. We searched the Cochrane Central Register of Controlled Trials database, PubMed, EMBASE, Chinese National Knowledge Internet, Chinese Biomedicine Database, and VIP. All studies were analyzed using the criteria of the Cochrane Handbook and were assessed in terms of quality and the risk of bias. Review Manager ver. 5.3.5 software was used for the data analysis, and GRADE profiler software was employed to evaluate quality.Two studies were included (n = 126 Chinese participants). We found that compared with against conventional treatment, one Chinese medicinal herbs formula plus conventional treatment reduced 24-hours urinary total protein (mean differences -3.16 g/24 h, 95% confidence intervals -4.03 to -2.29), and two Chinese medicinal herbs formulae increased serum albumin levels (mean differences 3.18 g/L, 95% confidence intervals 1.12 to 5.52; I2 = 0%).Chinese medicinal herbs formulae may reduce 24-hours urinary total protein and increase serum levels of albumin. However, larger and multicenter studies with high methodological quality are still needed.

B Cells in Primary Membranous Nephropathy: Escape from Immune Tolerance and Implications for Patient Management

Membranous nephropathy (MN) is an important cause of nephrotic syndrome and chronic kidney disease (CKD) in adults. The pathogenic significance of B cells in MN is increasingly recognized, especially following the discovery of various autoantibodies that target specific podocytic antigens and the promising treatment responses seen with B cell depleting therapies. The presence of autoreactive B cells and autoantibodies that bind to antigens on podocyte surfaces are characteristic features of MN, and are the result of breaches in central and peripheral tolerance of B lymphocytes. These perturbations in B cell tolerance include altered B lymphocyte subsets, dysregulation of genes that govern immunoglobulin production, aberrant somatic hypermutation and co-stimulatory signalling, abnormal expression of B cell-related cytokines, and increased B cell infiltrates and organized tertiary lymphoid structures within the kidneys. An understanding of the role of B cell tolerance and homeostasis may have important implications for patient management in MN, as conventional immunosuppressive treatments and novel B cell-targeted therapies show distinct effects on proliferation, differentiation and reconstitution in different B cell subsets. Circulating B lymphocytes and related cytokines may serve as potential biomarkers for treatment selection, monitoring of therapeutic response and prediction of disease relapse. These recent advances in the understanding of B cell tolerance in MN have provided greater insight into its immunopathogenesis and potential novel strategies for disease monitoring and treatment.

The spectrum of biopsy-proven glomerular diseases in a tertiary Hospital in Southern Brazil

Background

The prevalence and distribution of glomerular diseases differ among countries, and the indication to perform a kidney biopsy varies among centres. In this study, we assessed the prevalence of primary and secondary glomerulopathies based on histological diagnoses, and the correlation between glomerulopathies and demographic and clinical data was evaluated.

Methods

In this study, 1051 kidney biopsies were retrospectively reviewed between 2000 and 2018. Patient demographic, clinical and laboratory data were assessed. The prevalence of primary glomerulonephritis (PG) and secondary glomerulopathies (SG), as well as tubulointerstitial diseases (TIDs), hereditary nephropathies (HNs) and other diagnoses, were determined. The frequency of primary and secondary glomerulopathies was evaluated by age group, and the temporal variation in frequencies across three time periods (2000-2005, 2006-2011, and 2012-2018) was reported.

Results

The prevalence of SG predominated (52.4%), followed by PG (29.6%), other diagnoses (10.7%), TID (6.6%) and HN (1.1%). Among the primary forms of glomerular disease, focal segmental glomerulosclerosis (FSGS) was the most common (37.3%), followed by IgA nephropathy (IgAN, 24.4%), membranous nephropathy (MN, 18.6%) and minimal change disease (MCD, 8.4%). Lupus nephritis (LN, 41.1%) was most common in patients with SG, followed by diabetic kidney disease (DKD, 17.8%), systemic vasculitis (SV, 10.2%) and secondary FSGS (2nd FSGS, 10%). Nephrotic syndrome was the most common clinical presentation in patients with PG and also in patients with DRD and 2nd FSGS, whereas in patients with IgAN and SV, nephritic syndrome was the main presentation. For the age group between 18 and 50 years, LN, FSGS and IgAN predominated; for patients aged between 51 and 65 years, the proportion of DKD and 2nd FSGS increased, and SV was more common in patients > 65 years. The temporal variation in PG across the three time periods showed a statistically significant increase in IgAN (p = 0.001) and a reduction in FSGS over time (p < 0.001). In SG, there was a reduction in LN (p = 0.027) and an increase in DKD (p < 0.001) over time, with a tendency for 2nd FSGS to decrease over time (p = 0.053).

Conclusions

In the studied kidney biopsy registry, FSGS and IgAN were the most prevalent diagnoses in patients with PG, and LN and DKD were the most prevalent in patients with SG. Nephrotic syndrome was the major indication for biopsy. When comparing the temporal variation in glomerulopathies, there was a reduction in FSGS and an increase in IgAN in patients with PGs over time, and for patients with SGs, there was a reduction in LN with an increase in cases of DKD over time.

Analysis and Study on Epidemiological Features and Prognosis of Nephrotic Syndrome in Xinjiang and Heilongjiang

Backgrounds

The pathogenesis of nephrotic syndrome (NS) is complex, and there are differences between regions. This study attempted to collect clinicopathological data of patients diagnosed with NS in Xinjiang and Heilongjiang in the past 2 years, so as to explore the onset features of NS and treatment and prognosis of patients in the two regions.

Methods

Clinical data of 375 patients diagnosed with NS using renal biopsy in Xinjiang and Heilongjiang from March 2019 to March 2021 were collected. Clinical data of patients before treatment were collected, and the chi-square test was utilized to compare the differences in the sex distribution of two groups. The U test was utilized to compare abnormal distribution continuous data between two groups, such as age, hemoglobin, plasma albumin, proteinuria, and triglycerides. Independent sample t-test was utilized to compare normal distribution continuous data between two groups, such as serum total protein, serum creatinine, blood urea nitrogen, glomerular filtration rate, and total cholesterol. The independent sample t-test was also used to compare the immunoglobulin levels and complement levels between the two groups after treatment, including IgA, IgG, IgM, C3, and C4. Kaplan-Meier method was used to analyze and plot the cumulative curves of complete remission rate and partial remission rate.

Results

For 275 NS patients from Xinjiang, the male-to-female ratio was 0.81 : 1. For 84 patients from Heilongjiang, the male-to-female ratio was 1.05 : 1. The onset ages of patients in Xinjiang and Heilongjiang were 22-45 years old and 22-47 years old, respectively. Respectively, there were 221 cases (80.36%) and 66 cases (78.57%) of primary NS in Xinjiang and Heilongjiang. There were 54 cases (19.64%) and 18 cases (21.43%) of secondary NS in Xinjiang and Heilongjiang, respectively. There was no statistically significant difference in cause distribution between the two regions (p = 0.756). After treatment, immunoglobulin levels (IgA (p = 0.009), IgG (p = 0.002), IgM (p < 0.001)) and complement C3 (p < 0.001) and C4 (p < 0.001) levels in Xinjiang and Heilongjiang were statistically significant. 129 cases in Xinjiang (46.91%) and 55 cases in Heilongjiang (65.48%) were treated with glucocorticoid (GC) combined with immunosuppressive therapy, respectively. After receiving treatment, 67 (24.36%) of 275 patients in Xinjiang achieved complete remission, 166 (60.36%) achieved partial remission, 22 (26.19%) of 84 patients in Heilongjiang achieved complete remission, and 56 (66.67%) achieved partial remission, and there was no statistically significant difference in remission rate between the two regions (p = 0.159). Patients in Xinjiang and Heilongjiang achieved complete remission at an average of 10.34 weeks (9.98-10.70) and 9.95 weeks (9.26-10.65), respectively. There was no significant difference in complete remission rates between the two regions (p = 0.663). Patients in Xinjiang and Heilongjiang achieved partial remission at an average of 8.76 weeks (8.38-9.14) and 7.99 weeks (7.33-8.65), respectively. There was no significant difference in the partial remission rate between the two regions (p = 0.065).

Conclusion

The causes of NS in Xinjiang and Heilongjiang were similar. After treatment, there were differences in immunoglobulin levels (IgA, IgG, IgM) and complement levels (C3, C4) in the two regions. The main treatment methods used in the two regions were GC combined with immunosuppressive therapy. The prognosis of patients in the two regions was similar. The complete remission rate and partial remission rate after treatment in the two regions were similar, and the average time required to achieve complete remission and partial remission was also similar.

[Kidney biopsy in Reunion Island between 2015 and 2017, an epidemiological study]

INTRODUCTION

Reunion Island's population is characterized by a multiethnic origin, which makes it impossible to transpose epidemiological data of Metropolitan France. Only REIN Registry provides a macroscopic view of kidney disease, limited to the causes of end stage renal disease.

METHODS

This is a regional retrospective study whose main objective is to describe renal pathologies in Reunion Island's adults over a period of 3 years. Kidney transplants are excluded.

RESULTS

Between 2015 and 2017, 338 native adult kidney biopsies performed on the island are collected. The annual biopsy rate is 132/million/year with preponderance in the northern part of the island due to a higher density of nephrologists. Nephrotic syndrome is the first indication with 30% of cases. The four main results are represented by IgA nephropathy (16%), diabetic nephropathy (12.4%), lupus nephropathy (11.2%) and isolated vascular nephropathy (11%). Incidence of glomerulopathies is similar to the worldwide incidence, nevertheless a preponderant place of diabetic nephropathy is found. On the biopsies performed, incidence of complications is evaluated at 7.5%, with no difference between the detection technique used.

CONCLUSION

This is the first study illustrating main renal pathologies in Reunion Island. Diabetes' frequency in general population is a major confounding factor in diagnosis and management of kidney diseases on the island.

Increasing prescription of renin-angiotensin-aldosterone system blockers associated with improved kidney prognosis in Korean IgA nephropathy patients

BACKGROUND

We aimed to describe the characteristics of immunoglobulin A nephropathy (IgAN) in Korea with assessment for time trends.

METHODS

We performed a multicenter retrospective observational cohort study including biopsy-confirmed native IgAN cases from four tertiary hospitals in Korea. Time eras of diagnosis were stratified into 1979-2003, 2004-9 and 2010-17. The prognostic variable was progression to end-stage kidney disease (ESKD) analyzed by multivariable Cox regression analysis.

RESULTS

We included 1366 (from 1979 to 2003), 1636 (from 2004 to 2009) and 1442 (from 2010 to 2017) IgAN patients in this study. In the recent periods, IgAN had relatively better clinical characteristics, as patients had higher estimated glomerular filtration rates and lower baseline blood pressures than before. The use of renin-angiotensin-aldosterone system (RAAS) blockers increased from 57.7% in 1979-2003 to 80.0% in 2010-17. During a median follow-up duration of 11.3 years, 722 patients progressed to ESKD with an incidence rate of 12.5 per 1000 person-years. The 10-year risk of progression to ESKD was lower in 2010-17 compared with that of 1979-2003 [adjusted hazard ratio 0.692 (95% confidence interval 0.523-0.915)], even after adjustment for multiple clinicopathologic characteristics. The use of RAAS blockers was a significant mediator (P < 0.001) for the association between time trends and lower 10-year ESKD risk.

CONCLUSIONS

Clinicopathologic characteristics of IgAN in Korea have changed over time. Although the limitation of a retrospective observational study remains, the result showed that the prognosis of IgAN has improved over the study period, possibly related to increased prescription of RAAS blockers.

The Serum Uric Acid Level Is Related to the More Severe Renal Histopathology of Female IgA Nephropathy Patients

Hyperuricemia is a significant risk factor for cardiovascular morbidity and chronic kidney disease progression. IgA nephropathy (IgAN) is a well-known primary glomerular nephropathy. Hyperuricemia is associated with a poor prognosis in IgAN patients. We evaluated the association of hyperuricemia with the histopathological severity of IgAN in male and female patients; 658 patients diagnosed with IgAN via kidney biopsy were initially included. Baseline patient data were collected by eight university hospitals affiliated with the College of Medicine of the Catholic University of Korea. Pathological features were independently evaluated by eight expert pathologists working in the hospitals, and the consensus was reached. Of the initial 658 patients, 517 were finally included (253 males and 264 females). Hyperuricemia was defined as a serum uric acid (UA) level >7.0 mg/dL for males and >5.6 mg/dL for females; 108 (42.7%) males and 95 (35.9%) females exhibited hyperuricemia. Compared to the patients with normal UA levels, the global glomerulosclerosis, segmental sclerosis, mesangial matrix expansion (MME), endocapillary proliferation (ECP), interstitial fibrosis (IF), and tubular atrophy (TA) scores were higher in hyperuricemic males and females. In multivariable linear regression, the serum UA level correlated significantly with the MME, ECP, IF, and TA scores of female IgAN patients only.

Perspectives in membranous nephropathy

The identification of the phospholipase A2 receptor 1 (PLA2R) and thrombospondin type-1 domain-containing protein 7A (THSD7A) as podocyte antigens in adult patients with membranous nephropathy (MN) has strongly impacted both experimental and clinical research on this disease. Evidence has been furnished that podocyte-directed autoantibodies can cause MN, and novel PLA2R- and THSD7A-specific animal models have been developed. Today, measurement of serum autoantibody levels and staining of kidney biopsies for the target antigens guides MN diagnosis and treatment worldwide. Additionally, anti-PLA2R antibodies have been proven to be valuable prognostic biomarkers in MN. Despite these impressive advances, a variety of questions regarding the disease pathomechanisms, clinical use of antibody measurement, and future treatments remain unanswered. In this review, we will outline recent advances made in the field of MN and discuss open questions and perspectives with a focus on novel antigen identification, mechanisms of podocyte injury, clinical use of antibody measurement to guide diagnosis and treatment, and the potential of innovative, pathogenesis-based treatment strategies.

Validation of an international prediction model including the Oxford classification in Korean patients with IgA nephropathy

BACKGROUND

Recently, a new international risk prediction model including the Oxford classification was published which was validated in a large multi-ethnic cohort. Therefore, we aimed to validate this risk prediction model in Korean patients with IgA nephropathy.

METHODS

This retrospective cohort study was conducted with 545 patients who diagnosed IgA nephropathy with renal biopsy in three medical centers. The primary outcome was defined as a reduction in estimated glomerular filtration rate (eGFR) of >50% or incident end-stage renal disease (ESRD). Continuous net reclassification improvement (cNRI) and integrated discrimination improvement (IDI) were used to validate models.

RESULTS

During the median 3.6 years of follow-up period, 53 (9.7%) renal events occurred. In multivariable Cox regression model, M1 (hazard ratio [HR], 2.22; 95% confidence interval [CI], 1.02-4.82; p = .043), T1 (HR, 2.98; 95% CI, 1.39-6.39; p = .005) and T2 (HR, 4.80; 95% CI, 2.06-11.18; p < .001) lesions were associated with increased risk of renal outcome. When applied the international prediction model, the area under curve (AUC) for 5-year risk of renal outcome was 0.69, which was lower than previous validation and internally derived models. Moreover, cNRI and IDI analyses showed that discrimination and reclassification performance of the international model was inferior to the internally derived models.

CONCLUSION

The international risk prediction model for IgA nephropathy showed not as good performance in Korean patients as previous validation in other ethnic group. Further validation of risk prediction model is needed for Korean patients with IgA nephropathy.

The Association between Serum Hemoglobin and Renal Prognosis of IgA Nephropathy

Immunoglobin A (IgA) nephropathy causes chronic kidney disease worldwide. Therefore, identifying risk factors associated with the progression of IgA nephropathy is crucial. Anemia is a common complication of chronic kidney disease; however, few studies have investigated the effect of serum hemoglobin on the renal prognosis of IgA nephropathy. This study aimed to determine the effect of serum hemoglobin on the progression of IgA nephropathy. We retrospectively analyzed 4326 patients with biopsy-proven IgA nephropathy. We evaluated the effect of serum hemoglobin on IgA nephropathy progression using Kaplan-Meier survival analyses, the log-rank test, and the Cox proportional hazards model. The primary end-point was progression of IgA nephropathy, defined as dialysis initiation or kidney transplantation. Serum hemoglobin showed a nonlinear relationship with the progression of IgA nephropathy. The Cox proportional hazards model showed that the risk of progression of IgA nephropathy decreased 0.87 times for every 1.0 g/dL increase in serum hemoglobin. In subgroup analyses, reduced serum hemoglobin was an independent risk factor for IgA nephropathy progression only in women. There was no statistically significant interaction of serum hemoglobin between men and women (P _interaction = 0.177). Results of Sensitivity analysis were robust and consistent. Serum hemoglobin at diagnosis was an independent predictor for IgA nephropathy progression.

Comparison of the Efficacy and Safety of Tacrolimus and Low-Dose Corticosteroid with High-Dose Corticosteroid for Minimal Change Nephrotic Syndrome in Adults

BACKGROUND

Tacrolimus is used as a steroid-sparing immunosuppressant in adults with minimal change nephrotic syndrome. However, combined treatment with tacrolimus and low-dose steroid has not been compared with high-dose steroid for induction of clinical remission in a large-scale randomized study.

METHODS

In this 24-week open-label noninferiority study, we randomized 144 adults with minimal change nephrotic syndrome to receive 0.05 mg/kg twice-daily tacrolimus plus once-daily 0.5 mg/kg prednisolone, or once-daily 1 mg/kg prednisolone alone, for up to 8 weeks or until achieving complete remission. Two weeks after complete remission, we tapered the steroid to a maintenance dose of 5-7.5 mg/d in both groups until 24 weeks after study drug initiation. The primary end point was complete remission within 8 weeks (urine protein: creatinine ratio <0.2 g/g). Secondary end points included time until remission and relapse rates (proteinuria and urine protein: creatinine ratio >3.0 g/g) after complete remission to within 24 weeks of study drug initiation.

RESULTS

Complete remission within 8 weeks occurred in 53 of 67 patients (79.1%) receiving tacrolimus and low-dose steroid and 53 of 69 patients (76.8%) receiving high-dose steroid; this difference demonstrated noninferiority, with an upper confidence limit below the predefined threshold (20%) in both intent-to-treat (11.6%) and per-protocol (17.0%) analyses. Groups did not significantly differ in time until remission. Significantly fewer patients relapsed on maintenance tacrolimus (3-8 ng/ml) plus tapered steroid versus tapered steroid alone (5.7% versus 22.6%, respectively; P=0.01). There were no clinically relevant safety differences.

CONCLUSIONS

Combined tacrolimus and low-dose steroid was noninferior to high-dose steroid for complete remission induction in adults with minimal change nephrotic syndrome. Relapse rates were significantly lower with maintenance tacrolimus and steroid compared with steroid alone. No clinically-relevant differences in safety findings were observed.

Pattern of kidney diseases in Northern India: an overview through histopathological findings in biopsy-proven cases

Background

A kidney biopsy is being increasingly performed for the diagnosis of renal diseases. It is a reasonably safe procedure that helps not only to reach the correct diagnosis based on histopathological findings but also helps in predicting the clinical course and outcome. The pattern of kidney diseases varies not only in far apart geographical regions but also in the same country. This study was done to evaluate the demographic pattern and spectrum of kidney diseases in renal biopsy-proven cases in an admitted patient of a tertiary care hospital of northern India.

Results

The mean age of patients was 41.3 years ± 18.39 years, and the male-to-female ratio was 1.7:1. The most common indication for biopsy in this study was nephrotic syndrome (40.5%). The primary glomerular disease was most common, accounting for 57.5% of cases. Membranous nephropathy (MN) was the most frequently observed histopathological diagnosis not only in the primary glomerular disease category (22.9%) but of all cases (13.2%) as well. Among secondary cases, diabetic nephropathy was most frequent, constituting 43.4% cases. Interstitial and vascular diseases accounted for 18.8% and 1.8% of total cases, respectively. While minimal change disease (MCD) was the most common diagnosis in < 18-year age group, membranous nephropathy was most common above this age. Regarding the gender factor, membranoproliferative glomerulonephritis had an equal distribution among both genders, while MCD had a female preponderance.

Conclusions

Primary glomerular disease is the predominant kidney disease in northern India with MN being the most common histopathological diagnosis. The spectrum of kidney diseases varied with patient’s age and gender.

Lupus nephritis: clinical presentations and outcomes in the 21st century

Lupus nephritis (LN) is a frequent and severe manifestation of SLE. Along the decades, the epidemiology of LN and its clinical presentation have been changing. However, even though retrospective cohort studies report a decreased mortality rate and an improvement in the disease prognosis, the percentage of patients progressing into end stage renal disease (ESRD) keeps steady despite the improvements in therapeutic strategies. Current in-use medications have been available for decades now, yet over the years, regimens for optimizing their efficacy and minimizing toxicity have been developed. Therapeutic research is now moving towards the direction of precision medicine and several new drugs, targeting selectively different pathogenetic pathways, are currently under evaluation with promising results. In this review, we address the main changes and persistent unmet needs in LN management throughout the past decades, with a focus on prognosis and upcoming treatments.

Epidemiological features of primary glomerular disease in Turkey: a multicenter study by the Turkish Society of Nephrology Glomerular Diseases Working Group

Background

The largest data on the epidemiology of primary glomerular diseases (PGDs) are obtained from the databases of countries or centers. Here, we present the extended results of the Primary Glomerular Diseases Study of the Turkish Society of Nephrology Glomerular Diseases (TSN-GOLD) Working Group.

Methods

Data of patients who underwent renal biopsy and received the diagnosis of PGD were recorded in the database prepared for the study. A total of 4399 patients from 47 centers were evaluated between May 2009 and May 2019. The data obtained at the time of kidney biopsy were analyzed. After the exclusion of patients without light microscopy and immunofluorescence microscopy findings, a total of 3875 patients were included in the study.

Results

The mean age was 41.5 ± 14.9 years. 1690 patients were female (43.6%) and 2185 (56.3%) were male. Nephrotic syndrome was the most common biopsy indication (51.7%). This was followed by asymptomatic urinary abnormalities (18.3%) and nephritic syndrome (17.8%). The most common PGD was IgA nephropathy (25.7%) followed by membranous nephropathy (25.6%) and focal segmental glomerulosclerosis (21.9%). The mean total number of glomeruli per biopsy was 17 ± 10. The mean baseline systolic blood pressure was 130 ± 20 mmHg and diastolic blood pressure was 81 ± 12 mmHg. The median proteinuria, serum creatinine, estimated GFR, and mean albumin values were 3300 (IQR: 1467–6307) mg/day, 1.0 (IQR: 0.7–1.6) mg/dL, 82.9 (IQR: 47.0–113.0) mL/min and 3.2 ± 0.9 g/dL, respectively.

Conclusions

The distribution of PGDs in Turkey has become similar to that in other European countries. IgA nephropathy diagnosed via renal biopsy has become more prevalent compared to membranous nephropathy.

Association between PLA2R1 rs4664308 and susceptibility to idiopathic membranous nephropathy: Protocol for a systematic review and meta-analysis of case-control studies

Previous studies have evaluated the association between the phospholipase A2 m-type receptor (PLA2R1) rs4664308 polymorphism and the risk of idiopathic membranous nephropathy (IMN), but the results need to be integrated. We hypothesized that the PLA2R1 rs4664308 polymorphism is associated with IMN risk in different ethnicities and assessed this hypothesis by using meta-analysis and case-control studies.A literature searches on PLA2R1 rs4664308 and IMN risk was conducted using the EMBASE, PubMed, Cochrane Library, and Chinese Medical Databases. The relationship between PLA2R1 rs4664308 and IMN risk was evaluated in 5 genetic models, namely, allelic (AG), recessive (RG), dominant (DG), homozygous (HMG), and heterozygous (HTG) models. Subgroup analysis was conducted by ethnicity on Asian and non-Asian populations.Eight sets of data from 6 articles met study objectives were selected and 6797 subjects (IMN: 2324 Controls: 4,473) were included. Heterogeneity was found in the DG, HMG, and HTG models but not in the AG or RG models. The minor allele(G) of PLA2R1 rs4664308 showed a significant negative correlation with IMN risk in all genetic random models: odds ratio of AG: 0.44(0.37-0.51), RG: 0.35(0.29-0.42), DG: 0.38(0.31-0.48), HMG: 0.26(0.19-0.37), and HTG: 0.61(0.48-0.77; P < .00001), and Asians and non-Asians showed the same effect of PLA2R1 rs4664308 on IMN risk. Analysis of Asians and non-Asians revealed no publication bias in any of the 5 genetic models.The minor allele of PLA2R1 rs4664308 has a protective activity against IMN in Asians and non-Asians. It provided new insights into potential curative and preventative treatments for IMN.

Clinical features of acute kidney injury in patients with nephrotic syndrome and minimal change disease: a retrospective, cross-sectional study

Background:

Minimal change nephropathy (MCD) is a common pathological type of nephrotic syndrome and is often associated with acute kidney injury (AKI). This study aimed to investigate the clinical characteristics and related factors of AKI in patients with MCD and nephrotic syndrome.

Methods:

Patients from Chinese People's Liberation Army General Hospital who were diagnosed with pathological renal MCD with clinical manifestations of nephrotic syndrome were included from January 1, 2013 to December 31, 2017. Patients diagnosed with membranous nephropathy (MN) by renal biopsy from January 1, 2013 to December 31, 2017 are included as a control population. We retrospectively analyzed the clinical and pathological characteristics of patients as well as the percentages and clinical characteristics of AKI in different age groups. We assessed the correlation of pathological characteristics with serum creatinine using multivariate linear regression analysis.

Results:

A total of 367 patients with MCD were included in the analysis, with a sex ratio of 1.46: 1 (male: female) and an age range of 6 to 77 years. Among all the patients, 109 developed AKI (29.7%), and of these patients, 85 were male (78.0%). In the 586 patients with MN, 27 (4.6%) patients developed AKI. The percentage of AKI in MCD patients was significantly higher than that in MN patients (χ² = 41.063, P < 0.001). The percentage of AKI increased with age in the MCD patients. The percentage of AKI in patients aged 50 years or older was 52.9% (46/87), which was significantly higher than that [22.5% (63/280)] in patients under 50 years (χ² = 6.347, P = 0.013). We observed statistically significant differences in age (43 [27, 59] years vs. 28 [20, 44] years, Z = 5.487, P < 0.001), male (78.0% vs. 51.4%, χ² = 22.470, P < 0.001), serum albumin (19.9 ± 6.1 g/L vs. 21.5 ± 5.7 g/L, t = 2.376, P = 0.018), serum creatinine (129.5 [105.7, 171.1] μmol/L vs. 69.7 [57.7, 81.9] μmol/L, Z = 14.190, P < 0.001), serum urea (10.1 [6.2, 15.8] mmol/L vs. 4.7 [3.6, 6.4] mmol/L, Z = 10.545, P < 0.001), IgE (266.0 [86.7, 963.0] IU/ml vs. 142.0 [35.3, 516.5] IU/ml, Z = 2.742, P = 0.007), history of diabetes (6.4% vs. 1.2%, P = 0.009), and history of hypertension (23.9% vs. 5.1%, χ² = 28.238, P < 0.001) between the AKI group and the non-AKI group. According to multivariate linear regression analysis, among the renal pathological features analyzed, renal tubular epithelial cell damage (β = 178.010, 95% CI: 147.888−208.132, P < 0.001) and renal interstitial edema (β = 28.833, 95% CI: 11.966−45.700, P = 0.001) correlated with serum creatinine values.

Conclusions:

The percentage of AKI in MCD patients is significantly higher than that in MN patients. Patients over 50 years old are more likely to develop AKI. Renal tubular epithelial cell injury and renal interstitial edema may be the main pathological lesions that are associated with elevated serum creatinine in patients with MCD.

Urinary cMet as a prognostic marker in immunoglobulin A nephropathy

The prediction of prognosis in patients with immunoglobulin A nephropathy (IgAN) is challenging. We investigated the correlation between urinary cMet (ucMet) levels and clinical parameters and examined the effects of cMet agonistic antibody (cMet Ab) in an in vitro IgAN model. Patients diagnosed with IgAN (n = 194) were divided into three groups representing undetectable (Group 1), below‐median (Group 2) and above‐median (Group 3) levels of ucMet/creatinine (ucMet/Cr). Stained kidney biopsy samples were graded according to cMet intensity. Primary‐cultured human mesangial cells were stimulated with recombinant tumour necrosis factor (TNF)‐α and treated with cMet Ab. Our results showed that ucMet/Cr levels positively correlated with proteinuria (P < .001). During the follow‐up, patients in Group 3 showed a significantly lower probability of complete remission (CR; uPCr < 300 mg/g) than those in groups 1 and 2, after adjusting for blood pressure, estimated glomerular filtration rate, and proteinuria, which influence clinical prognosis (HR 0.60, P = .038); moreover, ucMet/Cr levels were also associated with glomerular cMet expression. After TNF‐α treatment, the proliferation of mesangial cells and increased interleukin‐8 and intercellular adhesion molecule‐1 expression were markedly reduced by cMet Ab in vitro. In conclusion, ucMet/Cr levels significantly correlated with proteinuria, glomerular cMet expression, and the probability of CR. Further, cMet Ab treatment alleviated the inflammation and proliferation of mesangial cells. Hence, ucMet could serve as a clinically significant marker for treating IgAN.

Spectrum of biopsy proven renal diseases in Central China: a 10-year retrospective study based on 34,630 cases

Chronic kidney diseases have become a major issue worldwide. The spectrum of biopsy proven renal diseases differs between locations and changes over time. It is therefore essential to describe the local epidemiological trends and the prevalence of renal biopsy in various regions to shine new light on the pathogenesis of various renal diseases and provide a basis for further hypothesis-driven research. We retrospectively analyzed 34,630 hospitalized patients undergoing native renal biopsy between January 1, 2009 and December 31, 2018. Indications for renal biopsy and histological diagnosis were analyzed to describe the prevalence of renal biopsy, and changing prevalence between period 1 (2009-2013) and period 2 (2014-2018) were further analyzed. Nephrotic syndrome (NS) was the most common indication for biopsy. Membranous nephropathy (MN, 24.96%) and IgA nephropathy (IgAN, 24.09%) were the most common primary glomerulonephritis (PGN). MN was most common in adults, with IgAN more prevalent in children. Lupus nephritis (LN) was the most common secondary glomerulonephritis (SGN) in adults, while Henöch-Schönlein purpura nephritis (HSPN) in children. The prevalence of MN increased significantly and nearly doubled from period 1 (15.98%) to period 2 (30.81%) (P = 0.0004). The same trend appeared with membranoproliferative glomerulonephritis (MPGN), diabetic nephropathy (DN) and obesity-related glomerulopathy (ORG), while the frequencies of minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), LN and hepatitis B associated glomerulonephritis (HBV-GN) significantly decreased between the two intervals. NS was the most common indication for biopsy across all age groups and genders. MN has overtaken IgAN to become the most common PGN in adults, while IgAN was the most common PGN in children. LN was the most common SGN in adults, and HSPN the most common in children.

Cancer development and mortality differences in patients with glomerulonephritis after renal biopsy: a single center retrospective cohort study

Background

The association between glomerulonephritis (GN) and cancer has been well known for decades. However, studies evaluating long-term de novo cancer development in patients with GN are limited. This study aimed to evaluate the incidence of cancer development among patients with renal biopsy-proven GN during post-biopsy follow-up and the differences in outcomes according to cancer occurrence.

Methods

We conducted a retrospective cohort study of adult patients who underwent renal biopsy at Seoul National Bundang Hospital between 2003 and 2017. After excluding 778 patients with age < 18 years, cancer diagnosis before or within 6 months after renal biopsy, immunosuppressant therapy before renal biopsy, or pathologic diagnoses other than GN, 822 patients were included in the analysis. Data on baseline clinical characteristics, renal biopsy results, and types and doses of immunosuppressant agents were collected from electronic medical records. The incidence of cancer was censored on the date when the first cancer was diagnosed. We evaluated rates of mortality and end-stage renal disease (ESRD) development during follow-up.

Results

During a mean follow-up period of 58.9 ± 44.5 months, 45 subjects (5.5%) developed de novo cancer. A comparison of clinical characteristics between subjects who did and did not develop cancer revealed that cancer patients were older and had higher comorbidities and immunosuppressant use. Overall, patients with GN had an elevated standardized incidence ratio (SIR) of 7.16 (95% confidence interval (CI): 5.22–9.61) relative to the age- and sex-matched general population. In particular, the SIR was significantly higher in GNs such as membranous nephropathy (MN), IgA nephropathy, lupus nephritis, and focal segmental glomerulosclerosis. Multivariable Cox proportional hazard model revealed that patients with MN had an increased risk of cancer development, with a hazard ratio of 2.30 [95% CI: 1.06–4.98]. Patients with MN who developed cancer had a significantly higher risk of mortality (hazard ratio: 6.59; 95% CI: 1.22–35.56, P = 0.03) than those without cancer, but there was a non-significant difference in ESRD development. Conclusions: Patients with GN without concurrent cancer, particularly those with MN, have significantly higher risks of cancer development and subsequent mortality and should remain aware of the potential development of malignancy during follow-up.

Changing Frequency of Glomerular Diseases in Western Saudi Arabia: A 26-Year Experience

Introduction:

The frequency of glomerulonephritis (GN) is reported to be changing in the world over the past four decades. Few studies arise from the western region of Saudi Arabia.

Aims:

The aim of this study was to address the frequency of primary GN (1ry GN) and secondary GN (2ry GN) over a period of 26 years in the western region of Saudi Arabia and compare to previous data from other regions of the country.

Subjects and Methods:

The records of adult renal biopsies, 448 1ry GN and 263 2ry GN, are analyzed. Frequencies of GN subtypes are compared for period 1 (1988–19999) and period 2 (2000–2013).

Results:

Postinfectious GN (PIGN) and minimal change disease (MCD) show significant changes (P ≤ 0.05). PIGN increased to 6.5% in period 2 from 0% in period 1. MCD decreased to 5.9% in period 2 from 13.5% in period 1. Membranous GN is the most common 1ry GN for both periods with similar percentages (23.8% and 24.2%, respectively). Focal segmental glomerulosclerosis (FSGSC) is the second in period 2 (23%); immunoglobulin A nephropathy at 9.6% became the third, and MCD is the last place instead of the fourth in period 1. Lupus nephritis is the most common 2ry GN. Pooled data from Saudi studies show FSGSC the most common 1ry GN in both periods.

Conclusions:

The western region of Saudi Arabia presents with a different 1ry GN pattern than the rest of the country that is likely attributed to its unique geographical and environmental characteristics.

Age-adjusted global glomerulosclerosis predicts renal progression more accurately in patients with IgA nephropathy

The Oxford classification was developed to predict the outcome of IgA nephropathy (IgAN). Based on the upper reference limit (95^th percentile) for the number of globally sclerotic glomeruli (GSG) expected on biopsy according to age, we evaluated whether the prognosis of IgAN was affected by the age-calibrated numbers of GSG independent of the Oxford classification. Patients diagnosed with IgAN on renal biopsy in a single center from January 2011 to December 2018 were analyzed retrospectively. Patients with more GSG number than the upper reference limit expected on biopsy according to age were categorized in a group of GSG abnormal for age. We analyzed in two ways, calculating the median rate of decline in estimated glomerular filtration rate (eGFR) and time-to-event defined as a decline of eGFR level to 40% lower than the baseline. There were 111 patients in the group of GSG abnormal for age. In this group, the rate of eGFR decline was faster by 1.85 (3.68–0.03) ml/min/1.73 m² per year in the fully-adjusted robust regression model. The adjusted hazard ratio for eGFR decline for renal outcome was 29.10 (2.18–388.49). The cumulative incidence of CKD progression was significantly higher, especially for those with T score of 0 in the Oxford classification. We suggest that GSG abnormal for age is an independent risk factor in predicting the renal outcome of IgAN.

Patterns in renal diseases diagnosed by kidney biopsy: A single-center experience

Background

The worldwide incidence of renal disease diagnosed by a kidney biopsy varies with age, race, sex, and region. Owing to a lack of studies and limited research resources for this disease in Korea, we investigated renal disease patterns by analyzing data from kidney biopsies performed over 13 years in a university-based teaching hospital in Korea.

Methods

Among 2,053 kidney biopsies performed from 2001 to 2013 at Kyungpook National University Hospital, 1,924 were retrospectively analyzed for histopathologic, demographic, and clinical data as well as laboratory results.

Results

Among the 1,924 studied kidney biopsies, 1,078 were males (56.0%) and the mean age was 37.7 ± 16.5 years. Asymptomatic urinary abnormalities were the most common clinical manifestation (62.5%). Immunoglobulin A nephropathy (IgAN) was the most common primary glomerular disease (37.4%), followed by minimal change disease (MCD), membranous nephropathy (MN), focal segmental glomerulonephritis and crescentic glomerulonephritis. Secondary glomerular diseases accounted for 10.3% of the total biopsies, with lupus nephritis being the most common (4.6%) followed by Henoch-Schönlein purpura nephritis and diabetic nephropathy. The most common cause of nephrotic syndrome was MCD (42.1%) followed by MN. Among patients seropositive for hepatitis B or C, IgAN (28.3% and 21.4%, respectively) was the most common cause.

Conclusion

IgAN and lupus nephritis were the most common primary and secondary glomerular diseases, respectively. Race, region, and practice patterns may affect renal disease patterns in different cohorts.

The Effects of Hyperuricemia on the Prognosis of IgA Nephropathy are More Potent in Females

Hyperuricemia is a potential risk factor for immunoglobulin A nephropathy (IgAN) progression but its sex-specific effects on IgAN progression remain unclear. This study aimed to determine the effect of serum uric acid on IgAN progression and whether its effect varied according to sex. A total of 4339 patients who diagnosed with IgAN by renal biopsy were retrospectively analyzed. We assessed the association of serum uric acid on IgAN progression using Kaplan–Meier survival analyses and Cox proportional hazards models. The study’s primary end point was IgAN progression that was defined as a 50% decline in the estimated glomerular filtration rate or the initiation of dialysis. On average, the serum uric acid levels were higher in the men than in the women. In the fully adjusted Cox proportional hazards model that considered all subjects, the risk of IgAN progression increased by about 25.6% for every 1 mg/dL increase in the baseline uric acid level. The serum uric acid level was an independent risk factor for IgAN progression in both sexes but its effect was more pronounced in the women (hazard ratio [HR], 1.383; confidence interval [CI],1.263 to 1.514; p < 0.001) than in the men (HR, 1.181; CI, 1.097 to 1.272; p < 0.001) (p_interaction < 0.001). A sensitivity analysis involving serum uric acid quartiles generated consistent and robust results. In conclusion, the serum uric acid level was an independent risk factor for IgAN progression and its effect was more pronounced among the women compared with that among the men.

Primary glomerular nephropathy among hospitalized patients in a national database in China

Background

Primary glomerular nephropathy (PGN) is a leading cause of end-stage renal disease in developing countries, however, nationwide studies investigating the spectrum of PGN are limited.

Methods

To evaluate the composition of various pathological types of PGN in a comprehensive geographic coverage in China, a national inpatient database covering 43.7 million patients was used in this analysis. Diagnoses were extracted from the discharge diagnoses.

Results

The percentage of patients with PGN in hospitalized patients decreased from 0.80% in 2010 to 0.67% in 2015. Among hospitalized patients with PGN, a decreasing trend of immunoglobulin A nephropathy (from 19.0% in 2010 to 10.6% in 2015) and an increasing trend of idiopathic membranous nephropathy (from 4.5% in 2010 to 8.8% in 2015) were revealed. A positive association between the percentage of idiopathic membranous nephropathy (iMN) and the exposure of particulate matter with a diameter < 2.5 μm was observed north of the Yangtze River (P < 0.001, R2 = 0.828). South of the Yangtze River, the proportion of the Zhuang population was positively correlated to the frequency of iMN (P = 0.012, r = 0.697).

Conclusions

In conclusion, a changing spectrum of PGN was observed between 2010 and 2015 in China and both environmental and genetic factors might play pivotal roles in the pathogenesis of iMN in the Chinese population.

Glomerular disease frequencies by race, sex and region: results from the International Kidney Biopsy Survey

Background

Large-scale studies comparing glomerular disease frequencies across continents are lacking.

Methods

We surveyed 29 nephropathology laboratories in four continents using a standardized data collection form. We obtained recent consecutive kidney biopsy diagnosis frequencies at each center and summary demographics for each diagnosis. This report focuses on glomerular disease frequencies by region and race/ethnicity.

Results

Among 42 603 glomerular disease diagnoses reported (median age 47 years, 52% male, 57% white), from a total of 60 340 diagnoses, glomerular disease subtype frequencies differed considerably by continent. Diabetic glomerulosclerosis (GS; 19.1%) and focal segmental glomerulosclerosis (FSGS; 19.1%) predominated in North America; lupus nephritis (38.1%) and FSGS (15.8%) predominated in Latin America; IgA nephropathy (IgAN; 22.1%) and FSGS (14.9%) predominated in Europe; and IgAN (39.5%) and lupus nephritis (16.8%) predominated in Asia. After stratifying by race, diabetic GS (17.4% versus 4.3%, P < 0.001) and FSGS (17.3% versus 11.8%, P < 0.001) were more, and lupus nephritis less (15.8% versus 45.6%, P < 0.001), frequent among Latinos in North versus Latin America; FSGS was more (13.1% versus 7.1%, P < 0.001), and IgAN less (27.4% versus 40.5%, P < 0.001), frequent among Asians in North America versus Asia; and FSGS (18.9% versus 13.5%, P < 0.001) and diabetic GS (18.7% versus 6.5%, P < 0.001) were more, and IgAN less (14.4% versus 25.4%, P < 0.001), frequent among whites in North America versus Europe.

Conclusions

We determined that glomerular disease frequencies differed by continent, even among patients of similar race/ethnicity. Regional environmental and lifestyle factors, and local biopsy policies, might influence glomerular disease epidemiology independently of race/ethnicity.