Biopsy-proven Kidney Diseases Research Articles

Screening for Peripheral Vascular Disease: The Role of Ankle-Brachial Index (ABI) and Estimated Glomerular Filtration Rate (eGFR) Changes in Chronic Kidney Disease.

Background Chronic kidney disease (CKD) is a significant public health issue worldwide, closely linked with cardiovascular events such as atherosclerosis, peripheral arterial disease (PAD), stroke, coronary artery disease (CAD), and heart failure. The ankle-brachial index (ABI) is a simple tool that compares blood pressure in the ankle and arm, helping to detect PAD and assess the risk of cardiovascular events. An increased ABI signifies an increased risk of cardiovascular disease (CVD), whereas a diminished ABI correlates with angiographically verified atherosclerosis along with heightened death rates. Recent research indicates a U-shaped relationship between ABI and mortality, underscoring the necessity for early detection and action to mitigate potential consequences. Aim This study aimed to correlate ABI changes with estimated glomerular filtration rate (eGFR) changes in CKD patients to screen for the development of peripheral vascular disease. Materials and methods This prospective cross-sectional study was conducted in the outpatient department of a tertiary care hospital in India, focusing on patients diagnosed with CKD admitted to the general medicine department. The inclusion criteria were CKD patients with an eGFR less than 60 ml/min/1.73 m², accompanied by indicators of renal damage such as albuminuria, reduced kidney size on ultrasound, abnormal urinary sediment, or biopsy-proven kidney disease. Patients with peripheral vascular disease, with end-stage renal disease (on dialysis), with limb amputations, with hemodynamic instability, or who declined participation were excluded. eGFR was calculated using the Modification of Diet in Renal Disease (MDRD) equation, and the ABI was measured at baseline, three months, and six months. ABI values below 0.9 indicated peripheral vascular disease, and the study aimed to correlate changes in ABI with eGFR to assess vascular disease development in non-dialyzed CKD patients. Results By the end of the third month, a positive correlation was observed between ABI and eGFR (r=0.259), which persisted at the end of the sixth month (r=0.245). Conclusion The study concludes that a direct relationship exists between decreasing eGFR and ABI, which increases susceptibility to PAD and CVD. A low ABI is linked to an accelerated decline in eGFR, indicating that systemic atherosclerosis predicts kidney function deterioration.

A Decade of Biopsy-Proven Kidney Diseases: Temporal Trends and Clinical Correlates from a Single Tertiary Center in Saudi Arabia, 2013-2022

A Decade of Biopsy-Proven Kidney Diseases: Temporal Trends and Clinical Correlates from a Single Tertiary Center in Saudi Arabia, 2013-2022

The Spectrum of Biopsy-Proven Kidney Disease in People Living with HIV in Tertiary-Care Centers in Mexico City

The Spectrum of Biopsy-Proven Kidney Disease in People Living with HIV in Tertiary-Care Centers in Mexico City

Management and Clinical Outcomes of Membranous Nephropathy, IgA Nephropathy, and Minimal Change Disease Two Years Post-Kidney Biopsy.

This study evaluated the phenotypic and pathology characteristics of patients undergoing kidney biopsy at a single center, while also determining the frequency and factors associated with clinical outcomes. The incidence and distribution of biopsy-proven kidney diseases in 2000-2019 were surveyed. Consecutive individuals diagnosed with membranous nephropathy (MN), immunoglobulin A nephropathy (IgAN), and minimal change disease (MCD) between August 2015 and December 2019 were enrolled in the prospective 2-year follow-up study. Outcomes included remission of proteinuria and kidney disease progression events. Multivariable-adjusted Cox proportional hazards model was applied. 4,550 kidney biopsies were performed in 2000-2019, showing a noticeable increase in the proportion of MN. 426 patients were enrolled in the follow-up cohort. 346 (81.2%) achieved remission of proteinuria, 39 (9.2%) suffered kidney disease progression and 51.3% of them were diagnosed with IgAN. Kidney pathological diagnosis (MN vs. MCD: hazard ratio [HR], 0.42; 95% confidence interval [95% CI], 0.31-0.57; IgAN vs. MCD: 0.58; 0.39-0.85), levels of 24-h urine protein at biopsy (1.04; 1.00-1.08) and presence of nodular mesangial sclerosis (0.70; 0.49-0.99) were significantly correlated with remission of proteinuria after adjusting for baseline variables. 24-h urine protein levels at biopsy (1.14; 1.04-1.25) and the presence of crescents (2.30; 1.06-4.95) were the independent risk factors for kidney disease progression events after adjusting for baseline variables. The increasing frequency of MN has been affirmed over the past 2 decades. The therapeutic status, clinical outcomes, and factors influencing these outcomes were presented in this single-center study for the three primary glomerular diseases.

Associations of urinary fetuin-A with histopathology and kidney events in biopsy-proven kidney disease.

Fetuin-A is implicated in the pathogenesis of vascular calcification in chronic kidney disease (CKD); however, the relationship between fetuin-A, histopathologic lesions and long-term kidney outcomes in patients with various types of kidney disease remains unclear. We measured urinary fetuin-A levels in 335 individuals undergoing clinically indicated native kidney biopsy. The expressions of fetuin-A mRNA and protein in the kidney were assessed using RNA sequencing and immunohistochemistry. The association of urinary fetuin-A with histopathologic lesions and major adverse kidney events (MAKE), defined as a decline in estimated glomerular filtration rate (eGFR) of at least 40%, kidney failure or death, was analyzed. Urinary fetuin-A levels showed a positive correlation with albuminuria (rs=0.67, P<.001) and a negative correlation with eGFR (rs=-0.46, P<.001). After multivariate adjustment, higher urinary fetuin-A levels were associated with glomerular inflammation, mesangial expansion, interstitial fibrosis and tubular atrophy, and arteriolar sclerosis. Using a 1 transcript per million gene expression cutoff, we found kidney fetuin-A mRNA levels below the threshold in both individuals with normal kidney function and those with CKD. Additionally, immunohistochemistry revealed reduced fetuin-A staining in tubular cells of CKD patients compared with normal controls. During a median 21-month follow-up, 115 patients experienced MAKE, and Cox regression analysis confirmed a significant association between elevated urinary fetuin-A and MAKE. This association remained significant after adjusting for potential confounding factors. Urinary fetuin-A is associated with chronic histological damage and adverse clinical outcomes across a spectrum of biopsy-proven kidney diseases.

The impact of SARS-CoV-2 infection on renal function in patients with biopsy-proven kidney diseases.

We sought to evaluate the long-term effects of COVID-19 on renal function in patients with biopsy-proven kidney diseases. A total of 451 patients with biopsy-proven kidney disease and at least 12 months of follow-up subsequent to COVID-19 pandemic onset were included in the study. The primary study endpoint was a composite of a persistent decline of more than 30% in eGFR or ESRD. 23.1% of patients had COVID-19 during a follow-up period of 2.5 y (0.8-2.6), while 17.6% of patients reached the composite endpoint. Those with COVID-19 were more likely to reach the composite endpoint [26.7% vs. 14.8%; OR, 2.1 (95%CI, 1.23-3.58), p = 0.006). There was a significant eGFR change in the first year of follow-up between the two study groups [-2.24 (95%CI,-4.86; 0.37) vs. +2.31 (95%CI, 0.78; 3.85) ml/min, p = 0.004], with an adjusted mean difference of -4.68 ml/min (95%CI,-7.7; -1.59)(p = 0.03). The trend for worse renal outcomes remained consistent in patients with IgAN, MN and FSGS, but not in those with LN. After multivariate adjustment, the independent predictors of the composite endpoint were baseline eGFR (HR, 0.94; 95%CI, 0.92-0.95), COVID-19 (HR, 1.91; 1.16-3.12) and male gender (HR, 1.64; 95%CI, 1.01-2.66). In multivariate linear regression analysis, COVID-19 independently determined a reduction of eGFR at 12 months by 4.62 ml/min/1.73m2 (β coefficient, -4.62; 95%CI, -7.74 to -1.5, p = 0.004). There is a significant impact of COVID-19 on long-term renal function in patients with biopsy-proven kidney diseases, leading to a greater decline of eGFR and a worse renal survival.

The Spectrum of Biopsy-Proven Kidney Diseases, Causes, and Renal Outcomes in Acute Kidney Injury Patients

Introduction: Acute kidney injury (AKI) is a group of highly heterogeneous, complicated clinical syndromes. Although kidney biopsy plays an irreplaceable role in evaluating complex AKI, a few studies have focused on the clinicopathology of AKI biopsies. This study analyzed the pathological disease spectrum, causes, and renal outcomes of biopsied AKI patients. Methods: We retrospectively included 2,027 AKI patients who underwent kidney biopsies at a national clinical research center of kidney diseases from 2013 through 2018. To compare the biopsied AKI cases without and with coexisting glomerulopathy, patients were classified into acute tubular/tubulointerstitial nephropathy-associated AKI (ATIN-AKI) and glomerular disease-associated AKI (GD-AKI) groups. Results: Of 2,027 biopsied AKI patients, 65.1% were male, with a median age of 43 years. A total of 1,590 (78.4%) patients had coexisting GD, while only 437 (21.6%) patients had ATIN alone. The AKI patients with GD mainly (53.5%) manifested as stage 1 AKI, while most ATIN-AKI patients (74.8%) had stage 3 AKI. In the ATIN-AKI group, 256 (58.6%) patients had acute interstitial nephritis (AIN), and 77 (17.6%) had acute tubular injury (ATI). ATIN-AKI was mainly caused by drugs in 85.5% of AIN and 63.6% of ATI cases, respectively. In AKI patients with coexisting GD, the leading pathological diagnoses in over 80% of patients were IgA nephropathy (IgAN, 22.5%), minimal change disease (MCD, 17.5%), focal segmental glomerulosclerosis (FSGS, 15.3%), lupus nephritis (LN, 11.9%), membranous nephropathy (MN, 10.2%), and ANCA-associated vasculitis (AAV, 4.7%). A total of 775 patients were followed up within 3 months after renal biopsy; ATIN-AKI patients achieved statistically higher complete renal recovery than the GD-AKI patients (83.5% vs. 70.5%, p < 0.001). Conclusions: Most biopsied AKI patients have coexisting GD, while ATIN alone is seen less frequently. ATIN-AKI is mainly caused by drugs. In GD-AKI patients, IgAN, MCD, FSGS, LN, MN, and AAV are the leading diagnoses. Compared to AKI patients without GD, patients with GD suffer from worse renal function recovery.

Kidney Disease in Ankylosing Spondylitis: a case series and review of the literature.

Kidney disease is a rare manifestation of ankylosing spondylitis (AS) and its pathological alterations remain poorly described. The aim of this study was to investigate the clinical presentation and pathological alterations on kidney biopsy of AS patients and review and discuss the current literature on the issue. We retrospectively studied the clinical presentation and kidney pathological alterations of 15 Caucasian AS patients submitted to kidney biopsy between October 1985 and March 2021. Patients were predominantly male (66.7%) with median age at the time of kideney biopsy of 47 years [IQR 34 - 62]. Median serum creatinine at presentation was 1.3 mg/dL [IQR 0.9 - 3] and most patients also had either proteinuria (85.7%) and/or hematuria (42.8%). The most common indication for kidney biopsy was nephrotic syndrome (33.3%), followed by acute or rapidly progressive kidney injury (20%) and chronic kidney disease of unknown etiology (20%). Chronic interstitial nephritis (CIN) (n=3) and AA amyloidosis (n=3) were the most common diagnosis. Others included IgA nephropathy (IgAN) (n=2), focal segmental glomerulosclerosis (n=2), membranous nephropathy (n=1), and immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN)(n=1). We present one of the largest series of biopsy-proven kidney disease in Caucasian AS patients. We found a lower prevalence of IgAN than previously reported in Asian cohorts. We found a higher prevalence of CIN and a lower prevalence of AA amyloidosis than that described in previous series of Caucasian patients. We also present the first case of AS-associated IC-MPGN.

Patterns of biopsy-proven kidney disease amongst South African adults from 1995 to 2017

Introduction: Little data is available on biopsy-proven kidney disease in African countries. In this study, we have described the patterns of biopsy-proven kidney disease amongst South African adults encountered over a 23-year period and report whether these have changed over time.

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.

Analysis of Prevalence and Trends in the Biopsy-Proven Native Kidney Diseases in Iranian Population: A 12-year Survey from a Referral Center.

The prevalence of glomerular diseases, as the leading cause of chronic kidney disease, is increasing. Renal biopsy is still the gold standard for diagnosis of the most kidney disorders. Data on prevalence of the biopsy-proven kidney diseases in Iran is limited and none of the previously reported studies used electron microscopic (EM) evaluation for the diagnosis. This study was conducted to analyze the prevalence of biopsy-proven kidney diseases in a referral center in Iran. The reports of kidney biopsy samples from 2006 to 2018 referred to a pathology center, affiliated with Tehran University of Medical Sciences were reviewed. The prevalence of different disorders was assessed based on the clinical presentation in 3 age categories, including childhood, adulthood, and elderly. Among 3455 samples, 2975 were analyzed after excluding transplant-related specimens, suboptimal specimens, and those with uncertain diagnoses. Nephrotic syndrome (NS) (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%), lupus (4%) and the other non-specific manifestations such as hypertetion or malaise (each one less than 2%). The most common diagnoses included membranous nephropathy (MGN) (17.9%), focal segmental glomerulosclerosis (FSGS) (15.9%), lupus nephritis (LN) (13.7%), minimal histopathological findings (unsampled FSGS versus Minimal Change Disease, 12.1%), Immunoglobulin-A (IgA) nephropathy (6.5%) and Alport syndrome (6.1%). MGN was the most frequent disease before 2013, but FSGS became more frequent after that. NS and proteinuria were the most indications for kidney biopsy. Although MGN was the most common disease, the prevalence of FSGS has been increasing in recent years and making it the most common disease after 2013. LN and IgA nephropathy are the most common causes of secondary and primary GN presenting with proteinuria and hematuria, respectively.

The spectrum and changes of biopsy-proven kidney diseases in Chinese children.

The study aimed to investigate the spectrum of biopsy-proven kidney disease in Chinese children. Records of children 0-17years old who underwent native kidney biopsy from June 1st, 2013 to December 31st, 2018 in the national inpatients' database of China were analyzed. Biopsy-proven kidney diseases of different sex, age groups, and diagnosis, and the changing patterns of kidney disease compared with the previous study were analyzed. A total of 21,311 patients from 232 hospitals with a median age of 11.34years were included. Immunoglobulin A vasculitis with nephritis (IgAVN) was the most common pathological finding [29.17%, 95% confidence interval (confidence interval, CI) = 28.56-29.78], followed by IgA nephropathy (IgAN) (22.70%, 95% CI = 22.14-23.27). IgAN was the most common finding in patients with hematuria (60.75%, 95% CI = 58.83-62.65], proteinuria (33.43%, 95% CI = 30.54-36.42), and hematuria plus proteinuria (62.77%, 95% CI = 56.19-69.02). Minimal change disease was the most common finding (40.69%, 95% CI = 39.41-41.98) in nephrotic syndrome. The proportion of IgAVN in patients with biopsy-proven glomerular disease increased year by year during 2013-2018 (p for trend < 0.001) and washigher than that of2004-2014 [29.41% (95% CI = 29.10-29.72) in 2013-2018 vs. 13.35% (95% CI = 12.97-13.73) 2004-2014, p < 0.001]. The proportion of hepatitis B virus associated nephritis during 2013-2018 was lower than that of 2004-2014 [0.44% (95% CI = 0.36-0.54) in 2013-2018 vs. 0.87% (95% CI = 0.67-1.10) in 2004-2014, p < 0.001]. IgAVN and IgAN were the most common types of pathological findings in children who underwent kidney biopsies from 2013 to 2018. The pathological spectrum of kidney biopsy changed over time.

The Cleveland Clinic Kidney Biopsy Epidemiological Project.

The kidney biopsy is the gold standard for diagnosing glomerular diseases. Large-scale, epidemiologic studies describing the prevalence of kidney diseases are lacking, especially in the United States. We aimed to determine the spectrum of biopsy-proven kidney disease across the Cleveland Clinic enterprise. We identified all patients with a native kidney biopsy performed or reviewed at the Cleveland Clinic from January 2015 to September 2021. Retrospective chart review was performed to obtain clinical and demographic characteristics. Results were stratified by age, sex, race, and location to determine epidemiologic trends. Of >9600 patients, we excluded transplant and donor biopsies and unavailable records, and included 4128 patients with native kidney biopsy data. The median age was 60 years, with 46% female patients. Self-reported racial demographics included 73% White, 22% Black, 3% multiracial, and 2% Asian background, with 5% Hispanic. Common diagnoses were: FSGS (n=633, 15%), diabetic kidney disease (DKD) (n=602, 15%), IgA nephropathy (n=319, 8%), lupus nephritis (LN) (n=289, 7%), pauci-immune glomerulonephritis (n=275, 7%), membranous nephropathy (n=211, 5%), and amyloidosis (n=110, 3%). There were 3322 patients in Ohio, with 361 patients in Florida. Using multivariate analysis, those aged >70 years were more likely to have FSGS, whereas those <45 years were more likely to have IgA nephropathy or LN. Males were more likely to have FSGS or IgAN, and less likely to have LN. Black patients were more likely to have FSGS, DKD, or LN. Hispanic patients were more likely to have DKD. Finally, patients in Florida were more likely to have LN. There was no change in the disease spectrum before and during the COVID-19 pandemic. Our study catalogs the spectrum of biopsy-proven kidney disease across the Cleveland Clinic enterprise. This lays the foundation for glomerular disease clinical trials, and highlights the need for a standardized national kidney biopsy registry to bolster glomerular and kidney disease research in the United States.

Associations of left renal vein entrapment with IgA nephropathy and Henoch–Schönlein purpura nephritis

Objectives The aims of the study were to identify whether left renal vein (LRV) entrapment was more prevalent in IgA nephropathy (IgAN) and Henoch–Schönlein purpura nephritis (HSPN) compared with other types of renal diseases, and the association of LRV entrapment with glomerular incidental IgA and galactose-deficient-IgA1 (Gd-IgA1) deposition. Methods A total of 797 patients with biopsy-proven kidney diseases have been screened for LRV entrapment by color Doppler ultrasound, and the prevalence of LRV entrapment in different types of renal diseases were then analyzed. Propensity score matching analysis was used to adjust for age, gender, and body mass index. Immunostaining of Gd-IgA1 with KM55 was performed in paraffin-embedded sections of renal biopsy specimens. Results LRV entrapment was diagnosed in 47 patients (6%) with several kinds of renal diseases in our cohort. A total of 32 (68%) LRV entrapments were combined with expanded IgAN (idiopathic IgAN and HSPN). The prevalence of LRV entrapment in expanded IgAN was significantly higher than that in non-expanded IgAN (17 vs. 2%, p < 0.001), even after adjustment for age, gender, and body mass index by propensity score matching analysis (13 vs. 2%, p < 0.001). Removing expanded IgAN and LN, glomerular incidental IgA deposition was observed to be significantly more common in patients with LRV entrapment compared with patients without it (43 vs. 9%, p < 0.001). Furthermore, in glomerular diseases with incidental IgA deposits, significantly much larger proportion of patients with LRV entrapment were positive for glomerular Gd-IgA1 in contrast to patients without LRV entrapment (5/5 vs. 5/17, p = 0.01). Conclusions LRV entrapment coexisted with several kinds of renal diseases, with a significantly higher prevalence in patients with idiopathic IgAN and HSPN. In patients of LN and IgAN-unrelated disease with LRV entrapment, glomerular IgA and Gd-IgA1 deposition was more common compared with patients without LRV entrapment.

Kidney Disease Patterns diagnosed by Kidney Biopsy: A Single-center Experience from Central India.

We carried out a retrospective analysis of kidney biopsies done in our institute between January 2016 and June 2021, and clinical and histopathological correlation was done from the available medical records. Of the 411 kidney biopsies evaluated, 56.7% were females and the mean age of patients was 31.65 years. The elderly population (age ≥60 years) constituted 5% of patients. The most common indication for kidney biopsy was nephrotic syndrome (NS) (49.9%). On analysis of histological patterns, 59.3% of patients had primary glomerular disease (PGD), 28% had secondary glomerular disease (SGD), 5.2% had tubulointerstitial disease (TID), and 6.7% had vascular disease. In our study, focal segmental glomerulosclerosis (FSGS) was the most common PGD (28.9% of all PGD) followed by membranous nephropathy (MN) (19.7%), minimal change disease (MCD) (16.5%), and IgA nephropathy (IgAN) (15.4%). The most common SGD was lupus nephritis (LN) (23%) followed by diabetic nephropathy (DN) (1.99%). In patients aged ≤18 years, MCD was the most common PGD (26.5%) and FSGS was the most common PGD (30%) in patients aged between 19 and 59 years. In the elderly population (age ≥60 years), MN was the most common (38%) PGD. This is the largest study of kidney biopsies patterns from the central part of India, and it presents the combined analysis of the clinical, histopathological, and immunofluorescent features of biopsy-proven kidney diseases in our population.

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.

MO114: Incidence and Spectrum of Biopsy-Proven Dysproteinemic Kidney Diseases: A Single-Centre Experience

Abstract BACKGROUND AND AIMS We aimed to evaluate the incidence and clinical features of patients with biopsy-proven dysproteinemic kidney diseases (group 1), as well as spectrum of biopsy-proven kidney diseases of patients with monoclonal gammopathy (MG) or abnormal free light chain (FLC) ratio (group 2) at our institution. METHOD This was a single-centre retrospective study of all patients who had native kidney biopsies at the Singapore General Hospital between October 2015 and December 2021. Demographic, clinical, laboratory and histological data were retrieved from electronic medical records to identify patients with biopsy-proven dysproteinemic kidney diseases (group 1) and patients with positive MG and/or abnormal FLC (κ to λ) ratio who underwent kidney biopsy (group 2). Patients were considered to have MG if they tested positive on any of the following tests: serum protein electrophoresis, serum immunofixation, urine protein electrophoresis or urine immunofixation. Abnormal FLC ratio is defined as a ratio outside the range of 0.27–1.65 in patients with eGFR ≥60 mL/min/m2 or 0.37–3.10 in patients with eGFR &amp;lt;60 mL/min/m2. RESULTS Out of 1066 patients who underwent kidney biopsy between October 2015 and December 2021, 25 (2.3%) patients were diagnosed with dysproteinemic kidney diseases (group 1). The median age of the patients at diagnosis was 65.6 years (IQR 58.6, 68.2), and majority was male (17/25; 68.0%). Haematological diagnoses present in this cohort include multiple myeloma (5/25; 20.0%), chronic lymphocytic leukaemia (2/25; 8.0%), Waldenstrom's macroglobulinaemia (2/25; 8.0%) and mantle cell lymphoma (1/25; 4.0%). Two-thirds of the patients had acute kidney injury (AKI) at time of biopsy (17/25; 68.0%). All patients presented with proteinuria, and nephrotic syndrome was noted in approximately half of the patients (15/25; 60.0%). Hypocomplementemia was present in a third (7/21; 33.3%) of the patients who had complement levels performed prior to biopsy, with low C3 and low C3/C4 observed in 5 and 2 patients, respectively. The most common histological lesion is immunoglobulin-related amyloidosis (8/25; 32.0%), followed by proliferative glomerulonephritis with monoclonal immune deposits (PGNMID) (6/25; 24.0%) and light-chain cast nephropathy (4/25; 16.0%). Sixteen (64%) patients fulfilled criteria for monoclonal gammopathy of renal significance (MGRS). All patients with PGNMID had undetectable MG and normal FLC ratio at diagnosis. Among these 1066 patients who underwent kidney biopsy, 396 patients had serum/urine electrophoresis, serum/urine immunofixation and/or FLC performed prior to biopsy. A total of 44 (11.1%) patients with detectable MG and/or abnormal FLC ratio were identified (group 2), 5 of whom had previously known haematological conditions. Dysproteinemic kidney diseases were diagnosed in 14 (31.8%) patients. Amongst patients with non-dysproteinemic diagnosis, diabetic/hypertensive nephropathy was the most frequent (15/30; 50.0%). Majority of the remaining patients had a variety of glomerulonephritides and renal vasculitides (10/30; 33.3%), or tubulointerstitial diseases (2/30; 6.7%). In univariate analysis, non-diabetic status (P &amp;lt; .001), presence of AKI (P = .032) and abnormal FLC ratio (P = .005) increased the likelihood of diagnosing dysproteinemic kidney disease in this group of patients. CONCLUSION AKI and proteinuria are common in dysproteinemia kidney diseases. Non-diabetic status, presence of AKI and abnormal FLC ratio increased the likelihood of diagnosing dysproteinemic kidney disease.

MO976: Recurrence of Immune Complex And Complement-Mediated Membranoproliferative Glomerulonephritis in Kidney Transplantation

Abstract BACKGROUND AND AIMS Membranoproliferative glomerulonephritis (MPGN) represents a histologic pattern of glomerular injury which may be due to several etiologies. Few studies have comprehensively analyzed the recurrence of MPGN according to the current classification system. METHOD We collected a multicenter, retrospective cohort of 220 patients with biopsy-proven native kidney disease due to MPGN between 1981 and 2021 in 11 hospitals. Demographic, clinical and histologic parameters of prognostic interest were collected. The main outcomes were time to kidney failure, time to recurrence of MPGN, and disease remission after recurrence. RESULTS The study group included 34 complement-mediated and 186 immune complex-mediated MPGN. Eighty-one patients (37%) reached kidney failure in a median follow-up of 79 months. The main predictors of this event were the development of rejection episodes, and disease recurrence. Fifty-four patients (25%) had a disease recurrence in a median of 16 months after kidney transplantation. The incidence of recurrence was higher in patients with dysproteinemia (67%) and complement-mediated MPGN(62%). In the multivariable model, complement-mediated MPGN emerged as a predictor of recurrence. Thirty-three patients reached kidney failure after recurrence. The main determinants of no remission were: early time to recurrence (&amp;lt;15 months), eGFR &amp;lt;30 mL/min/1.73 m2 and serum albumin &amp;lt;3.5 g/dL at the time of recurrence. CONCLUSION One-fourth of patients with native kidney disease due to MPGN developed clinical recurrence in the allograft, especially in cases with complement-mediated disease or in those associated with dysproteinemia. The kidney outcomes of disease recurrence with currently available therapies are heterogeneous and thus, more effective and individualized therapies are needed.

Patterns of biopsy-proven renal disease in people living with HIV: 10\xa0years experience in Sydney, Australia

BackgroundAcute and chronic kidney diseases are important comorbidities in People Living With HIV (PLWH). Biopsy is often pursued in this cohort with ongoing renal impairment without a clear aetiology, in order to establish the diagnosis and to guide management. Despite the importance of renal disease in PLWH, there is a paucity of biopsy data—especially in the Australian setting. Consequently, who and when to biopsy is mainly based on clinical experience. The aims of this study were to describe biopsy-proven renal disease in PLWH at our institution and to assess for correlation between any demographic or laboratory characteristics with histological diagnosis.MethodsA retrospective review of all PLWH who underwent renal biopsy between January 2010 and December 2020 at Royal Prince Alfred Hospital, Sydney, Australia was performed. All PLWH over 18 years, who were not transplant recipients were included. Demographic, laboratory and biopsy data was extracted from the electronic medical records. Basic descriptive statistics were performed, and correlation was assessed using chi square and Kendall’s coefficient of rank test.Results19 renal biopsies were included in the study. The majority of PLWH were Australian born (53%), male (84%) and had a mean age of 48 years (SD 13). Comorbid hypertension and diabetes were present in 74% and 21% of people respectively. The mean serum creatinine was 132 µmol/L (SD 55) and the mean estimated glomerular filtration rate (eGFR) was 61 ml/min/1.73m2 (SD 24). The most common histological diagnosis was tubulointerstial nephritis in 5 people (24%). Hypertensive glomerulosclerosis and IgA nephropathy were present in 4 (19%) and 3 (14%) people respectively. There were no cases of HIV-associated nephropathy. There was no significant correlation between any cohort characteristics and diagnoses.ConclusionsThis study represents the first description of biopsy-proven kidney disease in the HIV-infected population of Australia. Our results support the use of renal biopsy in PLWH with ongoing renal impairment for accurate diagnosis and to guide further management. Although a small sample size, our study is larger than other published international biopsy studies.

Kidney Histopathologic Spectrum and Clinical Indicators Associated with MGRS.

Patients with monoclonal gammopathy and concomitant kidney diseases are frequently found in clinical practice. Some of them are diagnosed with monoclonal gammopathy of renal significance (MGRS) due to the presence of monoclonal Ig-related kidney injuries. This study aimed to investigate the histopathologic spectrum and clinical characteristics associated with MGRS in a large cohort of patients with monoclonal gammopathy and biopsy-proven kidney diseases from a single Chinese nephrology referral center. Patients who presented with monoclonal gammopathy (monoclonal spike on serum and/or urine immunofixation tests) and underwent kidney biopsy in the Peking University First Hospital from January 1, 1999 to December 31, 2020 were enrolled in this retrospective study. Patients with malignant hematologic diseases were excluded. Clinical and laboratory data were collected from the electronic medical record system. Comparisons of patients with and without MGRS and with and without amyloidosis were performed. The clinical characteristics associated with MGRS were identified using multivariable logistic regression. A total of 700 patients with monoclonal gammopathy and kidney biopsy were identified. Thirteen patients with repeat kidney biopsies were analyzed separately. For the remaining 687 patients with one kidney biopsy, 261 patients (38%) had MGRS lesions, and the rest (426 patients, 62%) had non-MGRS kidney diseases. Ig-related amyloidosis accounted for the most MGRS cases (n=164, 63%), followed by monoclonal Ig deposition disease (n=23, 9%) and thrombotic microangiopathy (n=22, 8%). In the non-MGRS group, membranous nephropathy was the most common diagnosis (n=171, 40%). In the multivariable logistic regression model, the presence of abnormal serum free light chain ratio, older age, and greater proteinuria were independently associated with MGRS. Monoclonal Ig amyloidosis is the leading cause of MGRS in Chinese patients with monoclonal gammopathy. The presence of abnormal free light chain ratio, older age, and greater proteinuria were associated with MGRS.