Association of high body mass index with development of interstitial fibrosis in patients with IgA nephropathy

The impact of metabolic component count on IgA nephropathy prognosis

Metabolic syndrome, a cluster of conditions including obesity, hyperglycemia, hypertension, and dyslipidemia, is increasingly recognized for its association with kidney disease. However, the impact of metabolic syndrome on the long-term prognosis of IgA nephropathy(IgAN) remains understudied. From August 2009 to December 2018, we conducted a retrospective cohort study at the Department of Nephrology, General Hospital of Ningxia Medical University, involving 698 patients with primary IgAN identified by the initial renal biopsy. Patients were divided into five groups based on the number of metabolic syndrome components they exhibited, including metabolic syndrome with hyperuricemia: Group A (no components), Group B (one component), Group C (two components), Group D (three components), and Group E (four or more components). We compared and analyzed the effect of metabolic components on the prognosis of IgAN. The mean age was 35.83 years, and 51.86% male. The prevalence of metabolic syndrome was 25.07%. The 24-h urine protein quantification correlated positively with metabolic components (P < 0.05), while eGFR correlated negatively (P < 0.05). Kaplan--Meier analysis showed decreased renal survival with more metabolic components, especially with four or more (P < 0.001). Blood pressure was the most important factor influencing the occurrence of endpoint events in IgAN patients, according to a random forest technique analysis. The incidence of metabolic abnormalities in patients with IgA nephropathy is closely related to the severity of clinical manifestations and poor renal prognosis, with blood pressure being the most critical factor.

Development and internal and external validation of a nomogram model for predicting the risk of chronic kidney disease progression in IgA nephropathy patients

Background

IgA nephropathy (IgAN) is the most common primary glomerular disease in chronic kidney disease (CKD), exhibiting significant heterogeneity in both clinical and pathological presentations. We aimed to explore the risk factors influencing short-term prognosis (≥90 days) and to construct a nomogram model for evaluating the risk of CKD progression in IgAN patients.

Methods

Clinical and pathological data of patients diagnosed with IgAN through biopsy at two centers were retrospectively collected. Logistic regression was employed to analyze the training cohort dataset and identify the independent predictors to construct a nomogram model based on the final variables. The predictive model was validated both internally and externally, with its performance assessed using the area under the curve (AUC), calibration curves, and decision curve analysis.

Results

Out of the patients in the modeling group, 129 individuals (41.6%) did not achieve remission following 3 months of treatment, indicating a high risk of CKD progression. A multivariate logistic regression analysis demonstrated that body mass index, urinary protein excretion, and tubular atrophy/interstitial fibrosis were identified as independent predictors for risk stratification. A nomogram model was formulated utilizing the final variables. The AUCs for the training set, internal validation set, and external validation set were 0.746 (95% confidence intervals (CI) [0.691-0.8]), 0.764 (95% CI [0.68-0.85]), and 0.749 (95% CI [0.65-0.85]), respectively. The validation of the subgroup analysis also demonstrated a satisfactory AUC.

Conclusion

This study developed and validated a practical nomogram that can individually predict short-term treatment outcomes (≥90 days) and the risk of CKD progression in IgAN patients. It provides reliable guidance for timely and personalized intervention and treatment strategies.

Relationship of body mass index and kidney outcomes in patients with primary glomerulonephritis: A systematic review and meta-analysis

BACKGROUND

Primary glomerulonephritis, is a major contributor to the development of chronic kidney disease and end-stage renal disease. Previous studies on the relationship between overweight/obesity with primary glomerulonephritis in the chronic kidney disease was inconsistent. This study aimed to systematically review and meta-analyze the relationship between body mass index and adverse kidney outcomes in patients with primary glomerulonephritis.

METHODS

PubMed, Embase, the Cochrane Library, and the China National Knowledge Infrastructure were searched. Patients were divided into an overweight/obesity group (group O) and a non-overweight/obesity group (group N) according to their body mass index values.

RESULTS

Twenty-six studies with 11,038 patients were selected. Patients in group O had deteriorated baseline characteristics, including worse baseline estimated glomerular filtration rate (weighted mean differences [WMD] = -5.99), higher Scr (WMD = 7.34), uric acid (WMD = 47.53), 24-hour proteinuria (WMD = 0.40), and a higher prevalence rate of hypertension (odds ratio, OR = 2.70) and diabetes mellitus (OR = 2.644). On the histopathologic level, patients in group O had a significantly lower total glomerular number (WMD = -2.30); however, no difference was observed in mesangial cell proliferation, endocapillary hypercellularity, crescents, sclerosis, and tubular atrophy/interstitial fibrosis between the 2 groups. The incidence of adverse renal outcomes in the 2 groups was similar (OR = 0.96). The meta-analysis of hazard ratios from Cox regressions indicated a strong association between overweight/obesity and poor renal outcomes in glomerulonephritis (HR = 1.17).

CONCLUSION

Overweight/obesity glomerulonephritis patients had remarkably poor baseline clinicopathological characteristics. Being overweight or obesity would likely impact the progression of primary glomerulonephritis but not serious enough to contribute to significant poor renal outcomes, which could be prevented by aggressive therapy.

Association of Obesity With Kidney and Cardiac Outcomes Among Patients With Glomerular Disease: Findings From the Cure Glomerulonephropathy Network

RATIONALE & OBJECTIVE

The influence of obesity on cardiorenal outcomes in individuals with glomerular disease is incompletely known. This study examined the association between obesity and kidney and cardiovascular outcomes in children and adults with glomerular kidney disease.

STUDY DESIGN

Prospective, multicenter, observational study.

SETTING & PARTICIPANTS

Participants in the Cure Glomerulonephropathy Network (CureGN) who were≥5 years of age at enrollment.

EXPOSURE

Adult body mass index (BMI) groups: 20-24 (healthy) versus 25-34 (overweight/class 1 obesity) versus≥35 (class 2-3 obesity); and pediatric BMI percentiles: 5th-84th (healthy) versus 85th-94th (overweight) versus≥95th (obese).

OUTCOME

A composite kidney outcome (40% estimated glomerular filtration rate [eGFR] decline or kidney failure) and a composite cardiovascular outcome (myocardial infarction, stroke, heart failure, or death).

ANALYTICAL APPROACH

Time to composite primary outcomes by BMI strata were estimated using Kaplan-Meier analysis. The adjusted associations between BMI and outcomes were estimated using Cox proportional hazards analysis.

RESULTS

The study included 2,301 participants (1,548 adults and 753 children). The incidence of the primary kidney end point was 90.8 per 1,000 person-years in adults with class 2-3 obesity, compared with 58.0 in normal weight comparators. In the univariable analysis, class 2-3 obesity was associated with the primary kidney outcome only in adults (HR, 1.6 [95% CI, 1.1-2.2], P=0.006) compared with the healthy weight groups. In the multivariable adjusted analysis, class 2-3 obesity did not remain significant among adults when controlling for baseline eGFR and proteinuria. Adults with class 2-3 obesity had an incidence of 19.7 cardiovascular events per 1,000 person-years and greater cardiovascular risk (HR, 3.9 [95% CI, 1.4-10.7], P=0.009) in the fully adjusted model.

LIMITATIONS

BMI is an imperfect indicator of adiposity. Residual confounding may exist from socioeconomic factors.

CONCLUSIONS

Among adult patients in CureGN, class 2-3 obesity is associated with cardiovascular but not kidney outcomes when adjusted for potential confounding factors.

PLAIN-LANGUAGE SUMMARY

Obesity is a risk factor for adverse heart and kidney outcomes in patients with chronic kidney disease, but whether it is associated with these outcomes in patients with glomerulonephropathy is not known. This study used existing data from a large sample of adults and children with glomerular diseases to address this question. The findings suggest that obesity increases the risk of cardiovascular but not kidney disease events in adult patients with glomerular disease.

Thickened Perirenal Fat Predicts Poor Renal Outcome in Patients with Immunoglobulin A Nephropathy: A Population-Based Retrospective Cohort Study

Introduction

Perirenal fat is a pad that fills the retroperitoneal space outside the kidney, which affects kidney function in various ways. However, the association between perirenal fat and IgA nephropathy (IgAN) has not yet been elucidated. This study aimed to investigate the role of perirenal fat in predicting IgAN progression.

Methods

A total of 473 patients with biopsy-proven IgAN and follow-up information were recruited, and perirenal fat thickness (PFT) was measured using color Doppler ultrasonography at renal biopsy. Patients were divided into two groups according to the median PFT: the low-PFT group (PFT ≤1.34 cm, n = 239) and the high PFT group (PFT >1.35 cm, n = 234). A total of 473 healthy participants were included in the control group. Basic clinical characteristics were assessed at the time of renal biopsy, and the relationship between PFT and combined endpoints was analyzed. The renal composite endpoints were defined as a two-fold increase in blood creatinine level, end-stage renal disease (dialysis over 3 months). Kaplan-Meier survival analysis was used to explore the role of PFT in the progression of IgAN. Three clinicopathological models of multivariate Cox regression analysis were established to evaluate the association between PFT and renal prognosis in patients with IgAN.

Results

Compared to healthy subjects, patients with IgAN showed significantly higher PFT. After a median follow-up of 50 months, 75 of 473 patients (15.9%) with IgAN reached renal composite endpoints. Among those, 13 of 239 patients (5.4%) were in the low PFT group, and 62 of 234 patients (26.5%) were in the high PFT group (p < 0.001). The results of three Cox regression models (including demographics, pathological and clinical indicators, and PFT) demonstrated that a higher PFT was significantly associated with a higher risk of reaching renal composite endpoints in patients with IgAN.

Conclusion

This study indicated a positive relationship between PFT at renal biopsy and renal progression in patients with IgAN, suggesting that perirenal fat might act as a marker of poor prognosis in patients with IgAN.

Evaluating Progression Risk in Patients With Immunoglobulin A Nephropathy

The highly variable rate of decline in kidney function in patients with immunoglobulin A nephropathy (IgAN) provides a major clinical challenge. Predicting which patients will progress to kidney failure, and how quickly, is difficult. Multiple novel therapies are likely to be approved in the short-term, but clinicians lack the tools to identify patients most likely to benefit from specific treatments at the right time. Noninvasive and validated markers for selecting at-risk patients and longitudinal monitoring are urgently needed. This review summarizes what is known about demographic, clinical, and histopathologic prognostic markers in the clinician's toolkit, including the International IgAN Prediction Tool. We also briefly review what is known on these topics in children and adolescents with IgAN. Although helpful, currently used markers leave clinicians heavily reliant on histologic features from the diagnostic kidney biopsy and standard clinical data to guide treatment choice, and very few noninvasive markers reflect treatment efficacy over time. Novel prognostic and predictive markers are under clinical investigation, with considerable progress being made in markers of complement activation. Other areas of research are the interplay between gut microbiota and galactose-deficient IgA1 expression; microRNAs; imaging; artificial intelligence; and markers of fibrosis. Given the rate of therapeutic advancement, the remaining gaps in biomarker research need to be addressed. We finish by describing our route to clinical utility of predictive and prognostic markers in IgAN. This route will provide us with the chance to improve IgAN prognosis by using robust, clinically practical markers to inform patient care.

Hyperuricemia is associated with the progression of IgA nephropathy in children

BACKGROUND

The objective of the study was to explore the potential biomarkers and risk factors in children with immunoglobulin A nephropathy (IgAN).

METHODS

Untargeted metabolomics analysis was performed on children with IgAN before and after treatment. Subsequently, a retrospective study involving the past 15 years and a follow-up study were performed to verify the role of hyperuricemia in IgAN children.

RESULTS

Serum metabolomics analyses showed that levels of serum xanthosine were closely related to the outcome of IgAN, and KEGG analyses showed that differential metabolites were significantly enriched in purine metabolism. Furthermore, retrospectively analyses of 252 children with IgAN showed that hyperuricemia was associated with poorer renal outcome. Logistic regression analysis showed that BMI, serum creatinine, eGFR, Lee's grade III, and crescents were risk factors of hyperuricemia in children with IgAN. Kaplan-Meier analysis revealed that kidney progression-free survival in IgAN children with hyperuricemia was lower than that without hyperuricemia, especially in females.

CONCLUSIONS

We first performed a dynamic metabolomics study to reveal that hyperuricemia is closely related to the progression of IgAN in children. Then retrospective and follow-up studies confirmed that hyperuricemia is an important risk factor for poor renal outcomes. We need to pay more attention to the hyperuricemia in children with IgAN.

IMPACT

We first performed a dynamic metabolomics study to reveal that hyperuricemia was closely related to the progression of IgAN in children. Retrospective analyses in past 15 years confirmed that IgAN children with hyperuricemia had poorer renal function and worse renal pathology. The BMI, Scr, eGFR, Lee's grade III, and crescents were risk factors of hyperuricemia in children with IgAN. The long-term follow-up study showed that hyperuricemia was an important risk factor for poor renal outcome in children with IgAN. We need to pay more attention to hyperuricemia in children with IgAN, especially in females.

Kidney Considerations in Pediatric Obesity

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is a common condition and a major cause of morbidity and mortality in adults, but children and adolescents are also at risk for early kidney injury and development of CKD. Obesity contributes both directly and indirectly to the development of CKD. The purpose of this review is to describe obesity-related kidney disease (ORKD) and diabetic kidney disease (DKD) and their impact in the pediatric population.

RECENT FINDINGS

Although obesity-related CKD in childhood and adolescence is uncommon, nascent kidney damage may magnify the lifetime risk of CKD. Glomerular hyperfiltration is an early phenotype of both ORKD and DKD and typically manifests prior to albuminuria and progressive decline in GFR. Novel treatments for obesity and type 2 diabetes exerting protective effects on the kidneys are being investigated for use in the pediatric population. It is important to understand the impact of obesity on the kidneys more fully in the pediatric population to help detect injury earlier and intervene prior to the onset of irreversible progression of disease and to guide future research in this area.

IgA nephropathy and kidney transplantation according to the Oxford classification

INTRODUCTION

IgA nephropathy (IgAN) is the most common glomerular disease globally, and its susceptibility and the risk for the development of end-stage kidney disease are related to genetic and environmental factors. IgAN recurrence after kidney transplantation is relatively common, impacting graft function and survival. This study evaluated the risk factors and the clinical, laboratory, and histological characteristics of post-transplant IgAN recurrence based on the Oxford classification.

MATERIAL AND METHODS

Retrospective single-center cohort study including kidney transplant recipients with biopsy-proven pre-transplantation IgAN, with analysis of risk factors and clinical, laboratory, and histological characteristics of the IgAN recurrence cases.

RESULTS

53 patients fulfilled the inclusion criteria and were included in the study. The majority was male, white, eutrophic, with a mean age of 27 ± 9 years at IgAN diagnosis. Systemic arterial hypertension and proteinuria were frequent in the pretransplant period. Four recipients (7.5%) presented IgAN recurrence in a period of 6 to 122 months post-transplant. According to the Oxford classification, they had high scores of mesangial hypercellularity and segmental glomerulosclerosis in the native kidney biopsies and there was mesangial hypercellularity in all analyzed graft biopsies. None of these patients had received induction immunosuppression and all of them presented graft failure in the follow-up.

CONCLUSIONS

In this series, there was a high prevalence of mesangial hypercellularity and segmental glomerulosclerosis on native kidney biopsies, and mesangial hypercellularity occurred in all IgAN recurrence graft biopsies. Despite the lower incidence of recurrence of IgAN post-transplant compared to previous reports, progression to graft loss was of 100%.

The Impact of BMI Changes on the Incidence of Glomerular Hematuria in Korean Adults: A Retrospective Study Based on the NHIS-HEALS Cohort

Obesity and recurrent hematuria are known risk factors for chronic kidney disease. However, there has been controversy on the association between obesity and glomerular hematuria. This study aimed to investigate the association between body mass index (BMI) and weight change and recurrent and persistent hematuria in glomerular disease using a large-scale, population-based Korean cohort. Data were collected from the National Health Insurance Service-National Health Screening Cohort. Cox proportional hazards regression analysis was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for recurrent and persistent hematuria in glomerular disease according to the BMI group. Compared with the BMI 23-25 kg/m² group, the HR (95% CI) for incident recurrent and persistent hematuria in glomerular disease was 0.921 (0.831-1.021) in the BMI <23 kg/m² group, 0.915 (0.823-1.018) in the BMI 25-30 kg/m² group, and 1.151 (0.907-1.462) in the BMI ≥30 kg/m² group. Compared with the stable weight group, the HRs (95% CIs) for incident recurrent and persistent hematuria in glomerular disease were 1.364 (1.029-1.808) and 0.985 (0.733-1.325) in the significant weight loss and gain groups, respectively. Despite adjusting for confounders, this result remained significant. Baseline BMI was not associated with the risk of incident recurrent and persistent hematuria in glomerular disease. Weight loss greater than 10% was associated with the incidence of recurrent and persistent hematuria in glomerular disease. Therefore, maintaining an individual's weight could help prevent recurrent and persistent hematuria in glomerular disease in middle-aged and older Korean adults.

Nefropatia por IgA e transplante renal segundo a classificação de Oxford

Resumo Introdução: Nefropatia por IgA (NIgA) é a doença glomerular mais comum mundialmente. Sua suscetibilidade e risco para desenvolvimento de doença renal em fase terminal estão relacionados a fatores genéticos e ambientais. A recidiva de NIgA pós-transplante é relativamente comum, impactando na função e sobrevida do enxerto. Este estudo avaliou fatores de risco e características clínicas, laboratoriais e histológicas da recidiva de NIgA pós-transplante, com base na classificação de Oxford. Material e métodos: Estudo de coorte retrospectivo de centro único, incluindo receptores de transplante renal com NIgA pré-transplante comprovada por biópsia, com análise dos fatores de risco e características clínicas, laboratoriais e histológicas dos casos de recidiva de NIgA. Resultados: 53 pacientes preencheram critérios de inclusão e foram incluídos no estudo. A maioria era homem, branco, eutrófico, com idade média de 27 ± 9 anos no diagnóstico de NIgA. Hipertensão arterial sistêmica e proteinúria foram frequentes no período pré-transplante. Quatro receptores (7,5%) apresentaram recidiva de NIgA entre 6-122 meses pós-transplante. Segundo a classificação de Oxford, eles apresentaram altos escores de hipercelularidade mesangial e glomeruloesclerose segmentar nas biópsias de rins nativos. Houve hipercelularidade mesangial em todas as biópsias de enxerto analisadas. Nenhum destes pacientes recebeu imunossupressão de indução. Todos apresentaram falência do enxerto no acompanhamento. Conclusões: Nesta série, houve alta prevalência de hipercelularidade mesangial e glomeruloesclerose segmentar em biópsias de rins nativos, e hipercelularidade mesangial ocorreu em todas as biópsias do enxerto de recidiva da NIgA. Apesar da menor incidência de recidiva de NIgA pós-transplante comparada a relatos anteriores, a progressão para perda do enxerto foi de 100%.

Association of obesity with the development of end stage renal disease in IgA nephropathy patients

BACKGROUND AND AIM

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. We aimed to evaluate whether obesity is a risk factor for IgAN patients.

METHODS

A total of 1054 biopsy-proven IgAN patients were analyzed in this retrospective study. Patients were divided into four groups according to their body weight index (BMI) at the period of renal biopsy: underweight group (BMI< 18.5, N=75), normal weight group (18.5≤BMI<24, N=587), overweight group (24≤BMI<28, N=291) and obesity group (28≤BMI, N=101). The endpoint of our study was end stage renal disease (ESRD: eGFR <15 mL/min/1.73 m² or having renal replacement treatment). Kaplan-Meier analyses and Cox proportional hazard models were performed to evaluate renal survival. Propensity-score matching (PSM) was performed to get the matched cohort to evaluate the role of obesity in IgAN patients. Besides, the effect modification of obesity and hypertension in IgAN patients was clarified by the synergy index.

RESULTS

IgAN patients complicated with obesity had more severe renal dysfunction at the time of renal biopsy than those with optimal body weight. In addition, patients with obesity tended to have higher risk of metabolic disorders, such as hyperuricemia (64.4% vs 37%, p<0.001), hypertriglyceridemia (71.3% vs 32.5%, p<0.001) and hypercholesterolemia (46.5% vs 35.6%, p=0.036). It was observed that obesity patients had higher rate of unhealthy behaviors, such as smoking (27.7% vs 16.4%, p=0.006) and alcohol drinking (29.7% vs 19.9%, p=0.027). Although obesity was not confirmed as an independent risk factor for IgAN patients, we found that IgAN patients with obesity presented with higher incidence of hypertension, as well as lower event-free renal survival rate (log-rank p < 0.001), especially in patients with 24-h urine protein ≥ 1g (log-rank p =0.002). In addition, the synergy index showed that there was positive interaction between obesity and hypertension in IgAN.

CONCLUSION

Obesity is an important risk factor for IgAN patients when combined with hypertension. Hypertension appears to be common in obese IgAN patients.

Prognostic Value of Triglyceride to High-Density Lipoprotein Cholesterol Ratio (TG/HDL-C) in IgA Nephropathy Patients

BACKGROUND

The triglycerides to high-density lipoprotein cholesterol (TG/HDL-C) ratio is an easy-to-use atherogenic and prognostic marker which has attracted increasing attention these days. However, whether TG/HDL-C correlate with outcomes in IgA nephropathy (IgAN) patients remains unknown. To clarify these issues, we conducted this study.

METHODS

A total of 1146 patients from West China Hospital of Sichuan University were retrospectively analysed between 2008 and 2018.The demographic, clinical and pathological data of all patients at the time of biopsy were collected. Then, patients were divided into the high TG/HDL group (TG/HDL ≥ 1.495, N=382) and the low TG/HDL group (TG/HDL-C < 1.495, N=764) based on the optimal cut-off value of the TG/HDL-C using receive operating curve. Cox proportional hazard models and Kaplan-Meier curves were used to evaluate the renal outcomes of IgAN.

RESULTS

The median age of the patients was 33 (26-42) years, and 44.5% were men. By correlation analysis, we found that the TG/HDL-C ratio was negatively correlated with the eGFR (r = 0.250, P < 0.001) but positively correlated with proteinuria (r = 0.230, P< 0.001), BMI (r=0.380, P<0.001) and serum uric (r =0.308, P< 0.001). Patients with a higher TG/HDL-C ratio tended to have hypertension [odds ratio (OR), 1.987; 95% CI, 1.527-2.587; P<0.001] and more severe pathologic lesions with tubular atrophy/interstitial fibrosis (OR, 1.610; 95% CI, 1.203-2.154; P=0.001). During a median follow-up period of 54.1 (35.6-73.2) months, a high TG/HDL ratio was strongly associated with worse renal survival in IgAN patients (log-rank: P <0.001). Multivariate Cox analysis demonstrated that a high TG/HDL-C ratio (HR 1.775, 95% CI 1.056-2.798; P=0.029) was an independent predictive marker to ESRD.

CONCLUSION

In this study, we addressed the importance of TG/HDL-C ratio as a predictive marker for IgAN progression.

High-calorie diet results in reversible obesity-related glomerulopathy in adult zebrafish regardless of dietary fat

Obesity is a risk factor for the development of kidney disease. The role of diet in this association remains undetermined, in part due to practical limitations in studying nutrition in humans. In particular, the relative importance of calorie excess versus dietary macronutrient content is poorly understood. For example, it is unknown if calorie restriction modulates obesity-related kidney pathology. To study the effects of diet-induced obesity in a novel animal model, we treated zebrafish for 8 wk with diets varied in both calorie and fat content. Kidneys were evaluated by light and electron microscopy. We evaluated glomerular filtration barrier function using a dextran permeability assay. We assessed the effect of diet on podocyte sensitivity to injury using an inducible podocyte injury model. We then tested the effect of calorie restriction on the defects caused by diet-induced obesity. Fish fed a high-calorie diet developed glomerulomegaly (mean: 1,211 vs. 1,010 µm2 in controls, P = 0.007), lower podocyte density, foot process effacement, glomerular basement membrane thickening, tubular enlargement (mean: 1,038 vs. 717 µm2 in controls, P < 0.0001), and ectopic lipid deposition. Glomerular filtration barrier dysfunction and increased susceptibility to podocyte injury were observed with high-calorie feeding regardless of dietary fat content. These pathological changes resolved with 4 wk of calorie restriction. Our findings suggest that calorie excess rather than dietary fat drives obesity-related kidney dysfunction and that inadequate podocyte proliferation in response to glomerular enlargement may cause podocyte dysfunction. We also demonstrate the value of zebrafish as a novel model for studying diet in obesity-related kidney disease.NEW & NOTEWORTHY Obesity is a risk factor for kidney disease. The role of diet in this association is difficult to study in humans. In this study, zebrafish fed a high-calorie diet, regardless of fat macronutrient composition, developed glomerulomegaly, foot process effacement, and filtration barrier dysfunction, recapitulating the changes seen in humans with obesity. Calorie restriction reversed the changes. This work suggests that macronutrient composition may be less important than total calories in the development of obesity-related kidney disease.

Correlation of Body Mass Index with Clinicopathologic Parameters in Patients with Idiopathic Membranous Nephropathy

OBJECTIVE

To investigate the association between body mass index (BMI) and clinicopathologic parameters in patients with idiopathic membranous nephropathy (IMN).

METHODS

This study was retrospective and included patients with biopsy-proven IMN from 2018 to 2021 in Hebei General Hospital. Patients were categorized into two groups based on BMI. Clinical and histopathologic data were analyzed at the time of renal biopsy. Pathological data included immunofluorescence staining, glomerulosclerosis (GS, 0-2), mesangial cell proliferation (MCP, 0-1), tubular atrophy (TA, 0-1), interstitial fibrosis (IF, 0-1), vascular wall thickness (VWT, 0-1) and a combination score (GMTIV) graded from 0 to 5.

RESULTS

Our study revealed that the obese group had a higher prevalence of hypertension and diabetes than the overweight/normal weight group (P=0.001, P=0.002). Systolic blood pressure (P=0.005), diastolic blood pressure (P<0.001), haemoglobin (P=0.006), triglycerides (P<0.001), serum uric acid (P=0.05), 24 h urine proteinuria concentration (UP) (P=0.012), MCP (P=0.042), IF (P=0.033), and GMITV (P=0.033) score were higher in obese group compared to the other group, while the high-density lipoprotein-cholesterol (P=0.034) and immunoglobulin A deposition score (P=0.005) were lower. Factors significantly associated with UP were the ratio of lymphocyte count to white blood cell count, serum pre-albumin, immunoglobulin G, microscopic hematuria, anti-phospholipase A2 receptor (anti-PLA2R), C3 deposit on multivariable analysis (adjusted R ²=0.343). Binary logistic regression analysis illustrated that MCP was correlated to BMI (OR=2.528, P=0.036). Ordinal logistic regression analysis demonstrated that GMTIV was associated with BMI (OR=1.114, P=0.010) and C3 deposit (OR=1.655, P=0.001).

CONCLUSION

High BMI was associated with MCP and GMTIV score in IMN patients. Obesity may play an essential role in mesangial lesions of IMN. This study emphasized the relation between BMI and histological parameters under the universal usage of anti-PLA2R antibodies for diagnosis and prognosis in IMN.

Obesity and chronic kidney disease: prevalence, mechanism, and management

The prevalence of childhood obesity is increasing worldwide at an alarming rate. While obesity is known to increase a variety of cardiovascular and metabolic diseases, it also acts as a risk factor for the development and progression of chronic kidney disease (CKD). During childhood and adolescence, severe obesity is associated with an increased prevalence and incidence of the early stages of kidney disease. Importantly, children born to obese mothers are also at increased risk of developing obesity and CKD later in life. The potential mechanisms underlying the association between obesity and CKD include hemodynamic factors, metabolic effects, and lipid nephrotoxicity. Weight reduction via increased physical activity, caloric restriction, treatment with angiotensin-converting enzyme inhibitors, and judicious bariatric surgery can be used to control obesity and obesity-related kidney disease. Preventive strategies to halt the obesity epidemic in the healthcare community are needed to reduce the widespread deleterious consequences of obesity including CKD development and progression.

Hypertriglyceridemia Is Associated with More Severe Histological Glomerulosclerosis in IgA Nephropathy

IgA nephropathy (IgAN) is a globally well-known primary glomerular nephropathy. Hypertriglyceridemia (HTG) is one factor contributing to atherosclerosis and is a common complication of renal failure. HTG is a significant risk factor for decreased renal function in patients with IgAN. We evaluated the association of HTG with the histopathological features of IgAN patients. A total of 480 patients diagnosed with IgAN via kidney biopsy from eight university hospitals affiliated with the College of Medicine of the Catholic University of Korea were included in the final cohort. Pathological features were evaluated by eight expert pathologists with hospital consensus. HTG was defined as a serum triglyceride (TG) level of ≥150 mg/dL. In the study population analysis, the HTG group was older, with more males; higher body mass index (BMI), low-density lipoprotein cholesterol (LDL-C) and spot urine protein ratio; and lower estimated glomerular filtration rate (eGFR). In the lipid profile analysis, eGFR was negatively correlated with TGs/ high-density lipoprotein cholesterol (HDL) and triglyceride-glucose index (TyG). Proteinuria positively correlated with TGs/HDL, non-HDL/HDL, LDL/HDL, TyG, TGs and LDL. The percentages of global sclerosis (GS), segmental sclerosis (SS) and capsular adhesion (CA), and the scores for mesangial matrix expansion (MME) and mesangial cell proliferation (MCP), were more elevated in the HTG group compared to the normal TG group. Multivariable linear regression analysis showed that the percentages of global sclerosis, segmental sclerosis and capsular adhesion, as well as the scores for mesangial matrix expansion and mesangial cell proliferation, were positively associated with TG level. In binary logistic regression, the HTG group showed a higher risk for global sclerosis and segmental sclerosis. In conclusion, HTG is a significant risk factor for glomerulosclerosis in IgAN.

Impact of body mass index on primary immunoglobulin A nephropathy prognosis: a systematic review and meta-analysis

PURPOSE

The impacts of body mass index (BMI) on the prognosis of primary IgA nephropathy (IgAN) remain controversial. This systematic review and meta-analysis aimed to solve these issues.

METHODS

We searched the PubMed, EMBASE, and Cochrane Library to screen articles investigating the BMI and primary IgAN. BMI was classified according to the World Health Organization as high (≥ 25.0 kg/m²) and low (< 25.0 kg/m²). The baseline renal indexes and the incidences of adverse renal outcomes were focused on.

RESULTS

Six studies with a total of 1723 patients were included in this study. High BMI was demonstrated to be associated with increased baseline levels of serum creatinine (weighted mean difference (WMD) 9.54, 95% confidence interval (CI) 0.63-18.45), blood uric acid (WMD 19.85, 95% CI 10.11-29.59) and urine protein (WMD 0.37, 95% CI 0.21-0.53). Patients with high BMI also showed compromised eGFR at diagnosis (WMD - 8.39, 95% CI - 11.62 to - 5.16) with a higher incidence rate of hypertension (odds ratios (OR) 2.59, 95% CI 1.44-4.66) and higher global optical scores (WMD 1.22, 95% CI 0.70-1.74). Regarding the prognosis, high BMI was significantly associated with the incidence of adverse renal outcomes (OR 2.43, 95% CI 1.66-3.55, P < 0.001) and deteriorated eGFR at the last follow-up (WMD - 11.10, 95% CI - 16.96 to - 5.25, P < 0.001), with non-significantly poorer renal disease-free survival (hazard ratio 1.79, 95% CI 0.58-5.50, P = 0.31).

CONCLUSION

High BMI was associated with severe onset and poor prognosis of primary IgAN. The management of BMI could be a novel method to promote the therapeutic outcomes of primary IgAN.

Management of Obesity in Adults with CKD

Obesity is a leading public health problem that currently affects over 650 million individuals worldwide. Although interest in the adverse effects of obesity has grown exponentially in recent years, less attention has been given to studying its management in individuals with CKD. This relatively unexplored area should be considered a high priority because of the rapid growth and high prevalence of obesity in the CKD population, its broad impact on health and outcomes, and its modifiable nature. This article begins to lay the groundwork in this field by providing a comprehensive overview that critically evaluates the available evidence related to obesity and kidney disease, identifies important gaps in our knowledge base, and integrates recent insights in the pathophysiology of obesity to help provide a way forward in establishing guidelines as a basis for managing obesity in CKD. Finally, the article includes a kidney-centric algorithm for management of obesity that can be used in clinical practice.

Coagulation parameters are associated with the prognosis of immunoglobulin a nephropathy: a retrospective study

Background

Interstitial fibrosis/tubular atrophy (T) score is a known determinant of the progression of immunoglobulin A nephropathy (IgAN). Strong evidence indicates that the components of the coagulation system closely linked with fibrotic events have been highlighted in the kidney. However, whether the coagulation system can affect the renal outcome of IgAN remains unclear. Herein, we investigated the association of coagulation parameters and pathological phenotype of IgAN and their combined effects on the deterioration of renal function.

Methods

This retrospective study included N = 291 patients with biopsy-proven IgAN from May 2009 to April 2013 in the Second Xiangya Hospital. Clinical data, pathological features were collected, and the associations of coagulation parameters at biopsy, T score, and renal outcome were evaluated. T score indicated the degree of tubular atrophy or interstitial fibrosis. The renal outcome was defined as an end-stage renal disease (ESRD) or an irreversible 50% estimated glomerular filtration rate (eGFR) reduction.

Results

Shorter prothrombin time (PT) and the activated partial thromboplastin time (APTT) were significantly associated with T (both p < 0.001). PT (< 11.15 s) or APTT (< 29.65 s) had worse cumulative survival rate (p = 0.008, p = 0.027 respectively) and were significantly but not independently associated with a higher risk of renal outcome (p = 0.012, p = 0.032 respectively). In the combined analyses of PT, APTT, and T lesions, the odd ratios for the outcome were significantly higher in the presence of T with PT (< 11.15 s) or APTT (< 29.65 s).

Conclusion

Shorter PT and APTT are associated with an increased incidence of the T lesion and are additional factors that portend a poorer prognosis in IgAN. Monitoring coagulation function might be important when assessing the risk of progression. Additional studies exploring the molecular mechanism between coagulation and IgAN pathology are needed.

The Impact of Obesity on the Severity of Clinicopathologic Parameters in Patients with IgA Nephropathy

Several studies reported the effect of obesity on the progression of IgA nephropathy (IgAN). However, the impact of obesity on the clinicopathologic presentation of IgAN remains uncertain. This is a retrospective cross-sectional study from eight university hospitals in South Korea. Patients were categorized into three groups using the Asia-Pacific obesity classification based on body mass index (BMI). Clinical and histopathologic data at the time of renal biopsy were analyzed. Among 537 patients with IgAN, the obese group was more hypertensive and had lower estimated glomerular filtration rate and more proteinuria than other groups. The histologic scores for mesangial matrix expansion (MME), interstitial fibrosis, tubular atrophy, and mesangial C3 deposition differed significantly between the three groups. Among these histopathologic parameters, BMI was independently positively associated with MME score on multivariable linear regression analysis (p = 0.028). Using multivariable logistic regression analysis, the obese group was independently associated with higher MME scores compared to the normal weight/overweight group (p = 0.020). However, BMI was not independently associated with estimated glomerular filtration rate or proteinuria on multivariable analysis. Obesity was independently associated with severe MME in patients with IgAN. Obesity may play an important pathogenetic role in mesangial lesions seen in IgAN.

Obesity is not associated with progression to end stage renal disease in patients with biopsy-proven glomerular diseases

Background

Body mass index (BMI) is associated with renal disease progression in unspecified CKD. The relationship between BMI and primary glomerular disease (GN) may be more complex. We aimed to evaluate the association between BMI and renal disease progression in patients with primary glomerular disease (GN).

Methods

This was a single-centre retrospective cohort study performed in adult patients with biopsy-proven primary GN (excluding minimal change disease) from January 2000 to December 2015, with follow-up data until June 2017. BMI at time of biopsy was categorised as ≤25 kg/m², > 25 to ≤30 kg/m² and > 30 kg/m². We used univariate and multivariate survival analyses to evaluate factors associated with progression to a composite endpoint of stage 5 CKD or renal replacement therapy (Major Adverse Renal Event - MARE) censoring for competing risk of death using Fine and Gray subdistribution hazards model.

Results

We included 560 patients with biopsy-proven primary GN and available BMI data: 66.1% were male with median age 54.8 (IQR 41.1–66.2) years and BMI 28.2 (IQR 24.9–32.1) kg/m². Those with BMI 25-30 kg/m² (n = 210) and with BMI > 30 kg/m² (n = 207) were older (p = 0.007) with higher systolic and diastolic blood pressures (p = 0.02 and 0.004 respectively) than those with BMI < 25 kg/m² (n = 132). There was a greater proportion of focal segmental glomerulosclerosis in those with higher BMI (3.9% in BMI < 25 kg/m², 7.9% in BMI 25–30 kg/m² and 10.7% in BMI > 30 kg/m² of biopsies (p = 0.01)), but similar proportions of other GN diagnoses across BMI groups. Baseline eGFR (p = 0.40) and uPCR (p = 0.17) were similar across BMI groups. There was no interaction between BMI and time to MARE (log-rank p = 0.98) or death (log-rank p = 0.42). Censoring for competing risk of death, factors associated with progression to MARE were: younger age, lower baseline eGFR and higher uPCR, but not BMI (SHR 0.99, 95%CI 0.97–1.01, p = 0.31) nor blood pressure or GN diagnosis.

Conclusion

BMI was not associated with progression to MARE in this patient cohort with primary GN. Efforts should be directed to managing other known risk factors for CKD progression.

A non-invasive diagnostic model of immunoglobulin A nephropathy and serological markers for evaluating disease severity

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is the most common pathological type of glomerular disease. Kidney biopsy, the gold standard for IgAN diagnosis, has not been routinely applied in hospitals worldwide due to its invasion nature. Thus, we aim to establish a non-invasive diagnostic model and determine markers to evaluate disease severity by analyzing the serological parameters and pathological stages of patients with IgAN.

METHODS

A total of 272 biopsy-diagnosed IgAN inpatients and 518 non-IgA nephropathy inpatients from the Department of Nephrology of Chinese People's Liberation Army General Hospital were recruited for this study. Routine blood examination, blood coagulation testing, immunoglobulin-complement testing, and clinical biochemistry testing were conducted and pathological stages were analyzed according to Lee grading system. The serological parameters and pathological stages were analyzed. The receiver operating characteristic (ROC) analysis was performed to estimate the diagnostic value of the clinical factors. Logistic regression was used to establish the diagnostic model.

RESULTS

There were 15 significantly different serological parameters between the IgAN and non-IgAN groups (all P < 0.05). The ROC analysis was performed to measure the diagnostic value for IgAN of these parameters and the results showed that the area under the ROC curve (AUC) of total protein (TP), total cholesterol (TC), fibrinogen (FIB), D-dimer (D2), immunoglobulin A (IgA), and immunoglobulin G (IgG) were more than 0.70. The AUC of the "TC + FIB + D2 + IgA + age" combination was 0.86, with a sensitivity of 85.98% and a specificity of 73.85%. Pathological grades of I, II, III, IV, and V accounted for 2.21%, 17.65%, 62.50%, 11.76%, and 5.88%, respectively, with grade III being the most prevalent. The levels of urea nitrogen (UN) (13.57 ± 5.95 vs. 6.06 ± 3.63, 5.92 ± 2.97, 5.41 ± 1.73, and 8.41 ± 3.72 mmol/L, respectively) and creatinine (Cr) (292.19 ± 162.21 vs. 80.42 ± 24.75, 103.79 ± 72.72, 96.41 ± 33.79, and 163.04 ± 47.51 μmol/L, respectively) were significantly higher in grade V than in the other grades, and the levels of TP (64.45 ± 7.56, 67.16 ± 6.94, 63.22 ± 8.56, and 61.41 ± 10.86 vs. 37.47 ± 5.6 mg/d, respectively), direct bilirubin (DB) (2.34 ± 1.23, 2.58 ± 1.40, 1.91 ± 0.97, and 1.81 ± 1.44 vs. 0.74 ± 0.57 μmol/L, respectively), and IgA (310.35 ± 103.78, 318.48 ± 107.54, 292.58 ± 81.85, and 323.29 ± 181.67 vs. 227.17 ± 68.12 g/L, respectively) were significantly increased in grades II-V compared with grade I (all P < 0.05).

CONCLUSIONS

The established diagnostic model that combined multiple factors (TC, FIB, D2, IgA, and age) might be used for IgAN non-invasive diagnosis. TP, DB, IgA, Cr, and UN have the potential to be used to evaluate IgAN disease severity.