Prognosis in IgA nephropathy: 30-year analysis of 1,012 patients at a single center in Japan

Epidemiology and risk factors for progression in Chinese patients with IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is one of the main causes of primary glomerulonephritis worldwide, and it is also the main primary disease leading to chronic kidney disease. The purpose of this study is to evaluate the epidemiology and risk factors for progression in Chinese patients with IgAN.

METHODS

In this retrospective study, 246 patients with renal biopsy-proven IgAN were enrolled from January 2012 to June 2018. The patients' data were divided into two groups according to eGFR at the end of follow-up: a high-eGFR group (eGFR≥60ml/min) and a low-eGFR group (eGFR<60ml/min).

RESULTS

At the end of the study, we identified 49 (19.92%) patients with low-eGFR from 246 IgAN patients. Renal function, represented by serum creatinine, urea nitrogen and cystatin-C, was significantly decreased in the low-eGFR group (P<0.001 for all) at the time of renal biopsy. Compared with the high-eGFR group, the age, mean arterial blood pressure (MAP), proteinuria, cholesterol, triglycerides and serum uric acid were significantly higher (P<0.05 for all). According to the Oxford evaluation, the proportion of S1-2 (59.2%) and T1-2 (65.3%) was significantly increased (P<0.001 for both) and the proportion that had a MEST-C score ≥3 was statistically increased in the low-eGFR group (83.7%, P=0.001).

CONCLUSIONS

Male, MAP, haematuria, Scr, cholesterol, hemoglobin, Lee classification more than 3 and C1-2 are independent risk factors for low-eGFR in Chinese IgAN patients.

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

Introduction: This systematic literature review analyzed published evidence on IgA nephropathy (IgAN), focusing on US epidemiology, health-related quality of life (HRQoL), and economic burden of illness. Methods: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, Embase®, MEDLINE®, Cochrane, and Econlit (January 2010 to June 2020) were searched, along with relevant congresses (2017-2020). Results: Of 123 epidemiologic studies selected for data extraction, 24 reported IgAN diagnosis rates ranging from 6.3% to 29.7% among adult and pediatric patients undergoing renal biopsy, with all reported US rates <15%. No US studies reported IgAN prevalence. A meta-analysis of US studies calculated an annual incidence of 1.29/100 000 people, translating to an annual US incidence of 4236 adults and children. Relative to Europe, the United States had more patients diagnosed with IgAN in later chronic kidney disease stages. US rates of transition to end-stage renal disease (ESRD) ranged from 12.5% to 23% during 3-3.9 years of observation, rising to 53% during 19 years of observation. Across 8 studies reporting HRQoL, pain and fatigue were the most reported symptoms, and patients consistently ranked kidney function and mortality as the most important treatment outcomes. Patients with glomerulopathy reported worse mental health than healthy controls or hemodialysis patients; proteinuria was significantly associated with poorer HRQoL and depression. Conclusion: While economic evidence in IgAN remains sparse, management of ESRD is a major cost driver. IgAN is a rare disease where disease progression causes increasing patient burden, underscoring the need for therapies that prevent kidney function decline and HRQoL deterioration while reducing mortality.

Tenofovir alafenamide nephrotoxicity: a case report and literature review

Background

Tenofovir alafenamide (TAF), a novel prodrug of tenofovir (TFV), has become the preferred drug for the treatment of HIV-1 and chronic hepatitis B infection in clinical practice. Results from clinical trials showed that it had better renal and bone mineral outcomes compared to tenofovir disoproxil fumarate (TDF). However, as we have seen with TDF, side effects from the new medication can be more prevalent and recognized after extensive use in real world situations. Sporadic cases of acute kidney injury in patients using TAF have started to emerge.

Case presentation

We report a case of 49-year-old Thai, HIV treatment-experienced female with hypertension presented with worsening renal function after switching her antiretroviral regimen from TDF, emtricitabine (FTC), and lopinavir/ritonavir (LPV/r) to TAF, FTC and dolutegravir (DTG) for 3 months. Kidney biopsy showed distinctive picture of tenofovir nephrotoxicity with acute tubular injury and mitochondrial injury. The possible causes of acute kidney injury and nephrotoxicity from TAF for this patient were discussed. We have extensively reviewed all published case reports of TAF-associated nephrotoxicity and summarized the essential information in this article.

Conclusion

Although TAF has less nephrotoxicity compared with TDF; renal function should always be monitored after the initiation of both drugs. Future large cohort studies are required to identify the risk factors of TAF-associated nephrotoxicity and to design an effective preventive strategy.

The association of microhematuria with mesangial hypercellularity, endocapillary hypercellularity, crescent score and renal outcomes in immunoglobulin A nephropathy

BACKGROUND

Microhematuria is common in immunoglobulin A nephropathy (IgAN). However, current prognostication is based on proteinuria and mesangial hypercellularity, endocapillary hypercellularity, segmental sclerosis, tubulointerstitial fibrosis and crescent (MEST-C) scores.

METHODS

In this retrospective study, we evaluated whether MEST-C score components are associated with the presence of microhematuria at biopsy and whether the degree of microhematuria during follow-up is associated with change in estimated glomerular filtration rate (eGFR), after adjusting for clinical and histological parameters. We identified 125 patients with biopsy-proven IgAN and MEST-C scoring who were not on immunosuppressive therapy at biopsy. Microhematuria was defined as ≥3 red blood cells (RBCs)/high-power field (hpf).

RESULTS

Of the 125 patients, 97 had microhematuria at baseline and were more likely to have M1, E1 and C ≥ 1 lesions (P < 0.05 for all) compared with patients without microhematuria. Of the 125 patients, 72 had follow-up data available. An increase in the degree of microhematuria was significantly associated with an eGFR decline of -0.81 mL/min/1.73 m2 [95% confidence interval (CI) -1.44 to -0.19, P = 0.01], after adjusting for follow-up time, proteinuria and T score. Severe microhematuria (≥21 RBCs/hpf) was associated with an even larger decline in eGFR (-3.99 mL/min/1.73 m2; 95% CI -6.9411 to -1.0552, P = 0.008), after similar adjustments.

CONCLUSION

Degree of microhematuria during follow-up is an independent predictor of eGFR decline after adjusting for clinical and histological parameters. Therefore, monitoring the degree of microhematuria as well as proteinuria is important when evaluating patients with IgAN. Additional studies using improvement in microhematuria as a primary surrogate outcome are needed.

Comparative efficacy of different renin angiotensin system blockade therapies in patients with IgA nephropathy: a Bayesian network meta-analysis of 17 RCTs

Background

IgA nephropathy (IgAN) is still one of the most prevalent forms of primary glomerulonephritis globally. However, no guidelines have clearly indicated which kinds of renin angiotensin system blockade therapies (ACEIs or ARBs or their combination) in patients with IgAN result in a greater reduction in proteinuria and a better preservation of kidney function. Thus, we conducted a Bayesian network analysis to evaluate the relative effects of these three therapy regimens in patients with IgAN.

Methods

The protocol was registered in PROSPERO with ID CRD42017073726. We comprehensively searched the PubMed, the Cochrane Library, Embase, China Biology Medicine disc, WanFang and CNKI databases for studies published since 1993 as well as some grey literature according to PICOS strategies. Pairwise meta-analysis and Bayesian network analysis were conducted to evaluate the effect of different regimens.

Results

Seventeen randomized controlled trials (RCTs) involving 1,006 patients were analyzed. Co-administration of ACEIs and ARBs had the highest probability (92%) of being the most effective therapy for reducing proteinuria and blood pressure, but ACEIs would be the most appropriate choice for protecting kidney function in IgAN.

Conclusion

The combination of ACEIs and ARBs seems to have a significantly better antiproteinuric effect and a greater reduction of blood pressure than ACEI or ARB monotherapy in IgAN. ACEIs appear to be a more renoprotective therapy regimen among three therapies.

Positive renal familial history in IgA nephropathy is associated with worse renal outcomes: a single-center longitudinal study

Background

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Although most IgAN cases are sporadic, few show a familial aggregation. However, the prevalence and prognosis of IgAN individuals with positive familial history (FH) of renal disorders remains uncertain. To address these issues, we conducted a longitudinal observational study on a single-institution cohort of patients with biopsy-proven IgAN.

Methods

A total of 467 IgAN patients who underwent renal biopsy during 1994 to 2019 were ascertained to have positive- or negative-FH by history taking and were followed for an average of 8.9 years. We compared the clinical and pathological features of the two subgroups. The primary outcome, a composite of a hard endpoint (end-stage renal disease [ESRD]) and surrogate endpoint (a 50% or more reduction in the estimated glomerular filtration rate [eGFR] from baseline), was evaluated. To estimate the risk for progression to ESRD, a Cox proportional hazards analysis was performed for a subset of patients who underwent follow-up for > 2 years and had an eGFR > 30 mL/min/1.73 m² at baseline (n = 389; observation, 8.7 years).

Results

Positive-FH subtype accounted for 11.6% (n = 54) of all IgAN patients. At baseline, there were no significant differences between the positive- and negative-FH subgroups regarding age, sex, comorbid disease, MEST-C score, observation period, and therapeutic interventions. However, the eGFR value at baselines was significantly lower in the positive-FH subgroup than in the negative-FH subgroup (P < 0.01). On multivariate analysis, positive-FH emerged an independent determinant of poorer renal outcomes (odds ratio, 2.31; 95% confidence interval, 1.10–4.85; P = 0.03), after adjusting for confounding factors. eGFR at follow-up was significantly lower in the positive-FH subgroup than in the negative-FH subgroup after adjustment for age and observation period.

Conclusions

Positive-FH was found in 11.6% of all IgAN patients, consistent with the incidence seen in previous literature. A significantly lower eGFR at baseline and last follow-up and unfavorable renal outcomes in the positive-FH subgroup suggest that certain genetic risk factors predisposing to renal failure may exist in a fraction of our IgAN cohort. (331 words).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02425-8.

Evaluation of appropriate treatment for IgA nephropathy with mild proteinuria and normal renal function

BACKGROUND

Tonsillectomy and steroid pulse therapy (TSP) for immunoglobulin A nephropathy (IgAN) is frequently employed in many Japanese institutions; however, performing this invasive treatment in patients with mild IgAN is controversial. This study aimed to evaluate the appropriate treatment for IgAN patients with mild proteinuria.

METHODS

In this retrospective cohort analysis, 122 IgAN patients with mild proteinuria (0.5-1.0 g/day) and estimated glomerular filtration rate of ≥ 60 mL/min/1.73 m² were classified into three groups as follows: patients treated with TSP (n = 32), oral prednisolone (oPSL, n = 33), and conservative therapy (CONS, n = 47). The clinical and histological backgrounds, 5-year remission rates of urinary findings, and 10-year renal survival rates were analyzed.

RESULTS

The backgrounds were similar among the three groups. The remission rates of hematuria, proteinuria, and both were significantly higher for TSP and oPSL than for CONS; however, they were similar for TSP and oPSL. In the multivariate Cox regression analysis, TSP and oPSL were independent factors for the remission of urinary findings compared with CONS; however, the relapse rates of urinary abnormalities were similar among the three groups. No patient progressed to end-stage renal disease (ESRD) within 10 years. Adverse effects of corticosteroid therapy were significantly more frequent in oPSL than in TSP.

CONCLUSION

In IgAN patients with mild proteinuria and stable renal function, similar to oPSL, TSP showed higher remission rates of hematuria and/or proteinuria than CONS, and no case progressed to ESRD regardless of the treatment methods. Therefore, appropriate treatments should be carefully considered for each patient.

Reduced fecal short-chain fatty acids levels and the relationship with gut microbiota in IgA nephropathy

BACKGROUND

IgA nephropathy(IgAN)) is the common pathological type of glomerular diseases. The role of gut microbiota in mediating "gut-IgA nephropathy" has not received sufficient attention in the previous studies. The purpose of this study was to investigate the changes of fecal short-chain fatty acids(SCFAs), a metabolite of the intestinal microbiota, in patients with IgAN and its correlation with intestinal flora and clinical indicators, and to further investigate the role of the gut-renal axis in IgAN.

METHODS

There were 29 patients with IgAN and 29 normal control subjects recruited from January 2018 to May 2018. The fresh feces were collected. The fecal SCFAs were measured by gas chromatography/mass spectrometry and gut microbiota was analysed by16S rDNA sequences, followed by estimation of α- and β-diversity. Correlation analysis was performed using the spearman's correlation test between SCFAs and gut microbiota.

RESULTS

The levels of acetic acid, propionic acid, butyric acid, isobutyric acid and caproic acid in the IgAN patients were significantly reduced compared with control group(P < 0.05). Butyric acid(r=-0.336, P = 0.010) and isobutyric acid(r=-0.298, P = 0.022) were negatively correlated with urea acid; butyric acid(r=-0.316, P = 0.016) was negatively correlated with urea nitrogen; caproic acid(r=-0.415,P = 0.025) showed negative correlation with 24-h urine protein level.Exemplified by the results of α-diversity and β-diversity, the intestinal flora of IgAN patients was significantly different from that of the control group. Acetic acid was positively associated with c_Clostridia(r = 0.357, P = 0.008), o_Clostridiales(r = 0.357, P = 0.008) and g_Eubacterium_coprostanoligenes_group(r = 0.283, P = 0.036). Butyric acid was positively associated with g_Alistipes (r = 0.278, P = 0.040). The relative abundance of those were significantly decreased in IgAN group compared to control group.

CONCLUSIONS

The levels of fecal SCFAs in the IgAN patients were reduced, and correlated with clinical parameters and gut microbiota, which may be involved in the pathogenesis of IgAN, and this finding may provide a new therapeutic approach.

Relationship between blood neutrophil-lymphocyte ratio and renal tubular atrophy/interstitial fibrosis in IgA nephropathy patients

BACKGROUND

The study aimed to explore the relationship between neutrophil-lymphocyte ratio(NLR) in peripheral blood and renal tubular atrophy/interstitial fibrosis and to evaluate the clinical significance of NLR in IgA nephropathy (IgAN) patients.

METHODS

A Total of 263 IgAN patients were included. The participants were categorized into four groups based on quartile of NLR. The clinical data, pathological features, and 2-year renal survival rates were compared among the four groups. The independent factors affecting renal tubular atrophy/interstitial fibrosis in IgAN were determined by multivariate linear regression analysis.

RESULTS

The percentage of renal tubular atrophy/interstitial fibrosis increased with the increase of NLR level (p=0.003). The tubular atrophy/interstitial fibrosis score T1 and T2 in Group Q4 was 40%, which was higher than that of other groups, especially Group Q1 (22.73%, p=0.033) and Group Q3 (22.39%, p=0.029). NLR [β=1.230, 95%CI (0.081, 2.379), p=0.036] might be an independent factor affecting renal tubular atrophy/interstitial fibrosis in IgAN. The area under curve predicted by NLR was 0.596 (95%CI 0.534~0.656, p=0.007) with the specificity 88.24% and the optimal critical value of NLR 3.25. Fourteen patients progressed to end-stage renal disease within 2 years, and the 2-year survival rate of kidney was 93.49%. The renal survival rate in Group Q4 was 87.04%, lower than that in other three groups, especially Group Q1 (98.11%, p=0.029).

CONCLUSION

NLR was correlated with the level of renal tubular atrophy/interstitial fibrosis and might be a significant factor for predicting the prognosis in the IgAN.

BACKGROUND

IgA nephropathy (IgAN) is an important cause of the end stage renal disease (ESRD). The study aimed to explore the relationship between neutrophil-lymphocyte ratio (NLR) in peripheral blood and renal tubular atrophy/interstitial fibrosis, and to evaluate the clinical significance of NLR in IgA nephropathy (IgAN) patients.

METHODS

Total 263 IgAN patients confirmed by renal biopsy pathology were included from January 2013 to May 2018 in Ningbo Hwamei Hospital, University of Chinese Academy of Sciences. The peripheral blood samples were taken from these participants and the NLR was analyzed. The participants were categorized into four groups based on the median and upper and lower quartile of NLR, which were Group Q1 (NLR<1.64), Group Q2 (1.64≤NLR<2.19), Group Q3 (2.19≤NLR<3.00), and Group Q4 (NLR≥3.00), respectively. The clinical data and pathological features were compared among four groups. The independent factors affecting renal tubular atrophy/interstitial fibrosis in IgAN were determined by multivariate linear regression analysis. The diagnostic ability of NLR for renal tubular atrophy/interstitial fibrosis was evaluated by the area under receiver operating characteristic curve (AUC). The 2-year renal survival rates were compared among the four groups.

RESULTS

The levels of white blood cell count, neutrophil count, highly sensitive C-reactive protein, and the percentage of renal tubular atrophy/interstitial fibrosis were increased while lymphocyte count and estimated glomerular filtration rate were decreased with the increase of NLR level (P < 0.05). The percentage of tubular atrophy/interstitial fibrosis 26%-50% (T1) and >50% (T2) in Group Q4 was 40%, which was higher than that of other groups, especially Group Q1 (22.73%) and Group Q3 (22.39%), with significant difference (P < 0.05). NLR [β = 1.230, 95%CI (0.081, 2.379), P = 0.036] might be an independent factor affecting renal tubular atrophy/interstitial fibrosis in IgAN according to multivariate linear regression analysis results. The AUC predicted by NLR was 0.596 (95%CI 0.534~0.656, P = 0.007) with the specificity 88.24%, the sensitivity 30.00% and the optimal critical value of NLR 3.25. Fourteen patients progressed to end-stage renal disease within 2 years; and the 2-year survival rate of kidney was 93.49%. The renal survival rate in Group Q4 was 87.04%, lower than that in other three groups, especially Group Q1 (98.11%), with significant difference (P < 0.05).

CONCLUSION

NLR was correlated with the level of renal tubular atrophy/interstitial fibrosis and might be an significant factor for predicting the prognosis in IgAN.

Mesangial IgM deposition predicts renal outcome in patients with IgA nephropathy: a multicenter, observational study

Mesangial IgM deposition is found in patients with immunoglobulin A nephropathy (IgAN). This study aims to investigate the relationships between mesangial IgM deposition and disease progression in IgAN patients. A total of 1239 patients with biopsy-proven primary IgAN were enrolled in this multicenter, observational study between January 2013 and August 2017. According to the degree of IgM deposition, 1239 patients were divided into three groups: Grade 0 (no or trace; n = 713, 57.55%), Grade 1 (mild; n = 414, 33.41%), Grades 2 + 3 (moderate and marked; n = 112, 9.04%). Using a 1:1 propensity score matching (PSM) method identifying age, gender and treatment modality to minimize confounding factors, 1042 matched patients (out of 1239) with different degrees of IgM deposition were enrolled to evaluate the severity of baseline clinicopathological features and renal outcome: Grade 0 (n = 521, 50.00%), Grade 1 (n = 409, 39.25%), Grades 2 + 3 (n = 112, 10.75%). Kaplan-Meier and Cox proportional hazards analyses were performed to determine whether different degrees of mesangial IgM deposition are associated with varying renal outcomes in IgAN. During a mean follow-up of 48.90 ± 23.86 and 49.01 ± 23.73 months, before and after adjusting for propensity scores, respectively, the rate of complete remission (CR) was progressively lower with increased IgM deposition in both unmatched (63.39%, 46.14%, 45.54%) and matched cohort (61.80%, 46.45%, 45.54%), whereas the proportion of patients progressing to end-stage renal disease (ESRD) showed reverse correlation (P < 0.001). Kaplan-Meier analysis indicated negative correlation between the intensity of mesangial IgM deposits and cumulative renal survival (all P < 0.05). Moreover, Cox regression analysis revealed that the degree of mesangial IgM deposition predicted renal outcome independent of MESTC score and clinical variables in the unmatched (Grade 1, HR, 1.59; 95% CI, 1.11-2.29; P = 0.01; Grades 2 + 3, HR, 1.69; 95% CI, 1.02-2.08; P = 0.04) and matched cohort (Grade 1, HR, 1.84; 95% CI, 1.19-2.85; P = 0.01; Grades 2 + 3, HR, 1.91; 95% CI, 1.01-3.24; P = 0.04). Mesangial IgM deposition is associated with histological activity, clinical severity and renal outcome and is an independent risk factor for poor renal prognosis in IgAN. TRIAL REGISTRATION: TCTR, TCTR20140515001. Registered May 15, 2014, http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trialsearch&smenu=fulltext&task=search&task2=view1&id=1074 .

Long term outcome of immunoglobulin A (IgA) nephropathy: A single center experience

INTRODUCTION

IgA nephropathy (IgAN) has a heterogeneous presentation and the progression to end stage renal disease (ESRD) is often influenced by demographics, ethnicity, as well as choice of treatment regimen. In this study, we investigated the long term survival of IgAN patients in our center and the factors affecting it.

METHODS

This study included all biopsy-proven IgAN patients with ≥ 1year follow-up. Patients with diabetes mellitus at diagnosis and secondary IgAN were excluded. Medical records were reviewed for demographics, clinical presentation, blood pressure, 24-hour urine protein, serum creatinine, renal biopsy and treatment received. The primary outcome was defined as combined event of 50% estimated glomerular filtration rate (eGFR) reduction or ESRD.

RESULTS

We included 130 (74 females; 56 males) patients of mean age 38.0 ± 14.0 years and median eGFR of 75.2 (interquartile range (IQR) 49.3-101.4) ml/min/1.73m2. Eighty-four (64.6%) were hypertensive at presentation, 35 (26.9%) had nephrotic syndrome and 57 (43.8%) had nephrotic range proteinuria (NRP). Median follow-up duration was 7.5 (IQR 4.0-13.0) years. It was noted that 18 (13.8%) developed ESRD and 34 (26.2%) reached the primary outcome. Annual eGFR decline was -2.1 (IQR -5.3 to -0.1) ml/min/1.73m2/year, with median survival of 20 years. Survival rates from the combined event (50% decrease in eGFR or ESRD) at 10, 20 and 30 years were 80%, 53% and 25%, while survival from ESRD were 87%, 73% and 65%, respectively. In the univariate analysis, time-average proteinuria (hazard ratio (HR) = 2.41, 95% CI 1.77-3.30), eGFR <45ml/min/1.73m2 at biopsy (HR = 2.35, 95% CI 1.03-5.32), hypertension (HR = 2.81, 95% CI 1.16-6.80), mean arterial pressure (HR = 1.02, 95% CI 1.01-1.04), tubular atrophy/interstitial fibrosis score (HR = 3.77, 95% CI 1.84-7.73), and cellular/fibrocellular crescent score (HR = 2.44, 95% CI 1.19-5.00) were found to be significant. Whereas only time-average proteinuria (TA-proteinuria) remained as a significant predictor in the multivariate analysis (HR = 2.23, 95% CI 1.57-3.16).

CONCLUSION

In our cohort, TA-proteinuria was the most important predictor in the progression of IgAN, irrespective of degree of proteinuria at presentation.

Clinicopathological features, risk factors, and outcomes of immunoglobulin A nephropathy associated with hepatitis B virus infection

BACKGROUND

Hepatitis B virus (HBV) infections are associated with an increased risk of kidney diseases. However, the effects of HBV infection on the prognosis of immunoglobulin A nephropathy (IgAN) are unclear.

METHODS

A total of 838 patients with biopsy-confirmed IgAN were enrolled in this retrospective cohort study. The patients were categorized into either affected by IgAN and HBV infection (HBsAg-IgAN) or by primary IgAN with no sign of HBV infection (P-IgAN). A 1:1 propensity-score matching was performed between the two groups, followed by a Kaplan-Meier survival analysis, to compare the prognoses, and a Cox regression analysis, to identify factors influencing the HBsAg-IgAN outcomes.

RESULTS

A total of 176 pairs of patients were successfully matched. A significant difference in the systolic blood pressure and urea, serum creatinine, uric acid, and 24-h urine protein levels was observed between the groups. A renal pathological analysis also revealed a significant difference in the mesangial hypercellularity between the groups. During a median follow-up period of 2.4 years, Kaplan-Meier analysis also revealed a significant difference in the renal survival between the groups. Furthermore, multivariate Cox analysis confirmed that HBV infection is an independent risk factor for IgAN progression (hazard ratio [HR] 2.096; 95% confidence interval [CI] 1.091-4.026). Finally, the HBsAg-IgAN patients who received treatment with renin-angiotensin-aldosterone system inhibitors had a better overall prognosis than those who received immunosuppressive therapy and antiviral treatment.

CONCLUSION

Our results indicate that the clinicopathological features and outcomes of patients with IgAN differ significantly between those with and without HBV infection, and that HBV is an independent risk factor for IgAN progression.

Efficacy and safety of immunosuppressive therapies in the treatment of high-risk IgA nephropathy: A network meta-analysis

BACKGROUND

IgA nephropathy (IgAN) is one of the significant contributing factors of end-stage renal disease (ESRD). It is reported that over half of patients with IgAN accompany multiple high-risk factors, which increase the risk of ESRD progression. Studies have shown that immunosuppressive agents were beneficial in high-risk IgAN, but the efficacy and safety have not been fully demonstrated yet. The present study aims to elucidate the efficacy of commonly used immunosuppressants in high-risk IgAN and their relative safety profiles via a network meta-analysis strategy.

METHODS

Randomized controlled trials (RCTs) eligible for this network meta-analysis were included to evaluate the efficacy and safety of different immunosuppressants for high-risk IgAN. Main outcomes and measures include incidence of renal composite end point, the rate of total remission, adverse events, and proteinuria. Besides, subgroup analysis and cluster analysis were carried out.

RESULTS

This network meta-analysis of 37 RCTs involving 3012 participants found that Mycophenolate mofetil (MMF) combined with corticosteroids (CS) was superior to other interventions in end point events and proteinuria. Cyclosporine A (CsA) plus CS was the best option for clinical remission rate, and supportive care (SC) was the safest treatment. Cluster analysis showed that MMF+CS and Leflunomide (LEF)+CS were best protocols in efficacy and safety. Subgroup analysis indicated the best benefits of MMF were presented among the Asian population, and the benefits increased with the increase of follow-up duration. The effect of Cyclophosphamide (CTX) +CS on crescent IgAN was better than that of other risk factors. Moreover, the increasing follow-up duration was negatively associated with the effect.

CONCLUSIONS

MMF+CS and LEF+CS appear to serve as the best choice for treating high-risk IgAN than other immunosuppressive therapies.

Grading system utilising the total score of Oxford classification for predicting renal prognosis in IgA nephropathy

The Oxford classification of IgA nephropathy (IgAN) can evaluate each MEST-C score individually. We analysed a new grading system that utilised the total MEST-C score in predicting renal prognosis. Altogether, 871 IgAN patients were classified into three groups using the new Oxford classification system (O-grade) that utilised the total MEST-C score (O-grade I: 0–1, II: 2–4, and III: 5–7 points), and the 10-year renal prognosis was analysed. The clinical findings became significantly severer with increasing O-grades, and the renal survival rate by the Kaplan–Meier method was 94.1%, 86.9%, and 74.1% for O-grades I, II, and III, respectively. The hazard ratios (HRs) for O-grades II and III with reference to O-grade I were 2.8 (95% confidence interval [CI] 1.3–6.0) and 6.3 (95% CI 2.7–14.5), respectively. In the multivariate analysis, mean arterial pressure and eGFR, proteinuria at the time of biopsy, treatment of corticosteroids/immunosuppressors, and O-grade (HR 1.63; 95% CI 1.11–2.38) were the independent factors predicting renal prognosis. Among the nine groups classified using the O-grade and Japanese clinical-grade, the renal prognosis had an HR of 15.2 (95% CI 3.5–67) in the severest group. The O-grade classified by the total score of the Oxford classification was associated with renal prognosis.

Epidemiology, baseline characteristics and risk of progression in the first South-Asian prospective longitudinal observational IgA nephropathy cohort

INTRODUCTION

Glomerular Research And Clinical Experiments-IgA Nephropathy in Indians (GRACE-IgANI) is the first prospective South Asian IgAN cohort with protocolized follow-up and extensive biosample collection. Here we report the baseline clinical, biochemical, and histopathologic characteristics of GRACE IgANI and calculate baseline risk of progression for the cohort.

METHODS

201 incident adults with kidney biopsy-proven primary IgAN were recruited into GRACE-IgANI between March 2015 and September 2017. As of April 30, 2020, the cohort had completed a median follow-up of 30 months (interquartile range [IQR] 16-39).

RESULTS

The commonest clinical presentation in GRACE IgANI was hypertension, with or without proteinuria, and nephrotic-range proteinuria was present in 34%, despite <10 months of lead time to kidney biopsy. The GRACE-IgANI kidney biopsy data demonstrated a disproportionate absence of active glomerular lesions and overrepresentation of segmental sclerosing lesions and tubulointerstitial fibrosis at presentation, often coexistent with relatively well-preserved estimated glomerular filtration rate (eGFR) and low levels of proteinuria, especially in males. Baseline risk of progression was calculated for each evaluable patient using 2 different risk prediction tools. The median 5-year absolute risk of end-stage kidney disease (ESKD) was 19.8% (IQR 2.7-57.4) and median 5-year risk of progression to the combined endpoint of 50% decline in eGFR or ESKD was 35.5% using the 2 tools.

CONCLUSIONS

The predicted risk of progression in this cohort was considerable. Over the next 5 years, we will dissect the pathogenic pathways that underlie this severe South Asian IgAN phenotype.

Immunofluorescence deposits in the mesangial area and glomerular capillary loops did not affect the prognosis of immunoglobulin a nephropathy except C1q:a single-center retrospective study

Background

Immunoglobulin A nephropathy (IgAN) is identified as mesangial IgA deposition and is usually accompanied by other immunofluorescence deposits. The impact of immunofluorescent features in IgAN patients, however, remains unclear.

Methods

Baseline clinicopathologic parameters and renal outcomes of 337 patients diagnosed with IgAN between January 2009 and December 2015 were analyzed. We then categorized these patients into four groups: without immunofluorescence deposits, mesangial-only, mesangial and glomerular capillary loops (GCLs), and GCLs-only. The study endpoint was end-stage kidney disease (ESKD) or a ≥ 50% decline in the estimated glomerular filtration rate (eGFR). Kaplan–Meier and Cox regression analyses were performed to calculate renal survival.

Results

Of the 337 IgAN patients, women comprised 57.0%. Compared to patients with IgA deposition in the mesangial-only group, patients with IgA deposition in the mesangial +GCLs group were much heavier, and exhibited higher systolic blood pressure, lower serum IgG levels, and heavier proteinuria (all P < 0.05). Patients with IgG deposition in the mesangial +GCLs group presented with higher levels of cholesterol, heavier proteinuria than IgG deposition in the mesangial-only group (both P < 0.05). Compared with the mesangial-only group exhibiting C3 deposits, patients in the mesangial +GCLs group with C3 deposition had a higher systolic blood pressure (P = 0.028). A total of 38 patients (11.3%) continued to the study endpoint after a median follow-up time of 63.5 months (range,49.8–81.4). Kaplan–Meier analysis and Cox regression analysis showed that C1q deposition in the mesangial +GCLs group predicted a poor renal prognosis.

Conclusions

IgA and IgG deposits in the mesangial region and GCLs were associated with more unfavorable clinical and histopathologic findings in IgAN patients. C1q deposition in the mesangial region and GCLs predicted a poor renal prognosis. However, the impact of the pattern of immunofluorescence deposits on renal outcomes remains to be proven by further investigation.

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.

Associations of Genetic Variants Contributing to Gut Microbiota Composition in Immunoglobin A Nephropathy

The gut microbiota and host genetics are implicated in the pathogenesis of IgAN. Recent studies have confirmed that microbial compositions are heritable (microbiome quantitative trait loci [QTL]).

The gut microbiota has been implicated in immunoglobin A nephropathy (IgAN) because the intestinal immune response is assumed to be one of the disease triggers. Since the microbial composition is heritable, we hypothesize that genetic variants controlling gut microbiota composition may be associated with susceptibility to IgAN or clinical phenotypes. A total of 175 gut-microbiome-associated genetic variants were retrieved from the Genome-Wide Association Study (GWAS) Catalog. Genetic associations were examined in 1,511 patients with IgAN and 4,469 controls. Subphenotype associations and microbiome annotations were undertaken for a better understanding of how genes shaped phenotypes. Likely candidate microbes suggested in genetic associations were validated using 16S rRNA gene sequencing in two independent data sets with 119 patients with IgAN and 45 controls in total. Nine genetic variants were associated with susceptibility to IgAN. Risk genotypes of LYZL1 were associated with higher serum levels of galactose-deficient IgA1 (Gd-IgA1). Other significant findings included the associations between the risk genotype of SIPA1L3 and early age at onset, PLTP and worse kidney function, and AL365503.1 and more severe hematuria. Besides, risk genotypes of LYZL1 and SIPA1L3 were associated with decreased abundances of Dialister and Bacilli, respectively. Risk genotypes of PLTP and AL365503.1 were associated with increased abundances of Erysipelotrichaceae and Lachnobacterium, respectively. 16S data validated a decreased tendency for Dialister and an increased tendency for Erysipelotrichaceae in IgAN. In this pilot study, our results provided preliminary evidence that the gut microbiota in IgAN was affected by host genetics and shed new light on candidate bacteria for future pathogenesis studies.

IMPORTANCE The gut microbiota and host genetics are implicated in the pathogenesis of IgAN. Recent studies have confirmed that microbial compositions are heritable (microbiome quantitative trait loci [QTL]). The relationship between host genetics and the microbiota and the role of the microbiota in IgAN are unclear. We retrieved the GWAS Catalog and associated microbiome QTL in IgAN, observing that nine genetic variants were associated with IgAN susceptibility and some clinical phenotypes. In a consistent way, the decreased abundance of Dialister was associated with higher serum levels of Gd-IgA1, and 16S rRNA gene analysis confirmed the decreased abundance of Dialister in IgAN. These data provided preliminary evidence that the gut microbiota in IgAN was affected by host genetics, which is a new strategy for future pathogenesis and intervention studies.

Dysbiosis in the Salivary Microbiome Associated with IgA Nephropathy-‍A‍ ‍Japanese Cohort Study

IgA nephropathy is one of the leading causes of chronic kidney disease in Japan. Since the origin and mechanisms by which IgA nephropathy develops currently remain unclear, a confirmed disease diagnosis is currently only possible by highly invasive renal biopsy. With the background of the salivary microbiome as a rich source of biomarkers for systemic diseases, we herein primarily aimed to investigate the salivary microbiome as a tool for the non-invasive diagnosis of IgA nephropathy. In a comparison of salivary microbiome profiles using 16S rRNA amplicon sequencing, significant differences were observed in microbial diversity and richness between IgA nephropathy patients and healthy controls. Furthermore, recent studies reported that patients with IgA nephropathy are more likely to develop inflammatory bowel diseases and that chronic inflammation of the tonsils triggered the recurrence of IgA nephropathy. Therefore, we compared the salivary microbiome of IgA nephropathy patients with chronic tonsillitis and ulcerative colitis patients. By combining the genera selected by the random forest algorithm, we were able to distinguish IgA nephropathy from healthy controls with an area under the curve (AUC) of 0.90, from the ulcerative colitis group with AUC of 0.88, and from the chronic tonsillitis group with AUC of 0.70. Additionally, the genus Neisseria was common among the selected genera that facilitated the separation of the IgA nephropathy group from healthy controls and the chronic tonsillitis group. The present results indicate the potential of the salivary microbiome as a biomarker for the non-invasive diagnosis of IgA nephropathy.

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

Introduction: This systematic literature review analyzed published evidence on IgA nephropathy (IgAN), focusing on US epidemiology, health-related quality of life (HRQoL), and economic burden of illness. Methods: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, Embase®, MEDLINE®, Cochrane, and Econlit (January 2010 to June 2020) were searched, along with relevant congresses (2017-2020). Results: Of 123 epidemiologic studies selected for data extraction, 24 reported IgAN diagnosis rates ranging from 6.3% to 29.7% among adult and pediatric patients undergoing renal biopsy, with all reported US rates <15%. No US studies reported IgAN prevalence. A meta-analysis of US studies calculated an annual incidence of 1.29/100 000 people, translating to an annual US incidence of 4236 adults and children. Relative to Europe, the United States had more patients diagnosed with IgAN in later chronic kidney disease stages. US rates of transition to end-stage renal disease (ESRD) ranged from 12.5% to 23% during 3-3.9 years of observation, rising to 53% during 19 years of observation. Across 8 studies reporting HRQoL, pain and fatigue were the most reported symptoms, and patients consistently ranked kidney function and mortality as the most important treatment outcomes. Patients with glomerulopathy reported worse mental health than healthy controls or hemodialysis patients; proteinuria was significantly associated with poorer HRQoL and depression. Conclusion: While economic evidence in IgAN remains sparse, management of ESRD is a major cost driver. IgAN is a rare disease where disease progression causes increasing patient burden, underscoring the need for therapies that prevent kidney function decline and HRQoL deterioration while reducing mortality.

Glomerular C4d in Post-Transplant IgA Nephropathy is associated with decreased allograft survival

Background

Glomerulonephritis (GN), including post-transplant IgAN (post-Tx IgAN) is an important contributor to decreased long-term allograft survival. The immunopathological detection of the complement degradation product C4d in glomeruli (C4dG) has been recently described as a risk factor in native kidney IgAN, however little is known about C4dG deposition in post-Tx IgAN. We hypothesized that glomerular C4d may indicate a more aggressive disease course and worse allograft survival in patients with post-Tx IgAN.

Methods

In this retrospective study we assessed the presence and clinical relevance of C4dG in patients with post-transplant IgAN. We analyzed 885 renal allograft recipients, including 84 patients with post-transplant GN. All patients were transplanted between January 1999 and April 2006 and underwent at least one biopsy for differnt causes. The primary endpoint was death-censored graft survival, with a median follow-up of 9.6 (IQR 3.8–13.2) years.

Results

The prevalence of post-Tx GN was 9.5%. Twenty-seven patients with post-Tx IgAN were included. C4dG positive patients (N = 18, 66.7%) had significantly worse allograft survival compared to C4dG negative post-Tx IgAN patients and patients without post-Tx IgAN [C4dG positive: 27.8% vs. 55.6% and 66.0%; log-rank: p = 0.01]. C4dG remained a significant risk factor (HR 2.22, 95% CI 1.27–3.87) for allograft loss even after adjustment for T cell mediated rejection (TCMR) and antibody mediated rejection.

Conclusion

Glomerular C4d deposition is an independent risk factor for worse graft-survival in patients with post-Tx IgAN, even after adjusting for other risk factors such as antibody mediated rejection.  Assessment of glomerular C4d deposition may provide a valuable prognostic risk assessment tool to identify high risk patients in post-Tx IgAN.

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s40620-020-00914-x) contains supplementary material, which is available to authorized users.

Emerging Modes of Treatment of IgA Nephropathy

IgA nephropathy is the most common primary glomerulonephritis with potentially serious outcome leading to end stage renal disease in 30 to 50% of patients within 20 to 30 years. Renal biopsy, which might be associated with risks of complications (bleeding and others), still remains the only reliable diagnostic tool for IgA nephropathy. Therefore, the search for non-invasive diagnostic and prognostic markers for detection of subclinical types of IgA nephropathy, evaluation of disease activity, and assessment of treatment effectiveness, is of utmost importance. In this review, we summarize treatment options for patients with IgA nephropathy including the drugs currently under evaluation in randomized control trials. An early initiation of immunosupressive regimens in patients with IgA nephropathy at risk of progression should result in the slowing down of the progression of renal function to end stage renal disease.

Increased serum uric acid levels are associated to renal arteriolopathy and predict poor outcome in IgA nephropathy

BACKGROUND AND AIMS

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide and a leading cause of end stage renal disease (ESRD). In addition to classical progression factors, other atherosclerosis-related factors, including hyperuricemia (HU), have been associated to the renal progression of IgAN. Increased serum uric acid (SUA) levels are well known to be concomitant of cardiovascular and kidney diseases, and have been proposed to be implicated in the development of arteriolar damage (AD). The aim of the present study was to explore the correlation between SUA levels, renal damage and its implication for outcome in IgAN patients.

METHODS AND RESULTS

Clinical, laboratory and histologic data of 145 patients with biopsy proven IgAN were collected and retrospectively analyzed to determine the correlation between SUA levels, renal damage and the primary outcome (death or ESRD). Biopsy-proven AD was defined by the presence of arteriolar hyalinosis and/or intimal thickening. HU, defined as the highest SUA gender-specific tertile, was >7.7 mg/dl for males and >6.2 mg/dl for females. The prevalence of AD increased with the increase in the SUA level tertiles (p = 0.02). At logistic regression analysis SUA was independently related to the presence of AD (OR 1.75 [95%CI 1.10-2.93], p = 0.03). HU and AD had a synergic impact on progression of IgAN. Patients having both AD and HU, showed a reduced survival free from the primary outcome as compared to those having only one risk factor or neither (p = 0.01).

CONCLUSIONS

SUA levels are independently associated with AD and poor prognosis in patients with IgAN.

Sex disparities in IgA nephropathy: a retrospective study in Chinese patients

AIM

The aim of this study was to explore the effect of sex on the clinicopathological features and long-term outcomes of IgAN patients.

METHODS

A total of 1096 adult IgAN patients were divided into male and female groups. Clinicopathological features and risk factors of IgAN patients of different genders were contrasted. The primary endpoint was the combined endpoint of a 50% reduction in estimated glomerular filtration rate (eGFR) and/or end stage renal disease (ESRD: eGFR < 15 mL/min/1.73 m² or dialysis). The effect of gender on prognosis of IgAN was assessed using Kaplan-Meier and Cox proportional hazards models.

RESULTS

In total, 475 male patients and 621 female patients were included in this study. At baseline, male patients had higher values for blood pressure, serum creatinine, urine protein and serum uric acid, as well as lower levels of eGFR. Further analysis indicated that tubular atrophy/interstitial fibrosis (T) lesions and vascular lesions were more frequent in male patients. During the follow-up period of 40.9 ± 24.2 months, kidney survival rates of male IgAN patients were remarkably lower than those of female patients. Using multivariate Cox regression analysis, male gender was identified as an independent risk factor for poor outcomes (β = 0.384, Wald = 4.290, Exp (β) = 1.47, p = 0.038), including hypertension, low eGFR, IgM deposition, arteriosclerosis lesions and T1-T2 lesions. However, male and female patients were characterized by different risk factors.

CONCLUSION

Male patients presented with more severe clinical and pathological changes than female patients. Renal survival rates of male patients were remarkably lower than those of female patients, and male gender was identified as an independent risk factor for poor outcomes.

The analysis of treatment of Immunoglobulin A-nephropathy

Aim. An evaluation of the effectiveness of immunosuppressive therapy (IST) and tonsillectomy (TE) in patients with IgA nephropathy (IgAN). Materials and methods. A retrospective cohort of the study included cases with biopsy proven primary IgAN (n=367, age 3412 years, men 55%). We used demographic and clinical and morphological parameters at the time of biopsy. Median followup period was 26 (10; 61) months. Outcomes were remission (complete or partial) and the progression of IgAN (defined as the start of dialysis or a decrease in glomerular filtration rate 50% from baseline). All patients received treatment with renin angiotensin system blockers. Evaluation of the effectiveness of therapy was carried out using propensity score (PS) methods matching, conventional double robust regression models with PS as independent covariate, and inverse probability weighting. Following patient subgroups were used for comparative analyses: with IST (n=176) and without IST (n=191); with TE (n=63) and without TE (n=304); without IST and without TE (IST-TE-; n=162); with TE and without IST (IST-TE+; n=29); with IST and without TE (IST+TE-; n=142); with IST and with TE (IST+ TE+; n=34). Results. All PS methods used gave close estimates of the comparative effectiveness of treatment in different subgroups: 1) patients on monotherapy with corticosteroids (CS) and combination of CS with other immunosuppressants did not have significant differences in probabilities of IgAN progression (hazard ratio 0.919; 95% CI 0.3332.950) and remission (odds ratio 0.919; 95% CI 0.3792.344) and were further combined into a group of IST; 2) IST was significantly associated with the lower risk of disease progression and increased odds ratio for remission; 3) the positive effects of IST were limited to cases with proteinuria 2 g/24 h; 4) the likelihood of IgAN remission and progression did not differ significantly between TE+ and TE-, IST-TE+ and IST-TE- groups. There were no cases of disease progression in the IST+TE+ group. The cumulative renal survival was higher in the IST+TE+ group compared to IST+ TE- group (p=0.010), while the probability of remission did not differ. Conclusion. IST was associated with a lower risk of IgAN progression and increased probability of remission, while these effects of IST were limited to patients with proteinuria 2 g/24 h. TE in combination with IST is associated with an additional reduction in the risk of disease progression.

Efficacy of corticosteroid therapy for IgA nephropathy patients stratified by kidney function and proteinuria

BACKGROUND

Steroid therapy is one of the important therapies for IgA nephropathy (IgAN), but the features of the IgAN patients who have the benefit from this therapy remained unclear.

METHODS

This retrospective observational study, using data of 874 patients with IgAN analyzed the proteinuria and kidney function of IgAN patients who had beneficial effect by steroid therapy. Two advantages of the present study were a large cohort and a long observational period.

RESULTS

Corticosteroid therapy had ameliorated the kidney prognosis [incident rate ratio (IRR) 0.57 (95%CI 0.34-0.92), P = 0.029]. Because of interaction between kidney function and use of corticosteroid (P = 0.047), stratification analysis by kidney function revealed that prognosis of kidney function in IgAN patients whose eGFR was less than 60 ml/min/1.73m² was ameliorated by corticosteroid therapy [IRR 0.50 (95%CI 0.26-0.97), P = 0.015); while, there was no change of kidney prognosis in IgAN patients whose eGFR was above 60 ml/min/1.73 m². To make the target of corticosteroid therapy for IgAN patients more clear, IgAN patients, whose eGFR were less than 60 ml/min/1.73 m², were stratified by proteinuria (1 g/day). In IgAN patients whose eGFR were under 60 ml/min/1.73 m² and whose proteinuria were over 1.0 g/day, corticosteroid therapy seemed to ameliorate kidney function [IRR 0.39 (95%CI 0.19-0.86), P < 0.05]; while, there was obviously no change by corticosteroid therapy in IgAN patients whose eGFR were less than 60 ml/min/1.73 m² and whose proteinuria were less than 1.0 g/day.

CONCLUSION

Our results suggested that steroid therapy was especially effective for IgAN patients whose eGFR was less than 60 ml/min/1.73 m² and whose proteinuria was more than 1.0 g/day.

Validation of the revised Oxford classification for IgA nephropathy considering treatment with corticosteroids/immunosuppressors

The Oxford classification for IgA nephropathy (IgAN) was updated in 2017. We have validated the revised Oxford classification considering treatment with corticosteroids/immunosuppressors. In this retrospective analysis, 871 IgAN patients were enrolled. Patients were divided into two groups, those treated with or without corticosteroids/immunosuppressors. The 20-year renal prognosis up to end-stage renal disease was assessed using the Oxford classification. In all patients, the renal survival rate was 87.5% at 10 years and 72.6% at 20 years. The T score alone was significantly related to renal prognosis in the Kaplan–Meier analysis and multivariate Cox regression analysis. In the non-treatment group (n = 445), E, S, T, and C scores were significantly related to renal survival rates, however, in the treatment group (n = 426), T score alone was significantly related to renal prognosis on Kaplan–Meier analysis, indicating that corticosteroids/immunosuppressors improved renal prognosis in E1, S1, and C1. In patients with E1, S1, or C1, the treatment group showed significantly better renal prognosis than the non-treatment group in univariate and multivariate analysis. The Oxford classification and T score were used to determine renal prognosis in IgAN patients. Corticosteroids/immunosuppressors improved renal prognosis, especially E1, S1, and C1 scores.

Remission of Proteinuria May Protect against Progression to Chronic Kidney Disease in Pediatric-Onset IgA Nephropathy

Immunoglobulin A nephropathy (IgAN) is one of the most common primary glomerulopathies diagnosed in children and adolescents. This study aimed to evaluate the clinical features in and outcomes of pediatric IgAN over the last 30 years. Patients who were diagnosed before age of 18 at 20 centers in Korea were evaluated retrospectively. Of the 1154 patients (768 males, 386 females) with a median follow-up of 5 years, 5.6% (n = 65) progressed to stage 3–5 chronic kidney disease (CKD). The 10- and 20-year CKD-free survival rates were 91.2% and 75.6%, respectively. Outcomes did not differ when comparing those in Korea who were diagnosed prior to versus after the year 2000. On multivariate analysis, combined asymptomatic hematuria and proteinuria as presenting symptoms and decreased renal function at the time of biopsy were associated with progression to CKD, while remission of proteinuria was negatively associated with this outcome. Patients who presented with gross hematuria or nephrotic syndrome tended toward positive outcomes, especially if they ultimately achieved remission. While remission of proteinuria might imply that the disease is inherently less aggressive, it also can be achieved by management. Therefore, more aggressive management might be required for pediatric-onset IgAN.

Persistent Disease Activity in Patients With Long-Standing Glomerular Disease

Introduction

Methods

Results

Conclusion

The precise long-term outcomes of adult IgA nephropathy by mail questionnaires: Better renal survival compared to earlier cohort studies

The estimated 20-year renal survival rate of immunoglobulin A (IgA) nephropathy is approx. 60%, but it is difficult to determine the 'big picture' for IgA nephropathy because a biopsy is essential for its diagnosis. Here we attempted to determine the longer and more precise renal prognosis of IgA nephropathy. We examined 310 patients with primary IgA nephropathy. Using the patients' clinical records and histological reports from our hospital and other clinics, we surveyed their renal prognoses and treatments within 1 year post-biopsy, and we sent questionnaires to the patients who had stopped visiting any hospital. We set renal death as the primary endpoint and analyzed factors related to renal death. The total patient cohort was 267: 159 males, 108 females; average age at biopsy, 37.7 years; average estimated glomerular filtration rate (eGFR), 69.7 mL/min/1.73m2; urinary protein, 1.3 g/day. The mean follow-up duration was prolonged to 13.8±8.9 years (vs. 9.2±8.5 years using only medical records). The 10- and 20-year follow-up rates were 61.7% and 27.3%. The 10-, 20-year renal survival rates were 83.6% and 72.5%. Lower eGFR, hypertension, and smoking were revealed as factors independently related to renal death. To study survival of relatively benign diseases such as IgA nephropathy, longer survival rate was affected by many censoring cases. The results regarding the long-term renal prognoses of IgA nephropathy patients (including those with a mild phenotype) obtained by our analysis of a questionnaire sent to the patients provided more precise and longer-term prognoses compared to earlier studies.

Clinical and Pathophysiological Insights Into Immunological Mediated Glomerular Diseases in Childhood

The kidney is often the target of immune system dysregulation in the context of primary or systemic disease. In particular, the glomerulus represents the anatomical entity most frequently involved, generally as the expression of inflammatory cell invasion or circulant or in situ immune-complex deposition. Glomerulonephritis is the most common clinical and pathological manifestation of this involvement. There are no universally accepted classifications for glomerulonephritis. However, recent advances in our understanding of the pathophysiological mechanisms suggest the assessment of immunological features, biomarkers, and genetic analysis. At the same time, more accurate and targeted therapies have been developed. Data on pediatric glomerulonephritis are scarce and often derived from adult studies. In this review, we update the current understanding of the etiologic events and genetic factors involved in the pathogenesis of pediatric immunologically mediated primitive forms of glomerulonephritis, together with the clinical spectrum and prognosis. Possible new therapeutic targets are also briefly discussed.

Insulin resistance is associated with urinary albumin-creatinine ratio in normal weight individuals with hypertension and diabetes: The REACTION study

BACKGROUND

The relationship between albuminuria and insulin resistance (IR) has not been clarified in previous studies. This study was conducted to examine whether IR is associated with albuminuria in subjects with diverse blood pressure and glycometabolism statuses.

METHODS

This study included 34 136 participants whose data were drawn from a cross-sectional survey named the 2011 REACTION study. The participants were divided into six groups. The urinary albumin-creatinine ratio (UACR) and glomerular filtration rate (GFR) were used as markers of chronic kidney disease (CKD). Variance tests and logistic regression models were performed for homeostatic model assessment of insulin resistance (HOMA-IR) in relation to UACR and eGFR.

RESULTS

First, UACR levels and HOMA-IR exhibited a positive correlation among participants (P < 0.05), and a negative correlation existed between GFR and HOMA-IR (P < 0.05). Second, in the hypertension with diabetes group, in individuals whose body mass index (BMI) was 18.5-24.0 kg/m² , age was 50-60 years old, low density lipoprotein cholesterol (LDL-C) was 2.6-3.4 mmol/L or high density lipoprotein cholesterol (HDL-C) was 0.9-1.55 mmol/L, HOMA-IR was positively associated with UACR (P < 0.05). However, there was a negative correlation between GFR and HOMA-IR in the hypertension with diabetes group in individuals whose BMI was 18.5-24.0 kg/m² or whose age was over 65 years old (P < 0.05).

CONCLUSIONS

In the context of different blood pressure and glycometabolism statuses, the positive correlation between UACR levels and HOMA-IR was affected by BMI, age, LDL-C, HDL-C, and GFR. In patients with hypertension and diabetes, the early detection and intervention of IR and related risk factors in patients with normal BMI may reduce the occurrence of microalbuminuria and delay the progression of CKD.

Identifying Outcomes Important to Patients with Glomerular Disease and Their Caregivers

BACKGROUND AND OBJECTIVES

Shared decision making in patients with glomerular disease remains challenging because outcomes important to patients remain largely unknown. We aimed to identify and prioritize outcomes important to patients and caregivers and to describe reasons for their choices.

DESIGN

, setting, participants, & measurementsWe purposively sampled adult patients with glomerular disease and their caregivers from Australia, Hong Kong, the United Kingdom, and the United States. Participants identified, discussed, and ranked outcomes in focus groups using the nominal group technique; a relative importance score (between zero and one) was calculated. Qualitative data were analyzed thematically.

RESULTS

Across 16 focus groups, 134 participants (range, 19-85 years old; 51% women), including 101 patients and 33 caregivers, identified 58 outcomes. The ten highest-ranked outcomes were kidney function (importance score of 0.42), mortality (0.29), need for dialysis or transplant (0.22), life participation (0.18), fatigue (0.17), anxiety (0.13), family impact (0.12), infection and immunity (0.12), ability to work (0.11), and BP (0.11). Three themes explained the reasons for these rankings: constraining day-to-day experience, impaired agency and control over health, and threats to future health and family.

CONCLUSIONS

Patients with glomerular disease and their caregivers highly prioritize kidney health and survival, but they also prioritize life participation, fatigue, anxiety, and family impact.

The role of hypertriglyceridemia and treatment patterns in the progression of IgA nephropathy with a high proportion of global glomerulosclerosis

PURPOSE

Many studies have focused on finding predictors for mild IgAN progression. However, the cases of severe IgAN with a high proportion of global glomerulosclerosis have received inadequate attention.

METHODS

A group of 172 primary IgAN patients with 50-75% global glomerulosclerosis was studied retrospectively between April 2007 and October 2017. Patients were divided into three groups according to the serum triglyceride tertiles:  < 1.42 µmol/L (Group 1), 1.42-2.29 µmol/L (Group 2), and > 2.29 µmol/L (Group 3). Groups 1 and 2 comprised non-hypertriglyceridemia subjects, while Group 3 was defined as the hypertriglyceridemia (HTG) group. The patients were followed for 4-96 months (median 39.43 months). The study end point was defined as a 50% decline in estimated glomerular filtration rate (eGFR) or ESRD.

RESULTS

A high proportion of global glomerulosclerosis is not absolutely correlated with severe clinical features and poor renal outcome. In our retrospective observation, eGFR decreased by less than 10% of the baseline during follow-up in 43.6% of the patients. However, in our patients with HTG, the cumulative renal survival rate was significantly lower compared to those without HTG. Multivariate Cox regression analysis also showed that triglyceride is an independent predictor of poor renal outcomes. Furthermore, in the HTG group, the cumulative renal survival rates were higher in patients treated with Tripterygium wilfordii Hook F (TwHF) compared to those without TwHF.

CONCLUSIONS

A high proportion of global glomerulosclerosis combined with HTG at biopsy have better predictive validity for the disease progression of IgAN than global glomerulosclerosis alone. TwHF may partially affect the renal outcome of severe IgAN with HTG, and this may relate to its regulation of lipid metabolism and immunoinflammatory response.

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.

The impact of tonsillectomy combined with steroid pulse therapy in patients with advanced IgA nephropathy and impaired renal function

BACKGROUND

Preventing progression to end-stage renal disease (ESRD) in advanced IgA nephropathy (IgAN) patients with impaired renal function remains challenging. We analyzed the efficacy of tonsillectomy combined with steroid pulse therapy (TSP).

METHODS

In this retrospective analysis, IgAN patients with proteinuria > 0.5 g/day and estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² were divided into three groups: patients treated with TSP (TSP group; n = 23), oral prednisolone (oPSL group; n = 41), and conservative therapy (CONS group, n = 51). We analyzed the clinical and histological backgrounds, remission of urinary findings, and renal survival rate to a 25% decline in eGFR from baseline, and incidence of ESRD.

RESULTS

There were significant differences in the patients' backgrounds among the groups. Therefore, we adjusted the background using propensity score marching between TSP group and oPSL or CONS group. The 5-year remission rate of hematuria was significantly higher in the TSP group than in the oPSL group, and that of both hematuria and proteinuria was significantly higher in the TSP group than in the CONS group. The 10-year renal survival rate was significantly higher in the TSP group than in the oPSL and CONS groups. In a multivariate Cox regression analysis, TSP was found to be an independent factor for the 25% decline in eGFR in entire cohort. The adverse effect frequency in the TSP group was similar to the CONS group.

CONCLUSIONS

TSP can effectively induce remission of urinary abnormality and improve the prognosis without frequent adverse effects in IgAN patients with impaired renal function.

Clinical, pathological characteristics and outcomes of immunoglobulin A nephropathy patients with different ages

AIM

To determine the clinical and pathological differences in immunoglobulin A (IgA) nephropathy (IgAN) with different ages, and to determine whether age is a risk factor for progression of IgAN.

METHODS

This was a single centre retrospective cohort study. Patients with biopsy-diagnosed primary IgAN were stratified into three groups: young-aged (14-29 years), middle-aged (30-49 years) and older-age (≥50 years). The primary outcome was end-stage renal disease (estimated glomerular filtration rate [eGFR] <15 mL/min/1.73 m² , dialysis or renal transplantation) or doubling of the baseline serum creatinine.

RESULTS

A total of 981 patients were enrolled, including 65 (6.6%) patients in older-age group, 517 (52.7%) in middle-aged group and 399 (40.7%) in young-aged group. The older-age group had significantly higher levels of serum IgA, cholesterol, triglycerides and creatinine, and a reduced eGFR. In contrast to the young adults who had a higher percentage of crescent formation in glomeruli, the older-aged patients had more severe chronic pathological changes including global glomerulosclerosis and vascular lesions (p < .01). The cumulative renal survival in the older-age group was slightly shorter than that in the young adult or middle-aged group, but not achieving significant (p > .05). The 3- and 5-year renal survival rates were similar among the three groups. A multivariate Cox regression analysis showed that age was not an independent predictor of an unfavourable prognosis.

CONCLUSION

The IgAN patients with aged 50 years or older had different clinical pathological changes as compared with younger patients. However, aging was not found as an independently predictor of renal progression of IgAN. Prolonged follow up is necessary to confirm this trend.

Has The Time Arrived to Refine The Indications of Immunosuppressive Therapy and Prognosis in IgA Nephropathy?

Immunoglobulin A nephropathy (IgAN) is the most frequent glomerular disease worldwide and a leading cause of end-stage renal disease. Particularly challenging to the clinician is the early identification of patients at high risk of progression, an estimation of the decline in renal function, and the selection of only those that would benefit from additional immunosuppressive therapies. Nevertheless, the pathway to a better prognostication and to the development of targeted therapies in IgAN has been paved by recent understanding of the genetic and molecular basis of this disease. Merging the data from the Oxford Classification validation studies and prospective treatment studies has suggested that a disease-stratifying algorithm would be appropriate for disease management, although it awaits validation in a prospective setting. The emergence of potential noninvasive biomarkers may assist traditional markers (proteinuria, hematuria) in monitoring disease activity and treatment response. The recent landmark trials of IgAN treatment (STOP-IgAN and TESTING trials) have suggested that the risks associated with immunosuppressive therapy outweigh the benefits, which may shift the treatment paradigm of this disease. While awaiting the approval of the first therapies for IgAN, more targeted and less toxic immunotherapies are warranted. Accordingly, the targeting of complement activation, the modulation of mucosal immunity, the antagonism of B-cell activating factors, and proteasomal inhibition are currently being evaluated in pilot studies for IgAN treatment.

Salivary microbial analysis of Chinese patients with immunoglobulin A nephropathy

Microbiota plays an important role in immunoglobulin A (IgA) nephropathy (IgAN); however, the pathogenesis, early diagnosis, and treatment of IgAN remain unclear. The aim of the present study was to develop a preliminary model based on saliva‑specific microbes and clinical indicators to facilitate the early diagnosis of IgAN and obtain insights into its treatment. The microbial profile of the saliva of 28 IgAN patients and 25 healthy control subjects was investigated using high‑throughput sequencing and bioinformatics analyses of the V4 region in microbial 16S rRNA genes. IgAN patients and healthy subjects did not differ significantly in α‑diversity indices (Chao1 and Shannon index) or phylum composition. At the genus level, however, Granulicatella was significantly less abundant in healthy individuals than in IgAN patients, while Prevotella and Veillonella were significantly more abundant in the healthy subjects than in IgAN patients (P<0.05 and P<0.01, respectively). Correlation analysis between biochemical indicators and operational taxonomic units (OTUs) revealed that the glomerular filtration rate was positively correlated with OTU86 and OTU287 at P<0.05, positively correlated with OTU165 at P<0.001, and negatively correlated with OTU455 at P<0.05. The serum creatinine index was negatively correlated with OTU287 at P<0.05 and negatively correlated with OTU165 at P<0.001. The pathological changes were positively correlated with OTU255 at P<0.05, OTU200 at P<0.01, and OTU455 and OTU75 at P<0.001, and negatively correlated with OTU86, OTU287, and OTU788 at P<0.05 and with OTU165 at P<0.01. The differences between Chinese IgAN patients and healthy subjects in terms of OTUs and biochemical indicators were analyzed and a mathematical model to facilitate the clinical diagnosis of IgAN was established.

Osteopontin Gene Polymorphism and Urinary OPN Excretion in Patients with Immunoglobulin A Nephropathy

Osteopontin (OPN) is a glycoprotein involved in the pathogenesis of multiple autoimmune and inflammatory conditions. However, the association of variants of secreted phosphoprotein 1 gene (SPP1), which encodes OPN, with immunoglobulin A nephropathy (IgAN) has not been examined up to date. Moreover, the role of OPN in disease pathogenesis and clinical manifestations is not fully known. Therefore, the aim of the study was to determine the frequency of four single nucleotide polymorphisms (SNiPs) of SPP1 gene, as well as the urinary OPN excretion in IgAN patients and healthy controls. In total, 58 Caucasian patients with biopsy-proven IgAN and 184 gender-, age-, and ethnically-matched healthy controls were genotyped for rs1126616, rs1126772, rs9138, and rs7687316/rs3841116 polymorphisms by real time polymerase chain reaction (RT-PCR). Urinary OPN concentration was determined by enzyme-linked immunosorbent assay (ELISA) in 58 IgAN patients and 19 controls. SPP1 SNiPs, as well as urinary OPN excretion, were analyzed in relation to their possible associations with the clinicopathological parameters. The frequency of the minor TT/CT genotypes of rs1126616 was significantly higher in IgAN patients compared to controls (P = 0.0217). Similarly, the minor (CC/AC) genotypes and the C allele of rs9138 were more frequent in IgAN patients (P = 0.0425 and P = 0.0112, respectively). Moreover, these two SNiPs were associated with the higher urinary OPN excretion (P < 0.05). These findings suggest that rs1126616, as well as rs9138, may be associated with IgAN development, however future studies in this field are required.

Recent advances in risk prediction, therapeutics and pathogenesis of IgA nephropathy

Immunoglobulin A nephropathy (IgAN) is the world's commonest primary glomerular disease with variable clinical presentation and progression rates that are dependent on clinical-pathologic phenotype and duration of follow-up. Overall 4-40% of patients progress to end-stage kidney disease (ESKD) by 10 years. Treatment decisions remain a challenge due to these variations. The ultimate goal of management is to prevent progression to ESKD and of vital importance is the potential reversible early detection of active glomerular inflammation prior to scarring. IgAN is globally, is the most common biopsy proven glomerulonephritis and a leading cause of ESKD. The Oxford pathological classification was devised by a collaborative pathology and nephrology network to provide an evidence-based scoring system with reproducible independent pathology features of predictive value. Clinical variables that alter prognosis include male sex, increasing age, increased body weight, smoking, Pacific Asian ethnicity, hypertension, proteinuria, and complement deficiency. Excellent conservative therapy is the cornerstone of therapy with tight blood control, renin-angiotensin system inhibition, and statin therapy. The role of immunosuppressive therapy including corticosteroids in IgAN remains open with ongoing clinical trials of low dose oral corticosteroids and enteric coated budesonide. Complement activation contributes to the pathogenic process of IgAN with evidence from genetic, serological, histological and in-vitro studies. This knowledge has translated to clinical trials of investigational agents directly targeting the alternative pathway.

Mortality in IgA Nephropathy: A Nationwide Population-Based Cohort Study

BACKGROUND

The clinical course of IgA nephropathy (IgAN) varies from asymptomatic nonprogressive to aggressive disease, with up to one in four patients manifesting ESRD within 20 years of diagnosis. Although some studies have suggested that mortality appears to be increased in IgAN, such studies lacked matched controls and did not report absolute risk.

METHODS

We conducted a population-based cohort study in Sweden, involving patients with biopsy-verified IgAN diagnosed in 1974-2011; main outcome measures were death and ESRD. Using data from three national registers, we linked 3622 patients with IgAN with 18,041 matched controls; we also conducted a sibling analysis using 2773 patients with IgAN with 6210 siblings and a spousal analysis that included 2234 pairs.

RESULTS

During a median follow-up of 13.6 years, 577 (1.1%) patients with IgAN died (10.67 per 1000 person-years) compared with 2066 deaths (0.7%) in the reference population during a median follow-up of 14.1 years (7.45 per 1000 person-years). This corresponded to a 1.53-fold increased risk and an absolute excess mortality of 3.23 per 1000 person-years (equaling one extra death per 310 person-years) and a 6-year reduction in median life expectancy. Similar increases in risk were seen in comparisons with siblings and spouses. IgAN was associated with one extra case of ESRD per 54 person-years. Mortality preceding ESRD was not significantly increased compared with controls, spouses, or siblings. Overall mortality did not differ significantly between patients with IgAN-associated ESRD and patients with ESRD from other causes.

CONCLUSIONS

Patients with IgAN have an increased mortality compared with matched controls, with one extra death per 310 person-years and a 6-year reduction in life expectancy.

Clinical and histological features and therapeutic strategies for IgA nephropathy

Chronic glomerulonephritis is the second most common reason, after diabetic nephropathy, for initiation of dialysis in Japan and IgA nephropathy (IgAN) is the most prevalent form of chronic glomerulonephritis. In the half century since IgAN was initially reported, our understanding of the long-term prognosis, clinical and histological features, pathogenesis of onset and progression, risk factors for progression, and appropriate treatment under different clinical and histological conditions, has steadily increased. Strong experimental and clinical evidence, the Clinical Practice Guidelines for IgA Nephropathy in Japan, the Oxford Classification, and the Kidney Disease Improving Global Outcomes guidelines have all contributed to the appropriate treatment of IgAN. Several intensive therapies, such as tonsillectomy, steroid therapy, and their combinations, can result in clinical remission, and prevent the progression to end stage renal disease (ESRD). However, some IgAN patients still progress to ESRD even when treated with intensive therapies. In this review, we discuss the clinical and histological features of IgAN, focusing primarily on our previous reports, and our opinions on therapeutic strategies for IgAN.

IgA-dominant glomerulonephritis with a membranoproliferative pattern of injury

Immunoglobulin A (IgA)-dominant membranoproliferative glomerulonephritis (MPGN) is a descriptive term for renal biopsies in which differential diagnoses of unusual IgA nephropathy (IgAN), infection-related GN, or other etiologies are considered. We sought to understand clinical and pathologic features of this finding. Native kidney biopsies with IgA-dominant immune deposits and diffuse MPGN features without significant exudative features or subepithelial deposits were retrospectively reviewed. Two groups (n = 27, 33 biopsies) were identified: patients with chronic liver disease and those without. Patients without chronic liver disease (n = 15) were men (73%, age 40) who presented with nephrotic-range proteinuria, hematuria, renal insufficiency, negative serologic studies, and no history of infection. At a median interval of 3 years, 11 had available follow-up information. Three (27%) progressed to end-stage renal disease. One had recurrent IgA-dominant GN in the renal allograft less than 1 year posttransplant. Four of 5 patients with repeat biopsies had persistent IgA-dominant MPGN. Patients with chronic liver disease (n = 12) had similar biopsy findings, but 42% had concurrent infections, some occult. At a median interval of 7 weeks, 8 patients (80% of those with follow-up) had died and 2 were dialysis dependent. In conclusion, IgA-dominant MPGN was seen in 2 clinical cohorts in this study. In patients without chronic liver disease, this appears to represent either a unique clinicopathologic entity with a poorer prognosis than IgAN or an aggressive variant of IgAN. Patients with chronic liver disease often have underlying infection, and regardless of treatment, die within 1 year because of complex medical conditions.

Assessment of active tubulointerstitial nephritis in non-scarred renal cortex improves prediction of renal outcomes in patients with IgA nephropathy

Background

The addition of tubulointerstitial inflammation to the existing pathological classification of IgA nephropathy (IgAN) is appealing but was previously precluded due to reportedly wide inter-observer variability. We report a novel method to score percentage of non-atrophic renal cortex containing active tubulointerstitial inflammation (ATIN) in patients with IgAN and assess its utility to predict clinical outcomes.

Methods

All adult patients with a native renal biopsy diagnosis of IgAN between 2010 and 2015 in a unit serving 1.5 million people were identified. Baseline characteristics, biopsy reports and outcome data were collected. ATIN was calculated by subtracting the percentage of atrophic cortex from the percentage of total cortex with tubulointerstitial inflammation, with ≥10% representing significant ATIN. The primary outcome was a composite of requiring renal replacement therapy or doubling of serum creatinine.

Results

In total 153 new cases of IgAN were identified, of which 111 were eligible for inclusion. Of these, 76 (68%) were male and 54 (49%) had ATIN on biopsy. During a median follow-up of 2.3 years, 34 (31%) reached the primary outcome. On univariable Cox regression analysis, ATIN was associated with a five-fold increase in the primary outcome [hazard ratio (HR) (95% confidence interval) 4.9 (95% confidence interval (CI) 2.1–11.3)]. On multivariable analysis, mesangial hypercellularity, tubular atrophy and interstitial fibrosis and ATIN independently associated with renal outcome (P = 0.02 for ATIN). Inter-observer reproducibility revealed fair agreement in the diagnosis of ATIN (κ=0.43, P = 0.05).

Conclusions

Within our centre, ATIN was significantly associated with renal outcome in patients with IgAN, independently of established histological features and baseline clinical characteristics.

Clinical significance of mesangial IgM deposition in patients with IgA nephropathy

BACKGROUND

Glomerular immunoglobulin G deposition in patients with immunoglobulin A nephropathy (IgAN) has been shown to be associated with adverse renal outcomes. Clinical significance of mesangial immunoglobulin M (IgM) deposition in these patients remains to be proven.

METHODS

One hundred patients who had a diagnosis of IgAN between 2001 and 2017 were enrolled. Patients were divided into two groups based on mesangial IgM deposition status. Groups were compared for demographic, clinical, and pathologic variables at baseline and in follow-up. Cox regression analysis was performed to evaluate the effect of mesangial IgM positivity on renal survival.

RESULTS

IgM-positive group included 51% of participants. Baseline demographic and clinical parameters were not significantly different between groups. Mesangial IgM deposition was significantly associated with a higher segmental sclerosis score (p = 0.008). At last visit, median serum creatinine was higher (p = 0.021) and eGFR was lower (p = 0.006) in IgM-positive group. Nineteen (19%) of all patients reached the combined primary outcome which includes doubling in serum creatinine or evolution to ESRD. Cumulative renal survival was lower (p = 0.001) and resistant disease was more frequent in IgM-positive group (p = 0.026). Renal survival at 15 years was 94.2% and 59.7% in IgM-negative and IgM-positive groups, respectively (p = 0.006). Time-averaged proteinuria (HR 2.9; 95% CI 1.9-4.5; p < 0.001) and mesangial IgM deposition (HR, 13.2; 95% CI 1.9-93.1; p = 0.01) were found to be independent predictors of unfavorable renal outcomes.

CONCLUSIONS

In conclusion, we demonstrated that mesangial IgM deposition independently associated with worse renal outcomes in patients with IgA nephropathy.

The association of the CMIP rs16955379 polymorphism with dyslipidemia and the clinicopathological features of IgA nephropathy

Immunoglobulin A nephropathy (IgAN) is among the most common primary glomerular diseases. The prognosis in IgAN is affected by dyslipidemia, a risk factor for cardiovascular disease. The c-Maf inducing protein (CMIP) gene has been found to be associated with lipid metabolism. But the association between the CMIP rs16955379 single nucleotide polymorphism (SNP) and dyslipidemia or the related clinicopathological features in IgAN have not been reported thus far. The present study investigated the correlation between them. The CMIP rs16955379 SNP genotypes of 300 subjects with IgAN recruited from the First Affiliated Hospital of Guangxi Medical University were identified by polymerase chain reaction and direct sequencing. Compared with the control (normal lipid) group, the dyslipidemia group with IgAN had higher blood uric acid, serum creatinine, blood urea nitrogen and urinary protein quantity, higher proportions of mesangial cell proliferation and renal tubular atrophy/interstitial fibrosis (IFTA), and a lower estimated glomerular filtration rate and serum albumin. The frequencies of the CMIP rs16955379 SNP TT genotype and T allele in the dyslipidemia group were higher than in the control group. Triglyceride, apolipoprotein A1 (ApoA1), ApoA1/B, incidences of mesangial cell proliferation, and IFTA were higher in TT genotype carriers than in CC/CT genotype carriers. Serum lipid profiles and dyslipidemia were significantly associated with renal dysfunction and IFTA. IgAN patients with the TT genotype were more likely to have dyslipidemia, renal dysfunction and IFTA (P < 0.05 for all above). These results indicate that CMIP rs16955379 SNP may be a genetic susceptibility gene for dyslipidemia and poor renal outcome in IgAN.

A Systematic Review on Materno-Foetal Outcomes in Pregnant Women with IgA Nephropathy: A Case of "Late-Maternal" Preeclampsia?

Background: IgA nephropathy is the most common primary glomerulonephritis in pregnancy and shares with other immunologic diseases and kidney diseases a relationship with adverse maternal outcomes, whose entity and pattern is only partially quantified. Recent studies provide new information and a systematic review regarded progression of kidney disease. The discussion of the outcomes with respect to low-risk pregnancies may help to perfect the estimation of the risks, and to identify specific research needs. Methods: A search strategy was built on Medline, EMBASE and the Cochrane review for the period January 2000–April 2017, aimed at retrieving both case series (defined as with at least 6 pregnancies in women with IgA nephropathy) and case reports, to look into rare occurrences. All papers, with or without control groups, were selected if they reported on at least one pregnancy outcome, or on long-term kidney function. Search strategy, paper selection and data extraction were done in duplicate (PROSPERO N 42016042623). Meta-analysis of case series was performed with Metanalyst Beta 3.13. Case reports were analysed narratively. Results: The search retrieved 556 papers, of which 27 were included (13 series and 14 case-reports). The case series report on 581 women with 729 pregnancies. The analysis was performed in comparison to the available control groups: 562 non-pregnant controls were available for the analysis of progression of kidney disease. As for pregnancy related outcomes (preeclampsia (PE), pregnancy induced hypertension (PIH), preterm birth, small babies), we meta-analyzed the data with respect to the only series of low-risk pregnancies (1418 pregnancies). When compared with women who never got pregnant after diagnosis of IgA nephropathy, in the present meta-analysis pregnancy in women with IgA nephropathy was not associated with a higher risk of progression of kidney disease, possibly due to the overall preserved kidney function at baseline: end-stage kidney disease (OR 0.68; CI 0.28–1.65). Conversely, the incidence of adverse pregnancy-related outcomes was increased compared to low-risk controls: PE and PIH were more than ten-fold increased (OR 11.80; CI 7.53–18.48 and OR 10.39; CI 5.45–19.80), while the increase in risk of preterm birth and “low birth weight babies” was less marked (OR 3.37; CI 1.91–5.95 and OR 2.36; CI 1.52–3.66), a discrepancy suggesting the occurrence of “late” or “maternal” PE, that may affect less severely foetal growth or shorten gestation. In conclusion, in the present meta-analysis IgA nephropathy was not associated with an increased progression of kidney disease. The more than ten-fold increased risk of PIH and PE, in combination with a doubled risk of small babies, suggests the occurrence of “late” or “maternal” PE, usually less affecting early foetal growth. This finding may be of help in defining control policies, while further research is needed to guide clinical management.

Clinical Characteristics and Treatment Patterns of Children and Adults With IgA Nephropathy or IgA Vasculitis: Findings From the CureGN Study

Introduction

The Cure Glomerulonephropathy Network (CureGN) is a 66-center longitudinal observational study of patients with biopsy-confirmed minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy (IgAN), including IgA vasculitis (IgAV). This study describes the clinical characteristics and treatment patterns in the IgA cohort, including comparisons between IgAN versus IgAV and adult versus pediatric patients.

Methods

Patients with a diagnostic kidney biopsy within 5 years of screening were eligible to join CureGN. This is a descriptive analysis of clinical and treatment data collected at the time of enrollment.

Results

A total of 667 patients (506 IgAN, 161 IgAV) constitute the IgAN/IgAV cohort (382 adults, 285 children). At biopsy, those with IgAV were younger (13.0 years vs. 29.6 years, P < 0.001), more frequently white (89.7% vs. 78.9%, P = 0.003), had a higher estimated glomerular filtration rate (103.5 vs. 70.6 ml/min per 1.73 m², P < 0.001), and lower serum albumin (3.4 vs. 3.8 g/dl, P < 0.001) than those with IgAN. Adult and pediatric individuals with IgAV were more likely than those with IgAN to have been treated with immunosuppressive therapy at or prior to enrollment (79.5% vs. 54.0%, P < 0.001).

Conclusion

This report highlights clinical differences between IgAV and IgAN and between children and adults with these diagnoses. We identified differences in treatment with immunosuppressive therapies by disease type. This description of baseline characteristics will serve as a foundation for future CureGN studies.