Prediction of immunotherapy response in idiopathic membranous nephropathy using deep learning-pathological and clinical factors

Background

Owing to individual heterogeneity, patients with idiopathic membranous nephropathy (IMN) exhibit varying sensitivities to immunotherapy. This study aimed to establish and validate a model incorporating pathological and clinical features using deep learning training to evaluate the response of patients with IMN to immunosuppressive therapy.

Methods

The 291 patients were randomly categorized into training (n = 219) and validation (n = 72) cohorts. Patch-level convolutional neural network training in a weakly supervised manner was utilized to analyze whole-slide histopathological features. We developed a machine-learning model to assess the predictive value of pathological signatures compared to clinical factors. The performance levels of the models were evaluated using the area under the receiver operating characteristic curve (AUC) on the training and validation tests, and the prediction accuracies of the models for immunotherapy response were compared.

Results

Multivariate analysis indicated that diabetes and smoking were independent risk factors affecting the response to immunotherapy in IMN patients. The model integrating pathologic features had a favorable predictive value for determining the response to immunotherapy in IMN patients, with AUCs of 0.85 and 0.77 when employed in the training and test cohorts, respectively. However, when incorporating clinical features into the model, the predictive efficacy diminishes, as evidenced by lower AUC values of 0.75 and 0.62 on the training and testing cohorts, respectively.

Conclusions

The model incorporating pathological signatures demonstrated a superior predictive ability for determining the response to immunosuppressive therapy in IMN patients compared to the integration of clinical factors.

Successful treatment of patients with refractory idiopathic membranous nephropathy with low-dose Rituximab: A single-center experience

BACKGROUND

The recognition of idiopathic membranous nephropathy (IMN) as an autoimmune disease has paved the way for the use of B-cell-depleting agents, such as Rituximab (RTX), which is now a first-line drug for treating IMN with proven safety and efficacy. Nevertheless, the usage of RTX for the treatment of refractory IMN remains controversial and challenging.

AIM

To evaluate the efficacy and safety of a new low-dose RTX regimen for the treatment of patients with refractory IMN.

METHODS

A retrospective study was performed on refractory IMN patients that accepted a low-dose RTX regimen (RTX, 200 mg, once a month for five months) in the Xiyuan Hospital of Chinese Academy of Chinese Medical Sciences’ Department of Nephrology from October 2019 to December 2021. To assess the clinical and immune remission data, we performed a 24 h urinary protein quantification (UTP) test and measured the serum albumin (ALB) and serum creatinine (SCr) levels, phospholipase A2 receptor (PLA2R) antibody titer, and CD19⁺ B-cell count every three months.

RESULTS

A total of nine refractory IMN patients were analyzed. During follow-up conducted twelve months later, the results from the 24 h UTP decreased from baseline [8.14 ± 6.05 g/d to 1.24 ± 1.34 g/d (P < 0.05)] and the ALB levels increased from baseline [28.06 ± 8.42 g/L to 40.93 ± 5.85 g/L (P < 0.01)]. Notably, after administering RTX for six months, the SCr decreased from 78.13 ± 16.49 μmol/L to 109.67 ± 40.87 μmol/L (P < 0.05). All of the nine patients were positive for serum anti-PLA2R at the beginning, and four patients had normal anti-PLA2R titer levels at six months. The level of CD19⁺ B-cells decreased to 0 at three months, and CD19⁺ B-cell count remained at 0 up until six months of follow-up.

CONCLUSION

Our low-dose RTX regimen appears to be a promising treatment strategy for refractory IMN.

Immunosuppression therapy for idiopathic membranous nephropathy: systematic review with network meta-analysis

BACKGROUND

Idiopathic membranous nephropathy is a common cause of nephrotic syndrome in adults. The Kidney Disease Improving Global Outcomes guidelines recommend rituximab or cyclophosphamide and steroids, or calcineurin inhibitor-based therapy. However, there have been few or no head-to-head comparisons of the relative efficacy and safety of different immunosuppression regimens. We conducted a network meta-analysis to evaluate the comparative efficacy and safety of available immunosuppression strategies compared to cyclophosphamide in adults with idiopathic membranous nephropathy.

METHODS

We performed a systematic search of MEDLINE, Embase and CENTRAL for randomized controlled trials in the treatment of adults with idiopathic membranous nephropathy. The primary outcome was complete remission. Secondary outcomes were kidney failure, partial remission, estimated glomerular filtration rate, doubling of serum creatinine, proteinuria, serious adverse events, discontinuation of treatment, serious infection and bone marrow suppression.

RESULTS

Cyclophosphamide had uncertain effects on inducing complete remission when compared to rituximab (OR 0.35, CI 0.10-1.24, low certainty evidence), mycophenolate mofetil (OR 1.81, CI 0.69-4.71, low certainty), calcineurin inhibitor (OR 1.26, CI 0.61-2.63, low certainty) or steroid monotherapy (OR 2.31, CI 0.62-8.52, low certainty). Cyclophosphamide had a higher probability of inducing complete remission when compared to calcineurin inhibitor plus rituximab (OR 4.45, CI 1.04-19.10, low certainty). Compared to other immunosuppression strategies, there was limited evidence that cyclophosphamide had different effects on other pre-specified outcomes.

CONCLUSIONS

The comparative effectiveness and safety of immunosuppression strategies compared to cyclophosphamide is uncertain in adults with idiopathic membranous nephropathy.

Immunosuppressive treatment for primary membranous nephropathy in adults with nephrotic syndrome

BACKGROUND

Primary membranous nephropathy (PMN) is a common cause of nephrotic syndrome in adults. Without treatment, approximately 30% of patients will experience spontaneous remission and one third will have persistent proteinuria. Approximately one-third of patients progress toward end-stage kidney disease (ESKD) within 10 years. Immunosuppressive treatment aims to protect kidney function and is recommended for patients who do not show improvement of proteinuria by supportive therapy, and for patients with severe nephrotic syndrome at presentation due to the high risk of developing ESKD. The efficacy and safety of different immunosuppressive regimens are unclear. This is an update of a Cochrane review, first published in 2004 and updated in 2013.

OBJECTIVES

The aim was to evaluate the safety and efficacy of different immunosuppressive treatments for adult patients with PMN and nephrotic syndrome.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 1 April 2021 with support from the Cochrane Kidney and Transplant Information Specialist using search terms relevant to this review. Studies in the Register were identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) investigating effects of immunosuppression in adults with PMN and nephrotic syndrome were included.

DATA COLLECTION AND ANALYSIS

Study selection, data extraction, quality assessment, and data synthesis were performed using Cochrane-recommended methods. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Sixty-five studies (3807 patients) were included. Most studies exhibited a high risk of bias for the domains, blinding of study personnel, participants and outcome assessors, and most studies were judged unclear for randomisation sequence generation and allocation concealment. Immunosuppressive treatment versus placebo/no treatment/non-immunosuppressive treatment In moderate certainty evidence, immunosuppressive treatment probably makes little or no difference to death, probably reduces the overall risk of ESKD (16 studies, 944 participants: RR 0.59, 95% CI 0.35 to 0.99; I² = 22%), probably increases total remission (complete and partial) (6 studies, 879 participants: RR 1.44, 95% CI 1.05 to 1.97; I² = 73%) and complete remission (16 studies, 879 participants: RR 1.70, 95% CI 1.05 to 2.75; I² = 43%), and probably decreases the number with doubling of serum creatinine (SCr) (9 studies, 447 participants: RR 0.46, 95% CI 0.26 to 0.80; I² = 21%). However, immunosuppressive treatment may increase the number of patients relapsing after complete or partial remission (3 studies, 148 participants): RR 1.73, 95% CI 1.05 to 2.86; I² = 0%) and may lead to a greater number experiencing temporary or permanent discontinuation/hospitalisation due to adverse events (18 studies, 927 participants: RR 5.33, 95% CI 2.19 to 12.98; I² = 0%). Immunosuppressive treatment has uncertain effects on infection and malignancy. Oral alkylating agents with or without steroids versus placebo/no treatment/steroids Oral alkylating agents with or without steroids had uncertain effects on death but may reduce the overall risk of ESKD (9 studies, 537 participants: RR 0.42, 95% CI 0.24 to 0.74; I² = 0%; low certainty evidence). Total (9 studies, 468 participants: RR 1.37, 95% CI 1.04 to 1.82; I² = 70%) and complete remission (8 studies, 432 participants: RR 2.12, 95% CI 1.33 to 3.38; I² = 37%) may increase, but had uncertain effects on the number of patients relapsing, and decreasing the number with doubling of SCr. Alkylating agents may be associated with a higher rate of adverse events leading to discontinuation or hospitalisation (8 studies 439 participants: RR 6.82, 95% CI 2.24 to 20.71; I² = 0%). Oral alkylating agents with or without steroids had uncertain effects on infection and malignancy. Calcineurin inhibitors (CNI) with or without steroids versus placebo/no treatment/supportive therapy/steroids We are uncertain whether CNI with or without steroids increased or decreased the risk of death or ESKD, increased or decreased total or complete remission, or reduced relapse after complete or partial remission (low to very low certainty evidence). CNI also had uncertain effects on decreasing the number with a doubling of SCr, temporary or permanent discontinuation or hospitalisation due to adverse events, infection, or malignancy. Calcineurin inhibitors (CNI) with or without steroids versus alkylating agents with or without steroids We are uncertain whether CNI with or without steroids increases or decreases the risk of death or ESKD. CNI with or without steroids may make little or no difference to total remission (10 studies, 538 participants: RR 1.01, 95% CI 0.89 to 1.15; I² = 53%; moderate certainty evidence) or complete remission (10 studies, 538 participants: RR 1.15, 95% CI 0.84 to 1.56; I² = 56%; low certainty evidence). CNI with or without steroids may increase relapse after complete or partial remission. CNI with or without steroids had uncertain effects on SCr increase, adverse events, infection, and malignancy. Other immunosuppressive treatments Other interventions included azathioprine, mizoribine, adrenocorticotropic hormone, traditional Chinese medicines, and monoclonal antibodies such as rituximab. There were insufficient data to draw conclusions on these treatments.

AUTHORS' CONCLUSIONS

This updated review strengthened the evidence that immunosuppressive therapy is probably superior to non-immunosuppressive therapy in inducing remission and reducing the number of patients that progress to ESKD. However, these benefits need to be balanced against the side effects of immunosuppressive drugs. The number of included studies with high-quality design was relatively small and most studies did not have adequate follow-up. Clinicians should inform their patients of the lack of high-quality evidence. An alkylating agent (cyclophosphamide or chlorambucil) combined with a corticosteroid regimen had short- and long-term benefits, but this was associated with a higher rate of adverse events. CNI (tacrolimus and cyclosporin) showed equivalency with alkylating agents however, the certainty of this evidence remains low. Novel immunosuppressive treatments with the biologic rituximab or use of adrenocorticotropic hormone require further investigation and validation in large and high-quality RCTs.

The management of membranous nephropathy - an update

In the last decades several important advances have taken place in the understanding of the pathogenesis underlying membranous nephropathy, which have sparked renewed interest in its management. Four landmark trials in membranous nephropathy, and a fifth clinical trial-which was a pilot study-, have been published in the last years. The results from some of these trials have had a significant impact in the recommendations included in the 2021 Kidney Disease: Improving Global Outcomes (KDIGO) Guideline for the Management of Glomerular Diseases, which represent a significant step forward compared to the previous guideline in several aspects such as diagnosis, disease monitoring and treatment strategies. However, considering the rapidly evolving advances in the knowledge of membranous nephropathy and the recent publication of the STARMEN and RI-CYCLO trials, several recommendations contained in the guideline warrant updates. This manuscript provides a perspective of the Immunonephrology Working Group of the European Renal Association (ERA) regarding the management of membranous nephropathy in native kidneys of adult patients.

The impact of coexisting diabetes mellitus on clinical outcomes in patients with idiopathic membranous nephropathy: a retrospective observational study

BACKGROUND

Idiopathic membranous nephropathy (IMN) is frequently coexisted with diabetes mellitus (DM). Few researches investigate clinical outcomes in IMN patients coexisting diabetes mellitus (DM), including remission rates, renal survival and complications. Concurrent DM also pose therapeutic challenges to IMN patients due to the influence of glucocorticoids and immunosuppressant on metabolic disorders. We performed this study to investigate the impact of DM on clinical outcomes in IMN and the influence of therapeutic regime on metabolic parameters in diabetic IMN patients.

METHODS

Two hundred and six adult hospitalized patients diagnosed with biopsy-proven IMN were retrospectively studied, including 42 patients coexisted with DM. Clinical outcomes including remission rates, renal outcome and complications were compared between groups. Impact of cyclophosphamide and ciclosporin on metabolism and complications were analyzed in IMN patients coexisting DM.

RESULTS

IMN patients coexisted with DM were presented with advanced age, lower level of eGFR and hemoglobin. Patients coexisted with DM experienced worse renal function deterioration and higher incidence of infection. COX regression analysis showed that DM was an independent risk factor for renal function deterioration in IMN patients. There was no significant difference in remission rates and incidence of venous thromboembolism between two groups. Further exploration on the impact of therapeutic regimens on complications and metabolism showed that cyclophosphamide and ciclosporin had no significant difference in incidence of complications including infection and venous thromboembolism, and posed comparable influences on blood glucose, uric acid and blood lipids in IMN patients coexisted with DM.

CONCLUSION

Coexisting DM was an independent risk factor for renal function deterioration in IMN patients but did not influence the remission of proteinuria. Glucocorticoids in combination with cyclophosphamide or ciclosporine had similar impact on complications and metabolic index including blood glucose, uric acid and blood lipids in IMN patients coexisted with DM.

Immunosuppressive regimens based on Cyclophospamide or Calcineurin inhibitors: Comparison of their effect in the long term outcome of Primary Membranous Nephropathy

INTRODUCTION

Management of the Primary Membranous Nephropathy (PMN) usually involves administration of immunosuppressives. Cyclophosphamide (Cyclo) and Calcineurin Inhibitors (CNIs) are both widely used but only limited data exist to compare their efficacy in long term follow-up.

AIM

The aim of the present study was to estimate and compare long term effects of Cyclo and CNIs in patients with PMN.

PATIENTS-METHODS

Clinical data, histologic findings and long term outcome were retrospectively studied. The response to treatment and rate of relapse was compared between patients treated with CNIs or Cyclo based immunosuppressive regimens.

RESULTS

Twenty three centers participated in the study, with 752 PMN patients (Mean age 53.4(14-87) yrs, M/F 467/285), followed for 10.1±5.7 years. All patients were initially treated with Renin Angiotensin Aldosterone System inhibitors (RAASi) for at least 6 months. Based on their response and tolerance to initial treatment, patients were divided into 3 groups, group I with spontaneous remission, who had no further treatment, group II, continued on RAASi only, and group III on RAASi+immunosuppression. Immunosuppressive regimes were mainly based on CNIs or Cyclo. Frequent relapses and failure to treatment were more common between patients who had started on CNIs (n = 381) compared to those initially treated with Cyclo (n = 110), relapse rate: 25.2% vs. 6.4%, p<0.0001, and no response rate: 22.5% vs. 13.6%, p = 0.04, respectively.

CONCLUSIONS

Long term follow up showed that administration of Cyclo in PMN is followed by better preservation of renal function, increased response rate and less frequent relapses, compared to CNIs.

The investigative burden of membranous nephropathy in the UK

Background

Membranous nephropathy (MN) represents two distinct disease entities. Primary MN is now recognized as an autoimmune condition associated with the anti-PLA₂R antibody and secondary MN occurs in tandem with malignancy, infection, drug therapy and other autoimmune conditions. Prior to the development of accessible enzyme-linked immunosorbent assays, the diagnosis of MN was one of exclusion. We studied whether the introduction of serum anti-PLA₂R antibody testing leads to a reduction in the frequency of investigations in MN patients.

Methods

Patients from three UK centres with a diagnosis of MN between 2009 and 2014 were identified. We compared patients who had a positive anti-PLA₂R test within 6 months of biopsy with those who had no test or a negative test. Records were reviewed for investigations that took place 6 months prior to and 6 months following the biopsy date to see if these were normal or identified a secondary cause of MN.

Results

In total, 184 patients were included: 80 had no test, 66 had a negative anti-PLA₂R test and 38 had a positive test within 6 months of diagnosis. In 2012, 46.5% of patients had an anti-PLA₂R test, increasing to 93.3% in 2014. From 2012 to 2014 the number of screening tests dropped from 10.03 to 4.29 and the costs from £497.92 to £132.94.

Conclusions

Since its introduction, a progressively higher proportion of patients diagnosed with MN had an anti-PLA₂R test. This has led to a reduction in the number of screening tests and in the cost of investigations carried out. The anti-PLA₂R test has the potential to reduce this burden as its use becomes more widespread.

The efficacy and safety of tacrolimus monotherapy in adult-onset nephrotic syndrome caused by idiopathic membranous nephropathy

Introduction: The purpose of the study is to evaluate the efficiency and safety of tacrolimus (TAC) monotherapy in the treatment of nephrotic idiopathic membranous nephropathy (IMN) compared with the protocol of cyclophosphamide (CTX) combined with corticosteroids.

Methods: In total, 58 patients with nephrotic syndrome and biopsy-proven IMN were included in this study. 30 patients received TAC monotherapy with an initial dose of 0.05–0.1 mg/kg/day. 28 patients received transvenous CTX at a dose of 0.5–0.75 g/m² once in every month initially for 6 months and once in every 2 or 3 months for the later period, and the regimen was combined with corticosteroids (prednisone 1 mg/kg/d). All patients were observed for the treatment effects, recurrence and side effects.

Results: Twelve months after the initial treatment, a total of 24 (80%) patients in the TAC group and 23 (82.1%) patients in the CTX group achieved remission (either partial or complete remission). The survival curve of the probability of remission and complete remission were similar between the two groups (p > .05). Proteinuria (based on 24 h urinary protein excretion) was significantly decreased, and serum albumin was significantly increased after immunosuppressive treatment in both the groups. Estimated glomerular filtration rate (eGFR) was comparable between before and after treatment. The main adverse effects in TAC treatment were glucose intolerance, diabetes and abnormal aminotransferase.

Conclusions: TAC monotherapy is an alternative therapeutic regimen for patients with nephrotic IMN. Its short-term efficiency and patient tolerance are both acceptable.

Response to immunosuppressive therapy in PLA2R- associated and non-PLA2R- associated idiopathic membranous nephropathy: a retrospective, multicenter cohort study

Background

According to renal M type phospholipase A₂ receptor (PLA₂R) immunohistochemistry, idiopathic membranous nephropathy (IMN) could be categorized into PLA₂R-associated and non-PLA₂R-associated IMN. We conducted a retrospective, multicenter cohort study with 91 patients to compare the effect of immunosuppressive therapy between PLA₂R-associated and non-PLA₂R-associated IMN patients.

Methods

A total of 91 biopsy-proven IMN patients from Huashan hospital and People’s Hospital of Wuxi in past 5 years were collected into this study. IMN with positive PLA₂R immunohistochemistry in kidney biopsies were designated as PLA₂R-associated IMN. Seventy-eight of the 91 IMN patients was PLA₂R-associated IMN and 13 were non-PLA₂R-associated IMN. Forty-five patients were treated with prednisone plus cyclophosphamide (CTX), and 46 with prednisone plus calcineurin inhibitors (CNIs). The follow-up duration was 15 months.

Results

The total remission rate (76.9% versus 44.9%, p = 0.032) and complete remission rate (30.8% versus 2.6%, p = 0.003) were both significantly higher in the non-PLA₂R-associated group than in the PLA₂R-associated group at the 3rd month visit point, and at the 6th month time point, the complete remission rate was still significantly higher in the non-PLA₂R-associated group (46.2% versus 11.5%,p = 0.007). But similar remission rates were found after the 9th month. Relapses were observed in 8 patients in PLA₂R-associated group and none in non-PLA₂R-associated group, although there was no significant difference between these two groups.

Conclusion

Compared with the PLA₂R-associated IMN, the non-PLA₂R-associated IMN responded quicker to the immunosuppressive therapy.

Membranous nephropathy: a retrospective observational study of membranous nephropathy in north east and central London

Background

Membranous nephropathy (MN) is the leading cause of nephrotic syndrome in adults. MN is a clinically heterogeneous disease and it is difficult to accurately predict outcomes (including end stage renal failure) at presentation and whom to treat with potentially toxic therapies. We aimed to identify factors predicting outcome in MN in our cohort from two large tertiary London units by undertaking a retrospective data analysis of 148 biopsy-proven MN patients from North East and Central London between 1995 and 2015.

Methods

Review of clinical and biochemistry databases.

Results

Surprisingly, patients that reached end stage renal failure (ESRF) had a less severe nephrosis compared to those that did not develop ESRF; serum albumin 33 g/L (3.3 g/dL) versus 24 g/L (2.4 g/dL), p = 0.002 and urinary protein creatinine ratio (uPCR) 550 mg/mmol (5500 mg/g) versus 902 mg/mmol (9020 mg/g), p = 0.0124. The correlation with ESRF was strongest with the presenting creatinine; 215 μmol/L (2.43 mg/dL) compared to 81 μmol/L (0.92 mg/dL), p < 0.0001. Patients presenting with creatinine of >120 μmol/L (1.36 mg/dL; corresponding to an eGFR of ≤60 ml/min in non-Black males) had an increased rate of ESRF and a faster decline. Other traditional risk factors for progression were not significantly associated with ESRF.

Black patients presented with higher serum creatinine but no statistically significant difference in the estimated glomerular filtration rate, a higher rate of progression to ESRF and had a poorer response to treatment.

Conclusions

This ethnically diverse cohort does not demonstrate the traditional risk profile associated with development of ESRF. Thus, careful consideration of therapeutic options is crucial, as current risk modelling cannot accurately predict the risk of ESRF. Further studies are required to elucidate the role of antibodies and risk genes.

Recent Treatment Advances and New Trials in Adult Nephrotic Syndrome

The etiology of nephrotic syndrome is complex and ranges from primary glomerulonephritis to secondary forms. Patients with nephrotic syndrome often need immunosuppressive treatment with its side effects and may progress to end stage renal disease. This review focuses on recent advances in the treatment of primary causes of nephrotic syndrome (idiopathic membranous nephropathy (iMN), minimal change disease (MCD), and focal segmental glomerulosclerosis (FSGS)) since the publication of the KDIGO guidelines in 2012. Current treatment recommendations are mostly based on randomized controlled trials (RCTs) in children, small RCTs, or case series in adults. Recently, only a few new RCTs have been published, such as the Gemritux trial evaluating rituximab treatment versus supportive antiproteinuric and antihypertensive therapy in iMN. Many RCTs are ongoing for iMN, MCD, and FSGS that will provide further information on the effectiveness of different treatment options for the causative disease. In addition to reviewing recent clinical studies, we provide insight into potential new targets for the treatment of nephrotic syndrome from recent basic science publications.

Early initiation of immunosuppressive treatment in membranous nephropathy patients

BACKGROUND/PURPOSE

Suggestion for the management of idiopathic membranous nephropathy (IMN) includes 6 months of observation, followed with steroid plus alkylating agent. However, delayed immunosuppression exposes the kidneys to persistent damage. This study aimed to examine the benefit of early immunosuppression in IMN patients.

METHODS

A retrospective study was performed. From 1993 to 2013, 161 IMN patients were enrolled. Patients receiving immunosuppression within 6 months after diagnosis were classified as initial-treatment group, whereas other patients as initial-no-treatment group. The clinical outcomes and complication were examined.

RESULT

Patients in the initial-treatment group had lower serum albumin concentration, less diabetes, and were younger. Steroid monotherapy is the main immunosuppression (64.5%) in this group. The initial-treatment group had a higher complete and partial remission rate than the initial-no-treatment group 6 months (52.9% vs. 35.0%, p=0.05) and 12 months (71.1% vs. 45.0%, p=0.003) after diagnosis. A similar result was seen between initial-steroid monotherapy and initial-no-treatment patients. Early immunosuppression is an independent predictor of remission within 1 year [hazard ratio (HR)=2.09; 95% confidence interval (CI)=1.25-3.49; p=0.005] and estimated glomerular filtration rate (eGFR) decline over 50% during the follow-up. (HR=0.33; 95% CI=0.13-0.86; p=0.02). The initial-treatment group also had a low frequency of eGFR decline over 50% (p=0.001) and low combined end-stage renal disease/mortality (p=0.001) compared with the initial-no-treatment group, but without more immunosuppression-related complication.

CONCLUSION

In contrast to Western countries, early immunosuppression (even steroid monotherapy) in our patients is associated with better remission in the 1^st year and renal preserve. Further randomized controlled trials are needed to clarify the benefit of early immunosuppression in IMN patients, especially with oriental ethnic background.

Primary glomerulonephritides

Most glomerulonephritides, even the more common types, are rare diseases. They are nevertheless important since they frequently affect young people, often cannot be cured, and can lead to chronic kidney disease, including end-stage renal failure, with associated morbidity and cost. For example, in young adults, IgA nephropathy is the most common cause of end-stage renal disease. In this Seminar, we summarise existing knowledge of clinical signs, pathogenesis, prognosis, and treatment of glomerulonephritides, with a particular focus on data published between 2008 and 2015, and the most common European glomerulonephritis types, namely IgA nephropathy, membranous glomerulonephritis, minimal change disease, focal segmental glomerulosclerosis, membranoproliferative glomerulonephritis, and the rare complement-associated glomerulonephritides such as dense deposit disease and C3 glomerulonephritis.

Treatment pattern in patients with idiopathic membranous nephropathy-practices in Sweden at the start of the millennium

Background

Idiopathic membranous nephropathy (MN) is one of the leading causes of nephrotic syndrome in adults and may result in end-stage renal disease (ESRD). In this retrospective study, we describe the outcomes and treatment patterns of patients with idiopathic MN in six nephrology clinics in the western part of Sweden.

Methods

Seventy-three consecutive patients with biopsy-proven MN in the years 2000–12 were classified as idiopathic, i.e. secondary forms were excluded. The patients were followed retrospectively for a mean period of 83 months and clinical data were collected through the medical files.

Results

A high proportion (88%) of the patients received supportive treatment with angiotensin-converting enzyme inhibition, angiotensin receptor blockade and/or statins. At the end of follow-up, 43 patients were in complete remission, 12 in partial remission, 10 patients had developed ESRD and 8 patients had on-going proteinuria. Fifty-one per cent of the patients received immunosuppressive therapy and the choice of therapy varied between and within the clinics. There was a tendency to initiate specific treatment at an early point instead of awaiting a possible spontaneous remission (21% of the patients), and non-recommended therapy such as corticosteroids only was used in a high proportion of these cases (47%).

Conclusions

Even though the treatment recommendations in idiopathic MN have not changed the last decade, the question of whom and when to treat seems to lead to uncertainty. Recent studies have presented promising results supporting the PLA₂R antibody the predictive marker needed for this patient group. The diverse treatment approach presented in this study might have resulted in a worse outcome than expected. Hopefully, unnecessary exposure to immunosuppressive therapy or delayed treatment can be avoided through better support, education and treatment forums, and thus result in an improved outcome.

Prognostic value of the dynamics of M-type phospholipase A2 receptor antibody titers in patients with idiopathic membranous nephropathy treated with two different immunosuppression regimens

CONTEXT

The dynamics of anti-phospholipase A2 antibody titers during treatment could predict clinical responses in patients with membranous nephropathy.

OBJECTIVES

We analyzed the predictive value of the dynamics of these antibodies on clinical responses.

MATERIALS AND METHODS

The serum antibody levels were measured before and during treatment in 79 patients with anti-phospholipase A2 receptor antibody membranous nephropathy treated with two different immunosuppression regimens

RESULTS

In both groups of patients, the relative reduction in antibody titers at 3 and 6 months preceded and predicted the clinical responses.

CONCLUSIONS

Antibody titer dynamics was useful for predicting clinical responses.

Immunosuppressive treatment for idiopathic membranous nephropathy in adults with nephrotic syndrome

BACKGROUND

Idiopathic membranous nephropathy (IMN) is the most common form of nephrotic syndrome in adults. The disease shows a benign or indolent course in the majority of patients, with a rate of spontaneous complete or partial remission of nephrotic syndrome as high as 30% or more. Despite this, 30% to 40% of patients progress toward end-stage kidney disease (ESKD) within five to 15 years. The efficacy and safety of immunosuppression for IMN with nephrotic syndrome are still controversial. This is an update of a Cochrane review first published in 2004.

OBJECTIVES

The aim of this review was to evaluate the safety and efficacy of immunosuppressive treatments for adult patients with IMN and nephrotic syndrome. Moreover it was attempted to identify the best therapeutic regimen, when to start immunosuppression and whether the above therapies should be given to all adult patients at high risk of progression to ESKD or only restricted to those with impaired kidney function.

SEARCH METHODS

We searched Cochrane Renal Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Chinese databases, reference lists of articles, and clinical trial registries to June 2014. We also contacted principal investigators of some of the studies for additional information.

SELECTION CRITERIA

Randomised controlled trials (RCTs) investigating the effects of immunosuppression in adults with IMN and nephrotic syndrome.

DATA COLLECTION AND ANALYSIS

Study selection, data extraction, quality assessment, and data synthesis were performed using the Cochrane-recommended methods. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes.

MAIN RESULTS

Thirty nine studies with 1825 patients were included, 36 of these could be included in our meta-analyses. The data from two studies could not be extracted and one study was terminated due to poor accrual. Immunosuppression significantly reduced all-cause mortality or risk of ESKD ((15 studies, 791 patients): RR 0.58 (95% CI 0.36 to 0.95, P = 0.03) and risk of ESKD ((15 studies, 791 patients): RR 0.55, 95% CI 0.31 to 0.95, P = 0.03), increased complete or partial remission ((16 studies, 864 patients): RR 1.31, 95% CI 1.01 to 1.70, P = 0.04), and decreased proteinuria ((9 studies,(393 patients): MD -0.95 g/24 h, 95% CI -1.81 to -0.09, P = 0.03) at the end of follow-up (range 6 to 120 months). However this regimen was associated with more discontinuations or hospitalisations ((16 studies, 880 studies): RR 5.35, 95% CI 2.19 to 13.02), P = 0.0002). Combined corticosteroids and alkylating agents significantly reduced death or risk of ESKD ((8 studies, 448 patients): RR 0.44, 95% CI 0.26 to 0.75, P = 0.002) and ESKD ((8 studies, 448 patients): RR 0.45, 95% CI 0.25 to 0.81, P = 0.008), increased complete or partial remission ((7 studies, 422 patients): RR 1.46, 95% CI 1.13 to 1.89, P = 0.004) and complete remission ((7 studies, 422 patients): RR 2.32, 95% CI 1.61 to 3.32, P < 0.00001), and decreased proteinuria ((6 studies, 279 patients): MD -1.25 g/24 h, 95% CI -1.93 to -0.57, P = 0.0003) at the end of follow-up (range 9 to 120 months). In a population with an assumed risk of death or ESKD of 181/1000 patients, this regimen would be expected to reduce the number of patients experiencing death or ESKD to 80/1000 patients (range 47 to 136). In a population with an assumed complete or partial remission of 408/1000 patients, this regimen would be expected to increase the number of patients experiencing complete or partial remission to 596/1000 patients (range 462 to 772). However this combined regimen was associated with a significantly higher risk of discontinuation or hospitalisation due to adverse effects ((4 studies, 303 patients): RR 4.20, 95% CI 1.15 to 15.32, P = 0.03). Whether this combined therapy should be indicated in all adult patients at high risk of progression to ESKD or only restricted to those with deteriorating kidney function still remained unclear. Cyclophosphamide was safer than chlorambucil ((3 studies, 147 patients): RR 0.48, 95% CI 0.26 to 0.90, P = 0.02). There was no clear evidence to support the use of either corticosteroid or alkylating agent monotherapy. Cyclosporine and mycophenolate mofetil failed to show superiority over alkylating agents. Tacrolimus and adrenocorticotropic hormone significantly reduced proteinuria. The numbers of corresponding studies related to tacrolimus, mycophenolate mofetil, adrenocorticotropic hormone, azathioprine, mizoribine, and Tripterygium wilfordii are still too sparse to draw final conclusions.

AUTHORS' CONCLUSIONS

In this update, a combined alkylating agent and corticosteroid regimen had short- and long-term benefits on adult IMN with nephrotic syndrome. Among alkylating agents, cyclophosphamide was safer than chlorambucil. This regimen was significantly associated with more withdrawals or hospitalisations. It should be emphasised that the number of included studies with high-quality design was relatively small and most of included studies did not have adequate follow-up and enough power to assess the prespecified definite endpoints. Although a six-month course of alternating monthly cycles of corticosteroids and cyclophosphamide was recommended by the KDIGO Clinical Practice Guideline 2012 as the initial therapy for adult IMN with nephrotic syndrome, clinicians should inform their patients of the lack of high-quality evidence for these benefits as well as the well-recognised adverse effects of this therapy. Cyclosporine or tacrolimus was recommended by the KDIGO Clinical Practice Guideline 2012 as the alternative regimen for adult IMN with nephrotic syndrome; however, there was no evidence that calcineurin inhibitors could alter the combined outcome of death or ESKD.

Is the red cell distribution width strong predictor for treatment response in primary glomerulonephritides?

BACKGROUND

Novel biomarkers are needed to predict the response to treatment in patients with nephrotic syndrome (NS) due to primary glomerulonephritides (PGN). We aimed to test the predictive value of red blood cell distribution width (RDW) for estimation of response to therapy in adult patients with NS. Study design, setting & participants, and intervention: We performed a prospective study including 176 patients with NS due to PGN. Patients were divided into three groups according to their response to the treatment. Group 1 was composed of patients with complete remission whereas group 2 was composed of patients with partial remission and group 3 was composed of patients who were resistant to the treatment.

RESULTS

The highest baseline mean RDW value was found in group 3 patients (17.8 ± 1.8) whereas the lowest in group 1 (13.4 ± 0.7) before treatment (p<0.05). We found a significant decrease in RDW value after an effective treatment in groups 1 and group 2 (p<0.05). However, there was no significant change in RDW values after treatment in group 3 (p>0.05). Most of the patient with complete remission had base-line RDW level ≤ 14% (n=45, 90%) (p<0.001, Kendal Tau: -0.86), and most of the patients who were resistant to the treatment had base-line RDW level p>15% (n=68, 86.1%) (p<0.001, Kendal Tau: -0.87).

CONCLUSION

Our results suggest that pre-treatment RDW value is a promising novel biomarker for predicting response to the treatment in adult patients with NS due to PGN.

Cancer risk after cyclophosphamide treatment in idiopathic membranous nephropathy

BACKGROUND AND OBJECTIVES

Cyclophosphamide treatment improves renal survival in patients with idiopathic membranous nephropathy. However, use of cyclophosphamide is associated with cancer. The incidence of malignancies in patients with idiopathic membranous nephropathy was evaluated, and the cancer risk associated with cyclophosphamide use was estimated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients who attended the clinic were included prospectively from 1995 on. A crude incidence ratio for the occurrence of malignancy was calculated. Incidence ratios were subsequently standardized to potential confounders. Latency between cyclophosphamide therapy and the occurrence of cancer was estimated by stratifying for time since the start of treatment. Finally, Poisson regression was used to obtain a multiple adjusted incidence ratio and investigate the dose-response relationship between cyclophosphamide and cancer.

RESULTS

Data were available for 272 patients; the mean age was 51 years, and 70% of the patients were men. Median follow-up was 6.0 years (interquartile range=3.6-9.5), and 127 patients were treated with cyclophosphamide. Cancer incidence was 21.2 per 1000 person-years in treated patients compared with 4.6 per 1000 person-years in patients who did not receive cyclophosphamide, resulting in crude and adjusted incidence ratios of 4.6 (95% confidence interval, 1.5 to 18.8) and 3.2 (95% confidence interval, 1.0 to 9.5), respectively.

CONCLUSION

Cyclophosphamide therapy in idiopathic membranous nephropathy gives a threefold increase in cancer risk. For the average patient, this finding translates into an increase in annual risk from approximately 0.3% to 1.0%. The increased risk of malignancy must be balanced against the improved renal survival.

Leflunomide plus oral prednisone in treatment of idiopathic membranous nephropathy: a retrospective clinical study of efficacy and safety

AIM

Treatment of idiopathic membranous nephropathy (IMN) remains a controversial issue. While clinical trials have shown that some immunosuppressants combined with glucocorticoid have a good efficacy on IMN patients. However, there is little data on leflunomide (LEF) in treatment of IMN.

METHODS

Records of every patient with biopsy-proven IMN in Department of Nephrology, the First Affiliated Hospital, Xi'an Jiaotong University from January 2005 to December 2011 (n=194) were retrospectively analyzed. Patients with nephrotic IMN were treated with LEF plus oral prednisone (n=32) for at least 12 months, whereas 31 patients who did not receive any immunosuppressants were used as controls.

RESULTS

Remission rates in the LEF group were 31.3%, 59.4%, 68.8% and 71.9% at 6, 9, 12 and 15 months, respectively, which were significantly higher than those in controls. In the LEF group, proteinuria decreased from 6.79 g/24 h at baseline to 5.63 g/24 h (P<0.01), 3.85 g/24 h (P<0.01) and 2.51 g/24 h (P<0.01) after treatment for 6, 9 and 12 months, respectively. Relapse occurred in five (21.7%) patients within a median of 14 months (range, 8-27) after cessation of LEF. No patients developed renal insufficiency during the therapeutic period. Multivariate analysis suggested that age negatively correlated with achievement of remission (odds ratio, 0.87; P<0.05). No serious adverse events were observed.

CONCLUSION

LEF plus oral prednisone may be an alternative treatment option in Chinese patients with nephrotic IMN.

Independent or synergistic relationship of proteinuria and glomerular filtration rate on patient and renal survival in patients with glomerulonephritis?

BACKGROUND

Glomerular filtration rate (GFR) in patients with chronic kidney disease (CKD) identifies patients at risk for death or end-stage renal disease (ESRD). CKD staging by GFR should incorporate proteinuria to augment risk stratification. We therefore tested the predictive power of the combination of GFR with proteinuria in patients with different histologically-diagnosed types of glomerulonephritis (GN).

METHODS

In a retrospective analysis, 2,687 patients with different forms of GN from 123 Austrian centres were investigated. Full data sets were available from 1,892 subjects. Classes of CKD on the basis of estimated GFR (eGFR) and of proteinuria grouped as <1, 1-3.5, and >3.5 g/24 h were tested for their association with all-cause mortality and ESRD.

RESULTS

During a median follow-up of 130 months [interquartile range (IQR) 90; 178] 478 patients (25.3 %) died. Median eGFR was 49 ml/min/1.73 m(2) (IQR 24; 81) and proteinuria 3.8 g/24 h (IQR 1.7; 8.0). Adjusted multivariate Cox regression indicated that renal survival but not overall survival is related to proteinuria >3.5 g/24 h [as opposed to <1 g/24 h; hazard ratio (HR) 1.91] and shows progression to ESRD. However, subgroup analyses revealed that this risk with proteinuria >3.5 g/24 h exists only in patients with immunoglobulin (Ig)A GN (HR 4.93), miscellaneous GN (HR 1.74), and CKD stage 5 (HR 2.50). Additionally, proteinuria is a risk factor for renal survival in males more than in females with GN and proteinuria >3.5 g/24 h (HR 1.91).

CONCLUSION

Proteinuria is a strong risk factor for renal survival particularly in patients with proteinuria >3.5 g/24 but not for all types of GN, nor for all CKD stages. Proteinuria is not a risk factor for overall survival in patients with GN.

Long-term outcomes in idiopathic membranous nephropathy using a restrictive treatment strategy

Recently published Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend limiting the use of immunosuppressive drugs in idiopathic membranous nephropathy to patients at the highest risk of kidney failure. However, recommendations are based on natural history rather than direct assessment of a restrictive treatment strategy. Here, we describe the long-term outcomes of treating a large cohort of patients with idiopathic membranous nephropathy according to a restrictive treatment policy. We analyzed data for 254 patients who visited our outpatient clinic between 1995 and 2009. All patients were treated with angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers. Immunosuppressive therapy was recommended in cases of deteriorating renal function or untreatable nephrotic syndrome. Primary outcomes for the present study were renal replacement therapy and death. Secondary outcomes included adverse events during follow-up and remission of proteinuria. In total, 124 patients (49%) received immunosuppressive therapy, which predominantly consisted of cyclophosphamide combined with steroids. Ten-year cumulative incidence rates were 3% for renal replacement therapy and 10% for death. Partial remission rates were 39%, 70%, and 83% after 1, 3, and 5 years, respectively; complete remission rates were 5%, 24%, and 38% at 1, 3, and 5 years, respectively. A serious adverse event occurred in 23% of all patients. The most notable complications were infections (17%), leukopenia (18%), cardiovascular events (13%), and malignancies (8%). In conclusion, the use of a restrictive treatment strategy in this cohort of patients with idiopathic membranous nephropathy yielded favorable outcomes while limiting the number of patients exposed to toxic drugs. These results support current KDIGO guidelines.

Treatment of idiopathic membranous nephropathy

Immunosuppressive treatment of patients with idiopathic membranous nephropathy (iMN) is heavily debated. The controversy is mainly related to the toxicity of the therapy and the variable natural course of the disease-spontaneous remission occurs in 40-50% of patients. The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for Glomerulonephritis provides guidance for the treatment of iMN. The guideline suggests that immunosuppressive therapy should be restricted to patients with nephrotic syndrome and persistent proteinuria, deteriorating renal function or severe symptoms. Alkylating agents are the preferred therapy because of their proven efficacy in preventing end-stage renal disease. Calcineurin inhibitors can be used as an alternative although efficacy data on hard renal end points are limited. In this Review, we summarize the KDIGO guideline and address remaining areas of uncertainty. Better risk prediction is needed to identify patients who will benefit from immunosuppressive therapy, and the optimal timing and duration of this therapy is unknown because most of the randomized controlled trials were performed in low-risk or medium-risk patients. Alternative therapies, directed at B cells, are under study. The discovery of anti-M type phospholipase A2 receptor-antibodies is a major breakthrough and we envisage that in the near future, antibody-driven therapy will enable more individualized treatment of patients with iMN.

Immunosuppression for membranous nephropathy: a systematic review and meta-analysis of 36 clinical trials

BACKGROUND AND OBJECTIVES

The efficacy and safety of immunosuppression for idiopathic membranous nephropathy (IMN) with nephrotic syndrome are still controversial. A systematic review and meta-analysis of randomized controlled trials (RCTs) was performed.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Cochrane Library, PUBMED, EMBASE, Chinese Database, and Clinical Trial Registries (June 2012) were searched to identify RCTs investigating the effect of immunosuppression on adults with IMN and nephrotic syndrome.

RESULTS

This review was an update (36 RCTs, 1762 participants) of the 2004 version (18 RCTs, 1025 participants). Immunosuppression significantly reduced all-cause mortality or ESRD (15 RCTs, 791 participants; risk ratio, 0.58 [95% confidence interval, 0.36-0.95]; P=0.03). However, the result was not consistent when prespecified subgroup analyses were undertaken. Immunosuppression increased complete or partial remission (CR + PR) (16 RCTs, 864 participants; 1.31 [1.01-1.70]; P=0.04) but resulted in more withdrawals or hospitalizations (16 RCTs, 880 participants; 5.35 [2.19-13.02]; P=0.002). Corticosteroids combined with alkylating agents significantly reduced all-cause mortality or ESRD (8 RCTs, 448 participants; 0.44 [0.26-0.75]; P=0.002) and increased CR + PR (7 RCTs, 422 participants; 1.46 [1.13-1.89]; P=0.004) but led to more adverse events (4 RCTs, 303 participants; 4.20 [1.15-15.32]; P=0.03). Cyclophosphamide was safer than chlorambucil (3 RCTs, 147 participants; 0.48 [0.26-0.90]; P=0.02). Cyclosporine and mycophenolate mofetil failed to show superiority over alkylating agents. Tacrolimus and adrenocorticotropic hormone significantly reduced proteinuria.

CONCLUSIONS

Alkylating agents plus corticosteroids had long-term and short-term benefits for adult IMN, but resulted in more withdrawals or hospitalizations.

The KDIGO practice guideline on glomerulonephritis: reading between the (guide)lines--application to the individual patient

The KDIGO guideline for glomerulonephritis is designed to assist health-care providers in treating patients with glomerular diseases. A guideline is not a set of rules but is intended to allow the practitioner to make an informed decision based on the available evidence. Due to its general nature and the variability of strength of the available studies, it is often difficult to directly apply a guideline to the care of an individual patient. This commonly relates to the limited generalizability of the evidence, i.e., does not cover every clinical scenario. To underscore this point, we have introduced within the context of the glomerulonephritis guideline cases with specific features to illustrate the constant need for clinical judgment. These vignettes are intended to demonstrate how the best treatment plans should be individualized and take into account patient preference and clinical acumen, as well as the best available evidence.

Treatment of idiopathic membranous nephropathy

Exciting progress recently has been made in our understanding of idiopathic membranous nephropathy, as well as treatment of this disease. Here, we review important advances regarding the pathogenesis of membranous nephropathy. We will also review the current approach to treatment and its limitations and will highlight new therapies that are currently being explored for this disease including Rituximab, mycophenolate mofetil, and adrenocorticotropic hormone, with an emphasis on results of the most recent clinical trials.

Kidney biopsy in patients with glomerulonephritis: is the earlier the better?

BACKGROUND

Interventional diagnostic procedures are established for several diseases in medicine. Despite the KDOQI guideline recommendation for histological diagnosis of kidney disease to enable risk stratification, its optimal time point has not been evaluated. We have therefore analyzed whether histological diagnosis of glomerulonephritis (GN) at an early stage of chronic kidney disease (CKD) is associated with different outcome compared to diagnosis at a more advanced stage.

METHODS

A cohort of 424 consecutive patients with histological diagnosis of GN were included in a retrospective data analysis. Kidney function was assessed by glomerular filtration rate (GFR) estimation at the time point of kidney biopsy and after consecutive immunosuppressive therapy. Censored events were death, initiation of dialysis or kidney transplantation, or progression of disease, defined as deterioration of CKD stage ≥ 1 from kidney biopsy to last available kidney function measurement.

RESULTS

Occurrence of death, dialysis/transplantation or progression of disease were associated with GFR and CKD stage at the time of kidney biopsy (p < 0.001 for all). Patients with CKD stage 1 and 2 at kidney biopsy had fewer endpoints compared to patients with a GFR of <60 ml/min (p < 0.001).

CONCLUSION

Kidney function at the time point of histological GN diagnosis is associated with clinical outcome, likely due to early initiation of specific drug treatment. This suggests that selection of therapy yields greatest benefit before renal function is impaired in GN.

Prognostic value of risk score and urinary markers in idiopathic membranous nephropathy

BACKGROUND AND OBJECTIVES

Accurate prediction of prognosis may improve management of patients with idiopathic membranous nephropathy. This study compared the Toronto Risk Score and urinary low-molecular weight proteins.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

One hundred four patients with biopsy-proven idiopathic membranous nephropathy who presented between 1995 and 2008 with a well-preserved kidney function and nephrotic range proteinuria were included. Urinary β2-microglobulin and α1-microglobulin measurements were obtained by timed standardized measurements, and the Toronto Risk Score was calculated using data obtained from medical records. The endpoint was progression, which was defined as an increase in serum creatinine > 50% or > 25% with a concentration > 135 μmol/L.

RESULTS

Forty-nine patients showed progression. The area under the receiver-operating characteristics curve was 0.78 (95% confidence interval = 0.69-0.88) for the risk score versus 0.80 (0.71-0.89) and 0.79 (0.71-0.88) for urinary β2- and α1-microglobulin, respectively. Differences were not significant. Persistent proteinuria did not add accuracy to the Toronto Risk Score. Conversely, its accuracy was not reduced when data from the first 6 months of follow-up were used. Furthermore, a score based on GFR estimated with the six-variable Modification of Diet in Renal Disease equation, calculated in the first 6 months of follow-up, gave an area under the receiver-operating characteristics curve of 0.83 (0.74-0.92), which was not statistically different from other markers.

CONCLUSIONS

The prognostic accuracies of the Toronto Risk Score and urinary low-molecular weight proteins were not significantly different. The risk score can be calculated within 6 months of diagnosis, and a simplified risk score using estimated GFR-Modification of Diet in Renal Disease may be sufficient.

Low-molecular-weight proteins as prognostic markers in idiopathic membranous nephropathy

BACKGROUND

Accurate prediction of prognosis in idiopathic membranous nephropathy (iMN) allows restriction of immunosuppressive therapy to patients at high risk for ESRD. Here we re-evaluate urinary low-molecular-weight proteins as prognostic markers and explore causes of misclassification.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a cohort of 129 patients with serum creatinine concentration <135 μmol/L and proteinuria ≥3.0 g/10 mmol, urinary α1- (uα1m) and β2-microglobulin (uβ2m) excretion rate was determined. Urinary α1m and uβ2m-creatinine ratio was also obtained. We defined progression as a rise in serum creatinine ≥50% or ≥25% and an absolute level ≥135 μmol/L.

RESULTS

Median survival time was 25 months, and 47% of patients showed progression. The area under the receiver operating characteristic curve for uβ2m was 0.81 (95% CI: 0.73 to 0.89). Using a threshold value of 1.0 μg/min, sensitivity and specificity were 73% and 75%, respectively. Similar accuracy was observed for the uβ2m-creatinine ratio with sensitivity and specificity of 75% and 73%, respectively, at a threshold of 1.0 μg/10 mmol creatinine. Similar accuracy was found for uα1m and uα1m-creatinine ratio. Blood Pressure and cholesterol contributed to misclassification. Repeated measurements improved accuracy in patients with persistent proteinuria: the positive predictive value of uβ2m increased from 72% to 89% and the negative predictive value from 76% to 100%.

CONCLUSIONS

Urinary excretion of uα2m and uβ2m predict prognosis in iMN. A spot urine sample can be used instead of a timed sample. A repeated measurement after 6 to 12 months increases prognostic accuracy.

Have we changed the outcome in membranous nephropathy? A propensity study on the role of immunosuppressive therapy

BACKGROUND AND OBJECTIVES

The long-term effect of immunosuppressive therapy (IS) on kidney survival in idiopathic membranous nephropathy (MGN) is debated. The introduction of renin angiotensin blockade, rigorous BP control, and the increasing age at presentation of patients with MGN adds further uncertainty. Given these important changes, we sought to determine whether implementation of IS has altered outcome.

DESIGN, SETTING, PARTICIPANTS, & METHODS

We prospectively evaluated 280 incident MGN patients from three distinct 10-year periods starting from 1975.

RESULTS

We found expected changes in treatment regimens but also variations in age, renal function, severity of proteinuria, and BP at presentation over this time. Outcomes did not differ over time if these significant variations in clinical characteristics were not accounted for across the eras. The effect of IS in the 57 patients treated with currently recommended regimens was assessed using propensity adjustment to address selection bias and the effect of newer, conservative therapies. A propensity score estimating the probability of receiving IS permitted the pairing of 39 treated patients with controls with similar high risk of progression of clinical features. Using this approach, IS was associated not only with remissions in proteinuria but also with substantially improved renal survival.

CONCLUSIONS

The study confirms that patient presenting characteristics and management regimens have changed significantly over time and the natural history of MGN has been altered. A study of propensity-matched patients confirms that current recommendations for IS have improved outcomes in MGN patients at high risk of progression.

Management of idiopathic membranous nephropathy

IMPORTANCE OF THE FIELD

Idiopathic membranous nephropathy (IMN) can have a variable natural course. Treatments able to induce remission can improve the long-term prognosis. However, the optimal therapy for IMN remains controversial.

AREA COVERED IN THIS REVIEW

We reviewed the historical and current literature from 1979 to 2010 regarding the natural course of IMN and the possible treatments giving special emphasis to randomized controlled trials and to more recent approaches.

WHAT THE READER WILL GAIN

The reader will gain a comprehensive review of the available treatments of IMN. A personal therapeutic algorithm for nephrotic patients with IMN is also provided.

TAKE HOME MESSAGE

At least five different treatments showed efficacy in many (but not all) patients with IMN.