Outcomes of membranous and proliferative lupus nephritis - analysis of a single-centre cohort with more than 30 years of follow-up

Short- and long-term outcomes of patients with pure membranous lupus nephritis compared with patients with proliferative disease

OBJECTIVES

Membranous LN (MLN) is thought to have a more benign course than proliferative LN (PLN). We aimed to determine the differences in short- and long-term outcomes between patients with MLN and PLN.

METHODS

We included patients with first biopsy-proven MLN and PLN. Short-term outcomes included complete proteinuria recovery (CPR), complete renal response (CRR) and primary efficacy renal response (PERR). Long-term outcomes included a sustained ≥40% reduction in baseline estimated glomerular filtration rate, end-stage kidney disease (ESKD), cardiovascular (CV) events, ≥2 increase in SLICC/ACR Damage Index and death. Univariable and multivariable Cox proportional hazard models were used to examine the effect of baseline characteristics on long-term outcomes.

RESULTS

Of 215 patients, 51 had pure MLN and 164 had PLN. We found no significant differences between the two groups in achieving CPR, CRR and PERR at 1 and 2 years. Median time to outcomes was slightly, but insignificantly, longer in the MLN group. For long-term outcomes, PLN was associated with worse renal and non-renal outcomes, but this was not statistically significant. In the multivariable Cox proportional hazard models, ESKD was associated with the following baseline variables: younger age [hazard ratio (HR) 0.92, 95% confidence interval (CI) 0.87-0.97], higher creatinine (HR 1.01, 95% CI 1.01-1.02), low complement (HR 4.0, 95% CI 1.04-11.10) and higher chronicity index (HR 1.28, 95% CI 1.08-1.51).

CONCLUSION

The resolution of proteinuria in LN is slow. MLN is not a benign disease and may be associated with deterioration of renal function, ESKD, damage, CV events and death.

Risk of chronic kidney disease in 260 patients with lupus nephritis: analysis of a nationwide multicentre cohort with up to 35 years of follow-up

OBJECTIVES

To compare proliferative (PLN) and membranous (MLN) lupus nephritis (LN) regarding clinical and laboratory presentation and long-term outcomes, and to investigate predictors of progression to chronic kidney disease (CKD).

METHODS

Multicentre observational study, with retrospective analysis of a prospective cohort, using data from the Rheumatic Diseases Portuguese Registry - Reuma.pt. Patients with biopsy-proven PLN, MLN and mixed LN were included. Cox regression survival analysis was used to investigate predictors of CKD.

RESULTS

A total of 260 patients were included. Median follow-up was 8 years (IQR 11; minimum 1, maximum 35 years). MLN patients presented with significantly lower serum creatinine [0.70 (IQR 0.20; minimum 0.50, maximum 1.30) mg/dl vs 0.80 (IQR 0.31; minimum 0.26, maximum 2.60) in PLN, P = 0.003]. Proteinuria levels did not differ between groups (P = 0.641). Levels of complement were reduced in PLN but nearly normal in MLN patients, and there were fewer patients with positive anti-dsDNA antibodies in the MLN group (P < 0.001). One year after the beginning of treatment, 62% of the patients achieved EULAR/ERA-EDTA complete response, with a further 5% achieving partial response. Patients with lower proteinuria at diagnosis were more likely to achieve a complete renal response at one year; however, proteinuria at diagnosis or at one year did not predict long-term CKD. Estimated glomerular filtration rate (eGFR) ≤75 mL/min/1.73 m2 at one year was the strongest predictor of progression to CKD (HR 23 [95% CI 8-62], P < 0.001). Other possible predictors included the use of azathioprine for induction of remission, older age at diagnosis and male sex.

CONCLUSION

Proteinuria levels did not predict LN histologic class in our cohort. eGFR cutoff of 75 mL/min/1.73 m2 after one year of treatment was strongly predictive of progression to CKD.

Rough hypervolume-driven feature selection with groupwise intelligent sampling for detecting clinical characterization of lupus nephritis

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease. Lupus nephritis (LN) is a major risk factor for morbidity and mortality in SLE. Proliferative and pure membranous LN have different prognoses and may require different treatments. This study proposes a binary rough hypervolume-driven spherical evolution algorithm with groupwise intelligent sampling (bRGSE). The efficient dimensionality reduction capability of the bRGSE is verified across twelve datasets. These datasets are from the public datasets, with feature dimensions ranging from seven hundred to fifty thousand. The experimental results indicate that bRGSE performs better than seven high-performing alternatives. Then, the bRGSE was combined with adaptive boosting (AdaBoost) to form a new model (bRGSE_AdaBoost), which analyzed clinical records collected from 110 patients with LN. Experimental results show that the proposed bRGSE_AdaBoost can identify the most critical indicators, including urine latent blood, white blood cells, endogenous creatinine clearing rate, and age. These indicators may help differentiate between proliferative LN and membranous LN. The proposed bRGSE algorithm is an efficient dimensionality reduction method. The developed bRGSE_AdaBoost model, a computer-aided model, achieved an accuracy of 96.687 % and is expected to provide early warning for the treatment and diagnosis of LN.

Development and validation of a predictive model for end-stage renal disease in systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) affects many populations. This study aims to develop a predictive model and create a nomogram for assessing the risk of end-stage renal disease (ESRD) in patients diagnosed with SLE. Data from electronic health records of SLE patients treated at the Affiliated Hospital of North Sichuan Medical College between 2013 and 2023 were collected. The dataset underwent thorough cleaning and variable assignment procedures. Subsequently, variables were selected using one-way logistic regression and lasso logistic regression methods, followed by multifactorial logistic regression to construct nomograms. The model's performance was assessed using calibration, receiver operating characteristic (ROC), and decision curve analysis (DCA) curves. Statistical significance was set at P < 0.05. The predictive variables for ESRD development in SLE patients included anti-GP210 antibody presence, urinary occult blood, proteinuria, white blood cell count, complement 4 levels, uric acid, creatinine, total protein, globulin, glomerular filtration rate, pH, specific gravity, very low-density lipoprotein, homocysteine, apolipoprotein B, and absolute counts of cytotoxic T cells. The nomogram exhibited a broad predictive range. The ROC area under the curve (AUC) was 0.886 (0.858-0.913) for the training set and 0.840 (0.783-0.897) for the testing set, indicating good model performance. The model demonstrated both applicability and significant clinical benefits. The developed model presents strong predictive capabilities and considerable clinical utility in estimating the risk of ESRD in patients with SLE.

Circulating neutrophil extracellular trap remnants as a biomarker to predict outcomes in lupus nephritis

OBJECTIVE

To determine if the serum levels of neutrophil extracellular trap (NET) remnants (Elastase-DNA and HMGB1-DNA complexes) at the time of a lupus nephritis (LN) flare predict renal outcomes in the following 24 months.

METHODS

This was a retrospective study performed in prospectively followed cohorts. The study included two cohorts: an exploratory cohort to assess the association between NET remnant levels and the presence of active LN, and a separate LN cohort to determine the utility of NET remnants to predict renal outcomes over the subsequent 24 months.

RESULTS

Ninety-two individuals were included in the exploratory cohort (49 active systemic lupus erythematosus (SLE), 23 inactive SLE and 20 healthy controls (HC)). NET remnants were significantly higher in patients with SLE patients compared with HC (p<0.0001 for both complexes) and those with active LN (36%) had significantly higher levels of NET remnants compared with active SLE without LN (Elastase-DNA: p=0.03; HMGB1-DNA: p=0.02). The LN cohort included 109 active LN patients. Patients with proliferative LN had significantly higher levels of NET remnants than non-proliferative LN (Elastase-DNA: p<0.0001; HMGB1-DNA: p=0.0003). Patients with higher baseline levels of NET remnants had higher odds of not achieving complete remission (Elastase-DNA: OR 2.34, p=0.007; HMGB1-DNA: OR 2.61, p=0.009) and of progressing to severe renal impairment (Elastase-DNA: OR 2.84, p=0.006; HMGB1-DNA: OR 2.04, p=0.02) at 24 months after the flare.

CONCLUSIONS

Elastase-DNA and HMGB1-DNA complexes predict renal outcomes, suggesting they could be used to identify patients requiring more aggressive therapy at flare onset.

Evaluating Sex Differences in the Characteristics and Outcomes of Lupus Nephritis: A Systematic Review and Meta-Analysis

Introduction

More frequent and severe lupus nephritis (LN) has been reported in men compared to women, but data are limited and inconsistent. We conducted a meta-analysis of the literature to compare the histopathologic findings and outcomes between men and women with biopsy-proven LN.

Methods

A systematic search of MEDLINE, Embase, Cochrane, and Web of Science databases was conducted through February 2021. Clinical information was extracted and synthesized from 25 studies that met inclusion criteria (1,210 men and 6,635 women). Pooled odds ratios (OR) with corresponding 95% confidence intervals (CIs) were generated via meta-analysis, and meta-regression was performed to assess the impact of several covariates, both using random-effects models.

Results

Twenty studies reported kidney histopathology, eleven reported kidney outcomes, and eight reported mortality rates. Men had greater odds of class IV ± V LN (OR 1.26, 95% CI: 1.01-1.56), and the composite of end-stage kidney disease, persistent eGFR <15 mL/min or doubling of serum creatinine (OR 2.20, 95% CI: 1.59-3.06), and lower odds of complete remission (OR 0.52, 95% CI: 0.39-0.68). Mortality was not statistically significantly different between sexes (OR 1.50, 95% CI: 0.92-2.46). Meta-regression did not reveal statistically significant study-level relationships between sex differences in any of the covariates that could account for the greater odds of worse kidney outcome in males.

Conclusion

Our analysis confirms the association between male sex and increased severity of LN as well as worse kidney outcomes. Larger prospective studies are needed to validate this association and inform treatment strategies adapted to this population.

[Diagnostic and therapy of lupus nephritis - 2023]

The manuscript summarizes the consensus of the Austrian Society of Nephrology on the diagnosis and therapy of lupusnephritis, which is built on existing studies and literature. We discuss in detail the immunosuppressive treatment in proliferative forms of lupusnephritis (III and IV ± V) and in pure lupusnephritis V with nephrotic-range proteinuria. Furthermore, the supportive medication in lupusnephritis is summarized in the consensus. The figures were designed to provide the reader a guidance through the therapeutical approach in lupusnephritis for the daily practice.

Response to therapy at 6 months predicts long-term renal outcome in lupus nephritis with poor kidney function

OBJECTIVE

It is unclear whether aggressive treatment would benefit lupus nephritis (LN) with poor renal function, which has been excluded from most clinical trials. We aimed at demonstrating their clinicopathological features and prognosis.

METHODS

From August 2012 to December 2018, patients with active LN with poor renal function (estimated glomerular filtration rate (eGFR) between 15 and 59 mL/min/1.73 m²) receiving induction therapy were included. Complete response (CR) was defined as proteinuria <0.5 g/24 hours, while partial response (PR) was defined as ≥50% proteinuria reduction to subnephrotic levels (<3.5 g/24 hours), with (near) normal eGFR. The primary outcome was end-stage renal disease (ESRD). The significant variables were selected via the least absolute shrinkage and selection operator method to construct prediction models for ESRD and treatment response.

RESULTS

A total of 107 patients were included. At 6 months, 18.7%, 38.3% and 43.0% of patients achieved CR, PR and no response (NR), respectively. During a median follow-up of 60 months, 40.2% ended up with reduced renal function (eGFR <60 mL/min/1.73 m²) and 14.0% progressed to ESRD. The proportions of NR at 6 months were significantly higher in these patients compared with those with recovered renal function (p<0.001). In multivariable analysis, baseline eGFR ≤33 mL/min/1.73 m² (HR 3.499, 95% CI 1.044 to 11.730), fibrous crescent (HR 3.439, 95% CI 1.029 to 11.490) and NR at 6 months (HR 17.070, 95% CI 2.155 to 135.240) independently predicted ESRD (C-index 0.911, 95% CI 0.866 to 0.956). Further, baseline hypertension (HR 2.517, 95% CI 0.820 to 8.580), SLE duration>3 months (2.517, 1.012-7.226) and chronicity index (HR 1.757, 95% CI 1.371 to 2.414) predicted NR at 6 months (C-index 0.833, 95% CI 0.756 to 0.910).

CONCLUSIONS

In patients with LN with poor renal function, no response at 6 months predicts a poor long-term renal outcome.

Dissecting the histological features of lupus nephritis highlights new common patterns of injury in class III/IV

OBJECTIVE

The International Society of Nephrology/Renal Pathology Society classification is the gold standard for the characterisation of lupus nephritis (LN) on renal biopsy, with therapeutic repercussions. Its recent revision simplified the current class subdivisions, eliminating the S/G forms of class IV, although data on a possible pathogenetic/clinical value of this subdivision are still contradictory.

METHODS

353 renal biopsies from Belimumab International Study in LN were assessed through central pathology review. Univariate logistic models and a decision tree were performed on 314 adequate biopsies to evaluate the impact of histological features on focal/diffuse classes. Removing class I/II (n=6) and 'pure' class V (n=34), principal component analysis (PCA) and heatmap were used to explore similarities among III, IVS and IVG biopsies either incorporating or not the mixed classes (+V, n=274). Finally, a method aimed at partitioning the cases into k clusters based on their similarity (KMeans), was used to study features from the cohort of 'pure' class III/IVS/IVG cases (n=214) to determine alternative subdivisions based on phenotypic data.

RESULTS

Segmental endocapillary hypercellularity (EH) was prevalent in class III, global EH, wire loops, hyaline thrombi and double contours were hallmarks of class IVG, with IVS cases showing intermediate characteristics. Heatmap and PCA confirmed the segregation of these features among classes, showing better segregation for focal/diffuse LN as compared with the mixed classes (+V). KMeans revealed the presence of two main clusters, membranoproliferative-like (n=83) or vasculitis-like (n=131).

CONCLUSIONS

This study reveals new phenotypic forms of LN surpassing the traditional classes as determined by the current classification. Future validation and confirmation are required to confirm these findings.

Predictors of Early Response, Flares, and Long-Term Adverse Renal Outcomes in Proliferative Lupus Nephritis: A 100-Month Median Follow-Up of an Inception Cohort

Objective: To define predictors of response, time to response, flares, and long-term renal outcome in an inception cohort of proliferative lupus nephritis (PLN). Methods: We included 100 patients (80% female; mean age 31 ± 13 years) with biopsy-proven PLN (III, IV, III/IV + V). Clinical, laboratory, histological and therapeutical parameters were recorded at baseline, 6, 9, 12, 18, 24, 36, 72 months, time of flare, and last follow-up visit. Logistic and Cox-regression models were applied. Results: After induction treatment (69% received cyclophosphamide (CYC) and 27% mycophenolic acid (MPA)), partial (PR) or complete (CR) response was achieved in 59% (26% CR, 33% PR) and 67% (43% CR, 24% PR) of patients at 3 and 6 months, respectively; median time to PR was 3 months (IQR 5) and median time to CR was 6 months (IQR 9). Baseline proteinuria <1.5 g/day correlated with a shorter time to CR (HR 1.77) and with CR at 3, 6, and 9 months (OR 9.4, OR 5.3 and OR 3.7, respectively). During 100-month median follow-up, 33% of patients had ≥1 renal flares (median time: 38 months). Proteinuria >0.8 g/day at 12 months was associated with a higher risk of flares (OR 4.12), while MPA and mixed classes with lower risk (OR 0.14 and OR 0.13, respectively). Baseline proteinuria >2 g/day and 12-month proteinuria >0.8 g/day correlated with a shorter time to flare (HR 2.56 and HR 2.57, respectively). At the end of follow-up, 10% developed stage 3–4 chronic kidney disease (CKD), and 12% end-stage renal disease (ESRD). Twelve-month proteinuria >0.8 g/day (OR 10.8) and interstitial fibrosis/tubular atrophy >25% (OR 7.7) predicted CKD or ESRD at last visit. Conclusions: Baseline proteinuria <1.5 g/day predicted time to CR. Twelve-month proteinuria >0.8 g/day correlated with flares (ever) and time to flare and, along with baseline interstitial fibrosis/tubular atrophy >25%, predicted CKD or ESRD at the last visit.

New Insights Into an Overlooked Entity: Long-Term Outcomes of Membranous Lupus Nephritis From a Single Institution Inception Cohort

Introduction

Pure membranous lupus nephritis (MLN) accounts for 10–20% of total cases of lupus nephritis and is generally associated with a better patient and renal survival compared to proliferative classes. Studies of MLN are limited by small sample size and heterogeneity of included populations since patients with pure MLN and those with mixed classes are usually examined together.

Aim of the Study

To describe clinical and laboratory characteristics of patients with pure MLN, therapeutic regimens, response to treatment, renal relapses, and their long-term renal survival and to define prognostic factors of remission and relapse.

Methods

We retrospectively studied an inception cohort of 27 patients with histologically proven pure MLN. Clinical, laboratory and therapeutical parameters were recorded at diagnosis, at different time points (3–6–9–12–18–24–36–72 months) during the course of the disease, at time of renal flare, and at last follow up visit.

Results

48.1% (13/27) of patients were treated with mycophenolic acid (MPA), 29.6% (8/27) with cyclophosphamide (CYC), and 3.7% (1/27) with cyclosporine (all in combination with corticosteroids). Five patients (18.5%) did not receive any immunosuppressive treatment. Mean duration of treatment was 4.7 ± 2.3 years. Median time to complete remission was 9 months (IQR = 7) and median time to partial remission was 4 months (IQR = 4). No clinical or laboratory parameter was found to be significantly associated with time to remission. Time to remission was not significantly affected by either of the two treatment regimens (CYC and MPA) (p = 0.43). Renal flare was observed in 6 (22%) of the 27 patients in a median time of 51 months (IQR = 63). Proteinuria >1 g/24 h at 1 year significantly correlated with risk of flare (OR 20, p = 0.02). After a median follow up period of 77 months, all patients had an eGFR > 60 ml/min/1.73 m² (mean eGFR 100 ± 32 ml/min/1.73 m²).

Conclusions

In a small cohort of patients with pure MLN, long-term renal survival was very good. With the limitation of the small sample size, we could not find any baseline clinical, biochemical or therapeutic factor that could predict time to remission. Proteinuria > 1 g/24 h at 1 year should be further examined in larger cohorts as a possible predictor of flare.

History of Proliferative Glomerulonephritis Predicts End Stage Kidney Disease in Pure Membranous Lupus Nephritis

OBJECTIVES

Pure membranous (class V) lupus nephritis (LN) is considered a less aggressive phenotype, but tissue fibrosis and chronic kidney disease may still develop. This study aimed to elucidate the prognostic value of a history of class switch in pure membranous LN.

METHODS

We included LN patients with at least two clinically indicated kidney biopsies. New onset of end stage kidney disease (ESKD) was defined as estimated glomerular filtration rate < 15 ml/min/1.73m2, initiation of dialysis, or kidney transplantation.

RESULTS

Among 220 patients (542 biopsies), 199 (90%) were female, and 118 (54%) were African American, 59 (27%) Caucasian, with median age of 28 years at the first kidney biopsy. Patients with pure class V in a first biopsy converted to proliferative LN in 41% of cases. Pure class V in a repeat biopsy was preceded by proliferative LN in 52%. Trajectory analysis of up to 4 repeat biopsies revealed that ISN class switch may happen at any time, even after multiple biopsies with the same class. New onset ESKD was observed within 2 years in 5/56 (9%) patients with pure class V in a repeat biopsy. All 5 patients had proliferative LN in the first biopsy (log rank p= 0.024).

CONCLUSIONS

The conversion from proliferative to membranous (and vice-versa) is frequent in SLE. It can occur at any time in the course of disease, limiting the prognostic value of the first biopsy. Evidence of prior proliferative LN is key as it is associated with higher risk of ESKD in non-proliferative LN.

Assessing outcomes in a lupus nephritis cohort over a 40-year period

OBJECTIVES

To characterize a LN cohort over 40 years, assessing its evolution, analysing two major outcomes: the development of end-stage renal disease and mortality rates in the first 5 years after LN diagnosis.

METHODS

An observational retrospective study of patients with LN, followed up from 1975 at University College Hospital. Patients were divided into four groups, depending on the decade of LN diagnosis: 1975-1985 (D1), 1986-1995 (D2), 1996-2005 (D3) and 2006-2015 (D4). Comparison between groups was performed with respect to demographic, clinical, serological and histological characteristics and outcome.

RESULTS

Two hundred and nineteen patients with LN were studied. There was a change in ethnic distribution, with a decreasing proportion of Caucasians (58.6% in D1 to 31.3% in D4, P = 0.018) and increase in African-ancestry (17.2% in D1 to 39.6% in D4, P = 0.040). Serological and histological patterns changed throughout time, with a reduction in class IV nephritis (51.7% in D1 to 27.1% in D4, P = 0.035), and increase in class II nephritis (10% in D2 to 18.8% in D4, P = 0.01) and anti-extractable nuclear antigen antibody positivity (17.2% in D1 to 83.3% in D4, P = 0.0001). The 5-year mortality rates decreased from D1 (24.1%) to D2 (4%), stabilizing for the next 30 years. The 5-year progression to end-stage renal disease remained stable over the decades.

CONCLUSION

Despite the changes in treatment of LN in the past 20 years, we have reached a plateau in 5-year mortality and progression to end-stage renal disease rates, suggesting that new therapeutic and management approaches, and strategies to enhance adherence, are needed to improve outcomes further in LN patients.

Secondary Membranous Nephropathy. A Narrative Review

Membranous nephropathy (MN) is a common cause of proteinuria and nephrotic syndrome all over the world. It can be subdivided into primary and secondary forms. Primary form is an autoimmune disease clinically characterized by nephrotic syndrome and slow progression. It accounts for ~70% cases of MN. In the remaining cases MN may be secondary to well-defined causes, including infections, drugs, cancer, or autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), urticarial vasculitis, sarcoidosis, thyroiditis, Sjogren syndrome, systemic sclerosis, or ankylosing spondylitis. The clinical presentation is similar in primary and secondary MN. However, the outcome may be different, being often related to that of the original disease in secondary MN. Also, the treatment may be different, being targeted to the etiologic cause in secondary MN. Thus, the differential diagnosis between primary and secondary MN is critical and should be based not only on history and clinical features of the patient but also on immunofluorescence and electron microscopy analysis of renal biopsy as well as on the research of circulating antibodies. The identification of the pathologic events underlying a secondary MN is of paramount importance, since the eradication of the etiologic factors may be followed by remission or definitive cure of MN. In this review we report the main diseases and drugs responsible of secondary MN, the outcome and the pathogenesis of renal disease in different settings and the possible treatments.