Circulating extracellular vesicles in Systemic Lupus Erythematosus: physicochemical properties and phenotype.

OBJECTIVE: This study aimed to identify the physicochemical and phenotypic characteristics of circulating Extracellular Vesicles (EVs) in the plasma of patients with SLE, with or without Lupus Nephritis (LN), and their potential utility as disease biomarkers. METHODS: Plasma-circulating EVs were concentrated using differential centrifugation from adult female patients (n=38) who met the 'American College of Rheumatology/European Alliance of Associations for Rheumatology 2019' criteria for SLE diagnosis with (LN) or without LN (nLN), confirmed by renal biopsy. Controls (n=18) were healthy volunteers matched by gender and similar age. The structure, size and Energy Dispersion Spectrum (EDS) of EVs were observed by electron microscopy. The surface charge and size distribution were evaluated using dynamic light scattering. The counts and phenotype of EVs from patients (SLE-EVs) and controls (Ctrl-EVs) were obtained using flow cytometry. Non-parametric statistical tests and exploratory analysis of multiple variables were performed. The discriminatory power of some variables as potential biomarkers of the disease was also evaluated. RESULTS: Circulating EVs were heterogeneous in morphology and size, but SLE-EVs reached larger diameters than Ctrl-EVs (p<0.0001). Small SLE-EVs and large SLE-EVs were increased compared with Ctrl-EV (p<0.0001 and p<0.05, respectively). Likewise, patients with SLE (LN or nLN) had higher concentrations of large EVs compared with controls (p<0.001 and p<0.0001, respectively). SLE-EVs showed a different EDS (p<0.001) and were less electronegative (p<0.0001) than Ctrl-EVs. EV-CD45+, EV-CD14+ and EV-IgM+ were more frequent in patients with SLE compared with controls (p<0.001, p<0.05 and p<0.001, respectively). The concentrations of large EVs and EV-IgM+ allowed better discrimination of patients from controls. CONCLUSIONS: Plasma-circulating EVs from patients with SLE with and without nephritis are increased in peripheral blood and have different physicochemical properties than controls. Characteristics of EVs such as larger size and the presence of IgM on the surface could help discriminate patients from controls.

Panel miRNAs are potential diagnostic markers for chronic kidney diseases: a systematic review and meta-analysis.

BACKGROUND: Accurate detection of kidney damage is key to preventing renal failure, and identifying biomarkers is essential for this purpose. We aimed to assess the accuracy of miRNAs as diagnostic tools for chronic kidney disease (CKD). METHODS: We thoroughly searched five databases (MEDLINE, Web of Science, Embase, Scopus, and CENTRAL) and performed a meta-analysis using R software. We assessed the overall diagnostic potential using the pooled area under the curve (pAUC), sensitivity (SEN), and specificity (SPE) values and the risk of bias by using the QUADAS-2 tool. The study protocol was registered on PROSPERO (CRD42021282785). RESULTS: We analyzed data from 8351 CKD patients, 2989 healthy individuals, and 4331 people with chronic diseases. Among the single miRNAs, the pooled SEN was 0.82, and the SPE was 0.81 for diabetic nephropathy (DN) vs. diabetes mellitus (DM). The SEN and SPE were 0.91 and 0.89 for DN and healthy controls, respectively. miR-192 was the most frequently reported miRNA in DN patients, with a pAUC of 0.91 and SEN and SPE of 0.89 and 0.89, respectively, compared to those in healthy controls. The panel of miRNAs outperformed the single miRNAs (pAUC of 0.86 vs. 0.79, p < 0.05). The SEN and SPE of the panel miRNAs were 0.89 and 0.73, respectively, for DN vs. DM. In the lupus nephritis (LN) vs. systemic lupus erythematosus (SLE) cohorts, the SEN and SPE were 0.84 and 0.81, respectively. Urinary miRNAs tended to be more effective than blood miRNAs (p = 0.06). CONCLUSION: MiRNAs show promise as effective diagnostic markers for CKD. The detection of miRNAs in urine and the use of a panel of miRNAs allows more accurate diagnosis.

[Clinical and morphological correlations in patients with lupus nephritis: a retrospective study].

AIM: To analyze associations between clinical and morphological features of kidney involvement in patients with systemic lupus erythematosus. MATERIALS AND METHODS: In the retrospective cohort study, we enrolled adult (≥18 years) patients with morphologically proven lupus nephritis (LN) stratified according to the ISN/RPS classification. Systemic lupus erythematosus was classified in accordance with ACR/EULAR classification criteria (2019). Antiphospholipid syndrome was diagnosed according to the 2006 classification criteria. Disease activity was assessed with SELENA-SLEDAI score. RESULTS: We enrolled 62 patients with LN, among them 84% were females. Median age of SLE onset was 23 (16,3; 30,8) years. In all cases kidney involvement was accompanied by extrarenal manifestations, among which joint (82%), skin (57%) and hematological involvement (68%) was the most common. LN class I was proven in one patient, class II - in three patients, class III - in 24, including III+V in seven, class IV - in 18, including IV+V in two, class V - in 13, class VI - in three patients. APS nephropathy was diagnosed in 4 (6.5%) of patients with LN. The most common clinical manifestation was proteinuria (85%), however its prevalence, level and the frequency of nephrotic syndrome showed no significant differences between the LN classes. LN III/IV±V was characterized by the highest levels of serum creatinine (and the lowest eGFR) at the time of biopsy. CONCLUSION: LN is characterized by the high heterogeneity of the clinical and morphological manifestations, which makes LN class prediction impossible without kidney biopsy.

[Lupus nephritis and thrombotic microangiopathy: A review].

Lupus nephritis (LN) is one of the most common organ-specific manifestations of systemic lupus erythematosus (SLE). Various clinical signs of LN develop in at least 50% of patients with SLE. In addition to LN, the spectrum of renal lesions associated with SLE also includes vascular pathology. One of the variants of renal microvascular injury is thrombotic microangiopathy (TMA), the mechanisms of which are diverse. The review focuses on the main forms of TMA, including antiphospholipid syndrome and nephropathy associated with antiphospholipid syndrome, TMA caused by complement system regulation disorders and deficiency of ADAMTS13. In most cases, these forms of TMA are combined with LN. However, they may also exist as a single form of kidney damage. This article discusses the TMA pathogenesis, the impact on kidney prognosis, and treatment options.

The Expression of Toll-like Receptors (TLR7 and TLR9) in Class III and Class IV of Recently Diagnosed Lupus Nephritis with 12-Month Follow-Up.

Renal involvement is an important cause of morbidity and mortality in systemic lupus erythematosus (SLE). The present study included patients with recently diagnosed Class III and Class IV lupus nephritis (LN) treated by Rheumatology who, upon the detection of alterations in their kidney function, were referred to Nephrology for the joint management of both medical specialties. The purpose of this study was to compare the plasma expression of Toll-Like Receptor 7 (TLR7) and TLR9 in healthy control (HC) subjects and newly diagnosed Class III and Class IV LN patients with 12-month follow-ups. The plasma expression of TLR7 and TLR9 proteins was determined by the ELISA method. A significant increase in the expression of TLR7 protein was found in Class III LN in the basal determination compared to the expression in the HC (p = 0.002) and at 12 months of follow-up (p = 0.03) vs. HC. The expression of TLR9 showed a behavior opposite to that of TLR7. TLR9 showed decreased protein expression in LN Class III patients' baseline and final measurements. The result was similar in the basal and final determinations of LN Class IV compared to the expression in HC. A significant decrease in SLEDAI -2K was observed at 12 months of follow-up in patients in Class III (p = 0.01) and Class IV (p = 0.0001) of LN. Complement C3 levels improved significantly at 12-month follow-up in Class IV patients (p = 0.0001). Complement C4 levels decreased significantly at 12-month follow-up in LN Class III compared to baseline (p = 0.01). Anti-DNA antibodies decreased significantly at 12 months of follow-up in Class IV LN (p = 0.01). A significant increase in proteinuria was found at 12 months of follow-up in Class III LN, compared to the baseline determination (p = 0.02). In LN Class IV, proteinuria decreased at 12 months of follow-up compared to baseline (p = 0.0001). Albuminuria decreased at 12 months of follow-up in LN Class IV (p = 0.006). Class IV LN, albuminuria also decreased at 12 months of follow-up (p = 0.009). Hematuria persisted in all patients and the glomerular filtration rate did not change. Three Class IV patients died before 12 months of follow-up from various causes. In conclusion, although the rheumatologic data appeared to improve, the renal function data remained inconsistent. Decreased expression of TLR9 and increased expression of TLR7 could be useful in the early diagnosis of Class III and Class IV LN is correct.

A Comprehensive and Practical Approach to the Management of Lupus Nephritis in the Current Era.

Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE) and is one of the leading causes of morbidity and mortality in patients with SLE. It is estimated that up to 60% of individuals with SLE will develop LN, which can manifest at any stage of a patient's life; however, it commonly emerges early in the course of SLE and tends to exhibit a more aggressive phenotype in men compared to women. Black and Hispanic patients are more likely to progress to kidney failure than white patients. LN is characterized by kidney inflammation and chronic parenchymal damage, leading to impaired kidney function and potential progression to kidney failure. This article provides a comprehensive overview of the epidemiology, pathogenesis, clinical presentation, diagnosis, and management of LN, highlighting the importance of early recognition and treatment of LN to prevent progressive, irreversible kidney damage and improve patient outcomes. Additionally, the article discusses current and emerging therapies for LN, including traditional immunosuppressive agents, biological agents, and novel therapies targeting specific pathways involved in LN pathogenesis, to provide a practical guide for clinicians in properly diagnosing LN and determining a patient-centered treatment plan.

A systematic review and meta-analysis of the diagnostic accuracy of the neutrophil-to-lymphocyte ratio and the platelet-to-lymphocyte ratio in systemic lupus erythematosus.

The wide range of clinical and serological manifestations in systemic lupus erythematosus (SLE) and the lack of accepted diagnostic criteria warrant the identification of novel, more accurate biomarkers. Hematological indices derived from full blood cell counts, particularly the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR), have shown promise in SLE; however, a critical appraisal of their diagnostic accuracy is lacking. We sought to address this issue by conducting a systematic review and meta-analysis of the diagnostic accuracy of the NLR and PLR in SLE. The electronic databases PubMed, Scopus, and Web of Science were systematically searched from inception to 15 March 2024 for studies reporting the sensitivity and specificity of the NLR and PLR, obtained by receiver operating characteristic (ROC) curve analysis, for the presence of SLE, disease severity, organ involvement (lupus nephritis, pericarditis, and pleural disease), and complications (infections). The risk of bias was assessed using the JBI Critical Appraisal Checklist (PROSPERO registration number: CRD42024531446). The NLR exhibited good accuracy for the diagnosis of SLE (eight studies; area under the curve, AUC = 0.81, 95% CI 0.78-0.85) and lupus nephritis (nine studies; AUC = 0.81, 95% CI 0.77-0.84), but not for severe disease (nine studies; AUC = 0.69, 95% CI 0.65-0.73) or infections (six studies; AUC = 0.73, 95% CI 0.69-0.77). The PLR exhibited good accuracy for the diagnosis of severe disease (six studies; AUC = 0.85, 95% CI 0.81-0.87). There were an insufficient number of studies to assess the accuracy of the PLR for the diagnosis of SLE, lupus nephritis, or infections. No study investigated the NLR and PLR in SLE patients with pericarditis or pleural disease. Therefore, the NLR and the PLR have a relatively high diagnostic accuracy for the presence of SLE and lupus nephritis (NLR) and severe disease (PLR). Further studies are warranted to determine whether the NLR and PLR, in combination with clinical evaluation and other serological biomarkers, can enhance the diagnosis and management of SLE.

Precision medicine in lupus nephritis.

Lupus nephritis (LN) is a prominent manifestation of systemic lupus erythematosus (SLE), characterized by diverse clinical and histopathological features, imposing a substantial burden on patients. Although the exact cause of SLE remain undetermined, several genetic, epigenetics, hormonal, and other factors are implicated in LN pathogenesis. The management of LN rely on invasive renal biopsies, while the standard therapy of the proliferative form of LN remains empirical and relies on indiscriminate immunosuppressants (IS). These treatments exhibit unsatisfactory remission rates, trigger recurrent renal flares, and entail grave adverse effects (ADEs). The advent of precision medicine into LN entails a concentrated effort to pinpoint essential biomarkers, reshaping the landscape of LN management. The primary objective of this review is to synthesize and summarize existing research findings by elucidating the most prevalent immunological, genetic, and epigenetic alterations and deliberate on management strategies that can pave the way for precision medicine in tackling LN. Novel clinical biomarker such as serum anti-complement component 1q (anti-C1q), with urinary markers including neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemoattractant protein-1 (MCP1) and tumour necrosis-like weak inducers of apoptosis (TWEAK) are strongly correlated with LN. These biomarkers have good sensitivity and specificity and perform better than conventional biomarkers in assessing LN activity. Similarly, more renal-specific genetic and epigenetic alteration have been correlated with LN susceptibility and severity. This includes variants of hyaluronan synthase 2 (HAS2), and platelet-derived growth factor receptor alpha (PDGFRA). In the future, integrating clinical, genetic, epigenetic, and targeted therapies holds promise for guiding precision medicine and improving LN outcomes.

Tubular biomarkers and histology in lupus nephritis.

INTRODUCTION: The relevance of tubulo-interstitial involvement for kidney prognosis has recently been emphasized, but validated biomarkers for predicting histology are still lacking. The aim of our study was to evaluate different serum and urinary markers of tubular damage in patients with lupus nephritis (LN) and to correlate them with kidney histopathology. METHODS: A single-center retrospective study was conducted from January 2016 to December 2021. Serum and urine samples were collected on the same day of kidney biopsy and correlated with histologic data from a cohort of 15 LN patients. We analyzed the following urinary markers, adjusted for urine creatinine: beta 2-microglobulin, alpha 1-microglobulin, NGAL, uKIM-1, MCP-1, uDKK-3, and uUMOD. The serum markers sKIM-1 and sUMOD were also analyzed. RESULTS: A positive and strong correlation was observed between the degree of interstitial fibrosis (rho = 0.785, p = .001) and tubular atrophy (rho = 0.781, p = .001) and the levels of uDKK3. uUMOD also showed an inverse and moderate correlation with interstitial fibrosis (rho = -0.562, p = .037) and tubular atrophy (rho = -0.694, p = .006). Patients with >10% cortical interstitial inflammation had higher levels of uKIM-1 [4.9 (3.9, 5.5) vs. 0.8 (0.6, 1.5) mcg/mg, p = .001], MCP-1 [3.8 (2. 3, 4.2) vs. 0.7 (0.3, 1.2) mcg/mg, p = .001], sKIM-1 [9.2 (5.9, 32.7) vs. 1.4 (0, 3.5) pg/mL, p = .001], and lower sUMOD [8.7 (0, 39.7) vs. 46.1 (35.7, 53) ng/mL, p = .028]. CONCLUSION: The use of specific urinary and serum biomarkers of tubular dysfunction or injury may help to predict certain histologic parameters in LN patients.

II Brazilian Society of Rheumatology consensus for lupus nephritis diagnosis and treatment.

OBJECTIVE: To develop the second evidence-based Brazilian Society of Rheumatology consensus for diagnosis and treatment of lupus nephritis (LN). METHODS: Two methodologists and 20 rheumatologists from Lupus Comittee of Brazilian Society of Rheumatology participate in the development of this guideline. Fourteen PICO questions were defined and a systematic review was performed. Eligible randomized controlled trials were analyzed regarding complete renal remission, partial renal remission, serum creatinine, proteinuria, serum creatinine doubling, progression to end-stage renal disease, renal relapse, and severe adverse events (infections and mortality). The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to develop these recommendations. Recommendations required ≥82% of agreement among the voting members and were classified as strongly in favor, weakly in favor, conditional, weakly against or strongly against a particular intervention. Other aspects of LN management (diagnosis, general principles of treatment, treatment of comorbidities and refractory cases) were evaluated through literature review and expert opinion. RESULTS: All SLE patients should undergo creatinine and urinalysis tests to assess renal involvement. Kidney biopsy is considered the gold standard for diagnosing LN but, if it is not available or there is a contraindication to the procedure, therapeutic decisions should be based on clinical and laboratory parameters. Fourteen recommendations were developed. Target Renal response (TRR) was defined as improvement or maintenance of renal function (±10% at baseline of treatment) combined with a decrease in 24-h proteinuria or 24-h UPCR of 25% at 3 months, a decrease of 50% at 6 months, and proteinuria < 0.8 g/24 h at 12 months. Hydroxychloroquine should be prescribed to all SLE patients, except in cases of contraindication. Glucocorticoids should be used at the lowest dose and for the minimal necessary period. In class III or IV (±V), mycophenolate (MMF), cyclophosphamide, MMF plus tacrolimus (TAC), MMF plus belimumab or TAC can be used as induction therapy. For maintenance therapy, MMF or azathioprine (AZA) are the first choice and TAC or cyclosporin or leflunomide can be used in patients who cannot use MMF or AZA. Rituximab can be prescribed in cases of refractory disease. In cases of failure in achieving TRR, it is important to assess adherence, immunosuppressant dosage, adjuvant therapy, comorbidities, and consider biopsy/rebiopsy. CONCLUSION: This consensus provides evidence-based data to guide LN diagnosis and treatment, supporting the development of public and supplementary health policies in Brazil.

[NETosis in lupus nephritis].

AIM: To evaluate the levels of MPO-DNA complex in patients with systemic lupus erythematosus (SLE) and its association with the presence of lupus nephritis (LN). MATERIALS AND METHODS: The study included 77 patients with SLE, of whom 30 had SLE without anti phospholipid syndrome (APS), 47 had SLE with APS, and 20 were healthy individuals serving as the control group. The MPO-DNA complex in the serum was investigated using ELISA. RESULTS: The levels of MPO-DNA complex in serum were significantly higher in patients with SLE compared to healthy controls (p=0.001). Among the patients with SLE, 30 (39%) had elevated levels of MPO-DNA complex. The presence of elevated MPO-DNA complex was significantly associated with the presence of a history of LN (p=0.009). Moreover, among the patients included in the study, 20 had active LN, and patients with elevated MPO-DNA complex levels were more likely to have active LN than patients without elevated MPO-DNA complex concentrations [12 (40%) of 30 vs 8 (17%) of 47, χ2=5.029; p=0.034]. An association was found between elevated levels of MPO-DNA complex and the presence of proteinuria, hematuria, cellular hematic/granular casts and aseptic leukocyturia. A direct correlation of MPO-DNA complex with SLEDAI-R was found in patients with active LN (rs=0.497; p=0.026). CONCLUSION: Elevated levels of MPO-DNA complex were detected in 39% of patients with SLE. These patients had a higher prevalence of LN in their medical history and at the time of inclusion in the study. The correlation between MPO-DNA complex levels and the activity of LN according to SLEDAI-R indicates the potential role of MPO-DNA complex as a biomarker for assessing the activity of renal damage in SLE.

Anti-dsDNA IgE: a potential non-invasive test for prediction of lupus nephritis relapse.

OBJECTIVES: Discontinuation or continuation of maintenance immunosuppressive therapy (MIST) after a severe lupus nephritis (LN) requires measuring the risk of relapse but reliable clinical and biological markers are lacking. The WIN-IgE study assesses the value of serum anti-dsDNA IgE autoantibodies as a biomarker for the prediction of relapse in severe LN. METHODS: WIN-IgE is an ancillary study of the WIN-Lupus study (NCT01284725), a prospective controlled clinical trial which evaluated the discontinuation of MIST after 2-3 years in class III or IV±V LN with active lesions. WIN-IgE included all patients with available serum collected at randomisation for continuation or discontinuation of MIST. In these sera, anti-dsDNA antibodies, IgE and IgG, were quantified by ELISA and compared between patients who experienced LN relapse and those who did not during the 24 months of follow-up. RESULTS: 52 patients were included, 25 in the MIST continuation group and 27 in the MIST discontinuation group, 12 experienced a biopsy-proven relapse of LN. Initial anti-dsDNA IgE antibodies levels were higher in patients with subsequent LN relapse. Anti-dsDNA IgG was not associated with relapse. Survival without LN relapse was lower in patients with anti-dsDNA IgE levels above vs below a threshold of 1.9 arbitrary units (p=0.019), particularly in the subgroup of patients randomised to discontinue MIST (p=0.002). In all patients, anti-dsDNA IgE above 1.9 arbitrary units had a positive predictive value of 0.8 for severe LN relapse. CONCLUSIONS: These results suggest blood anti-dsDNA IgE as a non-invasive predictive marker of LN relapse.

Longitudinal assessment of urinary ALCAM, HPX, and PRDX6 in Korean patients with systemic lupus erythematosus: implications for disease activity monitoring and treatment response.

Introduction: This study aimed to demonstrate the potential of activated leukocyte cell adhesion molecule (ALCAM), hemopexin (HPX), and peroxiredoxin 6 (PRDX6) as urine biomarkers for systemic lupus erythematosus (SLE). Methods: Urine samples were collected from 138 Korean patients with SLE from the Ajou Lupus Cohort and 39 healthy controls (HC). The concentrations of urine biomarkers were analyzed using enzyme-linked immunosorbent assay kits specific for ALCAM, HPX, and PRDX6, respectively. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic utility, and Pearson's correlation analysis was conducted to assess the relationships between the disease activity and urine biomarkers. Results: Patients with SLE and patients with lupus nephritis (LN) showed significantly elevated ALCAM, HPX, and PRDX6 levels compared with HCs. ALCAM, HPX, and PRDX6 showed significant diagnostic values, especially for lupus nephritis (LN), with areas under the receiver operating characteristic curve for LN was 0.850 for ALCAM (95% CI, 0.778-0.921), 0.781 for HPX (95% CI, 0.695-0.867), and 0.714 for PRDX6 (95% CI, 0.617-0.812). Correlation analysis revealed that all proteins were significantly associated with anti-double stranded DNA antibody (ALCAM, r = 0.350, p < 0.001; HPX, r = 0.346, p < 0.001; PRDX6, r = 0.191, p = 0.026) and SLEDAI (ALCAM, r = 0.526, p < 0.001; HPX, r = 0.479, p < 0.001; PRDX6, r = 0.262, p = 0.002). Results from the follow-up of the three biomarker levels in these patients revealed a significant decrease, showing a positive correlation with changes in SLEDAI-2k scores (ALCAM, r = 0.502, p < 0.001; HPX, r = 0.475, p < 0.001; PRDX6, r = 0.245, p = 0.026), indicating their potential as indicators for tracking disease activity. Discussions: Urinary ALCAM, HPX, and PRDX6 levels have diagnostic value and reflect disease activity in Korean patients with SLE, emphasizing their potential for non-invasive monitoring and treatment response evaluation.

Anti-C1q antibodies: a biomarker for diagnosis and management of lupus nephritis. A narrative review.

Nephritis is a frequent and severe complication of Systemic Lupus Erythematous (SLE). The clinical course of lupus nephritis (LN) is usually characterized by alternating phases of remission and exacerbation. Flares of LN can lead to deterioration of kidney function, necessitating timely diagnosis and therapy. The presence of autoantibodies against C1q (anti-C1qAb) in the sera of SLE patients has been reported in various studies. Some research suggests that the presence and changes in the titer of anti-C1qAb may be associated with the development of LN, as well as with LN activity and renal flares. However, the exact role of anti-C1qAb in LN remains a subject of debate. Despite variability in the results of published studies, anti-C1qAb hold promise as noninvasive markers for assessing LN activity in SLE patients. Measuring anti-C1qAb levels could aid in diagnosing and managing LN during periods of both inactive disease and renal flares. Nevertheless, larger controlled trials with standardized laboratory assays are necessary to further establish the utility of anti-C1qAb in predicting the reactivation and remission of LN and guiding treatment strategies.

[Update on lupus nephritis]. / Update Lupusnephritis.

In addition to the butterfly rash, lupus nephritis is the most specific manifestation of systemic lupus erythematosus (SLE). The perspective on this organ manifestation has fundamentally changed as well as the manifestation of SLE itself 40 years after the first multicenter clinical study on lupus nephritis. Even if there is a faint glimpse of hope of a cure, there is still the fight against the problem of nonresponders and also the progressive loss of organ function. This update gives an overview of the current importance of lupus nephritis in the context of the whole SLE disease, of the special features and on the options provided by the new diagnostic and therapeutic developments.

Machine learning models predicts risk of proliferative lupus nephritis.

Objective: This study aims to develop and validate machine learning models to predict proliferative lupus nephritis (PLN) occurrence, offering a reliable diagnostic alternative when renal biopsy is not feasible or safe. Methods: This study retrospectively analyzed clinical and laboratory data from patients diagnosed with SLE and renal involvement who underwent renal biopsy at West China Hospital of Sichuan University between 2011 and 2021. We randomly assigned 70% of the patients to a training cohort and the remaining 30% to a test cohort. Various machine learning models were constructed on the training cohort, including generalized linear models (e.g., logistic regression, least absolute shrinkage and selection operator, ridge regression, and elastic net), support vector machines (linear and radial basis kernel functions), and decision tree models (e.g., classical decision tree, conditional inference tree, and random forest). Diagnostic performance was evaluated using ROC curves, calibration curves, and DCA for both cohorts. Furthermore, different machine learning models were compared to identify key and shared features, aiming to screen for potential PLN diagnostic markers. Results: Involving 1312 LN patients, with 780 PLN/NPLN cases analyzed. They were randomly divided into a training group (547 cases) and a testing group (233 cases). we developed nine machine learning models in the training group. Seven models demonstrated excellent discriminatory abilities in the testing cohort, random forest model showed the highest discriminatory ability (AUC: 0.880, 95% confidence interval(CI): 0.835-0.926). Logistic regression had the best calibration, while random forest exhibited the greatest clinical net benefit. By comparing features across various models, we confirmed the efficacy of traditional indicators like anti-dsDNA antibodies, complement levels, serum creatinine, and urinary red and white blood cells in predicting and distinguishing PLN. Additionally, we uncovered the potential value of previously controversial or underutilized indicators such as serum chloride, neutrophil percentage, serum cystatin C, hematocrit, urinary pH, blood routine red blood cells, and immunoglobulin M in predicting PLN. Conclusion: This study provides a comprehensive perspective on incorporating a broader range of biomarkers for diagnosing and predicting PLN. Additionally, it offers an ideal non-invasive diagnostic tool for SLE patients unable to undergo renal biopsy.

Development and validation of a risk scoring system to identify patients with lupus nephritis in electronic health record data.

OBJECTIVE: Accurate identification of lupus nephritis (LN) cases is essential for patient management, research and public health initiatives. However, LN diagnosis codes in electronic health records (EHRs) are underused, hindering efficient identification. We investigated the current performance of International Classification of Diseases (ICD) codes, 9th and 10th editions (ICD9/10), for identifying prevalent LN, and developed scoring systems to increase identification of LN that are adaptable to settings with and without LN ICD codes. METHODS: Training and test sets derived from EHR data from a large health system. An external set comprised data from the EHR of a second large health system. Adults with ICD9/10 codes for SLE were included. LN cases were ascertained through manual chart reviews conducted by rheumatologists. Two definitions of LN were used: strict (definite LN) and inclusive (definite, potential or diagnostic uncertainty). Gradient boosting models including structured EHR fields were used for predictor selection. Two logistic regression-based scoring systems were developed ('LN-Code' included LN ICD codes and 'LN-No Code' did not), calibrated and validated using standard performance metrics. RESULTS: A total of 4152 patients from University of California San Francisco Medical Center and 370 patients from Zuckerberg San Francisco General Hospital and Trauma Center met the eligibility criteria. Mean age was 50 years, 87% were female. LN diagnosis codes demonstrated low sensitivity (43-73%) but high specificity (92-97%). LN-Code achieved an area under the curve (AUC) of 0.93 and a sensitivity of 0.88 for identifying LN using the inclusive definition. LN-No Code reached an AUC of 0.91 and a sensitivity of 0.95 (0.97 for the strict definition). Both scoring systems had good external validity, calibration and performance across racial and ethnic groups. CONCLUSIONS: This study quantified the underutilisation of LN diagnosis codes in EHRs and introduced two adaptable scoring systems to enhance LN identification. Further validation in diverse healthcare settings is essential to ensure their broader applicability.

Serum Uric Acid Combined with Homocysteine as a Predictive Biomarker of Lupus Nephritis.

Serum uric acid (UA) and homocysteine (Hcy) are potential biomarkers of systemic lupus erythematosus (SLE). In this study, the expressions of UA and Hcy in SLE patients and the predictive value of these two parameters for lupus nephritis (LN) were studied. A total of 476 SLE patients were recruited to this case-control study, of which 176 SLE patients diagnosed with LN and 300 without LN. Serum UA and Hcy levels were analyzed. Multivariate logistic regression analysis was used to evaluate the relationship between serum UA and Hcy and LN. The receiver operating characteristic (ROC) curves were used to predict the role of combination of serum UA and Hcy in LN. We found that serum UA and Hcy levels in SLE patients with LN were significantly higher than those in controls (p<0.05). Multivariate logistic regressions showed that serum UA (OR+=+1.003, 95+% CI: 1.001-1.006, p+=+0.003), apolipoprotein B (Apo B) (OR+=+21.361, 95+% CI: 2.312-195.373, p+=+0.007) and Hcy (OR+=+1.042, 95+% CI: 1.011-1.080, p+=+0.014) were independent markers of LN. Combined serum UA and Hcy revealed a better result (AUC+=+0.718, 95+% CI: 0.670-0.676, p<0.001) in prediction of LN compared to that of the serum UA (AUC+=+0.710) and Hcy (AUC+=+0.657) independently. In conclusion, serum UA and Hcy could be predictive biomarkers of LN, and joint detection of serum UA and Hcy might be useful in the clinical setting.

Healthcare resource utilization and costs in patients with a newly confirmed diagnosis of lupus nephritis in the United States over a 5-year follow-up period.

BACKGROUND: We aimed to describe healthcare resource utilization (HCRU) and healthcare costs in patients with newly confirmed lupus nephritis (LN) in the United States over a 5-year follow-up period. METHODS: This retrospective, longitudinal cohort study (GSK Study 214102) utilized administrative claims data to identify individuals with a newly confirmed diagnosis of LN between August 01, 2011, and July 31, 2018, based on LN-specific International Classification of Diseases diagnosis codes. Index was the date of first LN-related diagnosis code claim. HCRU, healthcare costs, and incidence of systemic lupus erythematosus (SLE) flares were reported annually among eligible patients with at least 5 years continuous enrollment post-index. RESULTS: Of 2,159 patients with a newly confirmed diagnosis of LN meeting inclusion and exclusion criteria, 335 had at least 5 years continuous enrollment post-index. HCRU was greatest in the first year post-LN diagnosis across all categories (inpatient admission, emergency room [ER] visits, ambulatory visits, and pharmacy use), and trended lower, though remained substantial, in the 5-year follow-up period. Among patients with LN and HCRU, the mean (standard deviation [SD]) number of ER visits and inpatient admissions were 3.7 (4.6) and 1.8 (1.5), respectively, in Year 1, which generally remained stable in Years 2-5; the mean (SD) number of ambulatory visits and pharmacy fills were 35.8 (25.1) and 62.9 (43.8), respectively, in Year 1, and remained similar for Years 2-5. Most patients (≥ 91.6%) had ≥ 1 SLE flare in each of the 5 years of follow-up. The proportion of patients who experienced a severe SLE flare was higher in Year 1 (31.6%) than subsequent years (14.3-18.5%). Total costs (medical and pharmacy; mean [SD]) were higher in Year 1 ($44,205 [71,532]) than subsequent years ($29,444 [52,310]-$32,222 [58,216]), driven mainly by inpatient admissions (Year 1: $21,181 [58,886]; subsequent years: $7,406 [23,331]-$9,389 [29,283]). CONCLUSIONS: Patients with a newly confirmed diagnosis of LN have substantial HCRU and healthcare costs, particularly in the year post-diagnosis, largely driven by inpatient costs. This highlights the need for improved disease management to prevent renal damage, improve patient outcomes, and reduce costs among patients with renal involvement.