Adding 6-month parameters for the prediction of kidney prognosis in ANCA-associated glomerulonephritis.

Background: Antineutrophil-cytoplasmic antibody (ANCA)-associated vasculitis (AAV) with kidney involvement (AAV-GN) frequently evolves to end-stage kidney disease (ESKD) despite aggressive immunosuppressive treatment. Several risk scores have been used to assess renal prognosis. We aimed to determine whether kidney function and markers of AAV-GN activity after 6 months could improve the prediction of ESKD. Methods: This retrospective and observational study included adult patients with AAV-GN recruited from six French nephrology centers (including from the Maine-Anjou AAV registry). The primary outcome was kidney survival. Analyses were conducted in the whole population and in a sub-population that did not develop ESKD early in the course of the disease. Results: When considering the 102 patients with all data available at diagnosis, Berden classification and Renal Risk Score (RRS) were not found to be better than kidney function [estimated glomerular filtration rate (eGFR)] alone at predicting ESKD (C-index = 0.70, 0.79, 0.82, respectively). Multivariables models did not indicate an improved prognostic value when compared with eGFR alone.When considering the 93 patients with all data available at 6 months, eGFR outperformed Berden classification and RRS (C-index = 0.88, 0.62, 0.69, respectively) to predict ESKD. RRS performed better when it was updated with the eGFR at 6 months instead of the baseline eGFR. While 6-month proteinuria was associated with ESKD and improved ESKD prediction, hematuria and serological remission did not. Conclusion: This work suggests the benefit of the reassessment of the kidney prognosis 6 months after AAV-GN diagnosis. Kidney function at this time remains the most reliable for predicting kidney outcome. Of the markers tested, persistent proteinuria at 6 months was the only one to slightly improve the prediction of ESKD.

Kidney injury molecule 1 (KIM-1): a potential biomarker of acute kidney injury and tubulointerstitial injury in patients with ANCA-glomerulonephritis.

Background: Kidney injury molecule 1 (KIM-1) is a transmembrane glycoprotein expressed by proximal tubular cells, recognized as an early, sensitive and specific urinary biomarker for kidney injury. Blood KIM-1 was recently associated with the severity of acute and chronic kidney damage but its value in antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis with glomerulonephritis (ANCA-GN) has not been studied. Thus, we analyzed its expression at ANCA-GN diagnosis and its relationship with clinical presentation, kidney histopathology and early outcomes. Methods: We assessed KIM-1 levels and other pro-inflammatory molecules (C-reactive protein, interleukin-6, tumor necrosis factor α, monocyte chemoattractant protein-1 and pentraxin 3) at ANCA-GN diagnosis and after 6 months in patients included in the Maine-Anjou registry, which gathers data patients from four French Nephrology Centers diagnosed since January 2000. Results: Blood KIM-1 levels were assessed in 54 patients. Levels were elevated at diagnosis and decreased after induction remission therapy. KIM-1 was associated with the severity of renal injury at diagnosis and the need for kidney replacement therapy. In opposition to other pro-inflammatory molecules, KIM-1 correlated with the amount of acute tubular necrosis and interstitial fibrosis/tubular atrophy (IF/TA) on kidney biopsy, but not with interstitial infiltrate or with glomerular involvement. In multivariable analysis, elevated KIM-1 predicted initial estimated glomerular filtration rate (ß = -19, 95% CI -31, -7.6, P = .002). Conclusion: KIM-1 appears as a potential biomarker for acute kidney injury and for tubulointerstitial injury in ANCA-GN. Whether KIM-1 is only a surrogate marker or is a key immune player in ANCA-GN pathogenesis remain to be determined.

Association between kinetic of anti-neutrophil cytoplasmic antibody (ANCA), renal survival and relapse risk in ANCA glomerulonephritis.

BACKGROUND: Anti-neutrophil cytoplasmic antibody (ANCA) kinetic in ANCA-associated vasculitis with glomerulonephritis (AAV-GN) has been suggested to be associated with AAV relapse. Few studies have focused on its association with renal prognosis. Thus we aimed to investigate the relationship between ANCA specificity and the evolutive profile and renal outcomes. METHODS: This multicentric retrospective study included patients diagnosed with ANCA-GN since 1 January 2000. Patients without ANCA at diagnosis and with fewer than three ANCA determinations during follow-up were excluded. We analysed estimated glomerular filtration rate (eGFR) variation, renal-free survival and relapse-free survival according to three ANCA profiles (negative, recurrent and persistent) and to ANCA specificity [myeloperoxidase (MPO) or proteinase 3 (PR3)]. RESULTS: Over a follow-up of 56 months [interquartile range (IQR) 34-101], a median of 19 (IQR 13-25) ANCA determinations were performed for the 134 included patients. Patients with a recurrent/persistent ANCA profile had a lower relapse-free survival (P = .019) and tended to have a lower renal survival (P = .053) compared with those with a negative ANCA profile. Patients with a recurrent/persistent MPO-ANCA profile had the shortest renal survival (P = .015) and those with a recurrent/persistent PR3-ANCA profile had the worst relapse-free survival (P = .013) compared with other profiles. The negative ANCA profile was associated with a greater eGFR recovery. In multivariate regression analysis, it was an independent predictor of a 2-fold increase in eGFR at 2 years [odds ratio 6.79 (95% confidence interval 1.78-31.4), P = .008]). CONCLUSION: ANCA kinetic after an ANCA-GN diagnosis is associated with outcomes. MPO-ANCA recurrence/persistence identifies patients with a lower potential of renal recovery and a higher risk of kidney failure, while PR3-ANCA recurrence/persistence identifies patients with a greater relapse risk. Thus ANCA kinetics may help identify patients with a smouldering disease.

Histopathological prognostic factors in ANCA-associated glomerulonephritis.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) are a group of multisystemic autoimmune diseases characterized by necrotizing inflammation of small vessels. Kidney involvement is frequent in granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), and accounts for a significant proportion of the morbidity and mortality related to these diseases. Despite improvement in therapeutic management of ANCA-glomerulonephritis (ANCA-GN), end-stage kidney disease (ESKD) still occurs in up to 30% of affected patients within 5 years following diagnosis. Thus, identifying patients for whom aggressive immunosuppressive therapy will be more beneficial than deleterious is of great importance. Several clinical, biological and histological factors have been proposed as predictors of ESKD. The kidney biopsy is essential not only for the diagnosis, but also for evaluating renal prognosis. In this review, we discuss the prognostic value of renal lesions at the diagnosis of ANCA-GN by analyzing each compartment of the nephron. We also review existing ESKD risk classification in ANCA-GN and finally propose an example of a standardized pathology report that could be used in routine practice.

Assessment of Renal Risk Score and Histopathological Classification for Prediction of End-Stage Kidney Disease and Factors Associated With Change in eGFR After ANCA-Glomerulonephritis Diagnosis.

Introduction: The "Renal Risk Score" (RRS) and the histopathological classification have been proposed to predict the risk of end-stage kidney disease (ESKD) in ANCA-associated glomerulonephritis (ANCA-GN). Besides, factors associated with kidney function recovery after ANCA-GN onset remain to be more extensively studied. In the present study, we analyzed the value of the RRS and of the histopathological classification for ESKD prediction. Next, we analyzed factors associated with eGFR change within the first 2 years following ANCA-GN diagnosis. Materials and Methods: We included patients from the Maine-Anjou ANCA-associated vasculitis registry with at least 6 months of follow-up. The values of ANCA-GN, histopathological classification, and RRS, and the factors associated with eGFR variations between ANCA-GN diagnosis and 2 years of follow-up were assessed. Results: The predictive values of the histopathological classification and RRS were analyzed in 123 patients. After a median follow-up of 42 months, 33.3% patients developed ESKD. The predictive value of RRS for ESKD was greater than that of the histopathological classification. Determinants of eGFR variation were assessed in 80/123 patients with complete eGFR measurement. The median eGFR increased from ANCA-GN diagnosis to month 6 and stabilized thereafter. The only factor associated with eGFR variation in our study was eGFR at ANCA-GN diagnosis, with higher eGFR at diagnosis being associated with eGFR loss (p<0.001). Conclusion: The RRS has a better predictive value for ESKD than the histopathological classification. The main determinant of eGFR variation at 2 years was eGFR at ANCA-GN diagnosis. Thus, this study suggests that eGFR recovery is poorly predicted by histological damage at ANCA-GN diagnosis.

Lymphopaenia at diagnosis of anti-neutrophil cytoplasmic antibody-vasculitis with renal involvement is correlated with severity and renal prognosis.

BACKGROUND: Lymphopaenia is commonly observed in autoimmune diseases, where it has been associated with disease activity or prognosis. However, in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) only a few small-scale studies have been targeted towards this issue. Research has not yet focused on AAV with renal involvement (AAV-RI). Thus the aim of this study was to analyse the association between lymphocyte counts and outcomes in a large cohort of AAV-RI patients. METHODS: We used the Maine-Anjou AAV registry that retrospectively gathers data on consecutive patients affected by AAV in four French nephrology centres, recorded since January 2000. We analysed clinical, biological and histological data at diagnosis of AAV-RI. Risk factors for end-stage kidney disease (ESKD) were analysed. Event-free survival was also assessed. RESULTS: Among the 145 patients included in the study, those with lymphopaenia at diagnosis had a lower renal function at baseline [estimated glomerular filtration rate (eGFR) 13 versus 26 mL/min; P = 0.002] and were more likely to require kidney replacement therapy (51% versus 25%; P = 0.003). Lymphopaenia was correlated with histological lesions and especially with the percentage of sclerotic glomeruli (P = 0.0027). ESKD-free survival was lower in lymphopaenic patients (P < 0.0001). In multivariate Cox analysis, lymphopaenia was an independent risk factor for ESKD [hazard ratio 4.47 (95% confidence interval 2.06-9.72), P < 0.001]. CONCLUSIONS: Lymphopaenia correlates with the severity of AAV glomerulonephritis at diagnosis and predicts poor renal outcome. In this view, lymphopaenia could be used as a simple and cost-effective biomarker to assess renal prognosis at AAV-RI diagnosis.

Unmet needs for CKD care: from the general population to the CKD clinics-how many patients are we missing?

INTRODUCTION: Prevalence of chronic kidney disease (CKD) varies around the world. Little is known about the discrepancy between the general population's needs and nephrology care offered. We aimed to contribute to filling this gap and propose a means to infer the number of patients needing follow-up. METHODS: All patients undergoing at least one nephrology consultation in 2019 were enrolled. We used the ratio between CKD Stages 3 and 4 reported in the literature, and considered that only 25-50% of CKD Stage 3 patients have progressive CKD, to hypothesize different scenarios to estimate the number of CKD Stage 3 patients still needing nephrology follow-up. RESULTS: The 1992 CKD patients were followed-up in our centre (56.93% males; age 66.71 ± 18.32 years; 16.82% Stage 1; 14.66% Stage 2; 39.46% Stage 3; 19.88% Stage 4; 7.68% Stage 5). The ratio between Stages 3 and 4 in population studies ranged from 7.72 to 51.29, being 1.98 in our centre. Hypothesizing that we followed-up 100, 70 or 50% of CKD Stage 4 patients, 528-2506 CKD Stage 3 patients in our area would need nephrology follow-up [1885-8946 per million population (p.m.p.)]. Three to 17 additional nephrologists p.m.p. would be necessary to fully cover the need for care. CONCLUSIONS: The number of patients with CKD Stage 3 who would benefit from nephrology care is high. Considering that one patient-year of delay of dialysis could cover a nephrologist's annual salary, interventions aimed to improve the care of advanced CKD may be economically sound.

Elderly Patients in a Large Nephrology Unit: Who Are Our Old, Old-Old and Oldest-Old Patients?

The world population is aging, and the prevalence of chronic kidney disease (CKD) is increasing. Whether this increase is also due to the methods currently being used to assess kidney function in the elderly is still a matter of discussion. We aimed to describe the actual referral pattern of CKD patients in a large nephrology unit and test whether the use of different formulae to estimate kidney function could affect the staging and the need for specialist care in the older subset of our population. In 2019, 1992 patients were referred to our center. Almost 28% of the patients were aged ≥80 and about 6% were ≥90 years old. Among the causes of kidney disease, glomerulonephritis displayed a higher prevalence in younger patients whereas hypertensive or diabetic kidney disease were more prevalent in older patients. The prevalence of referred patients in advanced CKD stages increased with age; estimated glomerular filtration rate (eGFR) decreased with age regardless of which equation was used (chronic kidney disease epidemiology collaboration (CKD-EPI), Lund-Malmö Revised (LMR), modification of diet in renal disease (MDRD), Full Age Spectrum (FAS), or Berlin Initiative Study 1 (BIS)). With CKD-EPI as a reference, MDRD and FAS underestimated the CKD stage while LMR overestimated it. The BIS showed the highest heterogeneity. Considering an eGFR threshold limit of 45 mL/min for defining "significant" CKD in patients over 65 years of age, the variability in CKD staging was 10% no matter which equation was used. Our study quantified the weight of "old" and "old-old" patients on follow-up in a large nephrology outpatient unit and suggested that with the current referral pattern, the type of formula used does not affect the need for CKD care within the context of a relatively late referral, particularly in elderly patients.

Incidence and Risk Factors of Venous Thromboembolic Events in Patients with ANCA-Glomerulonephritis: A Cohort Study from the Maine-Anjou Registry.

(1) Introduction: The incidence of venous thromboembolisms (VTE) has not been extensively analyzed in patients with antineutrophil cytoplasmic antibody (ANCA)-glomerulonephritis (ANCA-GN). Thus, the aim of the present study was to assess the frequency and the risk factors of VTE in patients with ANCA-GN. (2) Methods: Patients from the Maine-Anjou ANCA-associated vasculitis (AAV) registry with a biopsy showing pauci-immune glomerulonephritis were included. VTE events, site, and interval from AAV diagnosis were analyzed. (3) Results: 133 patients fulfilled the inclusion criteria of the study and were analyzed. VTE episodes were diagnosed in 23/133 (17.3%) patients at a median delay of 3 months from ANCA-GN diagnosis. Patients with VTE had lower serum albumin (p = 0.040), were less frequently on statin therapy (p = 0.009) and had less frequently proteinase-3 (PR3)-ANCAs (p = 0.078). Univariate analysis identified higher age (p = 0.022), lower serum albumin (p = 0.030), lack of statin therapy (p = 0.009), and rituximab treatment (p = 0.018) as significant risk factors of VTE. In multivariate analysis, only lack of statin therapy (HR 4.873; p = 0.042) was significantly associated with VTE. (4) Conclusion: Patients with ANCA-GN are at high risk of VTE, especially within the first months following AAV diagnosis. Our results suggest that statin therapy is associated with a lower risk of VTE in ANCA-GN patients.

Patients with ANCA-Associated Glomerulonephritis and Connective Tissue Diseases: A Comparative Study from the Maine-Anjou AAV Registry.

BACKGROUND AND OBJECTIVES: The overlap between antineutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis (ANCA-GN) and connective tissue diseases (CTD) has been reported mainly as case series in the literature. Frequency of this association, as well as presentation and outcomes are unknown. MATERIALS AND METHODS: Patients from the Maine-Anjou ANCA-associated vasculitides (AAV) registry with ANCA-GN diagnosed between 01/01/2000 and 01/01/2018, ANCA positivity, and at least six months of follow-up, were included. RESULTS: 106 out of 142 patients fulfilled the inclusion criteria and were analyzed. CTD was present at ANCA-GN diagnosis in 16 (15.1%) patients. The most common CTD were rheumatoid arthritis, Sjogren syndrome and systemic sclerosis. Compared to the control group, females were more represented in the CTD group (75%, p = 0.001). Renal presentation was comparable between groups, including the pathological analysis of renal biopsies. Patients of CTD group presented a higher rate of non-renal relapse (25% versus 7.7%, p = 0.037), and experienced more frequently a venous thrombotic event (31.2% versus 10%, p = 0.021). No difference between groups was observed according to major outcomes. CONCLUSION: Association between CTD and ANCA-GN is not a rare condition and predominantly affects females. While AAV presentation is not significantly different, CTD patients experience more frequently non-renal relapse and venous thrombotic events.