Performance of clinical and histological prognostic scores for kidney survival in ANCA-associated vasculitis.

OBJECTIVES: Integrating clinical and histological parameters into prognostic scores may enhance the prediction of progression to kidney failure in anti-neutrophil cytoplasm antibodies-associated vasculitis (AAV). This study aimed to evaluate the prognostic performance of histological classifications and scoring systems for kidney survival in AAV. METHODS: This retrospective cohort study included 101 AAV patients with kidney involvement diagnosed by biopsy and followed for ≥12 months. The main outcome was the time to kidney failure. The prognostic performance of each histological and prognostic score was evaluated using Harrell's C statistic and Akaike's Information Criteria. RESULTS: Among the 101 patients, 37 progressed to kidney failure over a median follow-up of 75 months (IQR 39-123). The Harrell's C statistic was 0.702 (0.620-0.784), 0.606 (0.473-0.738), 0.801 (0.736-0.867), 0.782 (0.706-0.858), and 0.817 (0.749-0.885) for the EUVAS/Berden classification, Mayo Clinic Chronicity Score, Percentage of ANCA Crescentic Score (PACS), ANCA renal risk score (ARRS), and the improved ANCA kidney risk score (AKRiS), respectively. The AKRiS best discriminated the risk of kidney failure progression among subgroups. The AKRiS performance decreased with longer follow-up intervals. Adding the peak estimated glomerular filtration rate attained post-therapy improved the AKRiS performance at all follow-up intervals. Kidney relapses precipitated kidney failure in 71% of cases that progressed after the first year of follow-up. CONCLUSION: The novel AKRiS enhances the prediction of kidney failure in AAV with kidney involvement. As the prognostic yield of AKRiS decreases over time, a second calculation of AKRiS, including post-therapy kidney function, may improve its long-term performance.

Exostosin-1/exostosin-2 expression and favorable kidney outcomes in lupus nephritis: a retrospective cohort study.

INTRODUCTION/OBJECTIVES: The heterodimer exostosin-1/exostosin-2 (EXO-1/2) is a novel antigen observed in membranous nephropathy associated with systemic lupus erythematosus. This study aimed to evaluate the association between EXO-1/2 positivity in kidney biopsy and kidney outcomes. METHODS: The kidney biopsy tissue from 50 class 5 lupus nephritis (LN) and 55 mixed class 3/4 + 5 LN patients was stained for EXO-1/2. Baseline clinical and histological characteristics were compared between EXO-1/2 positive and EXO-1/2 negative patients. Time-to-event analyses were performed to compare rates of response to therapy, kidney flares, and progression to a 40% decline of the glomerular filtration rate (eGFR), doubling of serum creatinine, and kidney failure. RESULTS: Fourteen out of 50 (28%) of class 5 and 5 out of 55 (9%) of mixed class 3/4 + 5 LN stained positive for EXO-1/2. Patients with class 5 LN and EXO-1/2 positive stain were younger, with better kidney function at presentation, and lower scarring in the kidney biopsy analysis. Over a median follow-up of 100 months, patients with positive EXO-1/2 staining had significantly lower rates of progression in the full cohort. When analyzed separately in class 5 and mixed class LN subgroups, there were significantly lower rates of progression to a 40% decline of the eGFR and non-statistically significant trends for doubling of serum creatinine and kidney failure. CONCLUSION: EXO-1/2 is a novel antigen detected in class 5 LN and associated with a good prognosis of kidney function. The incorporation of EXO-1/2 staining in clinical practice can potentially modify the management of LN due to its prognostic implications. Key Points • Exostosin-1/exostosin-2 antigen has been found in cases of membranous nephropathy associated with autoimmune diseases such as systemic lupus erythematosus. • Exostosin-1/exostosin-2 staining in the kidney biopsy of class 5 or mixed class 3/4 + 5 lupus nephritis is associated with a good long-term prognosis of kidney function. • The incorporation of exostosin-1/exostosin-2 staining into clinical practice can potentially modify management due to its prognostic implications.

Effect of antimalarials on clinical outcomes in lupus nephritis.

OBJECTIVES: To evaluate the effect of antimalarial drugs in response to therapy, incidence of LN flares, and progression of kidney disease in a large LN cohort. METHODS: We retrospectively studied 424 biopsy-proven LN patients followed for >3 years. We obtained demographic, clinical, laboratory, histopathological, and treatment variables. Antimalarial use was approached as 1) users versus no users, 2) according to prevalent vs incident use regarding the LN flare, and 3) according to the type of antimalarial. All outcomes were evaluated by time-to-event analyses. Adjusted hazard ratios were obtained by Cox regression. RESULTS: The cohort included 424 patients, median age of 29 years (IQR 23-37), 96% female, with a median eGFR of 81 ml/min/1.73m2 (IQR 48-118) and proteinuria of 3.4 g/g (IQR 1.9-5.5). Antimalarial use was associated with higher complete response (aHR 1.57, 1.08-2.27), lower incidence of kidney flares (aHR 0.63, 0.43-0.92), and lower progression to kidney failure (aHR 0.37, 0.23-0.53). The effect on these outcomes was modified by the presentation eGFR, histological class, and/or concomitant initial immunosuppressor. These protective effects were observed in patients with prevalent or incident use regarding the LN flare and patients using hydroxychloroquine. The incidence of toxic retinopathy was 1.7%, 5.7%, and 8.8% by 3-, 5-, and 7 years of continued antimalarial use. CONCLUSION: The use of antimalarial drugs is associated with increased response to therapy, lower incidence of kidney flares, and lower progression to kidney failure in LN patients. Conversely, this population is at high risk of toxic maculopathy, and yearly ophthalmologic examination is recommended.