Long-Term Kidney Outcomes in ANCA-Associated Vasculitis in a Mexican Hispanic Cohort

Background: The kidneys are frequently involved in anti-neutrophil cytoplasm antibody-associated vasculitis (AAV). Kidney outcomes are variable among centers and have been scarcely reported in the Latin American region Methods: Retrospective cohort study including all patients diagnosed with AAV and kidney involvement between 2001 and 2022. All patients were followed for ≥12 months, kidney failure, or death. All outcomes were evaluated by time-to-event analyses. Results: The cohort included 154 patients with AAV and kidney involvement, 133 (86%) diagnosed by kidney biopsy, with a median follow-up of 74 months (IQR 32-126). The median age was 52 years (IQR 38-61), 104 (67%) female, 82 (53%) diagnosed as granulomatosis with polyangiitis (GPA), 47 (31%) microscopic polyangiitis, and 25 (16%) as renal-limited vasculitis. At presentation, median serum creatinine was 2.4mg/dL (IQR 1.7-4.5), eGFR 23ml/min/1.73m2 (IQR 12-36), and proteinuria 1.8g/g (IQR 1.1-3.2). In the kidney biopsy, the median normal glomeruli were 18% (IQR 0-37), global sclerosis 39% (IQR 6-56%), interstitial fibrosis 30% (IQR 15-50), tubular atrophy 30% (10-60). 52 (34%) patients had renal replacement therapy requirements at presentation, of which x 19 (36%) recovered kidney function. Over long-term follow-up, 54 patients progressed to kidney failure with 5- and 10-year progression rates of 73% and 56%, respectively (Figure 1-A). Twenty-four patients died over follow-up, with patient survival being 88% and 83% by 5 and 10 years (Figure 1-B). The main cause of death was infection (75%) Conclusion: The kidney outcomes in this Mexican cohort are worse than those described in European and US cohorts. The percentage of patients with initial kidney replacement therapy requirements and advanced sclerosis is higher than in other cohorts, suggesting that late diagnosis is one of the factors associated with dismal prognosis in this cohort.