Renal Histopathology and Outcomes of Anti-Neutrophil Cytoplasmic Antibody-Associated Glomerulonephritis: The Qatar Experience.

Introduction: Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a severe small-vessel vasculitis with substantial morbidity. Data from the Gulf region are limited, restricting understanding of disease patterns and outcomes. This study describes the epidemiology, clinical features, kidney pathology, and management of ANCA-associated glomerulonephritis (ANCA-GN) in Qatar. Methods: We performed a retrospective cohort study of adults diagnosed with ANCA-GN between 2015 and 2025 at Hamad Medical Corporation. Demographic, clinical, serologic, histopathologic, and therapeutic data were extracted from electronic records. Primary outcomes were end-stage kidney disease (ESKD) and death; secondary outcomes included kidney function trends, proteinuria, ANCA titers, relapse, and infections. Statistical analyses included Student's t test, chi-square, Fisher's exact test, and Kaplan-Meier survival. Results: Twenty-eight patients were followed for a median of 16 months (IQR 16-43). Median age was 49 years, 71% were male, and 54% were of South Asian origin. Seasonal peaks occurred in winter (43%) and summer (32%). GPA and MPA accounted for 54% and 43% of cases; 57% had pulmonary involvement. PR3-ANCA was positive in 43% and MPO-ANCA in 36%, and 18% had atypical ANCA. Mixed (50%) and crescentic (25%) histologic classes predominated. Despite 61% having low-to-moderate ANCA Kidney Risk Score (AKRiS), 39% developed ESKD and 14% died. Maintenance therapy was given to only 54%. Infection-related mortality accounted for most deaths. Lack of hematuria resolution, failure of early proteinuria reduction, and absence of maintenance therapy were significantly associated with ESKD ( Conclusion: ANCA-GN in Qatar demonstrates seasonal clustering and high ESKD rates, pointing to opportunities for improved monitoring, timely therapy, and more consistent care pathways.