Sex differences in glomerular disease: data from the Spanish Registry of glomerulonephritis

Background . Sex and gender differences are increasingly recognized as critical determinants in kidney disease. Most primary glomerulonephritis shows male predominance, whereas lupus nephritis remains strongly female-biased. Large national cohorts with sex-specific analyses are limited. Methods . We analysed all native kidney biopsies (1994–2024) included in the Spanish Registry of Glomerulonephritis (n=34,258) across 120 centres. Patients were stratified by sex, age (≤45, 45–64, 65–74, ≥75 years), and study period (six-year intervals). Clinical syndromes and histological diagnoses were compared between sexes. Results . Overall, 59.9% of biopsies were performed in men and 39.8% in women, with persistent male predominance across all periods. Men exhibited higher serum creatinine, lower creatinine clearance, and greater proteinuria. Women more frequently presented with asymptomatic urinary abnormalities, whereas men more often had chronic kidney disease. Histological differences included: • IgA nephropathy: higher proportion in young women; women more often nephrotic or asymptomatic. • Membranous nephropathy: male predominance overall; young and very elderly women more represented. • Podocytopathies: nephrotic syndrome more frequent in women. • Lupus nephritis: strong female predominance; men presented with more aggressive syndromes. No significant sex differences were observed in ANCA-associated vasculitis. Conclusions : This nationwide registry shows male predominance in glomerulonephritis but highlights important sex-specific differences in age distribution, clinical presentation, and histological subtypes. Systematic incorporation of sex-based analyses in registries and clinical trials is essential to improve diagnostic accuracy, therapeutic strategies, and personalized nephrology.