Kidney Week

Abstract: FR-PO0846

Extracapillary Proliferation in IgAN: A Predictor of Disease Progression? Retrospective Spanish and Portuguese Study

Session Information

• Glomerular Outcomes: From Proteinuria to Prognosis
  November 07, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Diaz Encarnacion, Montserrat M., Fundacio Puigvert, Barcelona, CT, Spain

Montserrat M. Diaz Encarnacion, MD, PhD

• Domínguez Guasch, Anna, Fundacio Puigvert, Barcelona, CT, Spain

Anna Domínguez Guasch, MD

• Bardaji de Quixano, Beatriz, Fundacio Puigvert, Barcelona, CT, Spain

Beatriz Bardaji de Quixano, MSc, PhD

• Shabaka, Amir, Hospital Universitario Fundacion Alcorcon, Alcorcón, Community of Madrid, Spain

Amir Shabaka, MBChB

• León Machado, Lina Maria, Hospital Universitario La Paz, Madrid, Community of Madrid, Spain

Lina Maria León Machado, MD

• De Santos Wilhelmi, Antonio, Hospital Universitario de la Princesa, Madrid, Community of Madrid, Spain

Antonio De Santos Wilhelmi

• Viejo Boyano, Iris V., Hospital Universitari i Politecnic La Fe, Valencia, Valencian Community, Spain

Iris V. Viejo Boyano

• Martinez-Miguel, Patricia, Hospital Universitario Principe de Asturias, Alcala de Henares, Community of Madrid, Spain

Patricia Martinez-Miguel, MD, PhD

• Márquez, Eva, Hospital del Mar, Barcelona, CT, Spain

Eva Márquez, MD, PhD

• Ibernon, Meritxell, Hospital de Sant Joan Despi, Sant Joan Despí, CT, Spain

Meritxell Ibernon, PhD

• Piris González, Marcos, Hospital Universitario Ramon y Cajal, Madrid, Community of Madrid, Spain

Marcos Piris González, MD

• Bordignon, Juliana, Hospital Universitari de Bellvitge Servei de Nefrologia, L'Hospitalet de Llobregat, CT, Spain

Juliana Bordignon

• Fernandez, Loreto, Hospital Universitario de Navarra, Pamplona, Spain

Loreto Fernandez, PhD

• Huerta, Ana, Hospital Universitario Puerta de Hierro Majadahonda, Majadahonda, MD, Spain

Ana Huerta, MD

• González García, Celia, Hospital Universitario 12 de Octubre, Madrid, Community of Madrid, Spain

Celia González García, MD

• Martin Alemany, Nadia, University Hospital Dr. Josep Trueta, Girona, Spain

Nadia Martin Alemany, DrMed

• Gago Fraile, Maria, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain

Maria Gago Fraile, MD, PhD

• Martin, Adoración, Hospital de Poniente de Almeria, El Ejido, AL, Spain

Adoración Martin, MD

• Soto, Karina, Centro Hospitalar de Setubal EPE, Setúbal Municipality, Setubal, Portugal

Karina Soto, MD, PhD

• Carbayo, Javier, Hospital General Universitario Gregorio Maranon, Madrid, Community of Madrid, Spain

Javier Carbayo, MD, PhD

• Calle, Leonardo, Complejo Asistencial de Segovia, Segovia, CL, Spain

Leonardo Calle, PhD

• Barros, Xoana, Fundacio Puigvert, Barcelona, CT, Spain

Xoana Barros, PhD

• Arce, Yolanda, Fundacio Puigvert, Barcelona, CT, Spain

Yolanda Arce

• Marco, Helena, Fundacio Puigvert, Barcelona, CT, Spain

Helena Marco, PhD

Group or Team Name

• Spanish Glomerular Study Group (GLOSEN).

Background

IgA Nephropathy (IgAN) is the most common glomerulopathy worldwide and carries a substantial risk of progression to end-stage kidney disease (ESKD). Extracapillary proliferation on renal biopsy (RB) has been linked to more severe presentation; however, its prognostic impact remains controversial. To clarify the prognostic implications of this lesion and guide treatment, we conducted a multicenter study.

Methods

Multicenter retrospective observational study of patients ≥18 years, followed at 22 centers in Spain and Portugal, with RB between 2008-2023, showing evidence of IgAN with extracapillary proliferation and/or fibrinoid necrosis. Secondary causes of IgAN and Schönlein-Henoch purpura were excluded.

Results

135 patients were included (median age 42 y; 71% male; 84% Caucasian), with a median follow-up of 70 months. At presentation, 27% had rapidly progressive renal failure, and 8% required RRT. C1 (<25% glomeruli with crescents) was present in 73%, and C2 (≥25%) in 27%. C2 cases showed more proteinuria (3.7 vs 1.6 g/day), more rapidly progressive renal failure (45% vs 20%; p=0.014), and more RRT (18% vs 2%; p=0.005).
Immunosuppressive (IS) induction therapy was given to 78% of patients, more frequently in those with rapidly progressive renal decline (44% vs. 10%; p=0.031) and higher proteinuria (2.2 vs. 1.4 g/day; p=0.026). Cyclophosphamide was used more often in C2 (46% vs. 22%; p=0.013)
During follow-up, 26% progressed to ESKD, and 9% died. Those with C2 exhibited worse renal survival (56 vs 83%; p=0,002).

Conclusion

This is the largest reported series to date of IgAN and extracapillary proliferation. A higher percentage of crescents was associated with more severe clinical presentation and poorer renal prognosis, despite more intensive IS.
In light of these findings, the decision to start IS in IgAN with extracapillary proliferation should be individualized, rather than restricted to cases with rapidly progressive renal decline, as previously suggested by guidelines.

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025x0pcna1s