Abstract: TH-PO0763
Tubulointerstitial Fibrosis as a Mediator of Ethnic Disparities in Kidney Outcomes of IgAN: An Exploratory Mediation Analysis
Session Information
- Glomerular Histopathology: Evolving Insights
November 06, 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
- Vasquez-Rios, George, GN Center, Renal Medicine Associates, Albuquerque, New Mexico, United States
- Posso Paz, Mariam B, The University of New Mexico, Albuquerque, New Mexico, United States
- Rajasekaran, Arun, GN Center, Renal Medicine Associates, Albuquerque, New Mexico, United States
- Storey, Aaron J., Arkana Laboratories, Little Rock, Arkansas, United States
- Kumar, Jayant, GN Center, Renal Medicine Associates, Albuquerque, New Mexico, United States
- Madan, Arvind, GN Center, Central Florida Kidney Specialists, Orlando, Florida, United States
- Campbell, Kirk N., University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Coca, Steven G., Icahn School of Medicine at Mount Sinai, New York, New York, United States
- Caza, Tiffany, Arkana Laboratories, Little Rock, Arkansas, United States
- Sanchez Russo, Luis F., GN Center, Central Florida Kidney Specialists, Orlando, Florida, United States
Group or Team Name
- BRIDGE-GN Research Consortium.
Background
The MEST-C score is a validated histopathologic classification used to predict outcomes in IgA nephropathy (IgAN). However, the extent to which specific lesions, particularly tubulointerstitial fibrosis (T), mediate ethnic disparities in outcomes is unclear. This study evaluated whether MEST-C lesions contribute to worse outcomes among ethnic minority patients with IgAN.
Methods
Retrospective cohort study of biopsy-confirmed IgAN cases from an institutional registry. Patients with full MEST-C scoring, documented ethnicity, and ≥1 year of follow-up were included. Ethnicity was categorized as Caucasian vs. ethnic minority (Hispanic, Black, Asian, Native American). The primary outcome was a composite of ≥40% eGFR decline, eGFR <15, dialysis, or death. We compared MEST-C distribution by ethnicity, examined associations with outcomes, and assessed mediation using logistic regression. Mediation was inferred if adjusting for a lesion attenuated the ethnicity–outcome relationship.
Results
Among 47 patients, 74.5% were ethnic minorities. Mean age was 43.9 years; 51% were male. At biopsy, 72.3% had hypertension and 17.0% had diabetes. Mean creatinine was 1.66 mg/dL, eGFR 59.2 mL/min/1.73m2, and UPCR 2.34 g/g. The composite outcome occurred in 16.7% of Caucasians vs. 37.1% of minorities (p=0.18). Minorities had higher rates of T and C lesions. Ethnic minority status was associated with worse outcomes (OR 1.8, 95% CI 1.0–3.2; p=0.04). After adjusting for T score, the association attenuated (OR 1.3, 95% CI 0.7–2.5; p=0.19), suggesting 62.5% of the disparity may be mediated by T lesions. Crescents showed partial mediation; M, E, and S scores did not.
Conclusion
IFTA may account for much of the ethnic disparity in IgAN outcomes. These findings underscore the importance of early detection and targeted interventions for tubulointerstitial injury, particularly in high-risk ethnic groups.