Kidney Week

Abstract: TH-PO0492

BRIDGE-IgAN: A Multicenter Retrospective Cohort Study of Health Outcomes Disparities in IgAN Across Diverse US Populations

Session Information

• Glomerular Diseases: Clinical, Outcomes, and Therapeutics Research - IgAN
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Vasquez-Rios, George, Renal Medicine Associates, Albuquerque, New Mexico, United States

George Vasquez-Rios, MD, MSCR, FASN

• Oh, Wonsuk, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Wonsuk Oh, PhD

• Rajasekaran, Arun, Renal Medicine Associates, Albuquerque, New Mexico, United States

Arun Rajasekaran, MD, FASN

• Hsu, Raymond K., University of California San Francisco, San Francisco, California, United States

Raymond K. Hsu, MD, MA

• Al Jurdi, Ayman, Mass General Brigham Inc, Boston, Massachusetts, United States

Ayman Al Jurdi, MD, MPH, FASN

• Kalra, Kartik, Geisinger Health, Danville, Pennsylvania, United States

Kartik Kalra, MD, FASN

• Parada, Xavier F., University of Massachusetts Amherst, Amherst, Massachusetts, United States

Xavier F. Parada, MD, FASN

• Natarajan, Hariharasudan, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Hariharasudan Natarajan, MD

• Manns, Oni, Renal Medicine Associates, Albuquerque, New Mexico, United States

Oni Manns, RN, MPH

• Kumar, Jayant, Renal Medicine Associates, Albuquerque, New Mexico, United States

Jayant Kumar, MD

• Udani, Suneel M., Nephrology Associates, Oak Park, Illinois, United States

Suneel M. Udani, MD, FASN

• Madan, Arvind, Central Florida Kidney Specialists, Orlando, Florida, United States

Arvind Madan, MD, MBBS, FASN

• Chung, Miriam, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Miriam Chung, MD

• Athavale, Ambarish, University of California San Diego, La Jolla, California, United States

Ambarish Athavale, MD, MBBS

• Wadhwani, Shikha, The University of Texas Medical Branch at Galveston Department of Internal Medicine, Galveston, Texas, United States

Shikha Wadhwani, MD, MS, FASN

• Geara, Abdallah Sassine, University of Pennsylvania, Philadelphia, Pennsylvania, United States

Abdallah Sassine Geara, MD

• Coca, Steven G., Icahn School of Medicine at Mount Sinai, New York, New York, United States

Steven G. Coca, DO, MS

• Campbell, Kirk N., University of Pennsylvania, Philadelphia, Pennsylvania, United States

Kirk N. Campbell, MD, FASN

• Mariani, Laura H., University of Michigan, Ann Arbor, Michigan, United States

Laura H. Mariani, MD, MS, FASN

• Sanchez Russo, Luis F., Central Florida Kidney Specialists, Orlando, Florida, United States

Luis F. Sanchez Russo, MD, MS

Group or Team Name

• BRIDGE-IgAN investigators

Background

Real-world data evaluating ethnic differences in IgA nephropathy (IgAN) progression in the USA remain limited. We evaluated longitudinal kidney outcomes and proteinuria trajectories in a multiethnic IgAN cohort from the BRIDGE-IgAN registry.

Methods

Retrospective longitudinal cohort study of biopsy-proven IgAN patients enrolled across 7 U.S. centers. Patients with baseline eGFR <15 mL/min/1.73m2 at V0 were excluded. The primary outcome was a composite kidney event defined as ≥40% eGFR decline from V0 or eGFR <15 mL/min/1.73m2 during follow-up. Secondary outcomes included remission (UPCR <0.3 g/g). Longitudinal analyses used generalized linear mixed models, linear mixed models, Cox proportional hazards models, and Firth-penalized logistic regression.

Results

Among 155 patients, 45 were Caucasian and 110 belonged to ethnic minority populations. Baseline disease severity was similar between groups, including baseline eGFR (58.3±26.3 vs 60.4±27.7 mL/min/1.73m2, p=0.684) and UPCR (1.30 [0.71–3.50] vs 1.75 [0.71–3.08] g/g, p=0.912). Ethnic minority patients were more frequently female (54.5% vs 31.1%, p=0.013). Kidney-event risk increased longitudinally in the overall cohort (adjusted OR/month 1.15, 95% CI 1.06–1.26). Baseline eGFR independently predicted kidney outcomes in Cox and patient-level analyses. Proteinuria trajectories improved significantly overall and across ethnic groups. Adjusted log(UPCR) slopes improved among Caucasian (-0.212, 95% CI -0.393 to -0.030) and ethnic minority patients (-0.286, 95% CI -0.414 to -0.158). Despite comparable proteinuria improvement and similar baseline disease severity, ethnic minority patients demonstrated faster eGFR decline over time (adjusted slope -1.89 mL/min/1.73m2/year, 95% CI -3.38 to -0.40) compared to Caucasian patients: +0.78 mL/min/1.73m2/year, 95% CI -1.39 to 2.95, corresponding to an approximate between-group annualized eGFR slope difference of 2.7 mL/min/1.73m2/year.

Conclusion

Ethnic minority patients with IgAN experienced faster longitudinal kidney-function decline despite comparable proteinuria improvement. These findings suggest that longitudinal clinical trajectories in IgAN may differ across ethnic groups even when conventional clinical markers improve similarly. Expanded analyses including ~800 patients and deeper longitudinal phenotyping will be presented at Kidney Week 2026.

Funding

• Commercial Support – Calliditas therapeutics, Otsuka Pharmaceutical