Kidney Week

Abstract: FR-PO0875

Kidney Outcomes in Elderly Patients with IgAN: Post Hoc Study from the Japan IgAN Prospective Cohort Study (J-IGACS)

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

• Yokote, Shinya, Kawaguchi Shiritsu Iryo Center, Kawaguchi, Saitama Prefecture, Japan

Shinya Yokote, MD, PhD

• Sasaki, Takaya, Tokyo Jikeikai Ika Daigaku, Minato, Tokyo, Japan

Takaya Sasaki, MD, PhD

• Okabe, Masahiro, Tokyo Jikeikai Ika Daigaku, Minato, Tokyo, Japan

Masahiro Okabe, MD, PhD

• Shimizu, Akihiro, Tokyo Jikeikai Ika Daigaku, Minato, Tokyo, Japan

Akihiro Shimizu, MD, PhD

• Koike, Kentaro, Tokyo Jikeikai Ika Daigaku, Minato, Tokyo, Japan

Kentaro Koike, MD, PhD

• Ueda, Hiroyuki, Tokyo Jikeikai Ika Daigaku, Minato, Tokyo, Japan

Hiroyuki Ueda, MD, PhD

• Tsuboi, Nobuo, Tokyo Jikeikai Ika Daigaku, Minato, Tokyo, Japan

Nobuo Tsuboi, MD, PhD, FASN

• Hirano, Keita, Tokyo Jikeikai Ika Daigaku, Minato, Tokyo, Japan

Keita Hirano, MD, PhD

• Kawamura, Tetsuya, Tokyo Jikeikai Ika Daigaku, Minato, Tokyo, Japan

Tetsuya Kawamura, MD, PhD

• Yokoo, Takashi, Tokyo Jikeikai Ika Daigaku, Minato, Tokyo, Japan

Takashi Yokoo, MD, PhD

• Suzuki, Yusuke, Juntendo Daigaku, Bunkyo, Tokyo, Japan

Yusuke Suzuki, MD, PhD

Group or Team Name

• The Japan IgA Nephropathy Prospective Cohort Study (J-IGACS) Working Group.

Background

As the global population ages, the number of elderly patients with immunoglobulin A nephropathy (IgAN) is expected to increase. However, data regarding their clinical characteristics and renal prognosis remain limited.

Methods

This study aimed to assess the clinical characteristics and renal outcomes of elderly IgAN patients using data from the Japan IgA Nephropathy Prospective Cohort Study (J-IGACS). Patients were stratified into three age groups: Group 1 (<40 years), Group 2 (40–59 years), and Group 3 (≥60 years). The primary outcome was defined as progression to end-stage kidney disease or a ≥30% decline in estimated glomerular filtration rate (eGFR). Univariable analysis was performed using Kaplan–Meier curves and the log-rank test, while Cox proportional hazards regression was used to examine associations between clinical and histopathological variables and the primary outcome.

Results

Among 991 patients (median age: 37.1 years [IQR 26.8–50.3]; 50.7% female), the median baseline eGFR was 74.8 mL/min/1.73 m² (IQR 55.9–94.3), and median proteinuria was 0.58 g/day (IQR 0.28–1.18). Group 1 included 555 patients, Group 2 had 298, and Group 3 included 138 patients. The number of primary outcome events was 41, 43, and 35 in Groups 1, 2, and 3, respectively. Compared to younger groups, Group 3 had significantly lower baseline eGFR, higher proteinuria, and received fewer immunosuppressive therapies and tonsillectomies. The cumulative incidence of the primary outcome was highest in Group 3 (P < 0.001). However, in multivariable analysis, age category itself was not independently associated with the primary outcome. Rather, lower eGFR and higher proteinuria were associated with increased risk, while immunosuppressive therapy and tonsillectomy were associated with reduced risk. In a subgroup analysis of Group 3, those receiving immunosuppressive therapy had significantly better outcomes. Higher eGFR and immunosuppressive treatment remained independent predictors of favorable prognosis.

Conclusion

Although elderly patients with IgAN exhibit worse renal outcomes than younger patients, this difference appears to be driven more by clinical characteristics such as baseline eGFR and proteinuria, rather than age itself.

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025hwjqj3k5