Abstract: TH-PO0474
Initial Treatment Practices for IgAN in Japan: A Descriptive Study Based on Health Checkup Findings Using Claims Database
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
- Matsuzaki, Keiichi, Department of Public Health, Kitasato University School of Medicine, Sagamihara, Japan
- Kurihara, Hitomi, Medical Affairs, Otsuka Pharmaceutical Co., Ltd., Tokyo, Japan
- Toda, Rikiya, Medical Affairs, Otsuka Pharmaceutical Co., Ltd., Tokyo, Japan
- Shibasaki, Yoshiyuki, Medical Affairs, Otsuka Pharmaceutical Co., Ltd., Tokyo, Japan
Background
IgA nephropathy (IgAN) is the most common primary glomerulonephritis, and early therapeutic intervention is recommended to prevent loss of kidney function. In Japan, IgAN is often detected following hematuria or proteinuria in health checkups, suggesting that pre-diagnostic urinary abnormalities may be associated with subsequent treatment. However, evidence on treatment initiation timing and patterns by health checkup results remains limited. Therefore, this study aims to clarify initiation timing of representative IgAN treatments, and treatment patterns stratified by the most recent pre-diagnostic health checkup results in Japan.
Methods
This study used health insurance claims and health checkup data provided by JMDC Inc. Patients diagnosed with IgAN (ICD-10: N028) within one year after the kidney biopsy, aged 18–74 years, with available pre-biopsy health checkup data on eGFR, hematuria, and proteinuria, and followed for at least one year after the biopsy were included. Treatment initiation timing was analyzed using the biopsy as the reference point, from urinary abnormalities detected at pre-biopsy health checkups to one year after the biopsy. Treatment patterns were analyzed using the most recent pre-biopsy health checkup results, stratified by eGFR and urinary abnormalities (hematuria or proteinuria ≥+).
Results
Among 31,766 individuals diagnosed with IgAN, 743 patients were included. The median age was 45 years and 58.4% were male. Urinary abnormalities at pre-biopsy health checkups were observed in 706 patients (95.0%). Among these patients, 680 (96.3%) initiated representative IgAN treatments by one year after the biopsy and RAS inhibitors (RASi) were used in 477 (67.6%), including 257 treated prior to the biopsy. Based on pre-biopsy health checkup results, 52.5% (231/440) of patients with an eGFR ≥60 mL/min/1.73 m2 underwent tonsillectomy plus steroid pulse (TSP), compared with 12.5% (3/24) of those with an eGFR <30, while TSP was performed in 53.9% (257/477) of patients with both hematuria and proteinuria versus 20.6% (13/63) of those negative for both.
Conclusion
This study demonstrated frequent pre-diagnostic use of RASi and preferential use of TSP in patients with severe pre-diagnostic urinary abnormalities. These findings may enlighten diagnostic and treatment processes following health checkup abnormalities and optimize treatment pathways.
Acknowledgment
The authors thank Akishi Okabe, Toshiki Tanaka, and Shinichi Nishiwaki of Otsuka Pharmaceutical Co., Ltd., and Cibele Pinto and Sasikiran Nunna of Otsuka Pharmaceutical Development and Commercialization, Inc., for their support. They also thank Yujiro Funakoshi, Yoshimitsu Takamatsu, and Takumi Tajima of JMDC Inc. for data analysis. Microsoft Copilot was used to assist with English language editing, and the authors reviewed the output and take full responsibility for the content.
Funding
- Commercial Support – Otsuka Pharmaceutical Co., Ltd.