イタノ　セイジ   Seiji Itano   板野　精之    所属   川崎医科大学  医学部 臨床医学　腎臓・高血圧内科学    職種   講師
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	Proteinuria reduction as a surrogate endpoint for clinical study of IgA nephropathy in Japanese patients: data from the J-CKD-DB-Ex
掲載誌名	正式名：Clinical and Experimental Nephrology 略　 称：Clin Exp Nephrol ISSNコード：13421751/14377799
掲載区分	国外
出版社	Springer Japan KK
巻・号・頁	30(2),pp.309-319
著者・共著者	Naoki Kashihara , Seiji Itano , Takaya Nakashima , Tadahiro Goto , Keisuke Yoshihara , Shunsuke Eguchi , Kazuma Iekushi , Yoshitaka Isaka , Hajime Nagasu ; J-CKD-DB collaborators
担当区分	筆頭著者,責任著者
発行年月	2025/11/18
概要	Background: Early reduction in proteinuria has been validated as a surrogate endpoint for IgA nephropathy (IgAN) in Western trials and is used for accelerated drug approval. However, its applicability to Japanese patients remains unclear. We aimed to evaluate the association between early proteinuria reduction and long-term renal outcomes in Japanese patients with IgAN. Methods: This retrospective observational study used data from J-CKD-DB-Ex, a real-world database of CKD in Japan. Adult participants with IgAN, baseline urine protein/creatinine ratio (UPCR) ≥ 0.5 g/gCr, and eGFR ≥ 30 mL/min/1.73 m2 were included. The exposure was a ≥ 30% UPCR reduction at 9-12 months after the index date (UPCR reduction group), vs participants without such reduction (non-UPCR reduction group). The primary endpoint was a composite of 40% decline in eGFR from baseline or onset of CKD stage G5. Cox proportional hazards and linear mixed-effects models evaluated the association between UPCR reduction, renal events, and eGFR slope. Results: Among 385 participants (mean observation period 2,040 days), 245 achieved ≥ 30% reductions in UPCR. The UPCR reduction group showed significantly lower cumulative incidence of renal composite events than the non-UPCR reduction group. Annual eGFR decline was slower in the UPCR reduction group than that in the non-UPCR group (-1.9 vs -3.4 mL/min/1.73 m2/year). Greater UPCR reductions were linearly associated with more favorable eGFR slope. Conclusions: Early proteinuria reduction is associated with decreased risk of renal failure and attenuated eGFR decline in Japanese patients with IgAN, supporting its validity as a surrogate endpoint for renal prognosis. Keywords: Chronic kidney disease; IgA nephropathy; Surrogate endpoint.
DOI	10.1007/s10157-025-02788-4
PMID	41251922