Evidence map›Paper›PMID 41251922›Full record

Observational studyClinical and experimental nephrology2026

Proteinuria reduction as a surrogate endpoint for clinical study of IgA nephropathy in Japanese patients: data from the J-CKD-DB-Ex.

Naoki Kashihara, Seiji Itano, Takaya Nakashima, Tadahiro Goto, Keisuke Yoshihara, Shunsuke Eguchi, Kazuma Iekushi, Yoshitaka Isaka, Hajime Nagasu, J-CKD-DB collaborators

Abstract readObservational Study
PubMed Full text at PMC Publisher
In one paragraph

Observational study in Clinical and experimental nephrology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors.

Naoki Kashihara *Geriatric Medical Center, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan.
Seiji Itano *Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan. s.itano@med.kawasaki-m.ac.jp.ORCID http://orcid.org/0000-0002-9452-4117
Takaya Nakashima *Department of Anesthesiology and Intensive Care Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Tadahiro GotoDepartment of Health Data Science, Graduate School of Data Science, Yokohama City University, Kanagawa, Japan.
Keisuke YoshiharaMedical Affairs, Novartis Pharma K.K., Tokyo, Japan.
Shunsuke EguchiMedical Affairs, Novartis Pharma K.K., Tokyo, Japan.
Kazuma IekushiMedical Affairs, Novartis Pharma K.K., Tokyo, Japan.
Yoshitaka IsakaDepartment of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan.
Hajime NagasuDepartment of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan.
J-CKD-DB collaborators

Funding

Japan Agency for Medical Research and Development JP25ek0109812Ministry of Health, Labour and Welfare JPMH23FC1048Ministry of Health, Labour and Welfare JPMH24FD1001Wellcome Trust FC001048
6 · The paper itself

Abstract

backgroundEarly 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.

methodsThis 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 m

resultsAmong 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 m

conclusionsEarly 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.

Indexed as

Glomerulonephritis, IGAKidneyProteinuriaAdultBiomarkersCreatinineDatabases, FactualEast Asian PeopleEndpoint DeterminationFemaleGlomerular Filtration RateHumansJapanMaleMiddle AgedRetrospective StudiesBiomarkersCreatinineChronic kidney diseaseIgA nephropathySurrogate endpoint

Identifiers

PMID41251922
PMCPMC12886275

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.