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During the congress, E-Posters will be accessible to all participants on the congress website 24/7, as well as in the E-poster stations in the congress center.
Preparing your E-Poster
Please review the E-Poster format requirements carefully when preparing your E-Poster. Should your E-Poster not meet the mentioned requirements, it may not be displayed as described above.
E-Poster Submission Deadline
Please prepare and upload your E-Poster no later than March 14, 2026 11.59PM CET. After this date, you will no longer be able to prepare and upload your E-poster and it will not be displayed and accessible on the congress website.
Please follow the instructions below to input your abstract title.
Abstract titles should be brief and reflect the content of the abstract.
Nephrotic syndrome (NS) is an important clinical condition associated with a substantial risk of progression to end-stage kidney disease and serious complications such as thromboembolism and severe infections. While kidney biopsy is the gold standard for diagnosis and risk stratification, its invasive nature limits its use. Current non-invasive biomarkers are often limited by cost and accessibility, highlighting the need for a simple and widely available prognostic tool. The fractional excretion of potassium (FEK), which reflects net tubular potassium handling, is an inexpensive parameter. Although its utility has been shown in conditions like acute kidney injury, its prognostic value in NS is unexplored. This study aimed to investigate the association between baseline FEK and the subsequent achievement of proteinuria remission in a broad cohort of adult patients with NS.
This multicenter retrospective cohort study was conducted across nine institutions in Japan. We enrolled 401 adult patients who underwent a native kidney biopsy between January 2012 and June 2022 and were diagnosed with NS, defined as proteinuria ≥3.5 g/gCr and serum albumin ≤3.0 g/dL. The primary outcome was the first achievement of complete proteinuria remission (<0.3 g/gCr) within a 12-month follow-up period. Using receiver operating characteristic curve analysis, FEK demonstrated superior predictive performance for remission compared to other urinary potassium indices, and an optimal cutoff of 10% was identified. The association between high (≥10%) vs. low (<10%) FEK and remission was assessed using the Kaplan-Meier method and multivariable Cox proportional hazards models. The final model was adjusted for age, sex, BMI, hypertension, diabetes mellitus, eGFR, and urinary protein levels. A series of sensitivity analyses were conducted to confirm the robustness of the findings.
A total of 401 patients were included (median age, 61 years; 43% female). The distribution of FEK varied by histological diagnosis, with the lowest median FEK in minimal change disease (7.0%) and the highest in diabetic kidney disease (15.5%). The high FEK (≥10%) group had a significantly lower cumulative incidence of complete remission compared to the low FEK (<10%) group (P < 0.001, log-rank test). In a multivariable Cox regression model adjusted for key clinical variables, high FEK remained an independent predictor of a lower likelihood of complete remission (hazard ratio, 0.53; 95% confidence interval, 0.36–0.78). Further stratification into four FEK categories (0-5%, 5–10%, 10–15%, >15%) revealed a progressive, dose-dependent decline in remission rates with increasing FEK.
Elevated FEK at the time of diagnosis is an independent predictor for a lower likelihood of achieving proteinuria remission in Japanese adults with NS. FEK is a readily accessible and valuable biomarker that may aid in risk stratification and clinical management of patients with NS.
