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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.
The COVID-19 pandemic has substantially affected clinical practice, including the indications for performing renal biopsies. The Japan Renal Biopsy Registry (JRBR) is a nationwide, web-based registry study, that was transitioned to a revised system in 2018. This study aimed to summarize the epidemiology of kidney diseases diagnosed by renal biopsy in Japan, and to elucidate its changes before and after the COVID-19 pandemic.
We analyzed the J-RBR database spanning from January 2018 to December 2024. Clinical data collected at the time of biopsy, along with histopathological diagnoses, were utilized for epidemiological and clinicopathological analyses. Participants were divided into pediatric (<19 years) and adult (≥19 years) groups. Furthermore, the adult group was subdivided into younger adults (19–64 years) and older adults (≥65 years) for analysis. The period up to the declaration of the state of emergency in Japan in 2020 was defined as the pre-COVID-19, whereas the period from 2021 onward was defined as the post-COVID-19. For the analysis of the trend in disease prevalence over the study period, we used the Cochran–Armitage test and logistic regression analysis. A chi-squared test was used to compare the age distribution of patients diagnosed with immunoglobulin A (IgA) vasculitis before and after the COVID-19 pandemic.
The number of renal biopsies, excluding those of transplanted kidneys, was 27,550, with the highest number observed in patients in their 70s (5,882 cases, 21.6%). The predominant renal biopsy diagnoses were IgA nephropathy (37.8%), minimal change disease (6.9%), and lupus nephritis (5.7%), in younger adults (19–64 years), and antineutrophil cytoplasmic antibody-associated vasculitis or anti-glomerular basement membrane glomerulonephritis (15.0%), membranous nephropathy (13.7%), and IgA nephropathy (13.6%) in older adults (aged ≥65 years). In pediatric patients (aged <19 years), the predominant renal biopsy diagnoses were IgA nephropathy (36.1%), minimal change disease (17.4%), and IgA vasculitis (8.4%). Trends in renal biopsy diagnoses are summarized in Table 1. The overall number of biopsies remained relatively stable over the study period. Notably, the incidence of focal segmental glomerulosclerosis exhibited an increasing trend, whereas diagnoses of minimal change disease and IgA vasculitis showed a decreasing trend. Figure 1 demonstrates that, compared to the pre-COVID-19 period, the number of patients diagnosed with IgA vasculitis markedly decreased after the onset of the pandemic, particularly among children under 10 years of age.
This study describes the distribution and changes in kidney biopsy diagnoses in Japan over a 7-year period, including the three years before and after the COVID-19 pandemic. Throughout the entire study period, the diagnostic rate of minimal change disease demonstrated a consistent decline. In contrast, IgA vasculitis showed a marked reduction commencing from 2021, corresponding to the post-COVID-19. These trends in diagnostic numbers indicated that, in addition to long-term demographic shifts, short-term variations driven by substantial changes in societal behaviors during the COVID-19 pandemic should also be taken into account.
