Trends in the Incidence of Renal Replacement Therapy Due to Rapidly Progressive Glomerulonephritis in Japan, 2006-2021.

Objective Patients with rapidly progressive glomerulonephritis (RPGN) are at a high risk of progression to end-stage kidney disease (ESKD), requiring renal replacement therapy (RRT). The present study examined recent trends in the incidence of RRT due to RPGN in Japan. Methods The number of patients with incident RRT due to RPGN by sex from 2006 to 2021 was extracted from the Japanese Society of Dialysis Therapy Registry. The incidence rates of RRT were calculated for four-year periods with the census population as the denominator. Standardized incidence ratios (SIRs) and age-specific incidence rates were also calculated. Results From 2006 to 2021, the crude number of patients with incident RRT due to RPGN increased by 34% and 58% in men and women, respectively. The SIRs decreased significantly in 2010-2013 relative to the first period (2006-2009) for both men [0.90 (95% confidence interval (CI) 0.85-0.96)] and women [0.92 (0.86-0.99)] but then increased to 1.01 (0.96-1.07) for men and 1.20 (1.13-1.27) for women in 2018-2021. In the older age groups (≥70 years old), age-specific incidence rates initially decreased in 2010-2013 but increased thereafter, peaking in 2018-2021. Conclusion From 2006 to 2021, the number of patients with incident RRT due to RPGN increased, with an increase in the age-specific incidence of RRT due to RPGN in the older age groups (≥70 years old), suggesting that the number of patients with incident RRT due to RPGN will continue to increase as the population ages in Japan.