Secular trends in end-stage kidney disease requiring renal replacement therapy in Japan: Japanese Society of Dialysis Therapy Registry data from 1983 to 2016

Aim: We aimed to describe secular trends in the incidence of end-stage kidney disease (ESKD) requiring renal replacement therapy (RRT) in Japan, and to assess the effect of population aging on the incidence of ESKD.

Methods: The national incidence of ESKD requiring RRT was calculated using published data and Japan's population statistics. Age-standardized incidence was calculated by direct standardization using the World Standard Population. The average annual percentage of change (APC) in rates and corresponding 95% confidence interval (CI) were computed for trends by joinpoint regression analysis. To assess the effect of population aging on the incidence of ESKD requiring RRT, we used the method proposed by Bashir and Estève, which splits the crude incidence into three components: population structure, population size, and age-independent risk.

Results: Age-standardized incidence trends (1983-1996) increased significantly in both men (APC 6.33, 95% CI: 5.39-7.29) and women (APC 5.25, 95% CI: 4.26-6.24). With a significant inflection point in 1996, the trend was stable for men (APC -0.16, 95% CI: -0.48 to 0.17) but significantly decreased for women (APC -1.98, 95% CI: -2.38 to -1.59) from 1996 to 2016. The main reason for the increase in those with ESKD requiring RRT has changed; before 1996, the change in age-independent risk was the main contributor, but after 1996, the change in age structure with a higher proportion of older individuals was the main contributor.

Conclusion: The increase in number of ESKD patients requiring RRT dramatically changed in Japan during the 1983 to 2016 period.