Trends in the incidence of renal replacement therapy by type of primary kidney disease in Japan, 2006-2020.

Aim: Age-standardized incidence of end stage kidney disease requiring renal replacement therapy (RRT) has stabilized in men and declined in women in Japan since 1996. However, recent trends by primary kidney disease are unknown. The present study aimed to examine recent trends in incidence rates of RRT by primary kidney disease in Japan.

Methods: Numbers of incident RRT patients aged ≥20 years by sex and primary kidney disease from 2006 to 2020 were extracted from the Japanese Society of Dialysis Therapy registry. Using the census population as the denominator, annual incidence rates of RRT were calculated and standardized to the WHO World Standard Population (2000-2025). Average annual percentage change (AAPC) and corresponding 95% confidence intervals (CIs) were calculated for trends using Joinpoint regression analysis.

Results: From 2006 to 2020, the crude number of incident RRT patients due to nephrosclerosis increased by 132% for men and 62% for women. Age-standardized incidence rates of RRT due to nephrosclerosis increased significantly, by 3.3% (95% CI: 2.9-3.7) and 1.4% (95% CI: 0.8-1.9) per year for men and women, respectively. The AAPC of chronic glomerulonephritis (-4.4% [95% CI: -5.3 to -3.8] for men and -5.1% [95% CI: -5.5 to -4.6] for women) and diabetic nephropathy (-0.6% [95% CI: -0.9 to -0.3] for men and -2.8% [95% CI: -3.1 to -2.6] for women) significantly decreased from 2006 to 2020.

Conclusion: Incident RRT due to chronic glomerulonephritis and diabetic nephropathy decreased, while the number and incident rates of RRT due to nephrosclerosis increased, from 2006 to 2020 in Japan.