An increasing trend of overweight and obesity in the Japanese incident end-stage kidney disease population.

Aim: The global prevalence of overweight/obesity has been rising, and this trend is apparent in US and European incident end-stage kidney disease (ESKD) populations. We aimed to examine temporal trends in the prevalence of overweight/obesity and underweight among adult incident ESKD patients in Japan by year of dialysis initiation between 2006 and 2019 in comparison with those observed in the Japanese adult population during the same period.

Methods: Using data from the Japanese Society of Dialysis Therapy Renal Data Registry and the National Health and Nutrition Survey, the sex-specific prevalence of overweight/obesity and that of underweight (BMI ≥ 25 kg/m² and <18.5 kg/m², respectively) were calculated, adjusted for age according to the 2019 Population Census via the direct method. Average annual percentage changes (AAPCs) and corresponding 95% confidence intervals (CIs) were calculated to examine trends.

Results: From 2006 to 2019, the age-adjusted prevalence of overweight/obesity in the incident ESKD population increased for males (AAPC 3.36 [95% CI, 2.70 to 4.09]) and females (AAPC 2.86 [95% CI, 1.65 to 4.19]). The age-adjusted prevalence of overweight/obesity in the general population increased for males (AAPC 0.87 [95% CI, 0.26 to 1.42]) but not for females (AAPC 0.01 [95% CI, -0.55 to 0.57]). The age-adjusted prevalence of underweight in the incident ESKD population significantly decreased but was higher than that in the general population for both sexes.

Conclusion: An increasing trend of overweight/obesity was observed in the incident ESKD population in Japan. There is a pressing need to address both underweight and overweight/obesity in the incident ESKD population.