Prevalence and Health Correlates of Reduced Kidney Function Among Community-dwelling Chinese Older Adults: the China Health and Retirement Longitudinal Study

Objectives: We aimed to understand the prevalence of reduced kidney function in China by sociodemographics and geographical region, and to examine health correlates of reduced kidney function.

Design: Cross-sectional study.

Setting And Participants: Participants were 6706 adults ≥60 years from the 2015-2016 wave of the China Health and Retirement Longitudinal Study.

Outcome Measures: Reduced kidney function was defined as an estimated glomerular filtration rate of less than 60 mL/min per 1.73 m². The estimated glomerular filtration rate was calculated with the creatinine-cystatin C equation developed by the Chronic Kidney Disease Epidemiology Collaboration in 2012. The associations between reduced kidney function and potential risk factors were analysed using multivariable regression models.

Results: The prevalence of reduced kidney function was 10.3% (95% CI: 9.3% to 11.2%), corresponding to approximately 20 million older adults. Multivariable analysis showed that older adults with hypertension (β=-3.61, 95% CI: -4.42 to 2.79), cardiac disease (β=-1.90, 95% CI: -2.93 to 0.86), who had a stroke (β=-3.75, 95% CI: -6.35 to 1.15), kidney disease (β=-3.88, 95% CI: -5.62 to 2.13), slow gait speed (β=-2.23, 95% CI: -3.27 to 1.20), and living in the South (β=-4.38, 95% CI: -5.95 to 2.80) and South Central (β=-1.85, 95% CI: -3.15 to 0.56) were more significantly likely to have reduced kidney function.

Conclusions: Kidney function screening should be performed, especially in patients with hypertension, cardiac disease and who had a stroke. More efforts should be paid to improve the kidney function of older adults living in the South and South Central parts of China.