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.