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 m(2). 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 (beta=-3.61, 95% CI: -4.42 to 2.79), cardiac disease (beta=-1.90, 95% CI: -2.93 to 0.86), who had a stroke (beta=-3.75, 95% CI: -6.35 to 1.15), kidney disease (beta=-3.88, 95% CI: -5.62 to 2.13), slow gait speed (beta=-2.23, 95% CI: -3.27 to 1.20), and living in the South (beta=-4.38, 95% CI: -5.95 to 2.80) and South Central (beta=-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.