What is the real level of physical disability among elderly Chinese? A comparative study based on four national social surveys

Abstract

BackgroundAlong with the increasing availability of national surveys on elderly health, the real level of physical disability among elderly Chinese is still a myth due to the data incomparability. This study aims to add knowledge on this topic by improving data comparability across surveys.Methods Data were drawn from four national surveys, including Chinese Longitudinal Healthy Longevity Survey (CLHLS) 2014, Sample Survey of the Aged Population in Urban/Rural China (SSAPUR) 2015, China Health and Retirement Longitudinal Study (CHARLS) 2015, and China Longitudinal Aging Social Survey (CLASS) 2014. The study subjects were people aged 65 years or above living in communities. The final sample size in four surveys analyzed was between 5008 in CHARLS and 144.0 thousand in SSAPUR. Katz activities of daily living (ADL) index was used to assess physical functioning. A series of measures were taken to harmonize ADL index across surveys. The reliability and validity of index was examined with Cronbach’s alpha, confirmatory and exploratory factor analysis. A standardized physical disability prevalence was computed by applying sex and age structure in 2015 China national 1% sample survey to the crude prevalence.Results All the Katz ADL indexes in four surveys had good internal consistency with Cronbach’s alpha higher than 0.80 and good construct validity according to confirmatory and exploratory factor analysis results. After standardization, the physical disability prevalence remained significantly different across surveys, ranging from 10.21% (9.47%-10.95%) to 18.07% (17.88%-18.27%). The total number of older population with physical disability in China was between 14.68 million and 25.98 million, which was a wide range. The variation in physical disability prevalence was higher with respect to older age, rural residence, and mild disability.Conclusions Considering all the surveys have both advantages and disadvantages in assessing ADL disability, it’s difficult to conclude the best data source on this topic. We suggest that future studies on, such as elderly physical disability and long-term care need, use multiple data sources at the same time to produce robust results.