Effect of New Disability Subtype on 3-Year Mortality in Chinese Older Adults

OBJECTIVES To examine a new method of classifying disability subtypes by combining self-reported and performance-based tools to predict mortality in older Chinese adults. DESIGN Prospective cohort study. SETTING Community-dwelling older adults. PARTICIPANTS Sixteen thousand twenty Chinese adults aged 65 and older from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). MEASUREMENTS Self-reported activities of daily living (ADLs) and physical performance (PP) tests (chair standing, lifting a book from floor, turning 360 degrees) cross-classified to create mutually exclusive disability subtypes: subtype 0 (no limitations in PP or ADLs), subtype 1 (limitations in PP, no limitations in ADLs), subtype 2 (no limitations in PP, limitations in ADLs), and subtype 3 (limitations in PP and ADLs). Outcome was mortality over 3 years. RESULTS Cox proportional hazard models, controlling for sociodemographic variables, living situation, healthcare access, social support, health status, and life-style, showed that older adults without any limitations in ADLs or PP had significantly lower mortality risk than those with other disability subtypes and that there was a graded pattern of greater mortality according to subtype 1 (hazard ratio (HR)=1.31, 95% confidence interval (CI)=1.20-1.42), 2 (HR=1.39, 95% CI=1.23-1.59), and 3 (HR=1.88, 95% CI=1.72-2.05). When compared with the average survival curve in the cohort, subtypes of isolated performance deficits or self-reported disability did not substantially discriminate risks of death over 3 years. CONCLUSION Combined use of self-reported and PP tools is necessary when screening for mutually exclusive disability subtypes that confer significantly higher or lower mortality risks on a population of older adults.