Measuring functional status: cross-sectional and longitudinal associations between performance and self-report (Zutphen Elderly Study 1990-1993).
We investigated cross-sectional as well as longitudinal associations between performance-based measures of functional status and self-reported measures of functional status. In the Zutphen Elderly Study, 494 men, born between 1900 and 1920, were examined in 1990, of whom 303 were reexamined in 1993. A performance score was constructed on the basis of four tests: standing balance, walking speed, ability to rise from a chair, and external shoulder rotation. Self-reported functional status was based on disabilities in basic activities of daily living, mobility, and instrumental activities of daily living. A hierarchic disability scale was constructed. Cross-sectional correlation coefficients between the performance score and the disability scale were 0.22 in 1990 and 0.39 in 1993. Correlations were highest between the test for walking speed and self-reported mobility and IADL, and between the test for external shoulder rotation and self-reported disabilities in basic activities of daily living. The correlation between the 3-year changes in performance and in self-report was 0.20 (p < 0.001). Both performance and self-report at baseline predicted performance and self-report after 3 years. Performance-based measures of functional status are cross-sectionally and longitudinally associated at modest levels with self-reported disabilities. Performance measures and self-reported measures are complementary, but do not measure the same construct.
Hoeymans
N
N
Department of Chronic Diseases and Environmental Epidemiology, National Institute of Public Health and the Environment, Bilthoven, The Netherlands.
Feskens
E J
EJ
van den Bos
G A
GA
Kromhout
D
D
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004812:Epidemiologic Methods; D015577:Geriatric Assessment; D006305:Health Status Indicators; D006801:Humans; D008137:Longitudinal Studies; D008297:Male