Lower-extremity function in persons over the age of 70 years as a predictor of subsequent disability

Abstract

Background: Functional assessment is an important part of the evaluation of elderly persons. We conducted this study to determine whether objective measures of physical function can predict subsequent disability in older persons.

Methods: This prospective cohort study included men and women 71 years of age or older who were living in the community, who reported no disability in the activities of daily living, and who reported that they were able to walk one-half mile (0.8 km) and climb stairs without assistance. The subjects completed a short battery of physical-performance tests and participated in a follow-up interview four years later. The tests included an assessment of standing balance, a timed 8-ft (2.4-m) walk at a normal pace, and a timed test of five repetitions of rising from a chair and sitting down.

Results: Among the 1122 subjects who were not disabled at base line and who participated in the four-year follow-up, lower scores on the base-line performance tests were associated with a statistically significant, graduated increase in the frequency of disability in the activities of daily living and mobility-related disability at follow-up. After adjustment for age, sex, and the presence of chronic disease, those with the lowest scores on the performance tests were 4.2 to 4.9 times as likely to have disability at four years as those with the highest performance scores, and those with intermediate performance scores were 1.6 to 1.8 times as likely to have disability.

Conclusions: Among nondisabled older persons living in the community, objective measures of lower-extremity function were highly predictive of subsequent disability. Measures of physical performance may identify older persons with a preclinical stage of disability who may benefit from interventions to prevent the development of frank disability.

Figure 1.

Disability Status at Four Years According to the Base-Line Summary Performance Scores among 1121 Subjects with No Disability at Base Line. Higher scores indicate better performance on the tests and thus better functional status. One person with a score of 3 has been excluded. P<0.001 for the association between performance scores and disability status, by the chi-square test. ADL denotes activities of daily living.

Figure 2.

Disability Status at Four Years According to the Base-Line Summary Performance Score among 359 Subjects with Mobility-Related Disability at Base Line. ADL denotes activities of daily living.