Change in physical performance over time in older women: the Women's Health and Aging Study

Although lower and upper extremity performance measures are widely used and represent validated physical function measures in older adults, there is limited information regarding the magnitude of changes in these measures over time. This study (i) assesses prospective changes in physical performance measures, (ii) defines a summary score that demonstrates a significant amount of change over time, and (iii) examines rates of decline according to age and baseline performance levels.

Data from the Women's Health and Aging Study (WHAS) were analyzed to assess change in the one third most disabled older women living in the community. Lower extremity function was assessed using walking speed, balance, and chair stands tests. The putting-on-blouse test, the lock and key test, the Purdue Pegboard test, and grip strength were used to gauge upper extremity function. Continuous and categorical summary performance scores were calculated using continuous and categorical data of lower and upper performance measures.

After 3 years, lower extremity performance measures declined by 16%-27%, while upper extremity performance measures declined less (7%-24%). For lower extremity function, the continuous summary performance score showed a slightly greater 3-year decline from baseline (decline vs baseline mean: 23%; decline vs SD of the baseline mean: 59%) than the categorical score (22% and 41%, respectively). Older age and intermediate level of baseline performance were associated with the greatest decline, especially for lower extremity function.

In moderately to severely disabled women aged 65 or older, lower extremity measures show more change over 3 years than upper extremity measures. Among the lower extremity summary scores, the continuous score changes more over time than the categorical score with respect to the baseline SD. The lower extremity continuous summary performance score may be a useful outcome measure for clinical studies of physical performance in older women.