Background: Restricted activity is common among community-living older persons, but its prognostic significance is not known. We performed a prospective cohort study to evaluate the association between the occurrence of restricted activity and functional decline over an 18-month period.
Methods: We studied 680 community-living persons, 70 years or older, who were categorized into 3 groups according to their risk for disability (low, intermediate, or high) in activities of daily living (ADL). Participants were subsequently followed up with monthly telephone interviews to ascertain the occurrence of restricted activity, defined as having stayed in bed for at least half a day and/or having cut down on their usual activities due to an illness, injury, or other problem in the past month. Functional decline was defined as an increase in ADL disability scores between the baseline and 18-month follow-up assessments, which were completed in the home.
Results: After adjusting for the baseline risk of disability and other covariates, the disability score at 18 months increased (ie, worsened) by 11.2% (95% confidence interval [CI], 7.0%-15.6%) for each additional month with restricted activity. The association between restricted activity and functional decline differed significantly by risk group (P<.001). For the low- and intermediate-risk groups, the adjusted disability scores increased by 18.7% (95% CI, 10.3%-27.8%) and 7.5% (95% CI, 2.7%-12.5%), respectively, for each additional month with restricted activity. There was no association between restricted activity and functional decline in the high-risk group, as evidenced by a nonsignificant increase in the adjusted disability score of 2.7% (95% CI, -6.6% to 12.9%).
Conclusion: For older persons who are not otherwise at high risk for ADL disability, restricted activity is an important predictor of functional decline and not just a benign feature of old age.