The combined effects of baseline vulnerability and acute hospital events on the development of functional dependence among community-living older persons

Background, Many older persons who are highly vulnerable do not develop fun ctional dependence, whereas some older persons with low vulnerability do de velop functional dependence. Ne conducted this study to determine the combi ned effects of baseline vulnerability and precipitating events on the devel opment of functional dependence. Methods. We analyzed data from two prospective, population-based cohort stu dies. The development cohort included 799 community-living persons, 72 year s of age and older, who were independent in their activities of daily livin g (ADLs). The validation cohort included 1,051 comparable persons. Particip ants were classified by baseline vulnerability, defined on the basis of phy sical performance, cognitive status, and age, and by exposure to potential precipitating events, determined from information gathered from acute care hospital admissions. The primary outcome was the onset of functional depend ence, defined as a new disability in one or more of the seven ADLs at the I -year follow-up interview or admission to a skilled nursing facility prior to the I-year interview Results. Functional dependence developed in 109 (13.6%) participants in the development cohort and in 100 (9.3%) participants in the validation cohort . The rates of functional dependence for the low, intermediate, and high vu lnerability groups were 7.1%, 17.2%, and 40.1% (p < .001) in the developmen t cohort and 4.8%, 15.0%, and 28.05% (p < .001) in the validation cohort. F or the four categories (none, mild, moderate, severe) of precipitating even ts, the rates of functional dependence were 9.0%, 19.4%, 27.3%, and 53.2% ( p < .001) in the development cohort and 5.1%, 12.0%, 28.2%, and 53.3% (p < .001) in the validation cohort. For both cohorts, when baseline vulnerabili ty and precipitating events were analyzed in cross-stratified format, the r ate of functional dependence increased progressively from low-risk to high- risk groups in all directions (double-gradient phenomenon). The contributio ns of baseline vulnerability and precipitating events to the development of functional dependence were independent and statistically significant. Conclusions. Among community-living older persons, baseline vulnerability a nd precipitating hospital events contribute independently to the developmen t of functional dependence and should each be targeted for intervention whe n developing strategies aimed at forestalling the onset of functional depen dence.