The mediating effect of pain and fatigue on level of functioning in older adults

Background: Medical conditions and symptoms have been shown to predict level of functioning in older adults, but medical conditions and symptoms have rarely been investigated together in a comprehensive model that included both medical conditions and symptoms as predictors of functioning in older adults. Objective: The purpose of this study was to determine whether the adverse effect of medical conditions on different aspects of functioning in older adults is mediated by the level of symptoms (pain and fatigue). If so, level of functioning may improve if pain or fatigue can be mitigated, even when underlying medical conditions cannot be cured. Method: Data from 225 adults aged 65-90 were used to test whether medical conditions, symptoms (pain and fatigue), and six covariates predicted lower body performance, self-reported physical functioning, and self-reported role and social functioning. The fit of a series of models to the data was analyzed using structural equation modeling. Results: Medical conditions affected self-reported physical functioning and self-reported role and social functioning by increasing the level of symptoms, rather than by direct association. Further descriptive studies are needed to identify other symptoms and modifiable mechanisms by which medical conditions affect functioning. Researchers who investigate the causes of poor functioning in older adults are encouraged to include symptoms in models that hypothesize medical conditions as predictors of functioning outcomes.