Trajectories of mobility and IADL function in older patients diagnosed with major depression

Research has shown an association between depression and functional limitations in older adults. Our aim was to explore the latent traits of trajectories of limitations in mobility and instrumental activities of daily living (IADL) tasks in a sample of older adults diagnosed with major depression.

Participants were 248 patients enrolled in a naturalistic depression treatment study. Mobility/IADL tasks included walking one-fourth mile, going up/down stairs, getting around the neighborhood, shopping, handling money, taking care of children, cleaning house, preparing meals and doing yardwork/gardening. Latent class trajectory analysis was used to identify classes of mobility/IADL function over a 4-year period. Class membership was then used to predict functional status over time.

Using time as the only predictor, three latent class trajectories were identified: (1) Patients with few mobility/IADL limitations (42%), (2) Patients with considerable mobility/IADL limitations (37%) and (3) Patients with basically no limitations (21%). The classes differed primarily in their initial functional status, with some immediate improvement followed by no further change for patients in Classes 1 and 2 and a stable course for patients in Class 3. In a repeated measures mixed model controlling for potential confounders, class was a significant predictor of functional status. The effect of baseline depression score, cognitive status, self-perceived health and sex on mobility/IADL score differed by class.

These findings show systematic variability in functional status over time among older patients with major depression, indicating that a single trajectory may not reflect the pattern for all patients.