Outcomes and predictors of late-life depression trajectories in older primary care patients.

OBJECTIVES: The naturalistic outcomes of depression in older primary care patients have been poorly characterized. The authors sought to identify depressive trajectories over 2 years and to examine specified outcome predictors.
DESIGN: Two-year observational cohort study.
SETTING: University-based and independent practice primary care practices in greater Rochester. PARTICIPANTS: All patients aged >65 years presenting for care on selected recruitment days were eligible to participate. Of 392 subjects enrolled, 316 (80.6%) completed study measures over a 2-year follow-up. MEASUREMENTS: Depression trajectories were derived by applying longitudinal cluster analysis to weekly depression status from the Longitudinal Interval Follow-up Evaluation.
RESULTS: The authors identified six distinct trajectory clusters that followed clinically intuitive patterns. Although subjects initially nondepressed or in the subsyndromal to minor depression range had a range of possible outcomes over 2 years, the cluster initially near the major depression level remained at that level over time. Consistent predictors of depression trajectory were baseline depressive symptom severity, medical burden, and psychiatric functional status; for some clusters, previous history of depression and perceived social support also had prognostic significance.
CONCLUSION: The "real-world" outcomes of patients with more severe depressive symptoms are strikingly poor. Given the diverse outcomes of those with subsyndromal to mild forms of minor depression, clinicians might focus treatments on those at highest risk of poor outcome, i.e., those with greater depressive symptoms and medical burden and lower psychiatric functioning and social support. Preventive interventions research might focus on developing treatments to mitigate potentially modifiable risks such as deficits in social support.