Risks for depression onset in primary care elderly patients: potential targets for preventive interventions.

OBJECTIVE: Prevention of late-life depression, a common, disabling condition with often poor outcomes in primary care, requires identification of seniors at highest risk of incident episodes. The authors examined a broad range of clinical, functional, and psychosocial predictors of incident depressive episodes in a well-characterized cohort of older primary care patients.
METHOD: In this observational cohort study, patients age >/=65 years without current major depression, recruited from practices in general internal medicine, geriatrics, and family medicine, received annual follow-up assessments over a period of 1 to 4 years. Of 617 enrolled subjects, 405 completed the 1-year follow-up evaluation. The Structured Clinical Interview for DSM-IV (SCID) determined incident major depressive episodes. Each risk indicator's predictive utility was examined by calculating the risk exposure rate, incident risk ratio, and population attributable fraction, leading to determination of the number needed to treat in order to prevent incident depression.
RESULTS: A combination of risks, including minor or subsyndromal depression, impaired functional status, and history of major or minor depression, identified a group in which fully effective treatment of five individuals would prevent one new case of incident depression.
CONCLUSIONS: Indicators routinely assessed in primary care identified a group at very high risk for onset of major depressive episodes. Such markers may inform current clinical care by fostering the early detection and intervention critical to improving patient outcomes and may serve as the basis for future studies refining the recommendations for screening and determining the effectiveness of preventive interventions.