Depressive symptoms and the cost of health services in HMO patients aged 65 years and older - A 4-year prospective study

Objective.-To examine whether depressive symptoms in older adults contribute to increased cost of general medical services. Design.-A 4-year prospective cohort study. Setting.-Four primary care clinics of a large staff-model health maintenance organization (HMO) in Seattle, Wash. Patients.-A total of 5012 Medicare enrollees older than 65 years were invited to participate in the study; 2558 subjects (51%) were successfully enrolled. Nonparticipants were somewhat older and had a higher level of chronic medical illness. Main Outcome Measures.-Depressive symptoms as measured by the Center for Epidemiological Studies Depression scale, which was administered as part of a mail survey at baseline, at 2 years, and at 4 years; and total cost of medical services from the perspective of the HMO. Data were obtained from the cost accounting system of the HMO. Results.-In this cohort of older adults, depressive symptoms were common, persistent, and associated with a significant increase in the cost of general medical services. This increase was seen for every component of health care costs and was not accounted for by an increase in specialty mental health care. The increase in health care costs remained significant after adjusting for differences in age, sex, and chronic medical illness. Conclusions.-Depressive symptoms in older adults are associated with a significant increase in the cost of medical services, even after adjusting for the severity of chronic medical illness.