Depressive symptoms and 3-year mortality in older hospitalized medical patients

Background: Depressive symptoms are common in hospitalized older persons. H owever, their relation to longterm mortality is unclear because few studies have rigorously considered potential confounders of the relation between d epression and mortality, such as comorbid illness, functional impairment, a nd cognitive impairment. Objective: To measure the association between depressive symptoms and long- term mortality in hospitalized older persons. Design: Prospective cohort study. Setting: General medical service of a teaching hospital. Patients: 573 patients 70 years of age or older. Measurements: Depressive symptoms (Geriatric Depression Scale score), sever ity of acute illness (Acute Physiology and Chronic Health Evaluation II sco re), burden of comorbid illness (Charlson comorbidity index score), physica l function (a nurse assessed dependence in six activities of daily living), and cognitive function (modified Mini-Mental State Examination) were measu red at hospital admission. Mortality over the 3 years after admission was d etermined from the National Death Index. Mortality rates among patients wit h six or more depressive symptoms were compared with those among patients w ith five or fewer symptoms. Results: The mean age of the patients was 80 years; 68% of patients were wo men. Patients with six or more depressive symptoms had greater comorbid ill ness, functional impairment, and cognitive impairment at admission than pat ients with fewer depressive symptoms. Three-year mortality was higher in pa tients with six or more depressive symptoms (56% compared with 40%; hazard ratio, 1.56 [95% CI, 1.22 to 2.00]; P < 0.001). After adjustment for age, a cute illness severity, comorbid illness, functional impairment, and cogniti ve impairment at the time of admission, patients with six or more depressiv e symptoms continued to have a higher mortality rate during the 3 years aft er admission (hazard ratio, 1.34 [CI, 1.03 to 1.73]). Although depressive s ymptoms contributed less to the mortality rate than did the total burden of comorbid medical illnesses, the excess mortality rate associated with depr essive symptoms was greater than that conferred by one additional comorbid medical condition. Conclusions: Depressive symptoms are associated with long-term mortality in older patients hospitalized with medical illnesses. This association is no t fully explained by greater levels of comorbid illness, functional impairm ent, and cognitive impairment in patients with more depressive symptoms.