One-year mortality of elderly inpatients with delirium, dementia, or depression seen by a consultation-liaison service.

BACKGROUND: Delirium, dementia and depression are the most prevalent mental disorders in elderly patients, and are associated with higher mortality.
OBJECTIVE: The purpose of this study was to assess 1-year mortality among elderly patients with delirium, dementia, or depression seen by a psychiatry consultation-liaison service in a general hospital.
METHODS: We consecutively enrolled inpatients 65 years of age and older who were referred for psychiatric consultation (n = 614) from 2002 to 2006: 172 were diagnosed with delirium, 92 with dementia, and 165 with depression. The 1-year mortality rates for the three groups of patients were compared by log-rank test. Logistic regression analysis was used to identify any possible factors associated with mortality.
RESULTS: One-year mortality was significantly higher in the delirium group than in the depression group (p = 0.048), but not significantly different between the delirium and dementia groups (p = 0.206), or dementia and depression groups (p = 0.676). Male patients had a higher mortality rate than female patients in the depression group (p = 0.003), but there was no gender difference in the delirium and dementia groups. Furthermore, the 1-year mortality of all patients was significantly associated with older age (p < 0.001) and length of hospital stay (p < 0.001), but not with gender difference and multiple physical comorbidities.
CONCLUSION: These results suggest that elderly inpatients with delirium seen by a psychiatric consultation service have significantly higher mortality than elderly inpatients with depression, and that mortality is significantly associated with older age and length of hospital stay.