Depression as prognostic factor: 6 months follow-up in a geriatric institution.

Depression in the elderly and especially in the demented elderly is common, but it is unclear to what extent depression affects the prognosis of dementia. We performed a 6 months follow-up on the elderly to evaluate the effect of depression on the prognosis of dementia. Among the residents in a Korean geriatric institution, a total of 141 elderly residents were included in this study. Those residents who had geriatric depression scale (GDS) scores over 20 were considered as having depression. The subjects were assessed at baseline and at 6 months later with the Korean Mini-Mental State Examination (K-MMSE), Clinical Dementia Rating (CDR) and Barthel index (BI). For all the 141 subjects, the changes of the K-MMSE, CDR and BI scores were first compared between the depressed and non-depressed groups. Then, for the 58 depressed subjects subdivided into three groups (36 subjects in the non-demented group, 14 subjects in the Alzheimer disease (AD) group and 8 subjects in the vascular dementia (VaD) group), the changes of the scores among the three groups were compared. For all subjects, the changes of the K-MMSE and CDR scores were more severe in the depressed group than in the non-depressed group. For the 58 depressed subjects, the changes were significantly different among the three groups (p=0.02 for the K-MMSE, p<0.001 for the CDR), and the changes were the most severe in the VaD group. For the elderly, depression has a significant influence on the cognitive deterioration. Moreover, the effect of depression on the cognitive dysfunction and on the prognosis of dementia is more severe in the demented elderly, and especially for the VaD patients.