Aim: The study aimed to determine: (i) the diagnostic accuracy of four brief depression scales, the Geriatric Depression Scale (GDS), Even Briefer Assessment Scale for Depression (EBAS DEP), Single Question and Cornell Scale for Depression in Dementia (Cornell) in an elderly Chinese population with varying dementia severity; and (ii) which scale had the best diagnostic performance.
Method: All four scales were administered to 88 elderly outpatients with dementia: 66 without and 22 with depression. Receiver Operating Characteristic (ROC) analysis was used to establish the optimal cut-off scores of the GDS, EBAS DEP and Cornell scales. The patients' dementia-severity was dichotomously categorized into mild and moderate-severe dementia, and the above analysis was repeated in both these groups to look at changes in the scales' diagnostic performance as dementia advances.
Results: The best diagnostic scale for detecting depression in dementia was the Cornell scale. Its optimal cut-off score was 6/7 (sensitivity 91.7%, specificity 80.0%) in the mild dementia group and 12/13 (sensitivity 70.0%, specificity 87.0%) in the more advanced dementia group. The optimal cut-off scores of the GDS and EBAS DEP also shifted to higher values when moving from the mild to the more advanced dementia groups, indicating the increasing difficulty on all these scales to detect depression with worsening cognitive impairment. The Single Question, however, was more robust with much less changes in its diagnostic parameters in both dementia cohorts: sensitivity 58.3%, specificity 90.0% for mild dementia, and 60.0 and 84.8%, respectively, for more advanced dementia.
Conclusion: An efficient strategy to diagnose depression in dementia amongst elderly Chinese patients is to administer the Single Question followed by, when necessary, the Cornell scale.
Copyright 2004 John Wiley & Sons, Ltd.