Diagnostic validity and added value of the geriatric depression scale for depression in primary care: A meta-analysis of GDS30 and GDS15

Background: The Geriatric Depression Scale (GDS) has been evaluated in hospital settings but its validity and added value in primary care is uncertain. We therefore conducted a meta-analysis analysing the diagnostic accuracy, clinical utility and added value of the GDS in primary care. Methods: A comprehensive search identified 69 studies that measured the diagnostic validity of the GDS against a semi-structured psychiatric interview and of these 17 analyses (in 14 publications) took place in primary care. Seven studies examined the GDS(30) and 10 studies examined the GDS(15). Heterogeneity was moderate to high, therefore random effects meta-analysis was used. Results: Diagnostic accuracy of the GDS(30) after meta-analytic weighting was given by a sensitivity of 77.4% (95% CI= 66.3% to 86.8%) and a specificity= 65.4% (95% CI = 44.2% to 83.8%). For the GDS(15) the sensitivity was 81.3% (95% CI = 77.2% to 85.2%) and specificity =78.4% (95% CI = 71.2% to 84.8%). The fraction correctly identified (also known as efficiency) by the GDS(15) was significantly higher than the GDS(30) (77.6% vs 71.2%, Chi(2)= 24.8 P<0.0001). The clinical utility of both the GDS(30) and GDS(15) was "poor" for case-finding (UI+ 0.29, UI+ 0.32 respectively). However the GDS(15) was rated as "good" for screening (UI - 0.75) whereas the GDS(30) was "adequate" (UI - 0.60). Concerning added value, when identification using the GDS was compared with general practitioners' ability to diagnose late-life depressions unassisted by tools, at a prevalence of 15% the GDS(30) had no added benefit whereas the GDS(15) helped identify an additional 4 cases per 100 primary care attendees and also helped rule-out an additional 4 non-cases per 100 attendees. Thus we estimate the potential gain of the GDS(15) in primary care to be 8% over unassisted clinical detection but at a cost of 3-4 minutes of extra time per appointment. Conclusion: The GDS yields potential added value in primary care. We recommend the GDS(15) but not the GDS(30) in the diagnosis of late-life depression in primary care. (C) 2009 Elsevier B.V. All rights reserved.