Screening and case finding instruments for depression.

BACKGROUND: Screening or case finding instruments have been advocated as a simple, quick and inexpensive method to improve detection and management of depression in non-specialist settings, such as primary care and the general hospital. However, screening/case finding is just one of a number of strategies that have been advocated to improve the quality of care for depression. The adoption of this seemingly simple and effective strategy should be underpinned by evidence of clinical and cost effectiveness.
OBJECTIVES: To determine the clinical and cost effectiveness of screening and case finding instruments in: (1) improving the recognition of depression; (2) improving the management of depression, and (3) improving the outcome of depression. SEARCH STRATEGY: The researchers undertook electronic searches of The Cochrane Library (Issue 4, 2004); The Cochrane Depression, Anxiety and Neurosis Group's Register [2004); EMBASE (1980-2004); MEDLINE (1966-2004); CINAHL (to 2004) and PsycLIT (1974-2004). References of all identified studies were searched for further trials, and the researchers contacted authors of trials. SELECTION CRITERIA: Randomised controlled trials of the administration of case finding/screening instruments for depression and the feedback of the results of these instruments to clinicians, compared with no clinician feedback. Trials had to be conducted in non-mental health settings, such as primary care or the general hospital. Studies that used screening strategies in addition to enhanced care, such as case management and structured follow up, were specifically excluded. DATA COLLECTION AND ANALYSIS: Citations and, where possible, abstracts were independently inspected by researchers, papers ordered, re-inspected and quality assessed. Data were also independently extracted. Data relating to: (1) the recognition of depression; (2) the management of depression and (3) the outcome of depression over time were sought. For dichotomous data the Relative Risk (RR), 95% confidence interval (CI) were calculated on an intention-to-treat basis. For continuous data, weighted and standardised mean difference were calculated. A series of a priori sensitivity analyses relating to the method of administration of questionnaires and population under study were used to examine plausible causes of heterogeneity. MAIN
RESULTS: Twelve studies (including 5693 patients) met our inclusion criteria. Synthesis of these data gave the following results:(1) the recognition of depression: according to case note entries of depression, screening/case finding instruments had borderline impact on the overall recognition of depression by clinicians (relative risk 1.38; 95% confidence interval 1.04 to 1.83). However, substantial heterogeneity was found for this outcome. Screening and feedback, irrespective of baseline score of depression has no impact on the detection of depression (relative risk 1.00; 95% confidence interval 0.89 to 1.13). In contrast, three small positive studies using a two stage selective procedure, whereby patients were screened and only patients scoring above a certain threshold were entered into the trial, did suggest that this approach might be effective (relative risk 2.66; 95% confidence interval 1.78 to 3.96). Separate pooling according to this variable reduced the overall level of heterogeneity. Publication bias was also found for this outcome.(2) the management of depression: according to case note entries for active interventions and prescription data, a selected subsample of all studies reported this outcome and found that there was there was an overall trend to showing a borderline higher intervention rate amongst those who received feedback of screening/case finding instruments (relative risk 1.35; 95% confidence interval 0.98 to 1.85), although substantial heterogeneity between studies existed for this outcome. This result was dependant upon the presence of one highly positive study.(3) the outcome of depression: few studies reported the impact of case finding/screening instruments on the actual outcome of depression, and no statistical pooling was possible. However, three out of four studies reported no clinical effect (p<0.05) at either six months or twelve months. No studies examined the cost effectiveness of screening/case finding as a strategy. AUTHORS'
CONCLUSIONS: There is substantial evidence that routinely administered case finding/screening questionnaires for depression have minimal impact on the detection, management or outcome of depression by clinicians. Practice guidelines and recommendations to adopt this strategy, in isolation, in order to improve the quality of healthcare should be resisted. The longer term benefits and costs of routine screening/case finding for depression have not been evaluated. A two stage procedure for screening/case finding may be effective, but this needs to be evaluated in a large scale cluster randomised trial, with a prospective economic evaluation.