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Summary of the Evidence
By Michael P. Pignone, M.D., M.P.H.; Bradley N. Gaynes, M.D., M.P.H.; Jerry L. Rushton, M.D., M.P.H.; Catherine Mills Burchell, M.A.; C. Tracy Orleans, Ph.D.; Cynthia D. Mulrow, M.D., M.Sc.; Kathleen N. Lohr, Ph.D.
Address correspondence to: Michael Pignone, M.D., M.P.H.; 5039 Old Clinic Building; UNC Hospitals; Chapel Hill, NC 27599-7110; E-mail: firstname.lastname@example.org
The summaries of the evidence briefly present evidence of effectiveness for preventive health services used in primary care clinical settings, including screening tests, counseling, and chemoprevention. They summarize the more detailed Systematic Evidence Reviews, which are used by the U.S. Preventive Services Task Force (USPSTF) to make recommendations.
Effects of Screening and Feedback Alone
Effects of Screening and Feedback with Treatment Advice
Effects of Integrated Interventions to Improve Recognition and Management of Depression
Summary of the Effect of Screening and Feedback
Purpose: To clarify whether screening adults for depression in primary care settings improves recognition, treatment, and clinical outcomes.
Data Sources: The MEDLINE® database was searched from 1994 through August 2001. Other relevant articles were located through other systematic reviews; focused searches of MEDLINE® from 1966 to 1994; the Cochrane depression, anxiety, and neurosis database; hand searches of bibliographies; and extensive peer review.
Study Selection: We reviewed randomized trials conducted in primary care settings that examined the effect of screening for depression on identification, treatment, or health outcomes, including trials that tested integrated, systematic support for treatment after identification of depression.
Data Extraction: A single reviewer abstracted the relevant data from the included articles. A second reviewer checked the accuracy of the tables against the original articles.
Data Synthesis: Compared with usual care, feedback of depression screening results to providers generally increased recognition of depressive illness in adults. Studies examining the effect of screening and feedback on treatment rates and clinical outcomes had mixed results. Many trials lacked power to detect clinically important differences in outcomes. Meta-analysis suggests that overall, screening and feedback reduced the risk for persistent depression (summary relative risk, 0.87 [95 percent confidence interval [CI], 0.79 to 0.95]). Programs that integrated interventions aimed at improving recognition and treatment of patients with depression and that incorporated quality improvements in clinic systems had stronger effects than programs of feedback alone.
Conclusions: Compared with usual care, screening for depression can improve outcomes, particularly when screening is coupled with system changes that help ensure adequate treatment and followup.
Depressive disorders are common, chronic, and costly. Prevalence rates from community-based surveys range from 1.8 percent to 3.3 percent for depression within the last month and 4.9 percent to 17.1 percent for lifetime prevalence.1,2 In primary care settings, the point prevalence of major depression ranges from 4.8 percent to 8.6 percent.3 Depressive illness is projected to be the second leading cause of disability worldwide in 2020.4 The substantial public health and economic significance of depression is reflected by its considerable effect on health care utilization and great monetary costs: $43 billion annually, of which $17 billion represents lost work days.5,6
Despite the high prevalence and substantial impact of depression, detection and treatment in the primary care setting have been suboptimal. Studies have shown that usual care by primary care physicians fails to recognize 30 percent to 50 percent of depressed patients.7 Because patients in whom depression goes unrecognized cannot be appropriately treated, systematic screening has been advocated as a means of improving detection, treatment, and outcomes of depression.
In 1996, the U.S. Preventive Services Task Force found insufficient evidence to recommend for or against routine screening for depression with standardized questionnaires.8 They recommended that clinicians "maintain an especially high index of suspicion for depressive symptoms in adolescents and young adults, persons with a family or personal history of depression, those with chronic illnesses, those who perceive or have experienced a recent loss, and those with sleep disorders, chronic pain, or multiple unexplained somatic complaints."8 They also recommended physician education in recognizing and treating depression.
To help determine whether systematic, routine screening for depression in adults is warranted, we performed an updated systematic review for the U.S. Preventive Services Task Force. Specifically, we examined three key questions:
- What is the accuracy of case-finding instruments for depression in primary care populations?
- Is treatment of depression in primary care patients effective in improving outcomes?
- Is routine systematic identification with case-finding questions (screening), with or without integrated management and followup systems, more effective than usual care in identifying patients with depression, facilitating treatment of patients with depression, and improving clinical outcomes?
The results of the comprehensive review are available from the Agency for Healthcare Research and Quality.9 In brief, we found that several short, accurate, and easy-to-use instruments for detecting depression are available (Table 1).9,10 Brief instruments, including asking the patient two questions about the presence of depressed mood and anhedonia ("Over the past two weeks, have you felt down, depressed, or hopeless?" and "Over the past two weeks, have you felt little interest or pleasure in doing things?"), appear to perform as well as longer instruments. Effective treatments, including pharmacologic and behavioral or counseling interventions, are available for depressed patients identified in primary care settings.9
We also examined the evidence on whether screening for depression in primary care settings affects recognition, treatment, and clinical outcomes of adult patients with depression. In this article, we review the evidence pertaining to this overarching question.
To identify relevant articles, we searched the MEDLINE® database from January 1994 through August 2001 by using the Medical Subject Headings depression or depressive disorders, plus keyword searches for commonly used screening instruments. These terms were then combined with Medical Subject Headings mass screening or sensitivity and specificity or primary health care or ambulatory care or family practice. We supplemented these sources by searching the Cochrane database on depression, neurosis, and anxiety disorders; performing additional specific MEDLINE® searches from 1966 to 1994; hand-searching bibliographies; and querying experts.
We reviewed randomized trials conducted in primary care settings that examined the effect of screening for depression on identification, treatment, or health outcomes, including trials that tested integrated, systematic support for treatment after identification of depression.
Two of the authors independently reviewed the titles and abstracts of the articles identified by the literature searches and excluded ones on which they agreed that eligibility criteria were not met. When the initial reviewers disagreed, the articles were carried forward to the next review stage in which the authors reviewed the full articles and made a final decision about inclusion or exclusion by consensus.
One reviewer abstracted the relevant information from each article into evidence tables. A second author checked these tables and noted discrepancies, which were then resolved by consensus. We calculated absolute differences in outcomes and 95 percent confidence intervals [CIs] by using Stata software, version 6.0 (Stata Corp., College Station, Texas) when these results were not presented in the original articles.
To summarize the effect of screening on clinical outcomes, we performed meta-analysis by using RevMan software (Cochrane Collaboration, 2000) and the DerSimonian and Laird random-effects model.
The effect of routine screening of adult patients for depression in primary care was compared with usual care in 14 randomized trials in primary care settings.11-25 The main outcomes examined were differences in providers' rate of detection or recognition of depression, the proportion of patients with depression who were treated or referred for treatment, and clinical outcomes of depression. The screening interventions differed in intensity. Some trials provided feedback of screening results alone; others provided feedback and general or specific treatment advice to the providers; and some provided feedback and treatment advice and helped practices develop systematic means of improving the quality of treatment and followup. The trials, which were stratified by intensity of the intervention, are described below and summarized in Tables 2, 3, 4, and 5.
Johnstone and Goldberg applied the self-administered General Health Questionnaire to 1,093 primary care patients and identified 119 with depression.14 These 119 patients were randomly assigned to immediate feedback of the results to the physician or to usual care. The groups did not differ significantly in mean General Health Questionnaire scores at 12-month followup, except for the subgroup of patients with severe depression, for whom feedback improved scores. Among all patients, the total amount of time spent depressed within one year decreased by approximately two months (P< 0.01).
Three trials evaluated feedback of Zung Self-Depression Scale scores to providers. Moore and colleagues asked 212 consecutive patients 20 to 60 years of age who attended a university-based family medicine residency clinic to self-administer the Zung Self-Depression Scale.15 The 96 patients who scored higher than 50 were randomly assigned to a group whose providers were given immediate written feedback of results or to a group whose providers received a generic note saying that their patients had been screened. The same note was affixed to the charts of patients in each group who had scored 50 or less. Recognition of depression, as assessed by chart audit, was 56 percent in the intervention group (28 of 50 patients) and 22 percent in the control group (10 of 46 patients). Prescription of treatment was not assessed.
Linn and Yager tested immediate written feedback of Zung Self-Depression Scale results compared with no screening in 74 consecutive new patients from a primary care clinic, using chart audit to assess outcomes.16 Depression was more likely to be diagnosed in patients assigned to the feedback group than in those receiving usual care (29 percent vs. 8 percent); treatment rates were low and similar in each group (13 percent vs. 8 percent). Neither Moore and colleagues nor Linn and Yager reported clinical outcomes.
Magruder-Habib and associates screened 800 Veterans Administration patients for depression in a primary care clinic.18 Research assistants administered the Zung Self-Depression Scale and used the Diagnostic Interview Schedule to confirm diagnosis according to criteria from the Diagnostic and Statistical Manual of Mental Disorders, third edition (DSM-III).18,26 The 100 patients who screened positive (excluding those with scores higher than 75 or past history of depression) and met DSM-III criteria for major depression were randomly assigned to feedback of screening results or usual care; chart audit was used to assess outcomes. Patients whose physicians received feedback were three times more likely to be accurately identified as depressed at the index visit than were patients whose clinicians had not received such feedback (25 percent vs. 8 percent; difference, 17 percent; CI, 3 percent to 32 percent). At one year of followup, 42 percent of the intervention group and 21 percent of the control group had been recognized as depressed. At three months of followup, more patients in the feedback group were being treated for depression, but the difference was not statistically significant (37 percent vs. 27 percent; difference, 11 percent; CI, -8 percent to 29 percent). No clinical outcomes were measured.18
Dowrick studied 116 patients who were initially rated "not depressed" by their usual general practitioners but had self-administered Beck Depression Inventory scores greater than 14.20 The patients were randomly assigned to no feedback or feedback that was given to providers one week after the visit in which screening took place and noted in the chart for subsequent visits. At one year, rates of diagnosis and treatment of depression were higher in the intervention than the control group, although the differences were not statistically significant. Clinical outcomes were not measured.
Reifler et al. studied 358 primary care patients by using the self-administered Symptom-Driven Diagnostic System for Primary Care.23 The clinicians of intervention-group patients received results of the Symptom-Driven Diagnostic System for Primary Care; the clinicians of controls were not informed of the results. At three months, the research team observed no clinically or statistically significant differences in clinical outcomes but the actual proportions of patients who were still depressed were not presented in the report.
Lewis and colleagues used the self-administered General Health Questionnaire or the General Health Questionnaire plus a computer-based diagnostic tool (PROQSY) to examine the effect of feedback to providers of positive scores on outcomes in low-income primary care patients in London.22 At 6 weeks, compared with General Health Questionnaire scores in controls, scores were improved in patients whose providers received feedback on the PROQSY results but not in those whose providers received only General Health Questionnaire results. When a General Health Questionnaire score greater than 1 was used to indicate current depression, patients who were screened with PROQSY were slightly less likely than controls to be depressed at 6 weeks (69 percent vs. 74 percent; difference, 5 percent; CI, -14 percent to 3 percent). At 6 months of followup, mean General Health Questionnaire scores did not differ between groups.
Williams et al. tested the effect of immediate provider feedback of results of the Center for Epidemiologic Study Depression Scale or a single question about depressed mood with no feedback.11 They confirmed the presence or absence of depression by using criteria from the Diagnostic Interview Schedule and DSM-III, revised (DSM-III-R),27 but they did not use this information to determine eligibility for the trial. Current depression was defined as meeting the DSM-III-R criteria for major depression or dysthymia or having minor depression (depressed mood or anhedonia plus one to three additional DSM-III-R symptoms). On the basis of chart reviews, current depression was recognized in 39 percent of patients whose providers received feedback from screening and in 29 percent of controls (difference, 10 percent; CI, -8 percent to 28 percent). Rates of treatment were similar in each group. At 3 months, 37 percent of the intervention group and 46 percent of the control group met DSM-III-R criteria for depression (difference, -8 percent; CI, -21 percent to 4 percent).11
Zung and King screened 499 patients at one private physician's office by using the Self-Depression Scale screening test administered by a psychiatrist.17 Of the 60 patients who screened positive for depression, 49 had major depression according to DSM-III criteria. These 49 patients were randomly assigned to a group in which the provider received the results of screening (n= 23) or to usual care (n= 26). Patients identified as depressed were treated with alprazolam, a benzodiazepine drug that is currently not recommended for treating depression. At four weeks, followup data were available for 21 intervention-group patients and 20 controls. The intervention patients were less likely than control patients to remain depressed after one month followup: 33 percent of intervention patients were still depressed versus 65 percent of controls, when persistent depression was defined as a failure to improve by 12 or more points on the Zung depression scale (difference -32 percent; 95 percent CI, -61 percent to -3 percent).
Callahan and associates studied patients older than 60 years of age in an academic primary care setting that served low-income patients.19,21 Research assistants initially screened potential participants by using the Center for Epidemiologic Study Depression Scale. Participants who scored 16 or higher were given the Hamilton Depression Scale. Patients who scored higher than 14 on the Hamilton Depression Scale underwent randomization by physician group, in which certain clinic sessions were randomly assigned to the intervention group and others to the control group. All physicians received an educational talk at baseline. Providers of intervention-group patients received feedback from screening plus individually targeted educational information and specific treatment recommendations. Physicians in the intervention group also were asked to schedule three specific visits for study patients to address depression.
Depression diagnoses were documented more frequently for intervention-group patients than for controls (87 percent vs. 40 percent).21 Initiation of a treatment plan was more common among intervention patients (46 percent vs. 29 percent; difference, 17 percent; CI, 4 percent to 30 percent).19,21 The proportion of patients who were still depressed at 6 months of followup (Hamilton Depression Scale >10) was 87 percent for intervention-group patients and 88 percent for controls (difference, -1 percent; CI, -11 percent to 9 percent).
Whooley and colleagues25 studied the effect of screening with the Geriatric Depression Scale and feedback among patients older than 65 years of age in 13 practices in the Kaiser Permanente system. Research assistants screened patients on the day of a regularly scheduled clinic visit and gave same-day feedback (74 percent before visits and 26 percent after visits) to the providers in seven intervention clinics; they gave no feedback to providers in six usual-care practices. All providers received an initial education session on management of depression. Intervention-group patients were offered a series of six weekly group educational sessions led by a nurse. Rates of recognition of depression were similar in each group, but prescription of antidepressant medication (on the basis of pharmacy database review) was higher among controls. Continued depression, defined as a Geriatric Depression Scale score greater than six, was assessed two years after enrollment; data were available for 69 percent of patients. At two years of followup, 42 percent of intervention-group patients and 50 percent of controls were still depressed (difference, -8 percent; CI, -21 percent to 6 percent).25