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The American Journal of Managed Care November 2004 - Part 2
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Screening for Depression and Suicidality in a VA Primary Care Setting: 2 Items Are Better Than 1 Item
Kathryn Corson, PhD; Martha S. Gerrity, MD, MPH, PhD; and Steven K. Dobscha, MD
VA Health Services Research: Lessons for the World's Healthcare Organizations
Steven J. Bernstein, MD, MPH
Variation in Implementation and Use of Computerized Clinical Reminders in an Integrated Healthcare System
Constance H. Fung, MD, MSHS; Juliet N. Woods, MS; Steven M. Asch, MD, MPH; Peter Glassman, MBBS, MSc; and Bradley N. Doebbeling, MD, MSc
Dual-system Utilization Affects Regional Variation in Prevention Quality Indicators: The Case of Amputations Among Veterans With Diabetes
Chin-Lin Tseng, DrPH; Jeffrey D. Greenberg, MD, MPH; Drew Helmer, MD, MS; Mangala Rajan, MBA; Anjali Tiwari, MD; Donald Miller, ScD; Stephen Crystal, PhD; Gerald Hawley, RN, MSN; and Leonard Pogach, M
Assessing the Accuracy of Computerized Medication Histories
Peter J. Kaboli, MD, MS; Brad J. McClimon, MD, PharmD; Angela B. Hoth, PharmD; and Mitchell J. Barnett, PharmD, MS
The Relationship of System-Level Quality Improvement With Quality of Depression Care
Andrea Charbonneau, MD, MSc; Victoria Parker, DBA; Mark Meterko, PhD; Amy K. Rosen, PhD; Boris Kader, PhD; Richard R. Owen, MD; Arlene S. Ash, PhD; Jeffrey Whittle, MD, MPH; and Dan R. Berlowitz, MD,
Designing an Illustrated Patient Satisfaction Instrument for Low-literacy Populations
Janet Weiner, MPH; Abigail Aguirre, MPA; Karima Ravenell, MS; Kim Kovath, VMD; Lindsay McDevit, MD; John Murphy, MD; David A. Asch, MD, MBA; and Judy A. Shea, PhD
Problems Due to Medication Costs Among VA and Non-VA Patients With Chronic Illnesses
John D. Piette, PhD; and Michele Heisler, MD, MPA

Screening for Depression and Suicidality in a VA Primary Care Setting: 2 Items Are Better Than 1 Item

Kathryn Corson, PhD; Martha S. Gerrity, MD, MPH, PhD; and Steven K. Dobscha, MD

Objective: To evaluate the psychometric properties of a singleitem depression screen against validated scoring algorithms for the Patient Health Questionnaire (PHQ) and the utility of these algorithms in screening for depression and suicidality in a Department of Veterans Affairs (VA) primary care setting.

Study Design: Recruitment phase of a randomized trial.

Methods: A total of 1211 Portland VA patients with upcoming primary care clinic appointments were administered by telephone a single item assessing depressed mood over the past year and the PHQ. The PHQ-9 (9 items) encompasses DSM-IV criteria for major depression, the PHQ-8 (8 items) excludes the thoughts of death or suicide item, and the PHQ-2 (2 items) assesses depressed mood and anhedonia. Patients whose responses suggested potential suicidality were administered 2 additional items assessing suicidal ideation. Patients receiving mental health specialty care were excluded.

Results: Using the PHQ-9 algorithm for major depression as the reference standard, the VA single-item screen was specific (88%) but less sensitive (78%). A PHQ-2 score of ≥3 demonstrated similar specificity (91%) with high sensitivity (97%). For case finding, the PHQ-8 was similar to the PHQ-9. Approximately 20% of patients screened positive for moderate depression, 7% reported thoughts of death or suicide, 2% reported thoughts of harming themselves, and 1% had specific plans.

Conclusions: The PHQ-2 offers brevity and better psychometric properties for depression screening than the single-item screen. The PHQ-9 item assessing thoughts of death or suicide does not improve depression case finding; however, one third of patients endorsing this item reported recent active suicidal ideation.

(Am J Manag Care. 2004;10(part 2):839-845)

Depression is common among patients in primary care settings, yet it is underrecognized and undertreated by primary care providers.1-3 Given the high prevalence, morbidity, and mortality associated with untreated depression, many medical institutions have initiated systematic guideline-based screening programs.4-6 Widely used screening instruments include the Beck Depression Inventory, the Center for Epidemiologic Studies Depression Screen (CES-D), and the Zung Self-Assessment Depression Scale.7 Compared with a standardized diagnostic instrument, these screens demonstrate very good sensitivity and fair to good specificity.8

Still, administering and evaluating the 20 or more items typically found in measures of depression can be relatively time-consuming, and therefore difficult to integrate into busy primary care practices.9,10 Thus, shorter instruments have been introduced and tested.8,11-14 Of note, the recently developed 9-item Patient Health Questionnaire (PHQ-9)15-17 is increasingly being administered and tested in clinical and research settings.18-23 The PHQ-9 has good sensitivity (88%) and specificity (88%) for major depression compared with a diagnostic interview conducted by a mental health professional using SCID (Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Revised 3rd Edition [DSM-III-R]) criteria.17 The PHQ-9 offers concurrent validity with measures of functional impairment, high internal consistency and test-retest reliability, simplicity, and face validity15-19; in addition, severity scores may be used to track change over time.7,16,23-24

Looking at the shortest possible measures, Whooley et al13 found that 2 items (measuring depressed mood and anhedonia over the past month) demonstrated excellent sensitivity (96%) but only fair specificity (57%) compared with the Diagnostic Interview Schedule. Kroenke et al25 tested the validity of the first 2 items (depressed mood and anhedonia over the past 2 weeks) of the PHQ (PHQ-2) in a population of community primary care and obstetrics-gynecology patients. They found that a PHQ-2 score of 3 or higher (PHQ-2 ≥3) had a sensitivity of 83% and specificity of 92% compared with a diagnostic interview by a mental health professional. Also using a diagnostic interview as the criterion, Williams et al26 reported that the sensitivity and specificity for a single question ("Have you felt depressed or sad much of the time in the past year?") approached that of the CES-D (85% vs 88% and 66% vs 75%, respectively). Although the data of Williams et al suggest that 1 item performs well, the characteristics of their sample—predominantly female and Hispanic—limit generalization to other settings.

In 1999, the Portland Veterans Affairs Medical Center (VAMC) primary care clinics introduced a similar single item ("Have you been depressed or sad most of the past year?") as a routine annual depression screen. In contrast to Williams et al's population, the VA patient population is predominantly male, Caucasian, and older adults.27 The primary objective of this study was to evaluate the sensitivity and specificity of the single-item screen with the PHQ-9 as the reference standard in a VA primary care clinic. We also sought to estimate the proportion of primary care patients not currently receiving mental health specialty care who would screen positive for depression and possible suicidality.

PATIENTS AND METHODS

Setting

The study was conducted in the Portland VAMC primary care clinics, which include 2 hospital-based and 2 community-based clinics. In 2002, about 23 000 patients were followed in these clinics. Our local population is primarily older (mean age 62 years), Caucasian (87% of patients with recorded ethnicity) men (94%), reflecting national VA demographics. The modal panel size for physicians is 1100-1200 patients; for nurse practitioners and physician assistants, 760-960 patients.

Study Sample and Procedure

In July 2002 we initiated recruitment for a randomized, controlled trial of a low-intensity collaborative intervention for depression in primary care (DEP-PC). All patients screened for participation in DEP-PC between July 2002 and February 2003 were eligible for the current study. Potential participants in DEP-PC were identified by using computerized lists of patients due to see their primary care providers within a month and whose primary care providers (n = 41) were participating in DEP-PC. We excluded patients who had received treatment from a mental health care clinician within the prior 6-month period or who had Alzheimer's disease, cognitive problems, psychotic symptoms, or terminal illness documented in their medical records (the Figure).

Figure

Patients who met inclusion criteria for DEP-PC were sent a brief letter outlining the study. One to two weeks later, a research assistant telephoned, explained the purpose of the study, and asked permission to continue with a 5-minute telephone interview. Up to 3 call attempts were made to reach each patient. It has been established that depression data collected by telephone are comparable to depression data obtained by in-person interviews.28 Research assistants were trained in procedures for obtaining clinical assistance for severely depressed or potentially suicidal patients. Investigators contacted patients who expressed active suicidal ideation for assessment and to offer care. The local institutional review board approved the study.

All eligible patients who agreed to be screened for DEP-PC were administered the PHQ and the single-item screen currently used in the primary care clinics. Over the first 5 months of recruitment, 977 patients were screened. Of the 587 patients who answered "not at all" to the first 2 PHQ-9 items (anhedonia and depressed mood), more than half (54%) also answered "not at all" to each of the remaining 7 PHQ items. Moreover, only 3 of 587 (0.5%) patients had PHQ scores suggesting moderate depression (PHQ-9 ≥ 10). Therefore, to limit the length of screening calls, we began administering the full PHQ-9 only when patients endorsed at least 1 of the first 2 PHQ items. Those interviewed using this "abbreviated screen" who did not endorse either of the first 2 items (n = 167) received a score of zero and the interview ended.

Over the 7-month study period, 1447 veterans enrolled in the primary care clinics were contacted by phone for screening (the Figure). Of these, 1240 (85.7%) patients completed the screening, 171 (11.8%) declined to be screened, and 36 (2.5%) indicated that they had seen a mental health clinician in the past 6 months. Among the 1240 screened, 14 (0.1%) patients skipped 2 or more PHQ items and 15 (0.1%) patients did not answer the single-item screen, leaving a final sample size of 1211. Veterans screened for DEP-PC were slightly more likely to be Caucasian (93% of patients with recorded ethnicity) and older (mean age 66 years) than veterans in the general primary care population.

Measures

Patient Health Questionnaire-9. The PHQ-9 depression scale is derived from the PRIME-MD,15-17 a measure of mood, anxiety, alcohol, somatoform, and eating disorders with demonstrated diagnostic and concurrent validity. Patients use an ordinal scale (0 = not at all, 1 = several days, 2 = more than half the days, 3 = nearly every day) to rate the frequency of symptoms of depression over the past 2 weeks. The 9 items are based on the 9 DSM-IV criteria for the diagnosis of depression,29 and total scores range from 0 to 27. Options for administering and scoring the PHQ include using all 9 items, using the first 8 items (PHQ-8; excludes thoughts of death or suicide item), and using only the first 2 items (PHQ-2; anhedonia and depressed mood items). For classification, either the cut-point system (score of 5-9 = mild, 10-14 = moderate, 15-19 = moderately severe, and 20-27 = severe depression) or the algorithm developed and validated by Spitzer and his colleagues17 to be congruent with the DSM-IV criteria ("major depression algorithm") can be used. The PRIME-MD also contains an item to assess global functional impairment that can be administered in conjunction with the PHQ as a 10th item. Our screening protocol used the 9-item version, previously validated against clinician interview and measures of functional impairment.15,17,19

The last item of the PHQ-9 evaluates the frequency of "thoughts that you would be better off dead or of hurting yourself in some way." We developed 2 additional follow-up questions for patients endorsing this item. The first was designed to clarify whether the patient is experiencing active suicidal ideation ("Are these thoughts that you would be better off dead, or thoughts of hurting or killing yourself?"). The second asks about active planning ("Over the past 2 weeks have you thought about specific ways you might hurt or kill yourself?").

Single-Item Screen. In 1997, the Veterans Health Administration (VHA) released clinical practice guidelines for major depressive disorder, which included annual screening for all general medicine patients.4 At the Portland VAMC, primary care patients are screened annually for depression unless they are currently undergoing specialty mental health treatment. The screening item "Have you been depressed or sad most of the past year?" uses a yes/no response format and is based on the single-item tested by Williams and his colleagues.26

Statistical Analysis

When a patient skipped a single PHQ item (17/1211, or <1.5%), the omitted value was imputed using mean substitution.30 Imputed data were not used in the analysis of detection of suicidal ideation. Internal consistency (Cronbach's alpha) was calculated by using data from patients interviewed during the first 5 months of recruitment who answered all 9 items (n = 962). There were no differences between the 962 (79%) patients assessed with the full PHQ and the 249 patients assessed with the abbreviated screen in terms of demographics or depression severity (ie, the proportion in each cohort classified as not depressed, mildly depressed, moderately depressed, etc).

Receiver operating characteristic (ROC) curve analyses comparing patients screened before and after the change in PHQ administration procedure showed no significant differences for the single item, PHQ-2 ≥ 2, or PHQ-2 ≥ 3 when the major depression diagnosis algorithm, PHQ-9 ≥ 10, or PHQ-9 ≥ 15 was used as the reference standard. Thus, the data were combined for all subsequent analyses except PHQ inter-item correlations. Frequencies, correlations, and z tests for differences were used for item-level analyses.

 
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