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 LETTERS TO THE EDITOR

No evidence for depression screening in cardiovascular care settings: A comment on CANMAT task force recommendations

Brett D. Thombs, PhD

Department of Psychiatry, McGill University, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada

KEYWORDS: depression, screening, cardiovascular disease

ANNALS OF CLINICAL PSYCHIATRY 2012;24(4):319-322

TO THE EDITOR:

A Canadian Network for Mood and Anxiety Treatments (CANMAT) task force recently published recommendations for managing depression in medically ill patients.1 The task force made recommendations for 9 chronic diseases, but addressed depression screening only in cardiovascular disease (CVD) and recommended “Routine screening for depression for patients with CVD in various settings, including hospitals, physicians’ offices, and cardiac rehabilitation centers.”1 They referenced several clinical guidelines that have recommended depression screening in CVD and suggested that these recommendations are controversial because treating depression in CVD has not been shown to impact cardiovascular outcomes. The authors also seem to argue that evidence of successful treatment of depression in CVD supports screening recommendations.

Whether or not treating depression may influence medical outcomes is not central to evaluating recommendations for depression screening. Similarly, while the ability to treat depression is a prerequisite for considering screening, effective treatment is not enough to recommend screening. Rather, benefits of screening in excess of potential harms should be demonstrated in well conducted randomized controlled trials (RCTs). Consistent with this, criticisms of depression screening recommendations in CVD2-4 have pointed out that no clinical trial has demonstrated that depression screening improves mental health in CVD.5

Beyond CVD, a meta-analysis of 11 trials of depression screening in primary care found that screening increased rates of depression treatment in several trials, but no trials found that screening improved depression outcomes.6 To date, there have been no clinical trials in any medical setting in which patients screened for depression had better depression outcomes than patients not screened, and there are many reasons why trials of depression screening have not produced positive results. First, as described in a recent analysis,7 screening only works to the degree that it identifies patients with unrecognized depression, successfully engages them in treatment, and produces symptom improvement that would not otherwise occur. Yet, existing rates of treatment are already high; in Ontario, 16% of patients age ≥65 with a recent myocardial infarction were prescribed antidepressants as early as 2002.8 Second, existing studies tend to exaggerate the accuracy of depression screening tools. One review found >96% of studies on depression screening tool accuracy included already treated patients. Including already treated patients, who normally would not undergo screening, in these studies overestimates accuracy and the number of new cases to be found through screening.7,9 Finally, depression treatment is more effective in patients with high levels of symptoms, and those who are detected via screening typically would not meet this criterion.7

The CANMAT task force described its recommendations as evidence-based, yet the task force did not document a systematic review of the literature, nor did it document evidence for its screening recommendations. CANMAT should reconsider this recommendation and require evidence of RCTs that show benefit of depression screening in excess of harms and costs before recommending this intervention.

DISCLOSURE: Dr. Thombs receives support from a New Investigator Award from the Canadian Institutes of Health Research and an Établissement de Jeunes Chercheurs award from the Fonds de la Recherche en Santé du Québec.

    REFERENCES

  1. Ramasubbu R, Taylor VH, Samaan Z, et al. The Canadian Network for Mood and Anxiety Treatments (CANMAT) task force recommendations for the management of patients with mood disorders and select comorbid medical conditions. Ann Clin Psychiatry. 2012;24:91–109.
  2. Ziegelstein RC, Thombs BD, Coyne JC, et al. Routine screening for depression in patients with coronary heart disease: never mind. J Am Coll Cardiol. 2009;54:886–890.
  3. Thombs BD, Jewett LR, Knafo R, et al. Learning from history: a commentary on the American Heart Association Science Advisory on depression screening. Am Heart J. 2009;158:503–505.
  4. Ziegelstein RC, Thombs BD. Is routine screening a parachute for heart disease patients with depression? J Psychosom Res. 2011;71:3–5.
  5. Thombs BD, de Jonge P, Coyne JC, et al. Depression screening and patient outcomes in cardiovascular care: a systematic review. JAMA. 2008;300:2161–2171.
  6. Gilbody S, Sheldon T, House A. Screening and case-finding instruments for depression: a meta-analysis. CMAJ. 2008;178:997–1003.
  7. Thombs BD, Coyne JC, Cuijpers P, et al. Rethinking recommendations for screening for depression in primary care. CMAJ. 2012;184:413–418.
  8. Benazon NR, Mamdani MM, Coyne JC. Trends in the prescribing of antidepressants following acute myocardial infarction 1993-2002. Psychosom Med. 2005;67:916–920.
  9. Thombs BD, Arthurs E, El-Baalbaki G, et al. Risk of bias from inclusion of patients who already have diagnosis of or are undergoing treatment for depression in diagnostic accuracy studies of screening tools for depression: systematic review. BMJ. 2011;343:d4825.

AUTHORS’ RESPONSE

We thank Dr. Thombs for his comments on screening for mood disorders in cardiovascular care settings. Dr. Thombs raises several interrelated, but separate issues in his letter. Dr. Thombs presents 9 references—6 of which he is an author or coauthor—to provide rationale for his argument. First, he argues that screening for depression in cardiovascular disease (CVD), which was one of several recommendations for managing depression in medically ill patients from the Canadian Network for Mood and Anxiety Treatments (CANMAT) task force, is not empirically supported. Dr. Thombs further argues that current rates for depression treatment in individuals age >65 with a recent myocardial infarction is “already very high” based on results from a pharmaco-epidemiological database. Moreover, he asserts that studies “exaggerate the accuracy of depression screening tools” and treating depression is more effective in patients with high baseline of symptomatology.

With respect to the first issue, we agree that few studies have demonstrated that depression screening improves outcomes and cost effectiveness in individuals with CVD and other medical disorders. This could be broadened further to question recommendations for depression screening in primary care; the United Kingdom National Institute for Health and Clinical Excellence group cautiously supports this recommendation while the U.S. Preventative Services Task Force recommends routine screening in primary care.1,2 However, this should not be interpreted to mean that depression screening in patients with chronic medical illness does not improve outcome for either depression or other chronic medical disorders. For example, screening and treating depression as part of a collaborative model in patients with diabetes mellitus—which is highly prevalent among individuals with CVD—improves outcomes for the mood and metabolic disorder.3

With respect to the argument that treatment rates in depression are “already very high,” Dr. Thombs is extrapolating pharmaco-epidemiological evidence and interpreting it as “guideline concordant care.” Indeed, there is a high rate of antidepressant use in the general population and rapid increase of antidepressant use in pediatric and adult populations and subpopulations during the past 2 decades.4 Yet, there is no compelling evidence that guideline concordance is increased, nor of a “very high” treatment rate. Available evidence indicates that increased use of antidepressants often is for conditions other than major depressive disorder, such as anxiety disorders, migraine, or fibromyalgia.5

We agree that depression screening tools should not be considered diagnostic tools, nor should they replace a comprehensive clinical assessment. Indeed, results from a meta-analysis indicate that the true positive rate for detecting depression in primary care is not much greater than 50%.6 We would argue that although depression screening tools may have improved performance characteristics in high-risk populations (eg, greater baseline depression severity, CVD). We certainly believe that individuals with milder presentations of depression should be evaluated for a possible mood disorder, recognizing the limitations of screening instruments. The assertion that antidepressant therapy is superior to placebo only in individuals with high baseline depression severity may not be true.7

The CANMAT Task Force’s objective was to move the field forward by providing real-world recommendations that are informed by the evidence, but not limited to only those areas that have the highest levels of data. We welcome the call for more study of the specific benefits of depression screening in general, and in specific comorbid medical populations, which will inform future recommendations. In the interim, our recommendations are similar to those of the American Heart Association insofar as the high prevalence of depression in patients with CVD supports a strategy of increased awareness and screening. Indeed, screening efforts in any population would be futile without the availability of timely, comprehensive, and coordinated care to treat depressive symptomatology.8

DISCLOSURES: Dr. McIntyre receives research or grants from AstraZeneca, Eli Lilly and Company, Janssen-Ortho, Lundbeck, NARSAD, the National Institutes of Mental Health, Pfizer, Shire, and the Stanley Medical Research Institute; serves on advisory boards for AstraZeneca, Bristol-Myers Squibb, Eli Lilly and Company, the France Foundation, GlaxoSmithKline, Janssen-Ortho, Lundbeck, Merck, Organon, Pfizer, and Shire; is a speaker for AstraZeneca, Eli Lilly and Company, Janssen-Ortho, Lundbeck, Merck, and Pfizer; and has completed CME activities for AstraZeneca, Bristol-Myers Squibb, CME Outfitters, Eli Lilly and Company, the France Foundation, I3CME, Merck, OptumHealth, Pfizer, and Physicians’ Postgraduate Press. Dr. Rosenbluth is a speaker for AstraZeneca, Bristol-Myers Squibb, Eli Lilly and Company, and Lundbeck. Dr. Ramasubbu receives an investigator-initiated grant from AstraZeneca. Dr. Bond serves on advisory boards for AstraZeneca, Bristol-Myers Squibb, Janssen, and Lundbeck; receives research grants for clinical trials or studies from the Canadian Institutes of Health Research (CIHR), Coast Capital Depression Research Fund, and Pfizer; and has received honoraria or other fees from AstraZeneca, Bristol-Myers Squibb, the Canadian Network for Mood and Anxiety Treatments, the Canadian Psychiatric Association, Janssen, and Otsuka. Dr. Taylor receives grant or research support from Bristol-Myers Squibb and is a speaker for Allergan, Bristol-Myers Squibb, Eli Lilly and Company, Lundbeck, and Pfizer. Dr. Schaffer receives grant or research support from Pfizer Canada, and is a consultant and speaker for AstraZeneca, Bristol-Myers Squibb, Eli Lilly and Company, and Lundbeck. Dr. Beaulieu is a speaker for AstraZeneca, Biovail, Bristol-Myers Squibb, Eli Lilly and Company, GlaxoSmithKline, Janssen-Ortho, Lundbeck, Organon, Oryx, and Wyeth Pfizer; is a consultant or advisor to AstraZeneca, Bristol-Myers Squibb, Eli Lilly and Company, GlaxoSmithKline, Janssen-Ortho, Lundbeck, Oryx, Otsuka, Schering-Plough Merck, and Wyeth Pfizer; receives peer-reviewed funding from CIHR, Fonds de Recherche du Québec, NARSAD, Revue Santé Mentale au Québec, and the Stanley Foundation; and receives research support and contracts from AstraZeneca, Biovail, Bristol-Myers Squibb, Eli Lilly and Company, Janssen-Ortho, Lundbeck, Merck-Frosst, Novartis, Pfizer, and Servier.

    REFERENCES

  1. Pignone MP, Gaynes BN, Rushton JL, et al. Screening for depression in adults: a summary of the evidence for the U.S. Preventive Services Task Force. Ann Intern Med. 2002;136:765–776.
  2. Gilbody S, Sheldon T, Wessely S. Should we screen for depression? BMJ. 2006;332:1027–1030.
  3. Katon WJ, Lin EH, Von Korff M, et al. Collaborative care for patients with depression and chronic illnesses. N Engl J Med. 2010;363:2611–2620.
  4. Marcus SC, Olfson M. National trends in the treatment for depression from 1998 to 2007. Arch Gen Psychiatry. 2010;67:1265–1273.
  5. Beck CA, Patten SB, Williams JV, et al. Antidepressant utilization in Canada. Soc Psychiatry Psychiatr Epidemiol. 2005;40:799–807.
  6. Mitchell AJ, Vaze A, Rao S. Clinical diagnosis of depression in primary care: a meta-analysis. Lancet. 2009;374:609–619.
  7. Gibbons RD, Hur K, Brown CH, et al. Benefits from antidepressants: synthesis of 6-week patient-level outcomes from double-blind placebo-controlled randomized trials of fluoxetine and venlafaxine. Arch Gen Psychiatry. 2012;69:572–579.
  8. Lichtman JH, Bigger JT Jr, Blumenthal JA, et al; American Heart Association Prevention Committee of the Council on Cardiovascular Nursing; American Heart Association Council on Clinical Cardiology; American Heart Association Council on Epidemiology and Prevention; American Heart Association Interdisciplinary Council on Quality of Care and Outcomes Research; American Psychiatric Association. Depression and coronary heart disease: recommendations for screening referral, and treatment: a science advisory from the American Heart Association Prevention Committee of the Council on Cardiovascular Nursing, Council on Clinical Cardiology, Council on Epidemiology and Prevention, and Interdisciplinary Council on Quality of Care and Outcomes Research: endorsed by the American Psychiatric Association. Circulation. 2008;118:1768–1775.

CORRESPONDENCE: Brett D. Thombs, PhD, Jewish General Hospital, 3755 Côte-Sainte-Catherine Road, Montréal, Québec H3T 1E4 Canada, E-MAIL: brett.thombs@mcgill.ca.