Depression in the Cardiac Patient: A Call for Action

Despite a long-standing popular belief that stress and emotions affect the cardiovascular system, it was not until the mid-1980s that the first studies linking depression to higher mortality after a myocardial infarction (MI) began to appear in the medical literature. Since then, scientific interest in the link between depression and heart disease has grown steadily over time, with an increasing number of research studies addressing depression as a prognostic factor in cardiac patients. There is now a sufficient consensus that depression is a risk factor for coronary heart disease (CHD), as well as an important prognostic factor in cardiac patients. It is also recognized that depression is a growing global problem. By 2030, depression is projected to be the second leading cause of disability worldwide (after HIV/AIDS) and the number one cause of disability in high-income countries.[1]

Surprisingly, the accumulating evidence of the importance of depression as a risk factor and its impact on health status has not translated well into clinical practice. Currently, less than half of depressed medical patients are recognized by their physicians, and recognition has only mildly increased in the last 10 years.[2] During an admission for acute MI, less than 15% of patients with depression are being identified [3], and evaluation and treatment of depression continue to be mostly ignored during routine cardiac care.[4] In response to this lack of recognition, a growing number of commentaries, management guidelines, and expert panel reports have been published to highlight the importance of depression and facilitate its diagnosis and management in the cardiac patient.[5-9]

There are many potential reasons for the underrecognition and undertreatment of depression in the medical setting. Many symptoms of depression, for example, fatigue, weight loss, poor appetite, or trouble sleeping, can be confused with those of other medical illnesses and are, therefore, often attributed to physical diseases. Time constraint is also a barrier: adding psychological evaluations may be cumbersome in a busy clinical practice. Furthermore, mental health problems have been historically the domain of the psychiatrist, and there is also the potential concern of patient stigma. Limitations in reimbursement or insurance coverage for mental health services are additional potential barriers. Several of these obstacles could be ameliorated by improving providers' education. For example, quick screening tools and effective treatments for depression are now available. They can be efficiently implemented in the cardiology or primary-care office, reserving psychiatric referral for the most complex or severe cases. In light of this, the AHA Science Advisory on screening, referral, and treatment of depression in the CHD patient provides a useful practical informational guide for the busy clinician, thus facilitating the dissemination of such strategies.

Another reason why management of depression may be lagging in the cardiac patient is a skepticism concerning whether depression is truly related to cardiovascular risk, or is, rather, an epiphenomenon of comorbidity and illness severity. Most studies, however, have shown a relationship after taking into account other illnesses and risk factors. There is also uncertainty about whether treatment will improve outcomes. Indeed, studies to date have not proved that treating depression can improve cardiovascular outcomes. Investigation in this area has been limited, however, and the resulting lack of evidence does not prove ineffectiveness. Furthermore, depression remains an important illness in and of itself, which deserves proper evaluation and treatment. By recognizing and treating depression, we can improve patients' overall well-being and their adherence to medical treatments and healthy-lifestyle behaviors. There are a number of unresolved issues that, although not addressed in the brief AHA Science Advisory, deserve some mention. Clearly, depression should be recognized and treated; however, it is unclear what the best treatment might be for the cardiac patient. This uncertainty particularly applies to psychotherapy or other psychosocial approaches. Although such treatments are believed to be useful in CHD patients [5-7], results are widely inconsistent in regard to both their ability to improve depression and to improve outcome in cardiac patients. The recent Canadian Cardiac Randomized Evaluation of Antidepressant and Psychotherapy Efficacy (CREATE) trial, for example, provided further evidence for the antidepressant efficacy of the selective serotonin re-uptake inhibitor (SSRI) medications in patients with CHD but found no evidence of added benefit from interpersonal psychotherapy over a weekly clinical management strategy that included education, reassurance, and encouragement of adherence to medication.[10]

It is also unknown whether the same recommendations should apply to separate patient subgroups, such as women. For example, data suggest that women with CHD respond differently than men to psychological treatments. Subgroup analyses of the ENRICHD trial showed a significant treatment by sex interaction on cardiovascular outcomes, suggesting a protective effect of cognitive-behavioral therapy in men, but a tendency for harm in women.[11] These results mirrored those of an earlier trial, the Montreal Heart Attack Readjustment Trial (M-HART), which tested the effect of a nurse-based psychosocial support intervention at home for distressed patients after MI.[12] The M-HART program had no overall impact on cardiac or all-cause mortality over the year. Separate preplanned comparisons in men and women, however, revealed two times the odds of cardiac and all-cause mortality in treated women compared with control women, while there was no impact in men. Altogether, these data suggest that women and men respond differently to psychological interventions and highlight the importance of performing gender-specific trials or, at the very least, prespecifying gender-based stratification analyses in the trial planning phase, allowing sufficient power to examine women separately from men.

Despite these unresolved issues, we should no longer ignore depression in the cardiac patient. One cannot expect a detailed evaluation of coexisting illnesses in the busy cardiology office; however, recognition of a key comorbidity, such as depression, can lead to the delivery of higher-quality care. Current treatment guidelines from the American College of Cardiology and the American Heart Association do recommend evaluation of symptoms of depression in cardiac patients, such as those with an MI or angina pectoris, or after bypass surgery. The availability of simple instruments, such as those described in the AHA Advisory, makes this task easier and makes it possible to integrate the management of depression into routine cardiac care.