Patients who have had a myocardial infarction (MI) should be screened and appropriately treated for depression, according to a guideline recently issued by the American Academy of Family Physicians (AAFP).1 The group recommends use of a standardized depression symptom checklist during hospitalization and “at regular intervals” thereafter.
The guideline evolved from an AAFP panel’s review of literature published through 2006. There was particular focus on a 2005 report on the effect of depression on persons after an MI that was sponsored by the Agency for Healthcare Research and Quality (AHRQ).2 The panel did not find evidence that treatment of depression improves cardiac outcomes per se. However, the prevalence and morbidity of post-MI depression and the evidence of treatment effectiveness was sufficiently compelling for the panel to also recommend the establishment of systems for regular follow-up to ensure adherence and response to treatment.
“Depression is an important predictor of morbidity and mortality in patients with coronary heart disease, particularly after an MI,” the guideline statement observes. “As many as 65% of patients with acute MI report experiencing symptoms of depression, and major depression is present in 15% to 22% of these patients.”
The panel favors SSRIs over tricyclic antidepressants for their relative safety in this population. It notes, however, that there are not yet sufficient data to characterize the risk versus benefits of newer classes of antidepressants.
Psychosocial therapies, as well as antidepressant medications, were associated with improvement in depression—but not in cardiac outcomes. The panel recognized evidence of benefit from cognitive-behavioral therapy but did not recommend a specific intervention. It indicated that “the effects of psychotherapy are difficult to interpret because of the heterogeneity of the modalities used.”
In subgroup analysis of several studies, the panel found the greatest benefit from psychosocial intervention in patients with depression that predates the MI. “Patients whose initial symptoms appear after an MI have a very high placebo response rate,” the panel noted, “and generally improve regardless of therapy.”
Examining evidence
The panel found that the prevalence of depression after hospitalization for MI was generally lower in studies that employed structured interviews than in studies that employed validated rating scales (such as the Beck Depression Inventory). The panel recommended screening with a standardized checklist for relative ease of use, as well as for the apparent higher rate of detection.
There were few studies of post-MI depression persisting over 1 month after discharge that distinguished new-onset episodes, incident to the MI, from variable courses of depression that recurred with the cardiac event. In 3 studies that identified new-onset depression, the 1-month or greater prevalences ranged from 37% to 60%.
The question of whether depression affects post-MI cardiac care utilization was examined in the AHRQ study as well as by the AAFP panel, but the answer remains unclear. There was some suggestion that b-adrenergic blockers may be prescribed less frequently in the presence of depression, but no indication of effect on other drug use. There was no clear relationship between post-MI depression and the performance of invasive procedures.
The panel did find consistent evidence that depression is associated with reduced medication adherence and reduced adherence to lifestyle modification behaviors. The panel pointed to a conspicuous absence of studies that address the key issue of whether or how depression treatment affects adherence to post-MI recommendations that improve outcomes.
