ATLANTA — Depression after MI is associated with markedly increased mortality risk in the first several months following the coronary event, but not increased long-term mortality, Dr. Kapil Parakh said at the annual meeting of the American College of Cardiology.
In a previous report, he and his coinvestigators at Johns Hopkins University, Baltimore, prospectively followed 285 patients with MI who survived to hospital discharge. They determined that patients with at least mild to moderate depression, as evidenced by a Beck Depression Inventory score of 10 or more during hospitalization, had up to a fourfold increased relative risk of mortality at 4 months (Am. J. Cardiol. 2001;88:337–41).
Now Dr. Parakh and coworkers have looked at the same cohort at 3, 5, and 8 years post MI. They found that depression at baseline was not associated with increased mortality at any of these time points.
That depression is common in the first several days post MI and is associated with sharply increased overall mortality in the next several months has been well established in multiple studies.
In contrast, there have been far fewer studies looking at post-MI depression and long-term mortality. Three prior studies have reported increased long-term risk. However, the Hopkins cohort was older, sicker, and more representative of real-world coronary heart disease populations, with several-fold higher prevalences of hypertension and diabetes than in the other studies. The 49% mortality at 8 years in the Hopkins cohort was substantially higher, too. All this may account for the conflicting findings, Dr. Parakh said.
He offered two potential explanations for the lack of increased long-term mortality in the Hopkins patients with depression shortly after MI. One is that patients most vulnerable to the effects of depression got eliminated from the study population because they died early on.
The other possibility is that in a high-risk coronary heart disease population with multiple comorbidities, the association between any single risk factor—such as depression—and outcomes is diminished due to competing comorbidities.
“We've shown in previous work that patients with depression don't follow physician advice to modify their risk, so it may be especially important to look carefully at these patients to help them reduce their risk of events,” he said.