Objective: Cognitive-affective symptoms of depression may not be as strongly related to prognosis after myocardial infarction (MI) as somatic depressive symptoms. Because it is not known whether this pattern of results is influenced by the age at which patients are diagnosed as having MI, we examined whether the importance of these symptoms is age dependent in the Enhancing Recovery in Coronary Heart Disease study.
Methods: Patients with depression after MI (n = 1823) in the Enhancing Recovery in Coronary Heart Disease study were stratified into the following age groups: younger than 70 years (mean [standard deviation] = 55 [9.0] years) and 70 years or older (mean [standard deviation] = 76 [4.9] years). Measurements included demographic and clinical data and the Beck Depression Inventory. The end point was a composite of recurrent MI and mortality during a mean follow-up of 2.1 years.
Results: Patients 70 years or older had more severe manifestations of cardiac disease and somatic comorbidities than did patients younger than 70 years (p < .001). During follow-up, 456 patients died or had a recurrent MI. In patients 70 years or older, increasing age, disease severity, and comorbidities--but not depressive symptoms--independently predicted prognosis. In contrast, cognitive-affective symptoms of depression predicted death/MI in patients younger than 70 years (hazard ratio = 1.03, 95% confidence interval = 1.01-1.04, p = .011), after adjustment for disease severity and comorbidities. Somatic symptoms largely explained the link between cognitive-affective symptoms and adverse events, with the exception of hopelessness (hazard ratio = 1.47, 95% confidence interval = 1.11-1.95, p = .007), suggesting that somatic depressive symptoms accurately reflect the depressed mood state in this age group.
Conclusions: Somatic symptoms and hopelessness independently predicted death/MI in MI patients younger than 70 years. Research needs to reexamine the modulating effect of age in studies on somatic and cognitive-affective symptoms of post-MI depression.
Keywords: age; depression; hopelessness; mortality; myocardial infarction.