Symptom dimensions of post-myocardial infarction depression, disease severity and cardiac prognosis

BACKGROUND: Individual symptoms of post-myocardial infarction (MI) depression may be differentially associated with cardiac prognosis, in which somatic/affective symptoms appear to be associated with a worse cardiovascular prognosis than cognitive/affective symptoms. These findings hold important implications for treatment but need to be replicated before conclusions regarding treatment can be drawn. We therefore examined the relationship between depressive symptom dimensions following MI and both disease severity and prospective cardiac prognosis. METHOD: Patients (n=473) were assessed on demographic and clinical variables and completed the Beck Depression Inventory (BDI) within the first week of hospital admission for acute MI. Depressive symptom dimensions were associated with baseline left ventricular ejection fraction (LVEF) and prospective cardiac death and/or recurrent MI. The average follow-up period was 2.8 years. RESULTS: Factor analysis revealed two symptom dimensions--somatic/affective and cognitive/affective--in the underlying structure of the BDI, identical to previous results. There were 49 events attributable to cardiac death (n=23) or recurrent MI (n=26). Somatic/affective (p=0.010) but not cognitive/affective (p=0.153) symptoms were associated with LVEF and cardiac death/recurrent MI. When controlling for the effects of previous MI and LVEF, somatic/affective symptoms remained significantly predictive of cardiac death/recurrent MI (hazard ratio 1.31, 95% confidence interval 1.02-1.69, p=0.038). Previous MI was also an independent predictor of cardiac death/recurrent MI. CONCLUSIONS: We confirmed that somatic/affective, rather than cognitive/affective, symptoms of depression are associated with MI severity and cardiovascular prognosis. Interventions to improve cardiovascular prognosis by treating depression should be targeted at somatic aspects of depression.