Depression and Other Psychological Risks Following Myocardial Infarction

BACKGROUND: There is consistent evidence that depression symptoms predict long-term mortality following a myocardial infarction, and recent results show a dose-related gradient. The importance of other psychological variables remains unclear. METHODS: This study examines the relative importance of depression, anxiety, anger, and social support in predicting 5-year cardiac-related mortality following a myocardial infarction and assesses the role of any common underlying dimensions. The design of this cohort analytic study involves self-reports (Beck Depression Inventory, state scale of the State-Trait Anxiety Inventory, 20-item version of the General Health Questionnaire, Modified Somatic Perception Questionnaire, Anger Expression Scale, Perceived Social Support Scale, number of close friends and relatives, and visual analog scales of anger and stress). The study was conducted in 10 Montreal-area hospitals. The patients included 896 persons who experienced a myocardial infarction, aged 24 to 88 years (232 were women), followed up for 5 years using Medicare records; baseline data were complete for 95.0% of the patients. The intervention was usual care, and the main outcome measure was 5-year cardiac-related mortality. RESULTS: The Beck Depression Inventory (P<.001), the State-Trait Anxiety Inventory (P =.04), and the 20-item version of the General Health Questionnaire (P =.048) were related to outcome), but only depression remained significant after adjustment for cardiac disease severity (hazards ratio per SD, 1.46; 95% confidence interval, 1.18-1.79) (P<.001). Exploratory factor analysis revealed 3 underlying factors: negative affectivity, overt anger, and social support. There was also a covariate-adjusted trend between negative affectivity scores and outcome (P =.08). Furthermore, residual depression scores (P =.001) and negative affectivity scores (P =.05) were linked to cardiac-related mortality after adjustment for each other and cardiac covariates. CONCLUSIONS: Negative affectivity and some unique aspect of depression predict long-term cardiac-related mortality following a myocardial infarction independently of each other and cardiac disease severity. Additional research is needed to characterize the mechanisms involved.