New onset depression following myocardial infarction predicts cardiac mortality

Objective: Studies investigating the effects of depression on mortality following myocardial infarction (MI) have produced heterogeneous findings. We report on a study investigating whether the timing of the onset of depression, with regard to the MI, affected its impact on subsequent cardiac mortality. Methods: Five hundred and eighty-eight subjects admitted following MI underwent assessments of cardiac status, cardiac risk factors, and noncardiac illness. We identified separately subjects who were depressed before their MI (pre-MI depression) and those who developed depression in the 12 months after MI (new-onset depression), using a standardized questionnaire and a research interview. Patients dying of cardiac cause were identified during 8-year follow-up using information from death certificates. Results: Multivariate predictors of cardiac death during follow-up included: greater age (hazards ratio (HR) = 1.06, p =.007), previous angina (HR = 4.15, p < .0005), high Killip Class (HR = 2.21, p = .013), prescription of beta-blockers on discharge (HR = 0.37, p = .02), and new-onset depression (HR = 2.33, p = .038). Pre-MI depression did not convey any additional risk of cardiac mortality. Conclusion: We have shown increased cardiac mortality in patients who develop depression after suffering MI. Further observational studies need to separate pre- and post-MI depression if we are to determine underlying mechanisms by which depression is associated with mortality following MI.