New onset depression following myocardial infarction predicts cardiac mortality

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.

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.

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.

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.