Only incident depressive episodes after myocardial infarction are associated with new cardiovascular events.

OBJECTIVES The purpose of this research was to study whether incident and non-incident depression after myocardial infarction (MI) are differentially associated with prospective fatal and non-fatal cardiovascular events. BACKGROUND Post-MI depression is defined as the presence of depression after MI. However, only about one-half of post-MI depressions represent an incident episode, whereas the other half are ongoing or recurrent depressions. We investigated whether these subtypes differ in cardiovascular prognosis. METHODS A total of 468 MI patients were assessed for the presence of an International Classification of Diseases-10 depressive disorder during the year after index MI. A comparison was made on new cardiovascular events (mean follow up: 2.5 years) between patients with no, incident, and non-incident post-MI depression by survival analysis. RESULTS Compared with non-depressed patients, those with an incident depression had an increased risk of cardiovascular events (hazard ratio [HR] 1.65; 95% confidence interval [CI] 1.02 to 2.65), but not those with a non-incident depression (HR 1.12; 95% CI 0.61 to 2.06), which remained after controlling for confounders (HR 1.76; 95% CI 1.06 to 2.93 and HR 1.39; 95% CI 0.74 to 2.61, respectively). CONCLUSIONS Only patients with incident post-MI depression have an impaired cardiovascular prognosis. A more detailed subtyping of post-MI depression is needed, based on an integration of recent findings on the differential impact of depression symptom profiles and personality on cardiac outcomes.