Course of depressive symptoms after myocardial infarction and cardiac prognosis: A latent class analysis

Objective: The presence of depressive symptoms after myocardial infarction (MI) is a risk factor for new cardiovascular events. The importance of the course of post-MI depressive symptoms for cardiac prognosis is not clear. We therefore set out to investigate whether different courses of post-MI depressive symptoms can be identified and determine their associations with cardiac events. Methods: Data were derived from the Depression after Myocardial Infarction (DepreMI) study, a naturalistic follow-up study of patients admitted for an MI in four hospitals in the Netherlands (N = 475). Scores on the Beck Depression Inventory (BDI) during hospitalization and at 3, 6, and 12 months post-MI were analyzed. Using latent class analysis (LCA), we identified classes characterized by distinctive courses of depressive symptoms and then examined their link to cardiac prognosis. Results: The prevalence of significant depressive symptoms ranged from 22.7% to 25.5% throughout the post-MI year. Five distinct courses were found: no depressive symptoms (56.4%), mild depressive symptoms (25.7%), moderate and increasing depressive symptoms (9.3%), significant but decreasing depressive symptoms (4.6%), and significant and increasing depressive symptoms (4.0%). Subjects in this last class had, statistically, a significantly higher risk for a new cardiovascular event compared with subjects without depressive symptoms (hazard ratio (HR) = 2.73; p = .01). Controlling for baseline cardiac status and sociodemographic data did not alter the association (HR = 2.46; p = .03). Conclusions: Post-MI depressed subjects with significant and increasing depressive symptoms are at particular risk of new cardiac events. This subgroup may be most suited for evaluation of the effects of antidepressant treatment on cardiac prognosis.