Depression After First Hospital Admission for Acute Coronary Syndrome: A Study of Time of Onset and Impact on Survival

We examined incidence of depression after acute coronary syndrome (ACS) and whether the timing of depression onset influenced survival. All first-time hospitalizations for ACS (n = 97,793) identified in the Danish Patient Registry during 2001-2009 and a reference population were followed for depression and mortality via linkage to patient, prescription, and cause-of-death registries until the end of 2012. Incidence of depression (as defined by hospital discharge or antidepressant medication use) and the relationship between depression and mortality were examined using time-to-event models. In total, 19,520 (20.0%) ACS patients experienced depression within 2 years after the event. The adjusted rate ratio for depression in ACS patients compared with the reference population was 1.28 (95% confidence interval (CI): 1.25, 1.30). During 12 years of follow-up, 39,523 (40.4%) ACS patients and 27,931 (28.6%) of the reference population died. ACS patients with recurrent (hazard ratio (HR) = 1.62, 95% CI: 1.57, 1.67) or new-onset (HR = 1.66, 95% CI: 1.60, 1.72) depression had higher mortality rates than patients with no depression. In the reference population, the corresponding relative estimates for recurrent (HR = 1.98, 95% CI: 1.92, 2.05) and new-onset (HR = 2.42, 95% CI: 2.31, 2.54) depression were stronger. Depression is common in ACS patients and is associated with increased mortality independently of time of onset, but here the excess mortality associated with depression seemed to be lower in ACS patients than in the reference population.