Abstract MP79: Pre-Admission History of Depression and Mortality After Acute Myocardial Infarction

Abstract

Background: Whether a diagnosis of depression after developing an acute myocardial infarction (AMI) is linked to a worse prognosis remains a matter of debate after several RCTs of interventions to treat post-AMI depression have yielded negative results. A possible explanation is that depressive symptoms after AMI may be part of the normal adjustment to an adverse life event. A pre-admission history of depression could better identify patients who may derive the most benefit from depression treatment. The objective of this study was to evaluate whether a pre-admission history of depression was associated with a worse post-discharge prognosis among patients with AMI. Methods: This was a secondary analysis conducted among patients included (biennial basis between 1999-2009) in the Worcester Heart Attack Study, an ongoing epidemiologic study examining long-term trends in the clinical outcomes of AMI among residents of the Worcester, MA metropolitan area. The exposure was defined as a physician-recorded diagnosis of depression preceding the index hospitalization for AMI based on the review of hospital medical records (MR). The outcome was all-cause death rates in-hospital and 1-year post discharge. Information regarding demographics, medical history, in-hospital treatment, and discharge status was abstracted from the MR by trained study physicians and nurses. Survival status after discharge was obtained from the MR and from death certificates. Univariate and multivariate logistic regression models were used to assess associations between depression and the outcome. Results: This analysis included 5,068 patients (mean age 70 years, 44% women). Approximately 16% of patients had a history of depression pre-admission. No significant differences were found between patients with and without a history of depression with regard to in-hospital mortality (11.5% vs. 9.9%; unadjusted OR=1.18; 95% CI: 0.95, 1.48). At 1 year after discharge all-cause mortality was significantly higher among patients with a pre-admission history of depression (27.5% vs. 18.2%; unadjusted OR=1.71; 95% CI: 1.44, 2.02). While the association between history of depression and in-hospital mortality was largely explained by confounding, the association with 1 year mortality remained significant even after adjustment for demographics, coronary risk factors, co-morbidities, clinical characteristics and medications at discharge (OR=1.57; CI: 1.24, 1.98). Conclusions: In this community-based cohort of patients hospitalized with AMI at different hospitals in central MA, a pre-admission history of depression was an independent predictor of all-cause mortality 1 year after MI. Documentation of a history of depression in the medical record could be a simple tool for cardiologists and primary care physicians to identify high-risk patients who may benefit from depression treatment.