Depression as a risk factor for mortality after coronary artery bypass surgery

Background: Studies that have shown clinical depression to be a risk factor for cardiac events after coronary artery bypass graft (CABG) surgery have had small sample sizes, short follow-up, and have not had adequate power to assess mortality. We sought to assess whether depression is associated with an increased risk of mortality. Methods: We assessed 817 patients undergoing CABG at Duke University Medical Center between May, 1989, and May, 2001. Patients completed the Center for Epidemiological Studies-Depression (CES-D) scale before surgery, 6 months after CABG, and were followed-up for up to 12 years. Findings: In 817 patients there were 122 deaths (15%) in a mean follow-up of 5.2 years. 310 patients (38%) met the criterion for depression (CES-D ≥16): 213 (26%) for mild depression (CES-D 16-26) and 97 (12%) for moderate to severe depression (CES-D ≥27). Survival analyses, controlling for age, sex, number of grafts, diabetes, smoking, left ventricular ejection fraction, and previous myocardial infarction, showed that patients with moderate to severe depression at baseline (adjusted hazard ratio [HR] 2.4, [95% CI 1.4-4.0]; p=0.001) and mild or moderate to severe depression that persisted from baseline to 6 months (adjusted HR 2.2, [1.2-4.2]; p=0.015) had higher rates of death than did those with no depression. Interpretation: Despite advances in surgical and medical management of patients after CABG, depression is an important independent predictor of death after CABG and should be carefully monitored and treated if necessary.