Depression is associated with increased mortality 10 years after coronary artery bypass surgery.

OBJECTIVE: To determine if depression is independently associated with cardiac and all-cause mortality 10 years after coronary artery bypass graft (CABG) surgery. Although many studies have examined the relationship of depression and mortality in patients with myocardial infarction, there is less understanding of the relationship between depression and long-term mortality after CABG surgery.
METHODS: In a prospective study, we collected data on 309 patients hospitalized after CABG surgery. Before discharge, patients were assessed for depression using the Diagnostic Interview Schedule and the Beck Depression Inventory (BDI). Subsequently, mortality data were obtained from the National Center for Health Statistics and supplemented with phone interviews.
RESULTS: Sixty-three (20%) patients met modified Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for major depressive disorder (MDD) and 87 (28%) had BDI scores of ≥10, indicating elevated depressive symptoms. Time-to-event or last follow-up phone contact ranged from 9 days to 11.5 years (median, 9.3 years). The overall mortality rate was 37.9% (117 of 309), with 20.1% (62 of 309) due to cardiac causes. Cox proportional hazard modeling showed that age (hazard ratio [HR], 1.04; p = .005), left ventricular ejection fraction (EF) (EF <0.35 [HR], 3.9; p < .001; EF, 0.35-0.49 [HR], 1.9; p = .03), and MDD (HR, 1.8; p = .04) were independent predictors of cardiac mortality. The BDI and the cognitive-affective symptoms subset of BDI symptoms were also predictors of cardiac mortality. Age, EF, and diabetes predicted all-cause mortality, but MDD did not.
CONCLUSIONS: Depression, assessed both in structured interview and by BDI, was significantly associated with elevated cardiac mortality 10 years after CABG surgery.