Operative and late coronary artery bypass grafting outcomes in matched African-American versus Caucasian patients: evidence of a late survival-Medicaid association.

OBJECTIVES: This study sought to determine whether African-American versus Caucasian race is a determinant of early or late coronary artery bypass surgery (CABG) outcomes.
BACKGROUND: African Americans are referred to CABG less frequently than Caucasians and Medicaid coverage is disproportionately common among those who are referred. How these factors affect the relative early and late CABG outcomes in these groups is incompletely elucidated.
METHODS: A retrospective cohort comparison of operative and 12-year outcomes for 304 African-American and 6,073 Caucasian consecutive patients who underwent isolated CABG (1991 to 2003) at an urban community hospital was used. Results were further confirmed in propensity-matched subgroups (n = 301 each).
RESULTS: African Americans were younger (62 vs. 64 years, median), more were female (46% vs. 30%), more were on Medicaid (29% vs. 6.3%) and had more comorbidities. These differences were eliminated after matching. A total of 161 operative and 1,080 late deaths have been documented. Operative mortality was similar (African American versus Caucasian: 3.0% vs. 2.5%; p = 0.81). Unadjusted Kaplan-Meier survival at 1, 5, and 10 years (93.4%, 80.3%, and 66.1% vs. 94.8%, 86.5%, and 71.7%) was worse in African Americans (hazard ratio [HR] = 1.38; p = 0.004), but similar for matched groups (HR = 1.03; p = 0.97). After risk adjustment, race did not predict operative (odds ratio = 1.17; p = 0.69) or late (HR = 1.15; p = 0.28) mortality. However, Medicaid status (HR = 1.54; p < 0.005) predicted worse survival, which was verified in a case-matched Medicaid (n = 469) versus non-Medicaid analysis. The latter showed that in younger Medicaid patients without companion Medicare coverage, late mortality was nearly doubled (HR = 1.96; p = 0.003) with systematically increasing death hazard after the second year.
CONCLUSIONS: African-American race per se is not associated with worse operative or late outcomes underscoring that CABG should be based on clinical characteristics only. Alternatively, Medicaid status, which is more prevalent among African Americans, is associated with worse late survival, especially in non-Medicare patients. Studies are needed to elucidate this late Medicaid-CABG outcome association.