Are racial differences in hospital mortality after coronary artery bypass graft surgery real? A risk-adjusted meta-analysis

BackgroundDespite several reports, there are still conflicting data on the influence of ethnicity on mortality rates associated with coronary artery bypass grafting (CABG). We aimed to get further insights into the effect of race on mortality following CABG by performing a risk adjusted meta-analysis.MethodsRelevant studies were searched on PubMed, Embase, BioMed Central, and the Cochrane Central register. Pairwise meta-analysis was used to estimate the relative risk of hospital death of black, Hispanic, and Asian patients using white patients as reference. Risk adjusted meta-analytic estimates were obtained using generic inverse variance methods with random effect model.ResultsA total of 28 studies were selected for analysis. A total of 21 studies reported on hospital mortality in black (n = 222,892) versus white (n = 3,884,043) patients, 7 studies reported on Hispanic (n = 91,256) versus white (n = 1,458,524) and 9 studies reported on Asian (n = 27,820) versus white (n = 1,081,642). When compared with white patients, adjusted risk of hospital death was significantly greater for black patients (adjusted odds ratio [OR], 1.25; 95% confidence interval [CI], 1.13-1.39; P < .001), and not statistically different for Asian (OR, 1.33; 95% CI, 0.99-1.77; P = .05) and Hispanic patients (adjusted OR, 1.08; 95% CI, 0.94-1.23; P = .26). Meta-regression showed a significant trend toward lower mortality rates in most recent series in both black (P = .02) and white (P = .0007) and Asian (P = .01) but not for Hispanic (P = .41). However, as mortality rates were lower across the different races, the relative disadvantage between the study groups persisted, which may explain the lack of interaction between study period and race effect on mortality for black (adjusted P = .09), Asian (adjusted P = .63), and Hispanic (adjusted P = .97) patients.ConclusionsThe present meta-analysis showed that despite progress is being made in lowering in-hospital mortality rates among the major racial/ethnic groups, ethnical disparities in hospital mortality after CABG remain.