Comparison by meta-analysis of mortality after isolated coronary artery bypass grafting in women versus men

Abstract

Short- and long-term mortality in women who undergo coronary artery bypass grafting (CABG) has been evaluated in multiple studies with conflicting results. The investigators conducted a meta-analysis of all existing studies to evaluate the impact of female gender on mortality in patients who undergo isolated CABG. A comprehensive search of studies published through May 31, 2012 identified 20 studies comparing men and women who underwent isolated CABG. All-cause mortality was evaluated at short-term (postoperative period and/or at 30 days), midterm (1-year), and long-term (5-year) follow-up. Odds ratios (ORs) and 95% confidence interval (CIs) were calculated using a random-effects model. A total of 966,492 patients (688,709 men [71%], 277,783 women [29%]) were included in this meta-analysis. Women were more likely to be older; had significantly greater co-morbidities, including hypertension, diabetes mellitus, hyperlipidemia, unstable angina, congestive heart failure, and peripheral vascular disease; and were more likely to undergo urgent CABG (51% vs 44%, p <0.01). Short-term mortality (OR 1.77, 95% CI 1.67 to 1.88) was significantly higher in women. At midterm and long-term follow-up, mortality remained high in women compared with men. Women remained at increased risk for short-term mortality in 2 subgroup analyses including prospective studies (n = 41,500, OR 1.83, 95% CI 1.59 to 2.12) and propensity score-matched studies (n = 11,522, OR 1.36, 95% CI 1.04 to 1.78). In conclusion, women who underwent isolated CABG experienced higher mortality at short-term, midterm, and long-term follow-up compared with men. Mortality remained independently associated with female gender despite propensity score-matched analysis of outcomes.