Sex-based Disparities in Morbidity and Mortality Following Coronary Artery Bypass Grafting: an Updated Systematic Review and Meta-analysis

Sex is suggested to play a role in influencing outcomes after coronary artery bypass grafting (CABG). However, the evidence regarding its impact on long-term mortality and other clinical outcomes remains inconclusive. Our study aims to comprehensively analyze and elucidate sex differences in morbidity and mortality among individuals undergoing CABG. A systematic search was performed of the following databases MEDLINE (via PubMed), Google Scholar, the Cochrane Library, and ScienceDirect to identify studies on sex differences in post-CABG outcomes from January 2010 to April 2024. Statistical analysis was performed using RevMan 5.4, applying an inverse variance random effects model to pool hazard ratio (HR) and odds ratio (OR) for primary and secondary outcomes. The study protocol is registered with PROSPERO (CRD42024516859). The final analysis comprised 35 studies involving 14,740,743 participants, with 34.4% being females. The average age was 67.2 years for females and 63.7 years for males. Upon pooled analysis, no statistically significant differences were observed in the composite outcome of major adverse cardiovascular events (MACE) (HR: 1.03, 95% CI: 0.89 to 1.19, p = 0.69). However, there was a significant increase in the risk of all-cause mortality in females, with a reported HR of 1.14 (95% CI: 1.09 to 1.19, p < 0.00001). Similarly, females showed a statistically significant higher risk of short-term mortality (in-hospital/30-day mortality) with an OR of 1.73 (95% CI: 1.61 to 1.86, p < 0.00001) and postoperative stroke with an OR of 1.28 (95% CI: 1.15 to 1.43, p < 0.00001), respectively. In contrast, the incidence of myocardial infarction (MI) (OR: 1.13, 95% CI: 0.97 to 1.32, p = 0.12), cardiovascular mortality (OR: 1.67, 95% CI: 0.84 to 3.32, p = 0.14), and repeat revascularization (OR: 1.42, 95% CI: 0.30 to 6.68, p = 0.66) did not show statistically significant differences between females and males. In conclusion, females undergoing CABG exhibited an increased risk of all-cause mortality, short-term mortality, and postoperative stroke, underscoring the need for focused efforts to understand and mitigate this sex-based disparity.