Coronary disease & ACS

Intraoperative Anemia Mediates Sex Disparity in Operative Mortality After Coronary Artery Bypass Grafting

J Am Coll CardiolPublished Retrospective cohort study

Main finding · Operative mortalityResult — go to the resultAdjusted odds ratio 1.36 95% CI 1.30–1.41

Authors' conclusion

The association of female sex with increased CABG operative mortality is mediated to a large extent by intraoperative anemia.

Study context

Population
Patients undergoing isolated primary coronary artery bypass grafting (CABG), STS Adult Cardiac Surgery Database, 2011–2022
Participants
1,434,225 patients
Exposure
Women vs men
  • Womenn = 344,357
Outcome
Operative mortality
Methodological detailsregistry database, causal mediation analysis
  • Registry database
  • Causal mediation analysis

Main finding

Operative mortality

Adjusted odds ratio

1.36

95% CI 1.30–1.41

P < 0.001

By group

Women vs Men
adjusted OR 1.36 (95% CI 1.30–1.41); P < 0.001

As reported in the abstract

Attributable risk (AR) of female sex for operative mortality
1.21 (95% CI: 1.17-1.24)
AR after adjusting for nadir intraoperative hematocrit (reduced by 43%)
1.12 (95% CI: 1.09-1.16)
Proportion of increased mortality risk with female sex mediated by intraoperative anemia
38.5% (95% CI: 32.3%-44.7%)

Observational data: associations, not effects.

Further findings

Median

OutcomeWomenMenStandardized mean difference
Nadir intraoperative hematocrit22.0% (IQR 20.0%–25.0%)27.0% (IQR 24.0%–30.0%)97.0%

Operative mortality vs nadir hematocrit (spline regression)

Stronger association at hematocrit values <22.0%
P < 0.001

Original publication

Intraoperative Anemia Mediates Sex Disparity in Operative Mortality After Coronary Artery Bypass Grafting. J Am Coll Cardiol. Published 5 March 2024. doi:10.1016/j.jacc.2023.12.032

Summarised from the published abstract; every number is checked against it

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