Sex-based differences in 30-day readmission after coronary artery bypass grafting (CABG): a multisite retrospective study
M Abbs, L Mc Tier, S Matthews, J Angel, M Seitz, P Skillington, A Newcomb, R WynneAbstract
Background
Despite approximately 15% of patients globally experiencing unplanned 30-day readmission following coronary artery bypass grafting (CABG), sex-based rates and reasons are under-investigated.
Purpose
To explore sex-based differences in unplanned 30-day readmission rate, reasons for readmission, and temporal trends in readmission after first-time isolated CABG.
Methods
Retrospective cohort study using a decade (2014-2023) of data from a major metropolitan and regional centre in Victoria, Australia. Data were extracted from site specific Australia and New Zealand Society of Cardiothoracic Surgeons (ANZSCTS) repositories. Direct entry logistic regression modelling was used to examine sex-based differences.
Results
From 2014-2023, 5380 (60.2%) and 3555 (39.8%) consecutive adult (>18 years) patients from metropolitan and regional sites respectively, 2358 (43.8%) metropolitan and 1960 (55.1%) regional patients had first-time isolated CABG. Women (n=756, 17.5%) were older, less likely to have smoked, more likely to have diabetes, hypercholesterolaemia, hypertension, and lung disease. More women had ‘off pump’ surgery, and women had fewer grafts. Bradyarrhythmia requiring postoperative permanent pacemaker insertion was more common in women. There were no sex-based differences in incidence of other perioperative complications or in-hospital mortality, yet women were in hospital longer and less likely to be directly discharged home. Women (n=99, 13.2%) were more likely to be readmitted than men (n=319, 9.1%; p < 0.001) overall but reasons for readmission did not differ according to sex. The proportion of women having surgery was consistent across the decade (Range 14.6%-2022, 19.5%-2020). A model of factors associated with readmission (χ2 (7, n = 4318) = 35.6, p < 0.001; Hosmer-Lemeshow Goodness of Fit 0.17), did not explain variability in readmission rate (Nagelkere R2 1.8%). Sex (OR 1.5, 95% CI 1.2-1.9) and preoperative arrhythmia (OR 1.7, 95% CI 1.2-2.3) increased risk of readmission.
Conclusion
Women undergoing first-time isolated CABG had a significantly higher risk of unplanned 30-day readmission independent of co-morbidity burden, highlighting the need for sex-specific perioperative risk stratification and investigation of post-discharge management strategies.