Readmission destination following cardiac surgery and its association with mortality outcomes: a population-based...

It is unclear how pre-surgery transfer relates to readmission destination among patients undergoing cardiac surgery and whether readmission to a hospital other than the operating hospital is associated with increased mortality.

We analysed linked hospital and death records for residents of New South Wales, Australia, aged ≥18 years who had an emergency readmission within 30 days following coronary artery bypass graft (CABG) or surgical aortic valve replacement (SAVR) in 2003-2022. Mixed-effect multi-level modelling was used to evaluate associations of readmission destination with 30-day mortality, overall and stratified by pre-surgery transfer.

Of 102,540 patients undergoing cardiac surgery (isolated CABG = 63,000, SAVR = 27,482, combined = 12,058), 28.7% (n = 29,398) had pre-surgery transfer, while the 30-day readmission rate was 14.7% (n = 14,708). During readmission, 35.7% (3499/9795) of those without pre-surgery transfer and 12.0% (590/4913) of those with pre-surgery transfer returned to the operating hospital. Among readmitted patients, 30-day mortality did not differ significantly for those who were readmitted to a non-index hospital, both overall (adjusted odds ratio [aOR] = 1.03 95% CI 0.75-1.41), and in analyses stratified by pre-surgery transfer (no transfer: aOR = 1.07, 95% CI 0.75-1.52; transfer: aOR = 0.88, 95% CI 0.45-1.72). Among patients who had pre-surgery transfer, 30-day mortality was similar among patients who were readmitted to the index operating hospital (reference), the initial admitting hospital (aOR = 1.00, 95% CI 0.50-2.00) or a third, different, hospital (aOR = 0.70, 95% CI 0.33-1.48).

Although many Australian patients who are readmitted following cardiac surgery are readmitted to hospitals different to the operating or initial admitting hospital, such readmissions are not associated with increased mortality.

This study was funded by a National Health and Medical Research Foundation of Australia (NHMRC) Project Grant (#1162833).