Background Readmission following an acute coronary syndrome (ACS) is frequent in our community. Patient specific factors identifying those at risk of readmission are poorly described.

Methods Data were analysed from 5219 patients with an ACS enrolled in the Australian and New Zealand population of the Global Registry of Acute Coronary Events (GRACE) between 1999 and 2007. Patients who were readmitted for cardiovascular disease within 6 months of discharge were identified; regression analysis was used to predict independent patient factors associated with readmission 1 month and 1–6 months after discharge.

Results 1048 patients (20.1%) were readmitted within 6 months, with a significant proportion (n=434, 41.4%) of readmissions occurring within 30 days of discharge. Readmission within 6 months was associated with a higher incidence of unscheduled cardiac catheterisation (HR 25.64, 95% CI 18.41 to 35.71), unscheduled percutaneous coronary intervention (PCI) (HR 15.78, 95% CI 10.56 to 23.59), stroke (HR 1.92, 95% CI 1.08 to 3.43), and death (HR 2.40, 95% CI 1.66 to 3.49). Recurrent ischemia in hospital and a diagnosis of S-T elevation myocardial infarction during the index admission were associated with the strongest risk of early rehospitalisation, while revascularisation by PCI or coronary artery bypass surgery (CABG) was associated with lowest risk of early readmission. A history of heart failure, prior myocardial infarction or angina was associated with a greater likelihood of later rehospitalisation, whereas revascularisation by CABG was associated with the lowest risk of later rehospitalisation.

Conclusions Several patient and clinical factors identify patients at higher risk of readmission. Identifying these factors and escalating in-hospital and post-discharge care for these higher risk patients may prevent readmission and improve outcome.