Supplementary Material for: Multimorbidity and readmissions in older people with acute coronary syndromes

Aims: To examine the multimorbidity as well as the 30-day and one-year readmission rates, in a large, unselected cohort of elderly patients with acute coronary syndrome (ACS). Methods and results: All patients ≥70 years, hospitalized due to ACS during January 1st 2006 – December 31st 2013 and registered in the SWEDEHEART-registry were included. In-hospital multimorbidity and disease burden were determined. Outcomes included 30-day and one-year: all-cause mortality, any readmission, readmissions due to ACS, heart failure, ischemic stroke, or transient ischemic attack (TIA) and bleeding events. Out of 80 176 patients, 25.6% had ST-elevation myocardial infraction (STEMI) and 74.4% non-ST-segment elevation ACS (NSTE-ACS). The mean age was 79.8 (±6.4 standard deviation) and 43.4% were women. Multimorbidity, or two chronic diseases, were present in 67.7%, thereof in 53.0% of STEMI patients and 72.7% of NSTE-ACS patients. In-hospital mortality was 7.0%. Of the 74 577 patients who survived to discharge, 24.6% were readmitted within 30 days, and 59.5% were readmitted during the following year. Multimorbid patients had a higher risk of readmissions than those without multimorbidity. Multimorbid STEMI were admitted the following year in 56.2% of cases compared to 44.5% of STEMI patients without multimorbidity, adjusted odds ratio (OR) 1.35 (95% confidence interval: 1.26 - 1.45). Multimorbid patients with NSTE-ACS were readmitted in 63.4 of cases the following year compared with 49.1% of those without multimorbidity, adjusted OR 1.42 (1.35 - 1.50). More than half of the readmissions were due to cardiovascular causes (ACS, Stroke, TIA, or heart failure) or bleeding events. Conclusions: Older people with ACS have a high multimorbidity burden and a high readmission rate both within 30-days and one-year. Half of the readmissions were due to a cardiovascular event or a bleeding event. The presence of multimorbidity increases the risk of readmissions for patients with ACS. As hospital admissions are costly for the health care system and can include risks, especially for older patients, there may be opportunities in better risk stratifying this group at discharge for subsequent decrease in readmission rates.