Causes and Predictors of 30-Day Readmission in Patients With Acute Myocardial Infarction and Cardiogenic Shock

Abstract

Background: Acute myocardial infarction (AMI) occurs as a result of irreversible damage to cardiac myocytes secondary to lack of blood supply. Cardiogenic shock complicating AMI has significant associated morbidity and mortality, and data on postdischarge outcomes are limited.

Methods and results: We derived the study cohort of patients with AMI and cardiogenic shock from the 2013 to 2014 Healthcare Cost and Utilization Project National Readmission Database. Incidence, predictors, and causes of 30-day readmissions were analyzed. From 43 212 index admissions for AMI with cardiogenic shock, 26 016 (60.2%) survived to discharge and 5277 (20.2% of survivors) patients were readmitted within 30 days. More than 50% of these readmissions occurred within first 10 days. Cardiac causes accounted for 42% of 30-day readmissions (heart failure 20.6%; acute coronary syndrome 11.6%). Among noncardiac causes, respiratory (11.4%), infectious (9.4%), medical or surgical care complications (6.3%), gastrointestinal/hepatobiliary (6.5%), and renal causes (4.8%) were most common. Length of stay ≥8 days (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.70-2.44; P<0.01), acute deep venous thrombosis (OR, 1.26; 95% CI, 1.08-1.48; P<0.01), liver disease (OR, 1.25; 95% CI, 1.03-1.50; P=0.02), systemic thromboembolism (OR, 1.21; 95% CI, 1.02-1.44; P=0.02), peripheral vascular disease (OR, 1.16; 95% CI, 1.07-1.27; P<0.01), diabetes mellitus (OR, 1.16; 95% CI, 1.08-1.24; P<0.01), long-term ventricular assist device implantation (OR, 1.77; 95% CI, 1.23-2.55; P<0.01), intraaortic balloon pump use (OR, 1.10; 95% CI, 1.02-1.18; P<0.01), performance of coronary artery bypass grafting (OR, 0.85; 95% CI, 0.77-0.93; P<0.01), private insurance (OR, 0.72; 95% CI, 0.64-0.80; P<0.01), and discharge to home (OR, 0.85; 95% CI, 0.73-0.98; P=0.03) were among the independent predictors of 30-day readmission.

Conclusions: In-hospital mortality and 30-day readmission in cardiogenic shock complicating AMI are significantly elevated. Patients are readmitted mainly for noncardiac causes. Identification of high-risk factors may guide interventions to improve outcomes within this population.

Keywords: heart failure; mortality; myocardial infarction; readmission; shock, cardiogenic.