Outcomes after readmission at the index or nonindex hospital following acute myocardial infarction complicated by cardiogenic shock

Little is known about the prevalence and outcomes of readmission to nonindex hospitals after an admission for acute myocardial infarction complicated by cardiogenic shock (AMI‐CS). We aimed to determine the rate of nonindex readmissions following AMI‐CS and to evaluate its association with clinical factors, hospitalization cost, length of stay (LOS), and in‐hospital mortality rates. Hypothesis Nonindex readmission may lead to worse in‐hospital outcomes. Methods We reviewed the data of inpatients with AMI‐CS between 2010 and 2017 using the National Readmission Database. The survey analytical methods recommended by the Healthcare Cost and Utilization Project were used for national estimates. Multiple regression models were used to evaluate the predictors of nonindex readmission, and its association with hospitalization cost, LOS, and in‐hospital mortality rates. Results Of 238 349 patients with AMI‐CS, 28028 (11.76%) had an unplanned readmission within 30 days. Of these patients, 7423 (26.48%) were readmitted to nonindex hospitals. Compared with index readmission, nonindex readmission was associated with higher hospitalization costs (p < .0001), longer LOS (p < .0001), and increased in‐hospital mortality rates (p = .0016). Patients who had a history of percutaneous coronary intervention, received intubation/mechanical ventilation, or left against medical advice during the initial admission had greater odds of a nonindex readmission. Conclusions Over one‐fourth of readmissions following AMI‐CS were to nonindex hospitals. These admissions were associated with higher hospitalization costs, longer LOS, and higher in‐hospital mortality rates. Further studies are needed to evaluate whether a continuity of care plan in the acute hospital setting can improve outcomes after AMI‐CS.