Hospital mortality and thirty day readmission among patients with non-acute myocardial infarction related cardiogenic shock.

Background: Cardiogenic shock (CS) in absence of acute myocardial infarction (AMI) has significant morbidity and mortality. This population of patients has been excluded from prior major randomized trials and observational studies.

Methods: We included patients with CS in absence of AMI from the 2013-14 HCUP's National Readmission Database. 30-day readmissions were studied and etiology for readmission was identified by using ICD-9CM codes in primary diagnosis field. Multivariable mixed effect logistic regression models were created to identify predictors of 30-day readmission and in-hospital mortality, respectively.

Results: We studied 38,198 index admissions with non-AMI CS, with an in-hospital mortality of 35.4%. Mean age, length and cost of stay were 63.6 years, 16.9 days and 69,947$, respectively among survivors of index admission. Among those discharged, 22.6% were readmitted within 30 days with >50% readmissions occurring within 11-days. Cardiovascular etiologies (42.3%), especially heart failure (24.0%) comprised the commonest reason for readmission. Among non-cardiac causes were infectious (11.7%) and respiratory (9.2%) etiologies. Older age (50-64 years odds ratio:1.29, 65-79 years, OR:1.59, ≥80 years OR:2.69), ventilator use (OR:4.25), sepsis (OR:1.12), use of short term devices (intra-aortic balloon pump OR:2.67, Impella/TandemHeart OR:4.84, extracorporeal membrane oxygenation OR:3.68) and non-ischemic cardiomyopathy(OR:0.65) were among the predictors of in-hospital mortality. Older age (65-79 years, OR:1.25, ≥80 years OR:1.41), male sex (OR:1.08), and ventilator use (OR:1.21) predicted higher 30-day readmission.

Conclusion: Both, in-hospital mortality and 30-day readmission among those admitted for non-AMI CS were significantly elevated. The majority of readmissions were due to non-cardiovascular causes. Identifying high-risk factors may help devise strategies to improve quality of care and reduce adverse outcome rates.