Abstract 345: Hospital Variation in Admission to Intensive Care Units for Patients with Acute Myocardial Infarction

Abstract

Background: The intensive care unit (ICU) has been credited with reducing mortality for patients hospitalized with AMI in a past era when life-threatening post-infarction ventricular arrhythmias were more common. With the evolution in the clinical profile and treatment of AMI, the marginal benefit of ICU care for many patients is less clear. As a result, the use of ICU care for patients with AMI may vary substantially among institutions, creating implications for treatment strategies and patient outcomes. Methods: We identified 114,980 hospitalizations for AMI from 311 hospitals in the 2009-10 Premier database using ICD-9-CM codes. We excluded hospitals with <25 AMI admissions, patients <18 yrs, and transfers. Hospitals were stratified into quartiles by rates of ICU admission for AMI patients. For each quartile, we calculated (1) usage rates of critical care therapies and (2) in-hospital risk-standardized mortality rates (RSMRs) among all patients admitted with AMI. Kruskal-Wallis and Cochran-Armitage Trend tests assessed for statistical significance. Results: ICU admission rates for AMI patients varied markedly among hospitals (median 48%, IQR 35%-61%, range 0%-98%, Figure). Hospitals admitting more AMI patients to the ICU (higher quartiles) were (1) more likely to use critical care therapies in AMI patients overall (mechanical ventilation [Q1 to Q4: 13% to 16%], vasopressors/inotropes [17% to 21%], intra-aortic balloon pumps [4% to 7%], and pulmonary artery catheters [4% to 5%]; p for trend<0.05 in all comparisons). However, (2) there was no association between the hospital ICU admission rate and overall RSMR for all AMI patients (6% all quartiles; p=0.7271, Figure). Conclusion: ICU admission rates for AMI vary substantially across hospitals with evidence of greater use of ICU therapies in high admitting hospitals but without evidence of lower overall mortality. There is a need for further research to determine the optimal use of ICU care for contemporary populations of patients with AMI.