Elsevier

American Heart Journal

Volume 170, Issue 6, December 2015, Pages 1161-1169
American Heart Journal

Clinical Investigation
Hospital variation in admission to intensive care units for patients with acute myocardial infarction

https://doi.org/10.1016/j.ahj.2015.09.003Get rights and content

Background

The treatment for patients with acute myocardial infarction (AMI) was transformed by the introduction of intensive care units (ICUs), yet we know little about how contemporary hospitals use this resource-intensive setting and whether higher use is associated with better outcomes.

Methods

We identified 114,136 adult hospitalizations for AMI from 307 hospitals in the 2009 to 2010 Premier database using codes from the International Classification of Diseases, Ninth Revision, Clinical Modification. Hospitals were stratified into quartiles by rates of ICU admission for AMI patients. Across quartiles, we examined in-hospital risk-standardized mortality rates and usage rates of critical care therapies for these patients.

Results

Rates of ICU admission for AMI patients varied markedly among hospitals (median 48%, Q1-Q4 20%-71%, range 0%-98%), and there was no association with in-hospital risk-standardized mortality rates (6% all quartiles, P = .7). However, hospitals admitting more AMI patients to the ICU were more likely to use critical care therapies overall (mechanical ventilation [from Q1 with lowest rate of ICU use to Q4 with highest rate 13%-16%], vasopressors/inotropes [17%-21%], intra-aortic balloon pumps [4%-7%], and pulmonary artery catheters [4%-5%]; P for trend < .05 in all comparisons).

Conclusions

Rates of ICU admission for patients with AMI vary substantially across hospitals and were not associated with differences in mortality, but were associated with greater use of critical care therapies. These findings suggest uncertainty about the appropriate use of this resource-intensive setting and a need to optimize ICU triage for patients who will truly benefit.

Section snippets

Data source

We conducted a retrospective cohort study using a voluntary, fee-supported database maintained by Premier, Inc, for measuring quality and health care use. Through 2010, the Premier database contained data on >324 million cumulative hospital discharges, representing approximately 1 of every 5 hospital discharges nationwide. In addition to information available in standard hospital discharge files, this database contains a date-stamped log of all billed items at the patient level including

Hospital characteristics

We identified 114,136 hospitalizations for AMI in 307 hospitals over the 2-year study period. Of these, 54,527 (48%) involved admission to an ICU on the first hospital day. Among hospitals, the median bed size was 302 (IQR 186-432), median 2-year volume of hospitalizations for AMI was 258 (IQR 84-539), and median 2-year volume of ICU hospitalizations for AMI was 112 (IQR 34-265). Hospitals tended to be located in the South (39%), serve an urban population (83%), and identify as nonteaching

Discussion

We found that ICU admission rates for AMI varied substantially across hospitals but were not associated with differences in overall mortality after accounting for case mix. Hospitals admitting a greater percentage of AMI patients to the ICU were more likely to perform invasive critical care interventions overall, but their use of these interventions and risk-standardized mortality rates were significantly lower in the ICU subgroup of patients with AMI. Together with the similar mortality rates

Disclosures

Dr Krumholz reports that he is the recipient of research agreements with Medtronic and with Johnson & Johnson, through Yale University, to develop methods of clinical trial data sharing and is chair of a cardiac scientific advisory board for UnitedHealth. Dr Masoudi reports having contracts with the Oklahoma Foundation for Medical Quality and the American College of Cardiology Foundation.

References (41)

  • D.P. Wagner et al.

    Identification of low-risk monitor admissions to medical-surgical ICUs

    Chest

    (1987)
  • N.H. Fiebach et al.

    Outcomes in patients with myocardial infarction who are initially admitted to stepdown units: data from the Multicenter Chest Pain Study

    Am J Med

    (1990)
  • J.E. Zimmerman et al.

    The use of risk predictions to identify candidates for intermediate care units. Implications for intensive care utilization and cost

    Chest

    (1995)
  • Committee on Guidelines of the Society of Critical Care Medicine

    Guidelines for organization of critical care units

    JAMA

    (1972)
  • H.W. Day

    An intensive coronary care area

    Dis Chest

    (1963)
  • J.N. Katz et al.

    Evolution of the coronary care unit: clinical characteristics and temporal trends in healthcare delivery and outcomes

    Crit Care Med

    (2010)
  • D.A. Bodin

    Telemetry beyond the ICU

    Nurs Manage

    (2003)
  • R.W. Yeh et al.

    Population trends in the incidence and outcomes of acute myocardial infarction

    N Engl J Med

    (2010)
  • J. Chen et al.

    Recent declines in hospitalizations for acute myocardial infarction for Medicare fee-for-service beneficiaries: progress and continuing challenges

    Circulation

    (2010)
  • R.J. Goldberg et al.

    Thirty-year trends (1975 to 2005) in the magnitude of, management of, and hospital death rates associated with cardiogenic shock in patients with acute myocardial infarction: a population-based perspective

    Circulation

    (2009)

    • Cited by (0)

    Funding/Support: This study was funded by Grant DF10-301 from the Patrick and Catherine Weldon Donaghue Medical Research Foundation in West Hartford, CT; Grant UL1 RR024139-06S1 from the National Center for Advancing Translational Sciences in Bethesda, MD; and Grant U01 HL105270-05 (Center for Cardiovascular Outcomes Research at Yale University) from the National Heart, Lung, and Blood Institute in Bethesda, MD. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Donaghue Foundation or of the National Institutes of Health.

    Role of sponsors: The funding sponsors had no role in the design and conduct of the study; in the collection, management, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.

    m

    Drs Chen and Ranasinghe were affiliated with Yale University School of Medicine and the Center for Outcomes Research and Evaluation, Yale–New Haven Hospital in New Haven, CT, during the time the work was conducted.

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