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Changes in the Source of Unscheduled Hospitalizations in the United States

Kocher, Keith E. MD, MPH*,†; Dimick, Justin B. MD, MPH†,‡; Nallamothu, Brahmajee K. MD, MPH†,§

doi: 10.1097/MLR.0b013e3182992c7b
Original Articles

Background: Hospitalizations represent a significant portion of the annual expenditures for the US health care system. Understanding recent changes in the sources of unscheduled admissions may provide opportunities to improve the quality and cost of inpatient care.

Objectives: To examine sources of unscheduled hospitalization over a 10-year period and implications for inpatient mortality and length of stay (LOS).

Research Design: Observational study using the 2000–2009 Nationwide Inpatient Sample.

Subjects: We categorized unscheduled hospitalizations as those related to transfers, direct admissions from outpatient providers, and the emergency department (ED).

Measures: Hospitalization rates by source and clinical condition with multivariable regression analyses adjusted for patient demographics, comorbid conditions, and hospital factors to evaluate associated mortality and LOS outcomes.

Results: Unscheduled hospitalizations arising from direct admissions and the ED changed substantially while those due to transfers remained relatively stable. The ED admitted 64.9% [95% confidence interval (CI), 62.8%–66.9%] of unscheduled hospitalizations in 2000, rising to 81.8% (95% CI, 80.5%–83.1%) by 2009, whereas direct admissions from outpatient providers correspondingly declined. In 2009, despite higher illness severity and chronic disease burden, hospitalization through the ED as compared with direct admissions was associated with an overall lower mortality adjusted odds ratio of 0.85 (95% CI, 0.77–0.93) and shorter adjusted hospital LOS of −0.84 (95% CI, −0.99 to −0.70) days.

Conclusions: Sources of unscheduled hospitalization in the United States have evolved, mostly resulting from care for a variety of clinical conditions now originating in the ED. This trend does not seem to be harming patients or worsening LOS.

Supplemental Digital Content is available in the text.

*Department of Emergency Medicine

Center for Healthcare Outcomes and Policy (CHOP)

Department of Surgery, University of Michigan

§The VA Ann Arbor Health Services Research & Development Center of Excellence and the University of Michigan Division of Cardiovascular Medicine, Ann Arbor, MI

Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website,

The authors declare no conflict of interest.

Reprints: Keith E. Kocher, MD, MPH, Department of Emergency Medicine, University of Michigan, NCRC, 2800 Plymouth Rd, Building 16, Room 152S, Ann Arbor, MI 48109-2800. E-mail:

© 2013 by Lippincott Williams & Wilkins.