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.