title: Impact of the fall 2009 influenza A(H1N1)pdm09 pandemic on US hospitals.
abstract: BACKGROUND
  Understanding how hospitals functioned during the 2009 influenza A(H1N1)pdm09 pandemic may improve future public health emergency response, but information about its impact on US hospitals remains largely unknown.
  
  
  METHODS
  We matched hospital and emergency department (ED) discharge data from the Agency for Healthcare Research and Quality (AHRQ) Healthcare Cost and Utilization Project with community-level influenza-like illness activity during each hospital's pandemic period in fall 2009 compared with a corresponding calendar baseline period. We compared inpatient mortality for sentinel conditions at high-surge versus nonsurge hospitals.
  
  
  RESULTS
  US hospitals experienced a doubling of pneumonia and influenza ED visits during fall 2009 compared with prior years, along with an 18% increase in overall ED visits. Although no significant increase in total inpatient admissions occurred overall, approximately 10% of all study hospitals experienced high surge, associated with higher acute myocardial infarction and stroke case fatality rates. These hospitals had similar characteristics to other US hospitals except that they had higher mortality for acute cardiac illnesses before the pandemic. After adjusting for 2008 case fatality rates, the association between high-surge hospitals and increased mortality for acute myocardial infarction and stroke patients persisted.
  
  
  CONCLUSIONS
  The fall 2009 pandemic period substantially impacted US hospitals, mostly through increased ED visits. For a small proportion of hospitals that experienced a high surge in inpatient admissions, increased mortality from selected clinical conditions was associated with both prepandemic outcomes and surge, highlighting the linkage between daily hospital operations and disaster preparedness.
authors.affiliation: Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services, Washington, DC, USA.
authors.forename: Lewis
authors.initials: L
authors.lastname: Rubinson
authors.forename: Ryan
authors.initials: R
authors.lastname: Mutter
authors.forename: Cecile
authors.initials: C
authors.lastname: Viboud
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Hupert
authors.forename: Timothy
authors.initials: T
authors.lastname: Uyeki
authors.forename: Andreea
authors.initials: A
authors.lastname: Creanga
authors.forename: Lyn
authors.initials: L
authors.lastname: Finelli
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Iwashyna
authors.forename: Brendan
authors.initials: B
authors.lastname: Carr
authors.forename: Raina
authors.initials: R
authors.lastname: Merchant
authors.forename: Devi
authors.initials: D
authors.lastname: Katikineni
authors.forename: Frances
authors.initials: F
authors.lastname: Vaughn
authors.forename: Carolyn
authors.initials: C
authors.lastname: Clancy
authors.forename: Nicole
authors.initials: N
authors.lastname: Lurie
mesh_terms: D000328:Adult; D002648:Child; D004189:Disaster Planning; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D058872:Epidemics; D017052:Hospital Mortality; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology*; D010343:Patient Admission; D011014:Pneumonia / Q000453:epidemiology; D055872:Surge Capacity; D014481:United States / Q000453:epidemiology