title: Severe Influenza in 33 US Hospitals, 2013-2014: Complications and Risk Factors for Death in 507 Patients.
abstract: BACKGROUND
  Influenza A (H1N1) pdm09 became the predominant circulating strain in the United States during the 2013-2014 influenza season. Little is known about the epidemiology of severe influenza during this season.
  
  
  METHODS
  A retrospective cohort study of severely ill patients with influenza infection in intensive care units in 33 US hospitals from September 1, 2013, through April 1, 2014, was conducted to determine risk factors for mortality present on intensive care unit admission and to describe patient characteristics, spectrum of disease, management, and outcomes.
  
  
  RESULTS
  A total of 444 adults and 63 children were admitted to an intensive care unit in a study hospital; 93 adults (20.9%) and 4 children (6.3%) died. By logistic regression analysis, the following factors were significantly associated with mortality among adult patients: older age (>65 years, odds ratio, 3.1 [95% CI, 1.4-6.9], P=.006 and 50-64 years, 2.5 [1.3-4.9], P=.007; reference age 18-49 years), male sex (1.9 [1.1-3.3], P=.031), history of malignant tumor with chemotherapy administered within the prior 6 months (12.1 [3.9-37.0], P<.001), and a higher Sequential Organ Failure Assessment score (for each increase by 1 in score, 1.3 [1.2-1.4], P<.001).
  
  
  CONCLUSIONS
  Risk factors for death among US patients with severe influenza during the 2013-2014 season, when influenza A (H1N1) pdm09 was the predominant circulating strain type, shifted in the first postpandemic season in which it predominated toward those of a more typical epidemic influenza season.
authors.affiliation: 1Department of Medicine,University of Chicago,Chicago,Illinois.
authors.forename: Nirav S
authors.initials: NS
authors.lastname: Shah
authors.affiliation: 1Department of Medicine,University of Chicago,Chicago,Illinois.
authors.forename: Jared A
authors.initials: JA
authors.lastname: Greenberg
authors.affiliation: 1Department of Medicine,University of Chicago,Chicago,Illinois.
authors.forename: Moira C
authors.initials: MC
authors.lastname: McNulty
authors.affiliation: 2Department of Medicine,University of Michigan Medical School,Ann Arbor,Michigan.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Gregg
authors.affiliation: 2Department of Medicine,University of Michigan Medical School,Ann Arbor,Michigan.
authors.forename: James
authors.initials: J
authors.lastname: Riddell
authors.affiliation: 3Department of Medicine,Ohio State University Wexner Medical Center,Columbus,Ohio.
authors.forename: Julie E
authors.initials: JE
authors.lastname: Mangino
authors.affiliation: 3Department of Medicine,Ohio State University Wexner Medical Center,Columbus,Ohio.
authors.forename: Devin M
authors.initials: DM
authors.lastname: Weber
authors.affiliation: 3Department of Medicine,Ohio State University Wexner Medical Center,Columbus,Ohio.
authors.forename: Courtney L
authors.initials: CL
authors.lastname: Hebert
authors.affiliation: 5Department of Medicine,University of Colorado Denver,Denver,Colorado.
authors.forename: Natalie S
authors.initials: NS
authors.lastname: Marzec
authors.affiliation: 5Department of Medicine,University of Colorado Denver,Denver,Colorado.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Barron
authors.affiliation: 6Department of Medicine,Vidant Medical Center,Greenville,North Carolina.
authors.forename: Fredy
authors.initials: F
authors.lastname: Chaparro-Rojas
authors.affiliation: 7Department of Medicine,Baylor College of Medicine,Houston,Texas.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Restrepo
authors.affiliation: 7Department of Medicine,Baylor College of Medicine,Houston,Texas.
authors.forename: Vagish
authors.initials: V
authors.lastname: Hemmige
authors.affiliation: 8Department of Medicine,University of Iowa Hospitals and Clinics,Iowa City,Iowa.
authors.forename: Kunatum
authors.initials: K
authors.lastname: Prasidthrathsint
authors.affiliation: 8Department of Medicine,University of Iowa Hospitals and Clinics,Iowa City,Iowa.
authors.forename: Sandra
authors.initials: S
authors.lastname: Cobb
authors.affiliation: 8Department of Medicine,University of Iowa Hospitals and Clinics,Iowa City,Iowa.
authors.forename: Loreen
authors.initials: L
authors.lastname: Herwaldt
authors.affiliation: 9Department of Pediatrics,University of California San Diego and Rady Children's Hospital San Diego,San Diego,California.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Raabe
authors.affiliation: 9Department of Pediatrics,University of California San Diego and Rady Children's Hospital San Diego,San Diego,California.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Cannavino
authors.affiliation: 10Department of Medicine,University of Nebraska Medical Center,Omaha,Nebraska.
authors.forename: Andrea Green
authors.initials: AG
authors.lastname: Hines
authors.affiliation: 10Department of Medicine,University of Nebraska Medical Center,Omaha,Nebraska.
authors.forename: Sara H
authors.initials: SH
authors.lastname: Bares
authors.affiliation: 11Department of Medicine,Loyola University Medical Center,Maywood,Illinois.
authors.forename: Philip B
authors.initials: PB
authors.lastname: Antiporta
authors.affiliation: 13Department of Pharmacy,Loyola University Medical Center,Maywood,Illinois.
authors.forename: Tonya
authors.initials: T
authors.lastname: Scardina
authors.affiliation: 14Department of Pharmacy,Edward Hines VA Hospital,Maywood,Illinois.
authors.forename: Ursula
authors.initials: U
authors.lastname: Patel
authors.affiliation: 11Department of Medicine,Loyola University Medical Center,Maywood,Illinois.
authors.forename: Gail
authors.initials: G
authors.lastname: Reid
authors.affiliation: 15Department of Medicine,University of Texas Southwestern Medical Center,Dallas,Texas.
authors.forename: Parvin
authors.initials: P
authors.lastname: Mohazabnia
authors.affiliation: 15Department of Medicine,University of Texas Southwestern Medical Center,Dallas,Texas.
authors.forename: Suresh
authors.initials: S
authors.lastname: Kachhdiya
authors.affiliation: 15Department of Medicine,University of Texas Southwestern Medical Center,Dallas,Texas.
authors.forename: Binh-Minh
authors.initials: BM
authors.lastname: Le
authors.affiliation: 16Department of Medicine,Montefiore Medical Center/Albert Einstein College of Medicine,Bronx,New York.
authors.forename: Connie J
authors.initials: CJ
authors.lastname: Park
authors.affiliation: 16Department of Medicine,Montefiore Medical Center/Albert Einstein College of Medicine,Bronx,New York.
authors.forename: Belinda
authors.initials: B
authors.lastname: Ostrowsky
authors.affiliation: 1Department of Medicine,University of Chicago,Chicago,Illinois.
authors.forename: Ari
authors.initials: A
authors.lastname: Robicsek
authors.affiliation: 17Department of Medicine,Northshore University HealthSystem,Evanston,Illinois.
authors.forename: Becky A
authors.initials: BA
authors.lastname: Smith
authors.affiliation: 18Department of Pediatrics,University of Chicago,Chicago,Illinois.
authors.forename: Jeanmarie
authors.initials: J
authors.lastname: Schied
authors.affiliation: 18Department of Pediatrics,University of Chicago,Chicago,Illinois.
authors.forename: Micah M
authors.initials: MM
authors.lastname: Bhatti
authors.affiliation: 19Department of Medicine,University of Illinois at Chicago,Chicago,Illinois.
authors.forename: Stockton
authors.initials: S
authors.lastname: Mayer
authors.affiliation: 19Department of Medicine,University of Illinois at Chicago,Chicago,Illinois.
authors.forename: Monica
authors.initials: M
authors.lastname: Sikka
authors.affiliation: 19Department of Medicine,University of Illinois at Chicago,Chicago,Illinois.
authors.forename: Ivette
authors.initials: I
authors.lastname: Murphy-Aguilu
authors.affiliation: 21Department of Medicine,Community Care Networks,Munster,Indiana.
authors.forename: Priti
authors.initials: P
authors.lastname: Patwari
authors.affiliation: 22Department of Medicine,University of California San Diego,San Diego,California.
authors.forename: Shira R
authors.initials: SR
authors.lastname: Abeles
authors.affiliation: 22Department of Medicine,University of California San Diego,San Diego,California.
authors.forename: Francesca J
authors.initials: FJ
authors.lastname: Torriani
authors.affiliation: 23Department of Medicine,Methodist Hospitals,Merrillville,Indiana.
authors.forename: Zainab
authors.initials: Z
authors.lastname: Abbas
authors.affiliation: 23Department of Medicine,Methodist Hospitals,Merrillville,Indiana.
authors.forename: Sophie
authors.initials: S
authors.lastname: Toya
authors.affiliation: 24Department of Medicine,University of Miami/Jackson Health System,Miami,Florida.
authors.forename: Katherine
authors.initials: K
authors.lastname: Doktor
authors.affiliation: 24Department of Medicine,University of Miami/Jackson Health System,Miami,Florida.
authors.forename: Anindita
authors.initials: A
authors.lastname: Chakrabarti
authors.affiliation: 24Department of Medicine,University of Miami/Jackson Health System,Miami,Florida.
authors.forename: Susanne
authors.initials: S
authors.lastname: Doblecki-Lewis
authors.affiliation: 25Department of Medicine,VA San Diego/University of California San Diego,San Diego,California.
authors.forename: David J
authors.initials: DJ
authors.lastname: Looney
authors.affiliation: 1Department of Medicine,University of Chicago,Chicago,Illinois.
authors.forename: Michael Z
authors.initials: MZ
authors.lastname: David
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000998:Antiviral Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006761:Hospitals; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines / Q000627:therapeutic use; D007251:Influenza, Human / Q000188:drug therapy / Q000401:mortality*; D007362:Intensive Care Units; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D007252:Influenza Vaccines