title: Regional and seasonal variation in Clostridium difficile infections among hospitalized patients in the United States, 2001-2010.
abstract: BACKGROUND
  This study identified national regional and seasonal variations in Clostridium difficile infection (CDI) incidence and mortality among hospitalized patients in the United States over a 10-year period.
  
  
  METHODS
  This was a retrospective cohort study of the U.S. National Hospital Discharge Survey from 2001-2010. Eligible cases had an ICD-9-CM discharge diagnosis code for CDI (008.45). Data weights were used to derive national estimates. CDI incidence and mortality were presented descriptively. Regions were as defined by the U.S. Census Bureau. Seasons included the following: winter (December-February), spring (March-May), summer (June-August), and fall (September-November).
  
  
  RESULTS
  These data represent 2.3 million CDI discharges. Overall, CDI incidence was highest in the Northeast (8.0 CDIs/1,000 discharges) and spring (6.2 CDIs/1,000 discharges). CDI incidence was lowest in the West (4.8 CDIs/1,000 discharges) and fall (5.6 CDIs/1,000 discharges). Peak CDI incidence among children occurred in the West (1.7 CDI/1,000 discharges) and winter (1.5 CDI/1,000 discharges). Mortality among all CDI patients was highest in the Midwest (7.3%) and during the winter (7.9%).
  
  
  CONCLUSIONS
  The region and season with the highest CDI incidence rates among patients hospitalized in U.S. hospitals were the Northeast and spring, respectively. The highest CDI mortality rates were seen in the Midwest and winter. Children exhibited different regional and seasonal CDI variations compared with adults and older adults.
authors.affiliation: Pharmacotherapy Division, College of Pharmacy, University of Texas at Austin, Austin, TX; Pharmacotherapy Education and Research Center, School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Jacqueline R
authors.initials: JR
authors.lastname: Argamany
authors.affiliation: Division of Pharmacy, University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Aitken
authors.affiliation: Pharmacotherapy Division, College of Pharmacy, University of Texas at Austin, Austin, TX; Pharmacotherapy Education and Research Center, School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Grace C
authors.initials: GC
authors.lastname: Lee
authors.affiliation: Pharmacotherapy Division, College of Pharmacy, University of Texas at Austin, Austin, TX; Pharmacotherapy Education and Research Center, School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Natalie K
authors.initials: NK
authors.lastname: Boyd
authors.affiliation: Pharmacotherapy Division, College of Pharmacy, University of Texas at Austin, Austin, TX; Pharmacotherapy Education and Research Center, School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX. Electronic address: kdaniels46@utexas.edu.
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Reveles
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D016360:Clostridioides difficile / Q000302:isolation & purification*; D003015:Clostridium Infections / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D015331:Cohort Studies; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D003967:Diarrhea / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D005260:Female; D006761:Hospitals; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012621:Seasons; D062211:Spatio-Temporal Analysis; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Clostridium difficile; Epidemiology; Mortality