title: Evaluating risk factors for Clostridium difficile infection in adult and pediatric hematopoietic cell transplant recipients.
abstract: BACKGROUND
  Although hematopoietic cell transplant (HCT) recipients are routinely exposed to classic risk factors for Clostridium difficile infection (CDI), few studies have assessed CDI risk in these high-risk patients, and data are especially lacking for pediatric HCT recipients. We aimed to determine incidence and risk factors for CDI in adult and pediatric allogeneic HCT recipients.
  
  
  METHODS
  CDI was defined as having diarrhea that tested positive for C. difficile via PCR, cytotoxin assay, or dual enzyme immunoassays. We included all patients who received an allogeneic HCT from 2008 to 2012 at the Fred Hutchinson Cancer Research Center; those <1 year old or with CDI within 8 weeks pre-HCT were excluded. Patients were categorized by transplanting hospital ("adult" or "pediatric") and followed for 100 days post-HCT.
  
  
  RESULTS
  Of 1182 HCT recipients, CDI was diagnosed in 17 % (33/192) of pediatric recipients for an incidence of 20 per 10,000 patient-days, and 11 % (107/990) of adult recipients for an incidence of 12 per 10,000. Pediatric recipients were diagnosed a median of 51 days (interquartile range [IQR]: 5, 72) after HCT and adults at 16 days (IQR = 5, 49). Compared with calendar year 2008, pediatric recipients transplanted in 2012 were at increased risk for CDI (hazard ratio [HR] = 3.99, p =.02). Myeloablative conditioning increased CDI risk in adult recipients (HR = 1.81, p =.005).
  
  
  CONCLUSIONS
  Pediatric and adult allogeneic recipients are at high risk of CDI post-HCT, particularly adult recipients of myeloablative conditioning. Differences in CDI incidence between children and adults may have resulted from exposure differences related to age; therefore, separately evaluating these groups should be considered in future CDI studies.
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA USA.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Boyle
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA USA ; Department of Biostatistics, University of Washington, Seattle, WA USA ; Department of Laboratory Medicine, University of Washington, Seattle, WA USA.
authors.forename: Amalia
authors.initials: A
authors.lastname: Magaret
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA USA.
authors.forename: Zach
authors.initials: Z
authors.lastname: Stednick
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Morrison
authors.affiliation: Department of Laboratory Medicine, University of Washington, Seattle, WA USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Butler-Wu
authors.affiliation: Seattle Children's Hospital, Seattle, WA USA ; Department of Pediatrics, University of Washington, Seattle, WA USA.
authors.forename: Danielle
authors.initials: D
authors.lastname: Zerr
authors.affiliation: Seattle Children's Hospital, Seattle, WA USA.
authors.forename: Karin
authors.initials: K
authors.lastname: Rogers
authors.affiliation: Washington State Department of Health, Shoreline, WA USA.
authors.forename: Sara
authors.initials: S
authors.lastname: Podczervinski
authors.affiliation: Department of Biostatistics, University of Washington, Seattle, WA USA.
authors.forename: Anqi
authors.initials: A
authors.lastname: Cheng
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA USA ; Department of Laboratory Medicine, University of Washington, Seattle, WA USA ; Department of Medicine, University of Washington, Seattle, WA USA ; Department of Epidemiology, University of Washington, Seattle, WA USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Wald
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA USA ; Department of Medicine, University of Washington, Seattle, WA USA ; Infection Prevention, Seattle, WA USA.
authors.forename: Steven A
authors.identifier: 0000-0002-6333-5196
authors.initials: SA
authors.lastname: Pergam
keywords: Adult; Allogeneic; Clostridium difficile; Hematopoietic; Pediatric; Transplant