title: Risk factors forClostridium difficileinfection in HIV-infected patients.
abstract: BACKGROUND
  Clostridium difficileinfection is a healthcare-associated infection resulting in significant morbidity. Although immunosuppression is associated withClostridium difficileinfection acquisition and adverse outcomes, the epidemiology ofClostridium difficileinfection in HIV-infected patients has been little studied in the era of antiretroviral therapy. This study identifies the risk factors for acquisition ofClostridium difficileinfection in HIV-infected patients.
  
  
  METHODS
  A retrospective, propensity score-matched case-control study design was employed, with patients selected from our institution's outpatient HIV clinic.Clostridium difficileinfection cases were defined as having positive stool testing plus an appropriate clinical presentation. The propensity score was generated via multiple logistic regression from year of HIV diagnosis, age at first contact, duration of follow-up, gender, and initial CD4 count.
  
  
  RESULTS
  The 46 cases included were matched to a total of 180 controls. Prior antibiotic treatment was a significant predictor ofClostridium difficileinfection (odds ratio: 13, 95% confidence interval: 3.49-48.8,p< .001) as was number of hospital admissions in the preceding year (odds ratio: 4.02, confidence interval: 1.81-8.94,p< .001). Having both proton pump inhibitor use and CD4 count <200 cells/µL significantly increased odds ofClostridium difficileinfection in the multivariable model (odds ratio: 15.17, confidence interval: 1.31-175.9,p= .021).
  
  
  CONCLUSIONS
  As in the general population, frequent hospitalizations and exposure to antimicrobials are independent predictors ofClostridium difficileinfection acquisition in patients with HIV. Additionally, low CD4 count and proton pump inhibitor use are new potentially modifiable variables that can be targeted for prevention ofClostridium difficileinfection in future interventional studies.
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Hannah
authors.initials: H
authors.lastname: Imlay
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA; Division of Infectious Diseases, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kaul
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA; Division of Infectious Diseases, University of Michigan, Ann Arbor, MI, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
authors.forename: Krishna
authors.initials: K
authors.lastname: Rao
keywords: Clostridium difficile; HIV; immunosuppression