915. Hospital Incidence of Clostridium difficile Infection (CDI) as a Risk Factor for Hospital-Associated CDI
Session: Poster Abstract Session: Clostridium difficile Infections: Epidemiology and Diagnostics
Friday, October 9, 2015
Room: Poster Hall
  • Presure_Paper_Poster2.pdf (677.6 kB)
  • Background: To gain a better understanding of the environment as a risk factor for CDI, we investigated the association between the institutional incidence of CDI and hospital-associated (HA) CDI at an individual level. Although environmental risk factors have been previously studied, most research has been at the room or unit rather than the hospital level.

    Methods: This was a retrospective cohort study conducted using the HCUP state inpatient databases (SID) for the state of California from 2005 through 2011.

    For each patient’s hospital stay, we calculated the hospital's CDI incidence rate, using all CDI cases, corresponding to the patient's discharge year and quarter. Each patient’s own CDI status was excluded from this rate. HA-CDI cases were identified by CDI diagnoses coded not present on admission.

    A pooled logistic regression was used to estimate risk for HA CDI: all admissions from a given patient that occurred prior to, and including, a first CDI diagnosis were treated as multiple observations. We controlled for a range of patient and hospital characteristics including age, sex, race, length of stay, previous admission, dialysis, enteral feeding, intra-abdominal or gastrointestinal procedures, mechanical ventilation, nasogastric tube insertion, chemotherapy, comorbidity indicators, hospital size, hospital-average patient age, and percentage Medicaid at the hospital.


    A total of 10,329,988 patients (including 26,086 HA-CDI cases) had non-missing values for all of the risk factors analyzed.

    We found the CDI incidence that a patient encountered in the hospital to be associated with a significant increase in his/her risk for CDI: a percentage point increase in the CDI incidence rate a patient encountered increased his/her odds of CDI by a factor of 1.182. As a point of comparison, a one-percentage point increase in the CDI incidence rate that patient encountered had roughly the same impact on their odds of acquiring a CDI as a 55.8-day increase in their LOS or a 60 year increase in age.


    Patients treated in hospitals with a higher incidence of CDI were more likely to acquire CDI, even after controlling for a broad range of individual and institutional factors. Hospital incidence of CDI, whether community or hospital associated, may increase the likelihood of patient exposure to Clostridium difficile.

    Aaron Miller, PhD, Department of Economics & Business, Cornell College, Mount Vernon, IA, Linnea Polgreen, PhD, Pharmacy Practice & Science, University of Iowa, College of Pharmacy, Iowa City, IA, Joseph Cavanaugh, PhD, Biostatistics, University of Iowa, College of Public Health, Iowa City, IA and Philip M. Polgreen, MD, Division of Infectious Diseases, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA


    A. Miller, None

    L. Polgreen, None

    J. Cavanaugh, None

    P. M. Polgreen, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.