1374. Identification of “High” Risk Population for Future Clostridium difficile Infection (CDI)
Session: Poster Abstract Session: Clostridium difficile
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C

Background: Efforts to develop a Clostridium difficile vaccine are underway; identification of patients at risk for CDI is critical to inform vaccine trials. We identified groups at high risk of CDI >4 weeks after hospital discharge.

Methods: Hospital discharge data and pharmacy data from two large academic centers, one in New York (NY) and another in Connecticut (CT), were linked to active population-based CDI surveillance data from the Emerging Infections Program (EIP). Adult residents of the EIP surveillance area were included if they had an inpatient stay at a study hospital without prior history of CDI.  The primary outcome was CDI by either toxin or molecular assay >28 days after an index hospitalization.  Important predictors of CDI ≥ 28 days post discharge were initially identified through a Cox proportional hazards model (stepwise backward selection) using CT data, our derivation cohort; final model parameters were used to develop a risk index evaluated in the NY data, the validation cohort.

Results: Of the 21,553 index hospitalizations occurring in CT within one calendar year, 176 (0.82%) had CDI >28 days post discharge. After stepwise backward selection, age, number of ICD-9 procedures and hospitalizations in the prior 90 days, type of ICD-9 diagnosis and procedure codes, admission location, Gagne co-morbidity score, and the number of different antibiotic classes administered remained in the model.  Points for each characteristic were assigned by taking the integer of the model parameter estimates divided by the absolute value of the smallest parameter estimate to generate a propensity score. Using the NY data for evaluation, the raw score based on the CT model was highly predictive, p<0.001 (Figure). Based on the distribution of scores in the CT data, we divided the NY patients into low and high risk groups. The high risk group had a score greater than 32.5, and within that group 4.3% experienced CDI > 28 days post discharge compared to 0.90% among our low risk group (OR=5.0, 95% CI:3.2, 7.8).

Conclusion: Our study identified specific parameters for a risk index that can be applied at discharge to identify a patient population whose risk of CDI >28 days following an acute care hospitalization was 5 times greater than other patients.

James Baggs, PhD1, Kimberly Yousey-Hindes, MPH, CPH2, Elizabeth Dodds-Ashley, PharmD, MHS3, James Meek, MPH4, Ghinwa Dumyati, MD, FSHEA5, Jessica Cohen, MPH6, Matthew Wise, PhD6, L. Clifford Mcdonald, MD6 and Fernanda Lessa, MD1, (1)Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, (2)Emerging Infections Program, Yale, New Haven, CT, (3)University of Rochester Medical Center, Rochester, NY, (4)Connecticut Emerging Infections Program, New Haven, CT, (5)University of Rochester, Rochester, NY, (6)Centers for Disease Control and Prevention, Atlanta, GA

Disclosures:

J. Baggs, None

K. Yousey-Hindes, None

E. Dodds-Ashley, None

J. Meek, None

G. Dumyati, None

J. Cohen, None

M. Wise, None

L. C. Mcdonald, None

F. Lessa, None

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