1305. External validation of predictive scores for mortality following Clostridium difficile infection
Session: Poster Abstract Session: HAI: C. difficile Risk Assessment and Prevention
Friday, October 6, 2017
Room: Poster Hall CD
Background: The burden of Clostridium difficile infection (CDI) has increased in the last decade, with more adverse outcomes and related mortality. Although many predictive scores were developed, few were validated and their performances were sub-optimal. We conducted an external validation study of predictive scores or models for mortality in CDI.

Methods: Published predictive tools were identified through a systematic review. We included those reporting at least an internal validation approach. A multicenter prospective cohort of 1380 adults with confirmed CDI enrolled in two Canadian provinces was used for external validation. Most cases were elderly (median age 71), had a healthcare facility-associated CDI (90%), and 52% were infected by NAP1/BI/027 strains. All-cause 30-day death occurred in 12% of patients. The performance of each scoring system was analyzed using individual primary outcomes.

Results: We identified two scores which performances (95% CI) are shown in the table. Both had low sensitivity and PPV, moderate specificity and NPV, and similar AUC/ROC (0.66 vs 0.77 in the derivation cohort, and 0.69 vs 0.75 respectively). One predictive model for 30 days all-cause mortality (Archbald-Pannone 2015, including Charlson score, WBC, BUN, diagnosis in ICU, and delirium*) was associated with only 5% increase in odds of death (crude OR = 1.05 (1.03-1.06)) with an AUC of 0.74 (0.7-0.8).

Study, outcome (%)

Predictors (assigned points)

Cut-off/ max score

Sen %

Spe %

PPV %

NPV %

LR +

Accuracy %

Kassam 2016

In hospital CDI-related mortality (18%)

Age (2-4)

ICU admission (5)

Acute renal failure* (3)

Diabetes (-1)

Cardiopulmonary disease* (1)

Liver disease (2)

IBD (2)

Malignancy (2)

≥6 pts/19

44

(37-51)

79

(77-82)

31

(26-37)

87

(84-89)

2.1

(2-2.2)

73

(70-76)

Butt 2013

30-day all-cause mortality (12%)

Serum albumin ≤ 24.5 g/L (1)

CRP > 228 mg/L (1)

WBC > 12 and/or respiratory rate > 17/min (1)

≥2 pts/3

56

(46-64)

77

(74-80)

25

(20-30)

93

(90-94)

2.4

(2.3-2.5)

74

(71-77)

*Modified to match available data in validation cohort.

Conclusion: The predictive models of CDI mortality evaluated in our study have limitations in their methods and showed moderate performances in a validation cohort consisting of a majority of CDI caused by NAP1 strains. An accurate predictive tool is needed to guide clinicians in the management of CDI to prevent adverse outcomes.

Catherine Beauregard-Paultre, MD1, Claire Nour Abou Chakra, PhD1, Allison Mcgeer, MD, MSc2, Annie-Claude Labbé, MD3, Andrew E. Simor, MD, FRCPC, FACP4, Wayne Gold, MD5, Matthew P. Muller, MD, PhD, FRCPC6, Jeff Powis, MD, MSc, FRCPC7, Kevin Katz, MD, CM, MSc, FRCPC8, Suzanne Cadarette, PhD9, Jacques Pépin, M.D.1, Julian R. Garneau, MSc1 and Louis Valiquette, MD, MSc, FRCPC1,10, (1)Microbiology and Infectious Disease, Université de Sherbrooke, Sherbrooke, QC, Canada, (2)Infection Control, Sinai Health System, Toronto, ON, Canada, (3)Microbiology, CIUSSS de l’est-de-l’île-de-Montréal, Montreal, QC, Canada, (4)Microbiology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, (5)Toronto General Hospital, Toronto, ON, Canada, (6)Medicine, St.Michael's Hospital, Toronto, ON, Canada, (7)Michael Garron Hospital, Toronto, ON, Canada, (8)Department of Infection Control, North York General Hospital, Toronto, ON, Canada, (9)University of Toronto, Toronto, ON, Canada, (10)Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Sherbrooke, QC, Canada

Disclosures:

C. Beauregard-Paultre, None

C. N. Abou Chakra, None

A. Mcgeer, None

A. C. Labbé, None

A. E. Simor, None

W. Gold, None

M. P. Muller, None

J. Powis, Merck: Grant Investigator , Research grant
GSK: Grant Investigator , Research grant
Roche: Grant Investigator , Research grant
Synthetic Biologicals: Investigator , Research grant

K. Katz, None

S. Cadarette, None

J. Pépin, None

J. R. Garneau, None

L. Valiquette, None

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