Repeat stool testing for Clostridium difficile using enzyme immunoassay in patients with inflammatory bowel disease increases diagnostic yield

Abstract

Background:

The incidence and severity of Clostridium difficile infection (CDI) in patients with inflammatory bowel disease (IBD) is increasing. CDI is diagnosed by toxin enzyme immunoassay (EIA) or real-time polymerase chain reaction (PCR) performed on stool samples. An earlier study evaluating EIA in IBD patients with CDI suggested that more than one stool sample be tested to increase diagnostic yield. We investigated whether repeat stool testing improves diagnostic accuracy for CDI in hospitalized IBD patients compared to hospitalized patients with CDI and no IBD.

Methods:

We performed retrospective data analysis from January 2005–May 2011 on 63,086 hospitalized patients who were tested for CDI using EIA or PCR. Of these, 2579 patients had IBD. Transition probabilities were calculated based on results from repeated tests.

Results:

Inclusive of all inpatients tested for CDI, 56,583 were tested using toxin EIA and 6503 were tested using PCR. In patients with no IBD, the first stool sample tested was positive in 90% and 94% with EIA and PCR respectively. In IBD patients tested using EIA, 101 were diagnosed with CDI. The first stool sample tested was positive in 81% of patients. Successive second and third stool samples yielded additional 14% and 5% CDI positive IBD patients.

Conclusions:

Approximately one in five IBD patients with CDI required repeat testing to yield a positive result with EIA. There are minimal diagnostic gains of repeat testing by EIA or PCR in patients without IBD. We recommend repeat stool testing for CDI when using EIA to increase diagnostic yield in IBD patients.

Key words::

• Bacteria
• Clostridium difficile
• Diagnostic yield
• Hospital-acquired infection
• Inflammatory bowel disease

Transparency

Declaration of funding

This manuscript was not sponsored or funded by any agency, and no medical writers were involved in this writing.

Declaration of financial/other interests

A.D., V.P., P.P., C.P., M.P., G.H., B.H., A.J., D.D.K.R., T.J.S., and A.A. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article.

Author contributions: conception and design: A.D., V.P., P.P., A.A., D.D.K.R.; acquisition of data: A.D., B.H., P.P., A.A., M.P.; analysis and interpretation of data: A.D., V.P., B.H., P.P., A.A., M.P.; drafting of the article: A.D., V.P., A.A., D.D.K.R.; critical revision of the article for important intellectual content: D.D.K.R., A.J., G.H., A.A., P.P.; final approval of the article: A.D., V.P., P.P., C.P., M.P., G.H., B.H., A.J., D.D.K.R., T.J.S., A.A.; statistical expertise: B.H..

M.P. was supported by NIH T32 DK061917.

CMRO peer reviewers may have received honoraria for their review work. The peer reviewers on this manuscript have disclosed that they have no relevant financial relationships.