Clostridium difficile classification overestimates hospital-acquired infections.

Area of Science:

• Infectious Diseases
• Epidemiology
• Health Policy

Background:

• Clostridium difficile infections (CDI) are common in hospitalized patients, with acquisition occurring both in hospitals and communities.
• International guidelines define hospital-acquired CDI based on symptom onset >2 days post-admission.
• This standard classification lacks empirical validation through modeling studies.

Purpose of the Study:

• To evaluate the accuracy of current CDI acquisition classification methods.
• To utilize a simulation model as a reference standard for assessing classification accuracy.
• To identify optimal time cut-offs for distinguishing hospital-acquired from community-acquired CDI.

Main Methods:

• Simulated Clostridium difficile transmission across diverse hospital scenarios.
• Calculated sensitivity, specificity, and precision for various time cut-offs (0.25 hours to 40 days).
• Identified optimal and balanced cut-offs for accurate CDI acquisition classification.

Main Results:

• The standard 2-day cut-off significantly overestimated hospital-acquired CDI incidence (>100% in base scenario).
• The 2-day cut-off showed high sensitivity (96%) but low specificity (48%) and precision (52%).
• A 5-day cut-off demonstrated balanced sensitivity/specificity; a 6-day cut-off was optimal in the base scenario.

Conclusions:

• Existing guidelines for classifying CDI acquisition overestimate hospital-acquired cases.
• A revised classification using a 5-day window post-admission is recommended to reduce misclassification bias.
• This adjustment improves the accuracy of differentiating community- versus hospital-acquired Clostridium difficile infections.