Validation of clinical risk tools for recurrent Clostridioides difficile infection

We sought to validate available tools for predicting recurrent C. difficile infection (CDI) including recurrence risk scores (by Larrainzar-Coghen, Reveles, D'Agostino, Cobo, and Eyre et al) alongside consensus guidelines risk criteria, the leading severity score (ATLAS), and PCR cycle threshold (as marker of fecal organism burden) using electronic medical records.

Retrospective cohort study validating previously described tools.

Tertiary care academic hospital.

Hospitalized adult patients with CDI at University of Virginia Medical Center.

Risk scores were calculated within ±48 hours of index CDI diagnosis using a large retrospective cohort of 1,519 inpatient infections spanning 7 years and compared using area under the receiver operating characteristic curve (AUROC) and the DeLong test. Recurrent CDI events (defined as a repeat positive test or symptom relapse within 60 days requiring retreatment) were confirmed by clinician chart review.

Reveles et al tool achieved the highest AUROC of 0.523 (and 0.537 among a subcohort of 1,230 patients with their first occurrence of CDI), which was not substantially better than other tools including the current IDSA/SHEA C. difficile guidelines or PCR cycle threshold (AUROC: 0.564), regardless of prior infection history.

All tools performed poorly for predicting recurrent C. difficile infection (AUROC range: 0.488-0.564), especially among patients with a prior history of infection (AUROC range: 0.436-0.591). Future studies may benefit from considering novel biomarkers and/or higher-dimensional models that could augment or replace existing tools that underperform.