Does Clostridium difficile Increase the Risk of Surgical Resection in Pediatric Crohn’s Disease?

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A recent retrospective & prospective study (J Hellmann et al. Inflamm Bowel Dis 2020; 26: 1212-21. Microbial Shifts and Shorter Time to Bowel Resection Surgery Associated with C. difficile in Pediatric Crohn’s Disease. Associated editorial 1222-3) suggests that C difficile infection (CDI) is associated with an increased risk of bowel resection surgery.

In the retrospective arm with 75 pediatric patients (<22 years): Key findings:

  • 14 of 75 had positive C difficile testing (mainly PCR, especially after 2009).
  • The rate of bowel resection surgery increased from 21% in those without C. difficile to 67% in those with (P = 0.003).
  • From a Kaplan-Meier survival model, the hazard ratio for time to first surgery was 4.4 (95% CI, 1.2–16.2; P = 0.00) in patients with positive C. difficile testing in the first year after diagnosis.

Importantly, the study was unable to distinguish between C difficile colonization versus infection.

In the prospective arm with 70 patients, patients underwent meatgenomic sequencing. Those with a positive PCR assay (irregardless of symptoms or calprotectin) were considered to have CDI.

  • 10 of 70 (14%) tested positive for CDI
  • 40% of those with CD and positive CDI had a history of surgery vs 15% with negative C difficile testing
  • Fecal calprotectin levels were elevated (>250) in 40% of both those testing positive for CDI and those testing negative
  • The overall fecal microbiome composition was not statistically significantly different between CDI-positive and CDI-negative
  • There were significant differences in the fecal microbiome composition between those with prior surgery and those without prior surgery.  Depletion of Alistipes and Ruminococcus species and reduction in methionine biosynthesis were noted in patients with both C. difficile carriage and past surgery

My takes:

  1. Based on my reading, the authors assert an association of shorter time to surgery associated with CDI in the retrospective cohort.  Because testing for CDI is common in those with flare-ups, it is unclear if this is a temporal phenomenon or is a causal relationship.
  2. It is interesting that their prospective cohort did not have an increased calprotectin level in those with CDI-positivity or overall composition change in microbiome in the CDI-positive group.  It would be of interest if these studies were confined to those with cytotoxin-assay positivity which has been shown to correlate with clinical outcomes.  In previous studies, individuals with PCR-positive CDI & cytotoxin-assay negative had similar outcomes to those with negative PCR assays.

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