# Clostridioides difficile co-infection worsens prognosis in inflammatory bowel disease in patients with cytomegalovirus colitis

## TL;DR

Co-infection with CMV and C. difficile in IBD patients leads to worse outcomes, including more hospitalizations and slower recovery.

## Contribution

This study identifies co-infection with CMV and CDI as a significant risk factor for poor prognosis in IBD patients.

## Key findings

- Co-infection group had more diarrhea and abdominal pain compared to CMV alone.
- Co-infection prolonged remission and increased hospitalization duration.
- Biologic therapy was an independent predictor of CMV/CDI co-infection.

## Abstract

Cytomegalovirus (CMV) colitis and Clostridioides difficile infection (CDI) are both linked to disease exacerbation and poor prognosis in patients with inflammatory bowel disease (IBD). Nonetheless, the effect of co-infection on clinical outcomes in individuals with IBD remains underexplored. This retrospective study was designed to assess the clinical outcomes and determine predictors of co-infection with CMV and CDI in individuals with IBD.

This analysis involved hospitalized patients with IBD and confirmed CMV colitis (based on intestinal CMV immunohistochemical staining) and Clostridioides difficile toxin A/B test results, collected at the Linkou branch of Chang Gung Memorial Hospital between January 2001 and September 2023. The individuals in the study cohort were divided into two categories: those with CMV infection alone and those with CMV/CDI co-infection. Clinical manifestations, outcomes, and independent predictors of co-infection were assessed between the two groups.

Overall, 53 IBD inpatients were enrolled in this study, with 37 assigned to the CMV group and 16 to the CMV/CDI co-infection group. The co-infection group experienced significantly more diarrhea (54.1% vs. 93.8%, p = 0.005) and abdominal pain (54.1% vs. 87.5%, p = 0.020) compared to the CMV group. Hospitalization duration (1 vs. 2.5 admissions, p = 0.005) and CMV recurrence (0 vs. 1 recurrences, p < 0.001) were higher in the co-infection group. Additionally, co-infection prolonged the time to clinical (1 vs. 5 months, p < 0.001), steroid-free (4 vs. 10 months, p = 0.001), endoscopic (8.3 vs. 17.5 months, p = 0.011), and histological remission (11 vs. 18 months, p = 0.021) compared to CMV infection alone. The cumulative incidence of clinical, steroid-free, endoscopic, and histological remission showed a delayed course in the co-infection group. Multivariable analysis revealed that biologic therapy was an independent predictor for CMV/CDI co-infection (OR 13.33, 95% CI 1.52–117.15, p = 0.02).

Co-infection of CMV and CDI among individuals with IBD results in more frequent hospitalizations, higher CMV recurrence rates, and prolonged disease remission compared to CMV colitis alone. The administration of biologic therapy increases the risk of co-infection, emphasizing the importance of careful management in this patient population.