# Impact of the COVID-19 Pandemic on Clostridioides difficile Infection Rates in a Tertiary Hospital: A Retrospective Comparative Study

## TL;DR

This study found that Clostridioides difficile infections increased during the COVID-19 pandemic at a tertiary hospital, despite no major changes in severity or mortality.

## Contribution

The study provides new evidence of increased CDI incidence during the pandemic and highlights the need for stronger infection control measures.

## Key findings

- CDI incidence rates were significantly higher during the pandemic period compared to pre-COVID-19.
- CDI recurrence was significantly higher during the pandemic (10.9% vs. 5.6%).
- Hand hygiene compliance in general wards declined slightly during the pandemic.

## Abstract

Introduction

The impact of the COVID-19 pandemic on the incidence of Clostridioides difficile infection (CDI) remains uncertain, with conflicting findings reported in the literature. While some studies have shown an increase in CDI cases, others have found no significant change. This study aimed to compare healthcare-associated CDI incidence rates (including community-onset and hospital-onset cases) between the pre-COVID-19 and COVID-19 periods at our institution, with secondary analyses of ICU and hospital length of stay, mortality, severity, and recurrence rates.

Methods

This single-center retrospective study at Wollongong Hospital compared CDI rates before and during the COVID-19 pandemic. Adult patients with diarrhea and confirmed CDI were included. Data on demographics, comorbidities, antibiotic use, hospital and ICU length of stay, mortality, and infection control metrics were analyzed. CDI incidence was calculated per 1,000 patient-days and per 1,000 admissions.

Results

Among 544 CDI cases (215 pre-COVID-19 and 329 during COVID-19), 291 (53.5%) were community-onset and 253 (46.5%) hospital-onset. There were no significant differences between the two periods in CDI type (p = 0.599), time to acquisition (p = 0.388), severity (17.2% vs. 19.5%), ICU admission (18.1% vs. 20.4%), ICU (p = 0.415) or hospital length of stay (p = 0.788), or mortality (9.3% vs. 8.8%). However, CDI recurrence was significantly higher during the COVID-19 period (10.9% vs. 5.6%, p < 0.05), as were incidence rates per 1,000 patient admissions (2.2 vs. 1.47, p < 0.001) and per 1,000 patient-days (0.64 vs. 0.45, p < 0.001). Hand hygiene compliance in general wards declined slightly but significantly (from 88.5% to 87.9%, p = 0.003), while ICU compliance remained stable.

Conclusion

The incidence of CDI was significantly higher during the COVID-19 period compared to the pre-COVID-19 period at our institution. These findings underscore the importance of strengthened antimicrobial stewardship and preventive measures during healthcare crises.