Asymptomatic patients colonized with toxigenic Clostridioides difficile are at risk of progressing to C. difficile infection (CDI), but risk factors associated with progression are poorly understood. The objectives of this study were to estimate the incidence and identify risk factors to progression of hospital-onset CDI (HO-CDI) among colonized patients.

This was a nested case-control study at an academic medical center including adult patients colonized with toxigenic C. difficile, detected via polymerase chain reaction (PCR) on a rectal swab collected on admission from 2017 to 2020. Patients with prior CDI or symptoms on admission, neutropenia, prior rectal surgery, or hospitalization less than 24 hours were excluded. Colonized patients that developed HO-CDI were matched 1:3 to colonized patients who did not based on PCR test date. Bivariate and multivariable-adjusted Cox regression analyses were used to identify risk factors.

Of 2,150 colonized patients, 109 developed HO-CDI, with an incidence of 5.1%. After exclusions, 321 patients (69 with HO-CDI) were included, with an estimated incidence of 4.2%. Risk factors included cirrhosis (aHR 1.94), ICU admission (aHR 1.76), malignancy (aHR 1.88), and hospitalization within six months (aHR 1.6). Prior antibiotic exposure in the past three months (aHR 2.14) and receipt of at-risk antibiotics were also identified as potential risk factors (aHR 2.17).

Progression to HO-CDI among colonized patients was not uncommon. This study highlights key risk factors associated with progression, underscoring the importance of enhanced monitoring and prevention efforts tailored to high-risk populations to mitigate HO-CDI.

Examine the impact of vaccination status on hospital cost and course for patients admitted with COVID-19 infection.

Retrospective cohort study characterizing vaccinated and unvaccinated individuals hospitalized for COVID-19 between April 2021 to January 2022.

Large academic medical center.

Patients were included if they were greater than 18 years old, fully vaccinated or unvaccinated against COVID-19, and admitted for COVID-19 infection.

437 consecutively admitted patients for COVID-19 infection met inclusion criteria. Of these, 79 were excluded for unknown or partial vaccination status, transfer from an outside hospital, or multiple COVID-19 related admissions.

Overall, 279 (77.9%) unvaccinated patients compared to 79 (22.1%) vaccinated patients were hospitalized with a diagnosis of COVID-19. Average length of stay was significantly lower in the vaccinated group (6.47 days versus 8.92 days, P = 0.03). Vaccinated patients experienced a 70.6% lower risk of ICU admission (OR = 0.29, 95% CI 0.12–0.71, P = 0.006). The unadjusted cost of hospitalization was not found to be statistically significant ($119,630 versus $191,146, P = 0.06). After adjusting for age and comorbidities, vaccinated patients experienced a 26% lower cost of hospitalization compared to unvaccinated patients (P = 0.004). Unvaccinated patients incurred a significantly higher cost of hospitalization per day ($29,425 vs $13,845 P < 0.0001). Unvaccinated patients (n = 118, 42.9%) were more likely than vaccinated patients (n = 16, 20.3%) to require high-flow oxygen or mechanical ventilation (OR = 2.95, 95% CI 1.62–5.38, P = 0.0004).

Vaccinated patients experienced a lower cost of hospitalization after adjusting for age and comorbidities and shorter length of stay compared to unvaccinated patients admitted for COVID-19.