Impact of Functional Status on Development of Clostridioides difficile Infection and Increase in Inhospital Mortality among Antibiotic Users.

INTRODUCTION: Functional status is one of the surrogates of advanced age, an established risk factor for Clostridioides difficile infection (CDI). We aimed to investigate the usefulness of functional status in the clinical management of CDI. METHODS: We enrolled all hospitalized adult patients receiving antibiotics from a retrospective hospital-based cohort in Japan between 2016 and 2020. Using the Barthel index (BI), which is an objective scale of functional status, we investigated the association of BI with developing CDI and its impact on inhospital mortality in patients with CDI. RESULTS: We enrolled 17,131 patients with 100 cases of CDI. Multivariable analysis revealed that lower BI (≤25) was an independent risk factor for developing CDI (adjusted odds ratio, 4.11; 95% confidence interval, 2.62-6.46). Furthermore, a combination of BI and Charlson comorbidity index (CCI) showed an adjusted odds ratio of 36.40 (95% confidence interval, 17.30-76.60) in the highest risk group. A high-risk group according to the combination of BI and CCI was estimated to have significantly higher inhospital mortality in patients with CDI using the Kaplan-Meier method (p = 0.017). A combination of lower BI and higher CCI was an independent predictor of inhospital mortality even in the multivariable Cox regression model (adjusted hazard ratio, 3.00; 95% confidence interval, 1.01-8.88). CONCLUSIONS: Assessment of functional status, especially combined with comorbidities, was significantly associated with developing CDI and may also be useful in predicting inhospital mortality.