Excess risk of Clostridium difficile infection in ovarian cancer is related to exposure to broad-spectrum antibiotics

The purpose of the study was to determine if a diagnosis of ovarian cancer is independently associated with an increased risk of Clostridium difficile infection (CDI). The University HealthSystem Consortium database was queried to perform a retrospective cohort study of women with and without ovarian cancer who were diagnosed with CDI. Inpatients undergoing total hysterectomy from 2008 to 2012 were studied. Ovarian cancer patients were compared to non-ovarian cancer patients to evaluate relative risk (RR) of CDI. Adjustment was made for known or suspected CDI risk factors to determine RR of CDI independent of these variables. In this study, 115,203 patients were included. CDI was reported in 0.80 % of ovarian cancer patients and in 0.31 % of non-ovarian cancer patients (RR = 2.50; 95 % confidence interval (CI) = 2.02 to 3.35). Stratification by age, presence of other comorbidities, or administration of antineoplastic drugs did not significantly modify the elevated risk associated with ovarian cancer. Significantly increased risk in ovarian cancer patients was no longer observed after controlling for broad-spectrum antibiotic administration (RR = 1.28, 95 % CI = 0.39 to 4.13). Compared to non-ovarian cancer patients, ovarian cancer patients were more frequently treated with broad-spectrum antibiotics, had a 39 % longer mean duration of therapy, and had 2.5-fold greater mean total exposure to broad-spectrum antibiotics. After adjustment for antibiotic use, ovarian cancer patients are not at excess risk of CDI. Additional studies are needed to understand the patterns of broad-spectrum antibiotic prescription for ovarian cancer patients leading to increased exposure. If feasible, reduction of this exposure may decrease morbidity in this population.