Patterns and determinants of chemotherapy-associated Clostridium difficile infection among cancer patients in the United States: A population-based study.

e19111 Background: Elderly cancer patients comprise a population that is vulnerable for Clostridium difficile infection (CDI). In addition to the frequent hospitalizations, the administration of chemotherapeutic agents has been associated with the development of CDI. The objective of this study was to identify the patterns and determinants of chemotherapy-associated CDI (Chemo-CDI), in a nationwide sample of elderly patients. Methods: We used NCI’s Surveillance, Epidemiology, and End Results registry linked Medicare (SEER-Medicare) 2007-2012 files. We included patients’ aged ≥65 year, with diagnosis of lung/breast/ovarian/colorectal/prostate cancer, or lymphoma/multiple myeloma/leukemia during 2008-2011. We excluded those not receiving chemotherapy, with non-continuous Medicare enrollment, or HMO enrollment. Chemotherapy receipt was identified using appropriate ICD-9/HCPCS/CPT codes. Incidence of CDI following chemotherapy were determined by identifying any claim with primary/secondary diagnosis of CDI during the two-month follow-up period. Recurrent Chemo-CDI was identified by presence of any claim that was > 2 weeks and ≤8 weeks from the index CDI diagnosis date. Covariates including antibodies/proton pump inhibitors usage were captured and included in the analysis. Chi-square tests, and hierarchical generalized logistic models were conducted to identify determinants of Chemo-CDI. Results: We identified 41,470 elderly patients with lung/breast/ovarian/colorectal/prostate cancer, or lymphoma/multiple myeloma/leukemia diagnosis during the study years. While few (266) patients developed Chemo-CDI within one year of diagnosis, more than 50% (136) of those patients developed recurrent Chemo-CDI. Patient characteristics were not associated with risk of developing Chemo-CDI, however, significant differences were observed in antibiotics/proton pump inhibitors exposure across all cancer types (p < 0.001). Treatment for Chemo-CDI mostly comprised of Metronidazole and oral Vancomycin. Conclusions: While the incidence of Chemo-CDI is lower among patients receiving chemotherapy, the rate of recurrent Chemo-CDI was significantly higher. Strategies to prevent CDI recurrence in this population are therefore warranted. Future studies should also explore the association between increased disease burden and comorbidity, and the risk of developing Chemo-CDI.