OBJECTIVE: We evaluated mortality and total healthcare costs among contemporary Medicare patients with primary CDI (pCDI) and recurrent CDI (rCDI), as well as the main drivers of the costs.

METHODS: Using 100% Medicare Parts A, B, and D claims between 2009-2017, we identified patients aged ≥65, continuously enrolled for 12-months with no evidence of CDI prior to index CDI and up to 12-months post-index. Total costs of care were calculated as per-patient-per-month (PPPM) overall and separately for patients with CDI-linked death, defined as patients whose most proximal healthcare visit on or near date of death had CDI in primary/secondary diagnosis field.

RESULTS: Of 497,489 CDI patients included, 42.8% overall died within 12 months after index CDI. Mortality rates increased with recurrences for deaths that were CDI-linked (pCDI 2.7%, 1rCDI 16.4%, 2rCDI 30.9%, 3+rCDI 50%). CDI was a primary contributing diagnosis to 50% of the deaths in patients with 3+ recurrences. Mean (SD) PPPM costs for pCDI patients who died was $29,150 ($33,256) versus $6,348 ($7,117) for those who survived, and PPPM costs for patients with CDI-linked death was $24,883 ($16,435). Mean PPPM costs in patients with any recurrence was $35,767 for rCDI patients who died versus $7,959 who survived, and $28,443 for CDI-linked death. Costs were driven largely by inpatient stays (41%-75% of total cost); 99.9% of patients with recurrence and CDI-linked death were hospitalized, with 52.7% requiring intensive care, and 77.9% readmitted at least once.

CONCLUSION: Despite currently available treatments, CDI patients had substantial mortality and costs. Costly hospitalizations and readmissions requiring intensive patient care resulted in 3.5x higher monthly costs in rCDI patients who died than patients who survived. New treatments reducing CDI recurrences are needed to improve economic/clinical burden and mortality.