Health care resource utilization and costs of recurrent Clostridioides difficile infection in the elderly: a real-world claims analysis

BACKGROUND: Clostridioides difficile infection (CDI) affected an estimated 365,000 persons in the United States in 2017. Despite a nationally decreasing trend of CDI cases, the population incidence of recurrent CDI (rCDI) has not improved. Elderly individuals (aged ≥ 65 years) are at higher risk of CDI, rCDI, and complicated CDI compared with younger individuals. OBJECTIVE: To analyze Medicare fee-for-service data for 12 months after an initial CDI episode, in order to obtain real-world data on health care resource utilization (HRU) and costs for elderly patients with CDI and rCDI. METHODS: A retrospective cohort study of patients who were aged ≥ 65 years and had a first (index) CDI diagnosis from January 1, 2010, to December 31, 2016, and continuous enrollment in Medicare Parts A, B, and D during the 12-month pre-index and 12-month post-index periods was conducted. A CDI episode was identified by either an inpatient stay with CDI diagnosis code or an outpatient medical claim with a CDI diagnosis code plus a CDI treatment. Each CDI episode was followed by a 14-day CDI claim-free period after the last CDI claim or end of CDI treatment. rCDI was a second or subsequent episode of CDI that occurred within an 8-week window after the 14-day CDI claim-free period. The number of CDI and rCDI episodes, HRU, time to recurrence, and total all-cause direct medical costs were calculated over the 12-month pre-index (baseline) and 12-month follow-up periods and stratified by number of rCDI episodes (No rCDI, 1 rCDI, 2 rCDI, 3+ rCDI). RESULTS: A total of 268,762 patients with an index CDI were included. Mean age was 78.3 years, and 69.0% were female. HRU was higher during the 6 months immediately pre-index versus 7-12 months pre-index, including a higher proportion of patients with a hospital admission (55.1% vs. 27.5%) or emergency department visit (41.3% vs. 27.4%), respectively. Moreover, 34.7% of the study population experienced rCDI. Of those who experienced 1 recurrence, 59.1% had a second recurrence, and of those who had 2 recurrences, 58.4% had a third. During the 12-month follow-up, postacute care was used by at least 70% of each rCDI cohort. The proportion of patients with ≥ 4 hospital admissions during follow-up was highest for the 3+ rCDI cohort (24.9% of patients). During the 12-month follow-up, mean total all-cause direct costs were $76,024, $99,348, $96,148, and $96,517 for the No rCDI, 1 rCDI, 2 rCDI, and 3+ rCDI cohorts, respectively, largely driven by inpatient costs. Adjusted all-cause total costs were significantly higher for all 3 rCDI cohorts compared with the No rCDI cohort. CONCLUSIONS: Elderly individuals experienced high rates of recurrence after their first CDI episode, and especially after a prior recurrence. The intensity of HRU during follow-up was higher for patients who suffered recurrences. Patients with rCDI had the burden of higher costs of care, including the patient out-of-pocket responsibility, versus patients with a single CDI episode.