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

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. 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. 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). 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. 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. Funding for this study was provided by Ferring Pharmaceuticals. Nelson is an employee of Ferring Pharmaceuticals, and Scott, Boules, and Unni were employees of Ferring Pharmaceuticals at the time of this study. Teigland and Parente are employees of Avalere Health and provided consulting services to Ferring Pharmaceuticals. Feuerstadt has served as a consultant to and on the speakers bureau for Merck and Co. and has served as a consultant for Ferring Pharmaceuticals and Roche Pharmaceuticals. Portions of the data contained in this study appeared as an abstract/ePoster for the AMCP Annual Meeting 2020, April 2020.