Mortality and Costs in Clostridium difficile Infection Among the Elderly in the United States

OBJECTIVE. To examine attributable mortality and costs of Clostridium difficile infection (CDI) in the Medicare population. DESIGN. A population-based cohort study among US adults aged at least 65 years in the 2008-2010 Medicare 5% sample, with follow-up of 12 months. PATIENTS. Incident CDI episode was defined by the International Classification of Diseases, Ninth Revision, Clinical Modification code of 008.45 and no other occurrences within the preceding 12 months. To quantify the adjusted mortality and costs we developed a 1:1 propensity matched sample of CDI and non-CDI patients. RESULTS. Among 1,165,165 patients included, 6,838 (0.6%) had a CDI episode in 2009 (82.5% healthcare-associated). Patients with CDI were older (mean [SD] age, 81.0 +/- 8.0 vs 77.0 +/- 7.7 years, P < .001), were more likely to come from the Northeast (27.4% vs 18.6%, P < .001), and had a higher comorbidity burden (Charlson score, 4.6 +/- 3.3 vs 1.7 +/- 2.1, P < .001). Hospitalizations (63.2% vs 6.0%, P < .001) and antibiotics (33.9% vs 12.5%, P < .001) within the prior 90 days were more common in the group with CDI. In the propensity-adjusted analysis, CDI was associated with near doubling of both mortality (42.6% vs 23.4%, P < .001) and total healthcare costs ($64,807 +/- $66,480 vs $38,128 +/- $46,485, P < .001). CONCLUSIONS. Among elderly patients, CDI is associated with an increase in adjusted mortality and healthcare costs following a CDI episode. Nationwide annually this equals 240,000 patients with CDI, 46,000 potential deaths, and more than $6 billion in costs.