S2054 Clostridioides difficile Infection-Related Mortality Trends Among Older U.S. Adults (1999-2020): A Nationwide Analysis of Disparities by Race, Region, and Urbanization

Introduction: Clostridioides difficile infection (CDI) remains a major cause of morbidity and mortality in older adults in the United States. While previous studies have highlighted its burden in hospitalized and long-term care patients, nationwide mortality trends and their shifts over time remain underexplored. This study investigates CDI-related mortality among adults aged ≥65 in the U.S. over 2 decades. Methods: Using CDC WONDER data (1999-2020), we identified CDI-related deaths (ICD-10 code A04.7) among adults aged ≥65 years. Age-adjusted mortality rates (AAMRs) per 100,000 were calculated and stratified by sex, race/ethnicity, state, census region, and urbanization level. Joinpoint regression was used to estimate annual percent changes (APCs) with 95% confidence intervals (CIs). Results: A total of 169,229 CDI-related deaths were recorded. AAMRs increased sharply from 1999 to 2005 (APC: +34.5%; 95% confidence interval [CI]: 32.0-37.9), followed by slower increases until 2011 (APC: +3.6%; 95% CI: 2.1-6.0). A decline began in 2011 (APC: -5.7%; 95% CI: -8.1 to -2.8), accelerating through 2020 (APC: -14.2%; 95% CI: -18.3 to -11.8). AAMRs were comparable between sexes (males: 19.0; females: 18.0). Non-Hispanic (NH) White men (AAMR: 20.0) and NH White women (19.1) experienced the highest burden, followed by NH Black men (16.0). Urban areas exhibited greater mortality (urban men: 19.5; urban women: 18.4) than rural areas (rural men: 16.9; rural women: 16.3). Regional disparities showed higher rates in the Northeast. Conclusion: CDI-related mortality among older adults peaked in the early 2000s and declined steadily after 2011. This temporal shift corresponds with the introduction and increasing use of fecal microbiota transplantation (FMT) and fidaxomicin, which offer improved treatment outcomes and reduced recurrence rates. The sharp decline in mortality post-2011 is likely attributable to these advancements in therapeutic strategies. Continued efforts in early diagnosis, appropriate antimicrobial use, and equitable access to effective treatments such as FMT are essential. Further studies are needed to validate these trends and support policy initiatives aimed at sustaining the decline in CDI-related mortality.