Determinants of Clostridium difficile infection incidence across diverse United States geographic locations

• Authors: Fernanda C. Lessa, Centers for Disease Control and Prevention; Yi Mu, Centers for Disease Control and Prevention; Lisa G. Winston, University of California, San Francisco; Ghinwa K. Dumyati, University of Rochester; Monica Farley, Emory University; Zintars G. Beldavs, Oregon Health Authority; Kelly Kast, Colorado Department of Public Health and Environment; Stacy M. Holzbauer, Centers for Disease Control and Prevention; James I. Meek, Yale University; Jessica Cohen, Centers for Disease Control and Prevention; L. Clifford McDonald, Centers for Disease Control and Prevention; Scott Fridkin, Emory University
• Journal Title: Open Forum Infectious Diseases
• Volume: Volume 1, Number 2
• Publisher: Oxford University Press (OUP) | 2014-01-01, Pages ofu048-ofu048
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1093/ofid/ofu048
• Subjects: Health Sciences, Epidemiology; Health Sciences, Public Health
• Keywords: clostridium difficile infection; clostridium difficile; geographic area; inpatient; outpatients; surveillance; medical; nucleic acid amplification tests; community

Abstract

Background. Clostridium difficile infection (CDI) is no longer restricted to hospital settings, and populationbased incidence measures are needed. Understanding the determinants of CDI incidence will allow for more meaningful comparisons of rates and accurate national estimates. Methods. Data from active population- and laboratory-based CDI surveillance in 7 US states were used to identify CDI cases (ie, residents with positive C difficile stool specimen without a positive test in the prior 8 weeks). Cases were classified as community-associated (CA) if stool was collected as outpatients or =3 days of admission and no overnight healthcare facility stay in the past 12 weeks; otherwise, cases were classified as healthcare-associated (HA). Two regression models, one for CA-CDI and another for HA-CDI, were built to evaluate predictors of high CDI incidence. Site-specific incidence was adjusted based on the regression models. Results. Of 10 062 cases identified, 32% were CA. Crude incidence varied by geographic area; CA-CDI ranged from 28.2 to 79.1/100 000 and HA-CDI ranged from 45.7 to 155.9/100 000. Independent predictors of higher CACDI incidence were older age, white race, female gender, and nucleic acid amplification test (NAAT) use. For HACDI, older age and a greater number of inpatient-days were predictors. After adjusting for relevant predictors, the range of incidence narrowed greatly; CA-CDI rates ranged from 30.7 to 41.3/100 000 and HA-CDI rates ranged from 58.5 to 94.8/100 000. Conclusions. Differences in CDI incidence across geographic areas can be partially explained by differences in NAAT use, age, race, sex, and inpatient-days. Variation in antimicrobial use may contribute to the remaining differences in incidence.