Incidence of and risk factors for community-associated Clostridium difficile infection

Abstract

Clostridium difficile infection (CDI) is the most common cause of hospitalacquired infectious diarrhea in the United States. Although C. difficile is widelyrecognized as a pathogen among hospitalized populations, CDI has emerged in the community setting and may be under-diagnosed. This study sought to increase knowledge about the incidence of, risk factors for, and outcomes associated with community-associated CDI (CA-CDI). A retrospective nested case-control study was conducted using insurance claims data from the Wellmark Data Repository for the time period between January 1, 2003 and December 31, 2007. Persons with CDI were identified and were classified as communityassociated CDI and hospital-acquired CDI. During this time, 304 cases of CA-CDI and 338 cases of HA-CDI were identified. Within this population, the incidence rate for CACDI was 11.16 cases per 100,000 person-years, whereas the incidence rate for HA-CDI was 12.41 cases per 100,000 person-years. Conditional logistic regression was utilized to determine the risk for CA-CDI related to pharmacologic exposures, comorbidity, demographic characteristics, and healthcare utilization. Prior to controlling for other risk factors and covariates; being over the age of 50 years, gender, history of hospitalization, number of outpatient physician visits, antimicrobial use, gastric acid suppressant use, underlying comorbidity, and diagnosis of gastrointestinal disease (including IBD, diverticular disease, GERD) were associated with the development of CA-CDI. However, after adjustment for all covariates, increased risk for CA-CDI within this population was consistently associated with antimicrobial use, being between the age of 19 and 74 years, and diagnosis of inflammatory bowel disease. Gastric acid suppressant use was a risk factor in a number of models, although this association was not consistent. Furthermore, persons who last