Multicenter study of Clostridium difficile infection rates from 2000 to 2006

Abstract

Objective: To compare incidence rates of Clostridium difficile infection (CDI) during a 6-year period among 5 geographically diverse academic medical centers across the United States by use of recommended standardized surveillance definitions of CDI that incorporate recent information on healthcare facility (HCF) exposure.

Methods: Data on C. difficile toxin assay results and dates of hospital admission and discharge were collected from electronic databases. Chart review was performed for patients with a positive C. difficile toxin assay result who were identified within 48 hours after hospital admission to determine whether they had any HCF exposure during the 90 days prior to their hospital admission. CDI cases, defined as any inpatient with a stool toxin assay positive for C. difficile, were categorized into 5 surveillance definitions based on recent HCF exposure. Annual CDI rates were calculated and evaluated by use of the chi(2) test for trend and the chi(2) summary test.

Results: During the study period, there were significant increases in the overall incidence rates of HCF-onset, HCF-associated CDI (from 7.0 to 8.5 cases per 10,000 patient-days; P < .001); community-onset, HCF-associated CDI attributed to a study hospital (from 1.1 to 1.3 cases per 10,000 patient-days; P = .003); and community-onset, HCF-associated CDI not attributed to a study hospital (from 0.8 to 1.5 cases per 1,000 admissions overall; P < .001). For each surveillance definition of CDI, there were significant differences in the total incidence rate between HCFs.

Conclusions: The increasing incidence rates of CDI over time and across healthcare institutions and the correlation of CDI incidence in different surveillance categories suggest that CDI may be a regional problem and not isolated to a single HCF within a community.

Figure 1

Annual incidence rates of Clostridium difficile infection (CDI) for all 5 hospitals combined, according to surveillance definition. Solid lines indicate a significant increase in incidence over the study period (χ² test for trend p < 0.01). Open symbols, CDI cases per 10,000 patient-days; solid symbols, CDI cases per 1,000 admissions. HCF, healthcare facility.

Figure 2

Annual incidence rates of Clostridium difficile infection (CDI) for hospital-onset, healthcare facility (HCF)-associated CDI (A), community-onset, HCF-associated – study hospital CDI (B), community-onset, HCF-associated – other HCF (C), community-onset, community-associated CDI (D), and indeterminate CDI (E), according to hospital. Solid lines indicate a significant increase in incidence over the study period (χ² test for trend p < 0.01). The lower-case letters next to the hospital name denote the hospitals with a significantly different overall CDI incidence rate (p < 0.005 for all). For example, hospital A had a significantly different overall hospital-onset, HCF-associated CDI incidence rate than hospitals B, C, D, and E.

Figure 2

Annual incidence rates of Clostridium difficile infection (CDI) for hospital-onset, healthcare facility (HCF)-associated CDI (A), community-onset, HCF-associated – study hospital CDI (B), community-onset, HCF-associated – other HCF (C), community-onset, community-associated CDI (D), and indeterminate CDI (E), according to hospital. Solid lines indicate a significant increase in incidence over the study period (χ² test for trend p < 0.01). The lower-case letters next to the hospital name denote the hospitals with a significantly different overall CDI incidence rate (p < 0.005 for all). For example, hospital A had a significantly different overall hospital-onset, HCF-associated CDI incidence rate than hospitals B, C, D, and E.

Figure 2

Annual incidence rates of Clostridium difficile infection (CDI) for hospital-onset, healthcare facility (HCF)-associated CDI (A), community-onset, HCF-associated – study hospital CDI (B), community-onset, HCF-associated – other HCF (C), community-onset, community-associated CDI (D), and indeterminate CDI (E), according to hospital. Solid lines indicate a significant increase in incidence over the study period (χ² test for trend p < 0.01). The lower-case letters next to the hospital name denote the hospitals with a significantly different overall CDI incidence rate (p < 0.005 for all). For example, hospital A had a significantly different overall hospital-onset, HCF-associated CDI incidence rate than hospitals B, C, D, and E.

Figure 2

Annual incidence rates of Clostridium difficile infection (CDI) for hospital-onset, healthcare facility (HCF)-associated CDI (A), community-onset, HCF-associated – study hospital CDI (B), community-onset, HCF-associated – other HCF (C), community-onset, community-associated CDI (D), and indeterminate CDI (E), according to hospital. Solid lines indicate a significant increase in incidence over the study period (χ² test for trend p < 0.01). The lower-case letters next to the hospital name denote the hospitals with a significantly different overall CDI incidence rate (p < 0.005 for all). For example, hospital A had a significantly different overall hospital-onset, HCF-associated CDI incidence rate than hospitals B, C, D, and E.

Figure 2

Annual incidence rates of Clostridium difficile infection (CDI) for hospital-onset, healthcare facility (HCF)-associated CDI (A), community-onset, HCF-associated – study hospital CDI (B), community-onset, HCF-associated – other HCF (C), community-onset, community-associated CDI (D), and indeterminate CDI (E), according to hospital. Solid lines indicate a significant increase in incidence over the study period (χ² test for trend p < 0.01). The lower-case letters next to the hospital name denote the hospitals with a significantly different overall CDI incidence rate (p < 0.005 for all). For example, hospital A had a significantly different overall hospital-onset, HCF-associated CDI incidence rate than hospitals B, C, D, and E.