Multicenter study of the impact of community-onset Clostridium difficile infection on surveillance for C. difficile infection

Abstract

Objective: To evaluate the impact of cases of community-onset, healthcare facility (HCF)-associated Clostridium difficile infection (CDI) on the incidence and outbreak detection of CDI.

Design: A retrospective multicenter cohort study.

Setting: Five university-affiliated, acute care HCFs in the United States.

Methods: We collected data (including results of C. difficile toxin assays of stool samples) on all of the adult patients admitted to the 5 hospitals during the period from July 1, 2000, through June 30, 2006. CDI cases were classified as HCF-onset if they were diagnosed more than 48 hours after admission or as community-onset, HCF-associated if they were diagnosed within 48 hours after admission and if the patient had recently been discharged from the HCF. Four surveillance definitions were compared: cases of HCF-onset CDI only (hereafter referred to as HCF-onset CDI) and cases of HCF-onset and community-onset, HCF-associated CDI diagnosed within 30, 60, and 90 days after the last discharge from the study hospital (hereafter referred to as 30-day, 60-day, and 90-day CDI, respectively). Monthly CDI rates were compared. Control charts were used to identify potential CDI outbreaks.

Results: The rate of 30-day CDI was significantly higher than the rate of HCF-onset CDI at 2 HCFs (P < .01). The rates of 30-day CDI were not statistically significantly different from the rates of 60-day or 90-day CDI at any HCF. The correlations between each HCF's monthly rates of HCF-onset CDI and 30-day CDI were almost perfect (rho range, 0.94-0.99; P < .001). Overall, 12 time points had a CDI rate that was more than 3 standard deviations above the mean, including 11 time points identified using the definition for HCF-onset CDI and 9 time points identified using the definition for 30-day CDI, with discordant results at 4 time points ((kappa = 0.794; P < .001).

Conclusions: Tracking cases of both community-onset and HCF-onset, HCF-associated CDI captures significantly more CDI cases, but surveillance of HCF-onset, HCF-associated CDI alone is sufficient to detect an outbreak.

Conflict of interest statement

Potential conflicts of interest: E.R.D. has served as a consultant to Merck, Salix, and Becton-Dickinson and has received research funding from Viropharma. D.S.Y. has received research funding from Sage Products, Inc.

Figures

Figure 1

Time of onset of community-onset healthcare facility-associated cases of Clostridium difficile infection (CDI) after most recent discharge from hospital.

Figure 2

Rates of Clostridium difficile infection (CDI) by surveillance definition at hospital A. Solid black circles, abnormally high HO CDI incidence (> 3 SD); Outlined circles, abnormally high HO CDI incidence (within-limit); Solid black triangles, abnormally high HCFA-30 CDI incidence (> 3 SD); Outlined triangles, abnormally high HCFA-30 incidence (within-limit) (for definitions, see Methods).

Figure 3

Rates of Clostridium difficile infection (CDI) by surveillance definition at hospital B. Solid black circles, abnormally high HO CDI incidence (> 3 SD); Outlined circles, abnormally high HO CDI incidence (within-limit); Solid black triangles, abnormally high HCFA-30 CDI incidence (> 3 SD); Outlined triangles, abnormally high HCFA-30 incidence (within-limit) (for definitions, see Methods).

Figure 4

Rates of Clostridium difficile infection (CDI) by surveillance definition at hospital C. Solid black circles, abnormally high HO CDI incidence (> 3 SD); Outlined circles, abnormally high HO CDI incidence (within-limit); Solid black triangles, abnormally high HCFA-30 CDI incidence (> 3 SD); Outlined triangles, abnormally high HCFA-30 incidence (within-limit) (for definitions, see Methods).

Figure 5

Rates of Clostridium difficile infection (CDI) by surveillance definition at hospital D. Solid black circles, abnormally high HO CDI incidence (> 3 SD); Outlined circles, abnormally high HO CDI incidence (within-limit); Solid black triangles, abnormally high HCFA-30 CDI incidence (> 3 SD); Outlined triangles, abnormally high HCFA-30 incidence (within-limit) (for definitions, see Methods).

Figure 6

Rates of Clostridium difficile infection (CDI) by surveillance definition at hospital E. Solid black circles, abnormally high HO CDI incidence (> 3 SD); Outlined circles, abnormally high HO CDI incidence (within-limit); Solid black triangles, abnormally high HCFA-30 CDI incidence (> 3 SD); Outlined triangles, abnormally high HCFA-30 incidence (within-limit) (for definitions, see Methods).