Frequent hospital readmissions for Clostridium difficile infection and the impact on estimates of hospital-associated C. difficile burden

Abstract

Objective: Clostridium difficile infection (CDI) is associated with hospitalization and may cause readmission following admission for any reason. We aimed to measure the incidence of readmissions due to CDI.

Design: Retrospective cohort study.

Patients: Adult inpatients in Orange County, California, who presented with new-onset CDI within 12 weeks of discharge.

Methods: We assessed mandatory 2000-2007 hospital discharge data for trends in hospital-associated CDI (HA-CDI) incidence, with and without inclusion of postdischarge CDI (PD-CDI) events resulting in rehospitalization within 12 weeks of discharge. We measured the effect of including PD-CDI events on hospital-specific CDI incidence, a mandatory reporting measure in California, and on relative hospital ranks by CDI incidence.

Results: From 2000 to 2007, countywide hospital-onset CDI (HO-CDI) incidence increased from 15 per 10,000 to 22 per 10,000 admissions. When including PD-CDI events, HA-CDI incidence doubled (29 per 10,000 in 2000 and 52 per 10,000 in 2007). Overall, including PD-CDI events resulted in significantly higher hospital-specific CDI incidence, although hospitals had disproportionate amounts of HA-CDI occurring postdischarge. This resulted in substantial shifts in some hospitals' rankings by CDI incidence. In multivariate models, both HO and PD-CDI were associated with increasing age, higher length of stay, and select comorbidities. Race and Hispanic ethnicity were predictive of PD-CDI but not HO-CDI.

Conclusions: PD-CDI events associated with rehospitalization are increasingly common. The majority of HA-CDI cases may be occurring postdischarge, raising important questions about both accurate reporting and effective prevention strategies. Some risk factors for PD-CDI may be different than those for HO-CDI, allowing additional identification of high-risk groups before discharge.

Figure 1

CDI Burden among Hospitalized Adult Patients in Orange County, California, from 2000 to 2007. Incidence of HO-CDI, PD-CDI and HA-CDI is expressed per 10,000 adult admissions; incidence of CA-CDI is expressed per 100,000 Orange County adult population. HA-CDI consists of HO-CDI and PD-CDI.

Figure 2

Time to Readmission for Post-Discharge CDI Cases (PD-CDI), 2000–2007, for Cases Occurring within 1 Year after Discharge (N=1,766).

Figure 3

Hospital-specific Rankings by HA-CDI vs. HO-CDI Incidence for 2007. Shaded areas indicate the quartile of hospitals with the highest CDI incidence based upon HA-CDI vs HO-CDI.