The burden of Clostridium difficile in surgical patients in the United States.

BACKGROUND

Clostridium difficile colitis is the predominant hospital-acquired gastrointestinal infection in the United States and has emerged as an important nosocomial cause of morbidity and death. Although several institutional studies have examined the effects of C. difficile on hospitalized patients, its nationwide impact on surgical patients has yet to be defined.

METHODS

To provide a national estimate of the burden of C. difficile, we performed a five-year retrospective analysis of the Agency for Healthcare Research and Quality's National Inpatient Sample Database, which represents a stratified 20% sample of hospitals in the United States, from 1999 to 2003. All surgical inpatient discharge data from 997 hospitals in 37 states were analyzed to determine the association of C. difficile infections with patient demographics, hospital characteristics, surgical procedure, length of stay (LOS), total charges, and in-hospital mortality rate. Univariate analysis was performed to identify any association between the presence of C. difficile infection and the outcome variables using chi-square contingency table analysis or the Student t-test following the exclusion of patients with other medical complications. Multivariate regression analysis was used to determine whether the presence of C. difficile infection was an independent predictor of increased LOS, total charges, and in-hospital mortality rate when controlling for surgery type, age, sex, payor, and hospital characteristics.

RESULTS

Clostridium difficile infection was reported as a discharge diagnosis for 8,113 (0.52%) of all 1,553,597 inpatients who had undergone a general surgical procedure. The incidence increased significantly in 2002 (34% higher than in 2001; p < 0.0001). The following patient and hospital characteristics were associated with the highest incidence of C. difficile infection (all p < 0.0001): Age > 64 years (0.95%); Medicare beneficiary status (0.94%); north-eastern hospital location (0.73%); and large (0.55%), urban (0.56%), or teaching hospital (0.61%). Patients undergoing an emergency operation were at higher risk than those having operations performed electively (0.8% vs. 0.3%; p < 0.0001). Colectomy, small-bowel resection, and gastric resection were associated with the highest risk of C. difficile infection (incidence after colectomy 1.11%; odds ratio [OR] 2.77, 95% confidence interval [CI] 2.65, 2.89, p < 0.0001; small-bowel resection 1.17%, OR 2.40, 95% CI 2.26, 2.54, p < 0.0001; gastric resection 1.02%, OR 2.26, 95% CI 2.03, 2.52, p < 0.0001). Patients undergoing cholecystectomy and appendectomy had the lowest risk of C. difficile infection (cholecystectomy 0.41%, OR 0.37, 95% CI 0.35, 0.39, p < 0.0001; appendectomy 0.20%, OR 0.45, 95% CI 0.42, 0.49, p < 0.0001). Multivariable analysis demonstrated that C. difficile was an independent predictor of LOS, which increased by 16.0 days (95% CI 15.6, 16.4 days; p < 0.0001) in the presence of infection. Total charges increased by $77,483 (95% CI $75,174, $79,793; p < 0.0001), and there was a 3.4-fold increase in the mortality rate (95% CI 3.02, 3.77; p < 0.0001) compared with patients who did not acquire C. difficile.

CONCLUSIONS

Epidemiologic data suggest that the incidence of C. difficile infection is increasing in U.S. surgical patients and that the infection is most prevalent after emergency operations and among patients having intestinal tract resections. Infection with C. difficile is an independent predictor of increased LOS, total charges, and mortality rate after surgery and represents a considerable burden to both patients and hospitals. Preventing C. difficile infection offers a potentially significant improvement in patient outcomes, as well as a reduction in hospital costs and resource expenditures.