To assess the healthcare burden, morbidity, and mortality of nosocomial Clostridium difficile-associated diarrhea (N-CDAD) in Canadian hospitals.

Laboratory-based prevalence study.

Nineteen acute-care Canadian hospitals belonging to the Canadian Hospital Epidemiology Committee surveillance program.

Hospitalized patients in the participating centers.

Laboratory-based surveillance was conducted for C. difficile toxin in stool among 19 Canadian hospitals from January to April 1997, for 6 continuous weeks or until 200 consecutive diarrhea stool samples had been tested at each site. Patients with N-CDAD had to fulfill the case definition. Data collected for each case included patient demographics, length of stay, extent of diarrhea, complications of CDAD, CDAD-related medical interventions, patient outcome, and details of death.

We found that 371 (18%) of 2,062 tested patients had stools with positive results for C. difficile toxin, of whom 269 (13%) met the case definition for nosocomial CDAD. Of these, 250 patients (93%) had CDAD during their hospitalization, and 19 (7%) were readmitted because of CDAD (average readmission stay, 13.6 days). Forty-one patients (15.2%) died, of whom 4 (1.5% of the total) were considered to have died directly or indirectly of N-CDAD. The following N-CDAD-related morbidity was noted: dehydration, 3%; hypokalemia, 2%; gastrointestinal hemorrhage requiring transfusion, 1%; bowel perforation, 0.4%; and secondary sepsis, 0.4%. The cost of N-CDAD readmissions alone was estimated to be a minimum of $128,200 (Canadian dollars) per year per facility.

N-CDAD is a common and serious nosocomial infectious complication in Canada, is associated with substantial morbidity and mortality, and imposes an important financial burden on healthcare institutions.