Case-controlled review of Clostridium difficile-associated diarrhoea in southern Tasmania

While the incidence of Clostridium difficile-associated diarrhoea (CDAD) has increased sharply over the last 15 years, its risk factors are still not well defined. The aim of this study was to review cases of CDAD at the major teaching hospital in Tasmania, Australia, to identify risk factors for CDAD and their association with prognosis.

A retrospective review of the medical records of adult patients admitted to the hospital between January 1994 and December 1996 was performed. Sixty-four patients who developed CDAD prior to or during their admission, and an additional 120 diarrhoea-free patients (the control group) were studied. An extensive range of demographic and clinical variables were recorded, and the differences between the control group and patients with CDAD were evaluated.

The CDAD patients had a median age of 66 years (range 22-95 years), with females accounting for 52% of cases. There were no significant demographic differences from the control group. Identifiable risk factors for developing CDAD were severe underlying disease, renal impairment, exposure to antibiotics or antineoplastic agents, and the use of total parenteral nutrition or nasogastric feeding. Cephalosporins were the most frequently used antibiotics in both CDAD and control patients, with cefotaxime being the only antibiotic which was identified as being significantly associated with an increased risk of CDAD. The median length of diarrhoea episodes was 9 days (range 1-60 days). The mortality rate was 17.2%, and factors associated with a poor prognosis were older age, severe underlying disease, renal impairment and failure to treat with metronidazole or vancomycin. Delay in starting specific treatment and use of codeine were related to prolonged CDAD.

CDAD is a growing contributor to hospital morbidity and costs. Severely ill patients with compromised immune function are particularly susceptible, with antibiotic use being a major risk factor. Prompt diagnosis and initiation of treatment are important factors in the improvement of prognosis.