Outcome of metronidazole therapy for Clostridium difficile disease and correlation with a scoring system

To determine the response rate of Clostridium difficile disease (CDD) to treatment with metronidazole and assess a scoring system to predict response to treatment with metronidazole when applied at the time of CDD diagnosis.

Retrospective review of patients with CDD who received primary treatment with metronidazole. We defined success as diarrhea resolution within 6 days of therapy. A CDD score was defined prospectively using variables suggested to correlate with disease severity.

Among 102 evaluable patients, 72 had a successful response (70.6%). Twenty-one of the remaining 30 patients eventually responded to metronidazole, but required longer treatment, leaving 9 'true failures'. The mean CDD score was higher among true failures (2.89+/-1.4) than among all metronidazole responders (0.77+/-1.0) (p<.0001). The score was greater than 2 in 67% of true failures and 2 or less in 94% of metronidazole responders. Leukocytosis and abnormal CT scan findings were individual factors associated with a higher risk of metronidazole failure.

Only 71% of CDD patients responded to metronidazole within 6 days, but the overall response rate was 91%. A CDD score greater than 2 was associated with metronidazole failure in 6 of 9 true failures. The CDD score will require prospective validation.