C-reactive protein is a useful predictor of metronidazole treatment failure in mild-to-moderate Clostridium difficile infection.

OBJECTIVE: To assess the ability of C-reactive (CRP) protein, against the other commonly used metrics, to predict metronidazole treatment failure in Clostridium difficile infection.

METHODS: We retrospectively reviewed the case notes of 65 patients with C. difficile infection initially treated with metronidazole. Patients were grouped on the basis of outcome: those who responded to metronidazole within 6 days (cut-off as used by previous authors) versus those who required vancomycin. Individual predictor variables were examined between groups (using a t-test, Kruskal-Wallis test, or Fisher's exact test), and the strength of associations was assessed by logistic regression.

RESULTS: Of the 65 patients reviewed, 48 (74%) resolved with metronidazole alone. Regression analysis found that (CRP) white cell count and creatinine levels were significantly different across the metronidazole success/failure groups (P<0.01, P=0.01 and P=0.03, respectively).

CONCLUSION: (CRP) is a useful predictor of metronidazole treatment failure in mild-to-moderate C. difficile infection.