Effect of vancomycin dose on treatment outcomes in severe Clostridium difficile infection

Current guidelines recommend vancomycin 125 mg four times daily for the treatment of severe Clostridium difficile infection (CDI). However, the optimal dose of vancomycin has not been elucidated. This study was conducted to evaluate outcome differences in patients with severe CDI treated with either low-dose (≤500 mg daily) or high-dose (>500 mg daily) oral vancomycin. The medical records of 78 patients with severe CDI were evaluated retrospectively. The primary outcome was time to clinical cure of CDI, defined as the first day of resolution of diarrhoea for ≥48 h without development of a complication. Other endpoints included cure rates, complication rates and recurrence rates. Overall, 48 patients (61.5%) achieved clinical cure at Day 10 after treatment initiation. The cure rates in the high-dose and low-dose vancomycin groups were 60% and 64%, respectively (P = 0.76). Using a multivariate Cox proportional hazards model adjusting for baseline discrepancies, vancomycin dose was not independently associated with clinical cure. No difference in time to cure, complication rates or mortality was observed between the groups. There was a trend towards lower rates of recurrence associated with higher doses of oral vancomycin (12% vs. 1.9%; P = 0.09). In conclusion, these data suggest that there is no difference in treatment outcomes between high-dose and low-dose vancomycin for the treatment of severe CDI. The potential difference in recurrence rates between the groups warrants further investigation.