Comparison of treatment outcomes with vancomycin alone versus combination therapy in severe Clostridium difficile infection

Summary Background The recommended treatment for severe Clostridium difficile infection (CDI) is oral vancomycin alone. Combination therapy with metronidazole is only recommended in cases complicated by shock, ileus, or toxic megacolon. However, patients with severe infection are often treated with combination therapy despite a lack of data supporting this practice. Aim To evaluate differences in outcomes for patients with severe CDI treated with oral vancomycin alone versus combination therapy. Methods Medical records of 78 patients with severe CDI receiving either oral vancomycin alone or combination therapy for ≥72 h were retrospectively reviewed. 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. Findings There was no difference in the incidence of clinical cure between monotherapy and combination therapy (57.1% vs 65.1%, P = 0.49). Median time to clinical cure was 7.0 days for the monotherapy group and 8.0 days for combination therapy ( P = 0.19). After adjustment for potential confounders, the hazard ratio of the time to clinical cure for combination therapy compared with monotherapy was 0.58 ( P = 0.10). There was no difference in recurrence rate or rates of individual complications between groups; however, there was a significantly higher composite complication rate in the combination therapy group. Conclusion These data suggest that there is no difference in treatment outcomes between monotherapy and combination therapy for severe CDI.