Non-inferiority of metronidazole to vancomycin in the treatment of first episode non-severe Clostridioides difficile infection: a single center retrospective cohort study

Objectives We sought to assess the effectiveness of oral vancomycin compared to metronidazole on recurrence and mortality among hospitalized patients with non-severe Clostridioides difficile infection (CDI). Methods A single center retrospective cohort study was conducted, including adult patients hospitalized between 2015 and 2020 with a first episode of non-severe CDI, treated with metronidazole or vancomycin as monotherapy for at least 10 days. We assessed recurrence of CDI requiring hospitalization (primary outcome) and all-cause mortality up to 8 weeks, post discharge. Results Overall, 160 patients were treated with vancomycin and 149 treated with metronidazole. Re-hospitalization within 8 weeks due to CDI occurred in 10 (6.2%) patients in the vancomycin group, and 13 (8.7%) in the metronidazole group (P value = 0.407). Eight-week mortality occurred in 39 patients (26.2%) in the metronidazole group and 46 patients (28.8%) in the vancomycin group (P value = 0.61). After adjusting for age, gender, Ischemic heart disease, white blood cell count, neutrophile count and CRP, there was no significant difference between the two treatments (Re-hospitalization in 8 weeks due to CDI P = 0.5059; In-hospital death P = 0.7950; 4-week mortality P = 0.2988; 8-week mortality P = 0.8237). Conclusion There is no benefit of using vancomycin compared to metronidazole concerning recurrence rate requiring hospitalization, in-hospital and up to 4- and 8-week mortality rate in non-severe first episode of CDI.