A retrospective study published in JAMA Internal Medicine found no difference in the risk of Clostridium difficile infection (CDI) recurrence among patients treated with vancomycin or metronidazole but the risk of 30-day mortality was significantly lower among patients with severe CDI treated with vancomycin.
Metronidazole HCl has been considered first-line therapy for patients with mild to moderate CDI but vancomycin HCl has proven superior in regards to clinical cure. Secondary outcomes such as recurrence and mortality have not been as frequently studied following choice of treatment. A group of researchers, led by Vanessa W. Stevens, PhD, from the VA Salt Lake City Health Care System, UT, conducted a retrospective, propensity-matched cohort study to evaluate the risk of recurrence and all-cause 30-day mortality among patients receiving metronidazole or vancomycin for the treatment of mild to moderate CDI. Patient data was obtained from the U.S. Department of VA health care system from January 1, 2005 through December 31, 2012.
The main outcomes were CDI recurrence and all-cause 30-day mortality. Recurrence was defined as a second positive laboratory test result within 8 weeks of the initial diagnosis. All-cause 30-day mortality was defined as death from any cause within 30 days of the initial CDI diagnosis.
The study included 47,471 patients who developed CDI and were treated with vancomycin or metronidazole that met the inclusion criteria. Of the eligible first treatment episodes, 2,068 (4.4%) were treated with vancomycin and matched with 8,069 patients in the metronidazole group.
Study authors found no differences in the risk of recurrence between patients treated with vancomycin vs. metronidazole in any of the disease severity study arms. Among patients in the any severity cohort, vancomycin-treated patients were less likely to die (adjusted relative risk [aRR] 0.86, 95% CI: 0.74-0.98; adjusted risk difference –0.02, 95% CI: –0.03 to –0.01).
No significant difference was seen in the risk of death between the treatment groups in mild to moderate CDI, but vancomycin treatment significantly reduced the risk of all-cause 30-day mortality among those with severe CDI (aRR 0.79, 95% CI: 0.65-0.97, adjusted risk difference –0.04, 95% CI: -0.07 to –0.01).
“Our findings may further justify the use of vancomycin as initial therapy for severe CDI,” concluded Dr. Stevens.
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