Clinical question: Is a six-week regimen of antibiotics as effective as a 12-week regimen in the treatment of vertebral osteomyelitis?
Background: The optimal duration of antibiotic treatment for vertebral osteomyelitis is unknown. Previous guidelines recommending six to 12 weeks of therapy have been based on expert opinion rather than clinical trial data.
Study design: Multi-center, open-label, randomized controlled trial.
Setting: Seventy-one medical care centers in France.
Synopsis: Three hundred fifty-six adult patients with culture-proven bacterial vertebral osteomyelitis were randomized to six- or 12- week antibiotic treatment regimens. The primary outcome was confirmed cure of infection at 12 months, as defined by absence of pain, fever, and CRP <10 mg/L. Outcomes were determined by a blinded panel of physicians.
Results showed 90.9% of the patients in the six-week group, and 90.8% of the patients in the 12-week group, met criteria for clinical cure. The lower bound of the 95% confidence interval for the difference in percentages of cure between groups was -6.2%, satisfying the predetermined noninferiority margin of 10%.
Antibiotic therapy in this trial was governed by French guidelines, which recommend oral fluoroquinolones and rifampin as first-line agents for vertebral osteomyelitis. Median duration of IV antibiotic therapy was less than 14 days. Relatively few patients had abscesses, and only eight of the 145 patients with Staphylococcus aureus (SA) infections had methicillin-resistant SA (MRSA).
Bottom line: A six-week regimen of antibiotics was shown to be noninferior to a 12-week regimen for treatment of vertebral osteomyelitis. Treatment for longer than six weeks may be indicated in the setting of drug-resistant organisms, extensive bone destruction, or abscesses.
Citation: Bernard L, Dinh A, Ghout I, et al; on behalf of the Duration of Treatment for Spondylodiscitis (DTS) study group. Antibiotic treatment for 6 weeks versus 12 weeks in patients with pyogenic vertebral osteomyelitis: an open-label, non-inferiority, randomized, controlled trial [published online ahead of print November 5, 2014]. Lancet. doi: 10.1016/S0140-6736(14)61233-2.