3 weeks Antibiotic therapy okay for diabetic foot osteomyelitis instead of 6 weeks

Ilker Uçkay, MD, head of infectiology and clinical research in the department of orthopaedics at the University of Zurich, told "Antibiotic stewardship in the field of diabetic foot osteomyelitis (DFO) is a major component of antibiotic overuse in the world,"

The optimal duration of antibiotic treatment of osteomyelitis complicating foot wounds in non–surgically treated diabetic patients is currently unknown. International guidelines recommend ≥3 months of antibiotic therapy in the absence of surgery or in case of residual dead bone after surgery. Antibiotic use encourages antimicrobial resistance, incurs a financial cost, and may cause drug-related adverse effects. A recent study found that antibiotic therapy, mainly rifampin combinations, directed by bone culture results (compared with empiric antibiotic therapy) was associated with a significantly higher rate of remission of bone infection after a mean of 12 months of follow-up. A reduction in treatment duration might help to alleviate the drawbacks of the medical approach in these patients. Therefore, researchers of Geneva university hospital conducted a study to investigate whether a short (3 weeks), compared with a long (6 weeks) duration of systemic antibiotic treatment is associated with non-inferior results for clinical remission and adverse events (AE).

It was a prospective, randomized, non-inferiority, pilot study in 93 patients with DFO who have undergone surgical debridement. Patients were randomly assigned to either a 3-week (n=44) or a 6-week (n=49) course of antibiotic therapy with the minimal two months duration of follow-up after the end of therapy. The researchers compared outcomes between the groups using Cox regression and noninferiority analyses.

Key findings of the study were:

♦In the intention-to-treat (ITT) population researchers found, remission occurred in 37 (84%) of the patients in the 3-week arm compared with 36 (73%) in the 6-week arm.

♦They reported a similar number of adverse events in both groups (17/44 vs. 16/49).

♦They noted the remission incidences in the per-protocol (PP) population (33/39 vs. 32/43) were also similar.

♦On multivariate analysis, they found treatment with the shorter antibiotic course was not significantly associated with remission (for the ITT population: HR = 1.1; for the PP population: HR = 0.8)

The authors concluded, "In this randomized, controlled pilot trial, a post-debridement systemic antibiotic therapy course for DFO of 3-weeks gave similar (and statistically non-inferior) incidences of remission and AE to a course of 6 weeks".