320 - Does Guideline-Based Management of Diabetic Foot Osteomyelitis Reduce Risk of Further Proximal Amputations?

Background: The antibiotic management of diabetic foot osteomyelitis involving surgical limb-sparing amputation is controversial. While there are several guidelines that provide recommendations regarding antibiotic therapy for diabetic foot osteomyelitis after amputation, we do not know of any studies that show that adherence to guidelines improves clinical outcomes. We assessed whether adherence to antibiotic choice and duration in accordance with our institution’s guidelines, which are based on IDSA guidelines, reduced risk of future amputations.

Methods: We conducted a retrospective cohort study of 110 patients with diabetic foot osteomyelitis treated with limb-sparing amputations at a VA hospital. We collected relevant clinical data such as patient comorbidities, antibiotic allergies, labs, imaging, culture data, histopathologic reports, pre-op and post-op antibiotics. We used our institutional guidelines, which are based on the 2012 IDSA Guidelines for the Diagnosis and Treatment of Diabetic Foot Infections, to assess antibiotic choice and duration for diabetic foot osteomyelitis therapy after amputation. We stratified cases as either adherent or non-adherent based on whether antibiotic choice and duration were both in accordance with our institutional guideline. For each case, we recorded the primary outcome of further proximal amputation occurring within six months or death from all causes within three months.  

Results: We found a significant difference in primary outcomes between the groups that were treated with antibiotics adherent with guidelines and antibiotics non-adherent with guidelines. For patients who were treated with antibiotics that were non-adherent to guidelines, 15 of 36 (42%) patients needed further amputation or died. Of the patients treated according to guidelines,  12 of 74 (16%) patients needed further amputation or died. There was a statistically significant difference between these two groups (p=0.004).

Conclusion: Our study showed that guideline-based antibiotic therapy for diabetic foot osteomyelitis treated with amputation significantly lowered rates of further amputation compared to antibiotic therapies that were not adherent to guidelines.