SLR - April 2021 - Sahab K. Danesh

Surgical Diabetic Foot Infections: Is Osteomyelitis Associated with a Worse Prognosis?

Reference: Aragón-Sánchez J, Víquez-Molina G, López-Valverde ME, Rojas-Bonilla JM, Murillo-Vargas C. Surgical Diabetic Foot Infections: Is Osteomyelitis Associated With a Worse Prognosis? The International Journal of Lower Extremity Wounds. February 2021. doi:10.1177/1534734620986695

Level of Evidence: Level III 

Scientific Literature Review

Reviewed By: Sahab K. Danesh, DPM
Residency Program: Carl T. Hayden VA Medical Center – Phoenix, AZ

Podiatric Relevance: Urgency to address infection in the diabetic foot is of paramount importance when performing surgery for source control. Possibility of further spread of infection guides the aggressiveness of intervention to give the patient the best possible outcome. Although it is thought that diabetic foot infection (DFIs) with osteomyelitis (OM) have a worse prognosis than those with soft tissue infections (STIs), this has not been well supported in the literature. The aim of this study was to determine the differences in outcomes between patients with STIs and those with OM in a series of patients requiring surgical treatment for moderate and severe DFIs.

Methods: A retrospective series was done comparing outcomes of surgical intervention for DFIs in patients with OM versus STIs. A total of 150 patients were included in this study. The authors reclassified OM and STIs to moderate and severe infections using the Infection Diseases Society of America (IDSA) Classification. Variables used to compare prognosis were limb loss (minor amputation defined as limb salvage and major amputation defined as proximal to the ankle), length of hospital stay, duration of antibiotic treatment, recurrence of infection, and time to healing. 

Results: Of the 150 patients, 42 patients (28 percent) had STIs and 108 patients (72 percent) had OM. 64 patients (42.7 percent) presented with moderate infection and 86 patients (57.3 percent) presented with severe infection. Of the prognostic variables compared between OM and STI, no statistical difference was found between limb salvage, hospital stay, duration of antibiotic treatment, recurrence of the infection, and time to healing. Although not statistically significant, patients with moderate OM had a higher rate of minor reamputation due to recurrence of osteomyelitis after initial treatment and a longer time to healing when compared to patients with moderate STI. No statistical difference in all measured prognostic variables was found between severe infections with or without OM.

Conclusions: The authors of this study conclude that moderate and severe DFIs with OM are not associated with a worse prognosis when compared to moderate and severe STIs. This conclusion is inconsistent with the literature, which reports that OM is associated with a worse prognosis than STIs. This alone indicates the need for further investigation to validate these results. Urgency in taking patients to the operating room should therefore, not be dictated alone by presence or absence of OM. If OM is present, aggressive debridement should be performed with the goal of clear surgical margins in attempts to reduce risk of recurrence and decrease time to healing. The results of this study should be considered in pre-operative discussions in patients with DFIs to reinforce severity of potential outcomes. 

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