Lawrence A. Lavery
Researchers suggested that diabetic foot osteomyelitis — which results in worse outcomes compared with soft tissue infections — should be separated into its own category in the Infectious Diseases Society of America’s diabetic foot classification system to better guide treatment and improve outcomes.
“We need to base classification systems on evidence and not intuition,” Lawrence A. Lavery, DPM, MPH, podiatrist and professor of plastic surgery, orthopedic surgery and physical medicine and rehabilitation at the University of Texas Southwestern Medical Center, told Infectious Disease News.
The current severe infection identification system is based on systemic inflammatory response syndrome (SIRS) criteria, which do not suitably define moderate and severe infections, Lavery explained. He said this is because SIRS criteria “[do] not impact hospital treatments or complications and treatments after the index hospitalization.”
“Patients with osteomyelitis have more complicated hospital experiences and more complications during the year following discharge after their index hospitalization. The IDSA has recommendations for the duration of antibiotic therapy based on the presence of osteomyelitis and if the infected bone is completely resected, partially resected, if necrotic bone is left or if there is no surgery,” Lavery said. “However, the classification system has not included a treatment tier that reflected the importance of osteomyelitis.”
Changing the guidelines for the classification of diabetic foot infections may better guide treatment and improve outcomes.
Source: Adobe Stock.
Lavery and colleagues conducted a retrospective cohort study that included 294 patients with moderate and severe diabetic foot infections. Diabetic foot osteomyelitis was confirmed via bone culture or histopathology, whereas soft tissue infections were based on negative bone culture, MRI or single photon emission CT, the researchers explained.
They reported that patients with osteomyelitis had worse outcomes than patients with soft tissue infections. Specifically, 99.4% of patients with osteomyelitis required surgery, 83.4% required amputation, 56.7% became reinfected and 49.7% experience acute kidney injury. Comparatively, 55.5% of patients with soft tissue infection required surgery, 26.3% required amputation, 38% became reinfected and 37.2% experienced acute kidney injury. Moreover, those with osteomyelitis experienced longer antibiotic duration (32.5+/-46.8 vs. 63.8+/-55.1 days, P < .01) and length of stay (14.5+/-14.9 vs. 22.6+/-19.0 days, P < .01), and required more surgeries compared with patients with soft tissue infections (2.1+/-1.3 vs. 3.3+/-2.3, P < .01).
When Lavery and colleagues compared moderate and severe soft tissue infections, they found differences only for infection readmission, with readmittance occurring for 46.2% of moderate infections and 25% of severe infections, and acute kidney injury (31.2% vs. 50%).
When comparing moderate and severe osteomyelitis, the researchers noted differences in the number of surgeries (2.8+/-2.1 vs. 4.1+/-2.5, P < .01) and length of stay (18.6+/-17.5 vs 28.2+/-17.7, P < .01).
“We believe there is a need to stratify infection severity, but SIRS criteria [do] not seem to work,” Lavery said. “The presence of abscess, depth and extent of abscess are criteria we are evaluating. Osteomyelitis without soft tissue abscess or localized abscess (as opposed to abscess in multiple compartments) probably [does] not require surgery or amputation as often or have prolonged antibiotics experience during the index amputation as more extensive abscesses.” – by Marley Ghizzone
Disclosures: The authors report no relevant financial disclosures.