New international guidelines tackle diabetic foot infection diagnosis, treatment

Clinicians should consider hospitalizing all patients with diabetes and severe foot infection, according to new recommendations from the International Working Group on the Diabetic Foot (IWGDF) and the Infectious Diseases Society of America (IDSA).

The guidelines, which focus on diagnosing and treating diabetes-related foot infections, were developed by an international working group of clinical and scientific experts and update separate earlier guidelines from the IDSA and IWGDF on this topic. They were published Oct. 2 by Clinical Infectious Diseases.

Any soft-tissue infection related to diabetes should be diagnosed based on the presence of local or systemic signs and symptoms of inflammation, the guidelines said. In addition, clinicians should assess severity according to the IWGDF/IDSA classification. The guidelines define diabetic foot infection based on evidence of inflammation of any part of the foot, not just an ulcer, or findings of systemic inflammatory response syndrome. Clinicians should consider hospitalizing all patients with diabetes who have a severe foot infection according to the IWGDF/IDSA classification or a moderate infection associated with key relevant comorbidities, especially peripheral artery disease, the guidelines said.

If a patient with diabetes has a possibly infected foot ulcer and the clinical examination is diagnostically equivocal or uninterpretable, clinicians should assess inflammatory serum biomarkers (e.g., C-reactive protein, erythrocyte sedimentation rate, or procalcitonin), according to the guidelines. The guidelines suggest not using foot temperature or quantitative microbial analysis for diagnosis of diabetes-related soft-tissue infection. Clinicians can consider a culture, preferably by curettage or biopsy, to determine causative microorganisms in patients with suspected soft-tissue diabetic foot infection, the guidelines said. Conventional cultures are recommended for initial identification of pathogens from soft tissue or bone samples, rather than molecular microbiology techniques. To diagnose osteomyelitis of the foot in a person with diabetes, clinicians can consider using a combination of probe-to-bone test, X-rays, and erythrocyte sedimentation rate, C-reactive protein, or procalcitonin as initial studies. MRI can be done when these tests are inconclusive, with positron emission tomography, leucocyte scintigraphy, or single-photon emission CT as alternatives, the guidelines said.

Regarding treatment, patients with clinically uninfected foot ulcers should not receive systemic or local antibiotics when the goal is reducing risk for new infection or promoting ulcer healing, the guidelines said. Patients with diabetes and soft-tissue infection of the foot who need antibiotics can be treated with any of the known effective systemic regimens for one to two weeks, according to the guidelines. Clinicians can consider continuing treatment for up to three or four weeks if the infection is improving but extensive and resolving more slowly than expected, or if the patient has severe peripheral artery disease.

Other recommendations discuss whether and how to target therapy to specific pathogens, whether any antibiotic regimen is superior for infection resolution and recurrence, how to weigh surgical versus nonsurgical treatment for moderate to severe infection, and whether any specific adjunctive or topical antibiotic treatment is useful, among other topics. The guidelines also discuss key controversies, including how and when to determine whether an infection has resolved and which serum biomarkers are most useful in determining whether a diabetic foot ulcer is infected and osteomyelitis is present.