Post-treatment Leukocytosis Predicts an Unfavorable Clinical Response in Patients with Moderate to Severe Diabetic Foot Infections

Our aim was to determine whether post-treatment laboratory values could help to predict the clinical response in patients with advanced diabetic foot infections. One hundred and three consecutive patients hospitalized for moderate or severe diabetic foot infections at a large, university-affiliated hospital were identified and their records retrospectively reviewed. Definitive therapy during each patient’s hospital course was defined as any foot surgery when additional major surgery was not anticipated or when a course of deep soft tissue and/or bone culture-specific antibiotics had been initiated. The clinical response was assessed at 90 days after the start of definitive therapy. A poor response was recognized as persistent infection at the initial or a contiguous site or when unplanned revision surgery or amputation was subsequently required. The peripheral white blood cell count, neutrophil count, erythrocyte sedimentation rate, and C-reactive protein levels measured shortly after initiating definitive therapy (i.e., post-treatment) were examined for their association with the clinical response using logistic regression models. A total of 38 patients with the complete compliment of laboratory and clinical follow-up aged 59.7 ± 12.3 years with a diabetes duration of 13.3 ± 9.1 years were included. Leukocytosis, defined as a white blood cell count >11,000 cells/μL, observed an average of 3 ± 1.4 days after treatment, was the single most important marker for predicting a poor clinical response, and the only significant study variable in both univariate and multivariate analyses (multivariate odds ratio 9.7, 95% confidence interval 1.0 to 92, p = .048). We conclude that leukocytosis observed shortly after initiating definitive therapy is predictive of an unfavorable clinical response by 90 days.