Usefulness of Procalcitonin in Diagnosing Diabetic Foot Osteomyelitis

A Pilot Study

Venkat N. Vangaveti, PhD; Oliver G. Heyes, MD; Shaurya Jhamb, MD; Nagaraja Haleagrahara, PhD; Usman H. Malabu, MD, FACP, FRACP

Disclosures

Wounds. 2021;33(7):192-196. 

In This Article

Results

A total of 37 participants were enrolled in the study, with 19 participants in the osteomyelitis group and 18 participants in the control group. The baseline characteristics were similar in both groups, as detailed in Table 1. The mean age for the osteomyelitis group was 62.0 ± 12 years, and the control group was 65.0 ± 8.0 years (P = .5). The majority of participants in both groups were patients with type 2 diabetes; both groups had a similar percentage of participants taking oral hypoglycemic agents and insulin as well as similar percentages of non-traumatic lower-limb amputations (59% vs 74%, respectively) (P = .7). Fifty-seven ulcers were studied, comprising 28 and 29 ulcers in the DFO group and control group, respectively. The majority of patients in both groups (81%) had forefoot ulcers, including 78% in the DFO group and 86% in the control group as shown in Table 2. Further analysis of the ulcer location (ie, forefoot, midfoot, and hindfoot) revealed similar distribution in both groups. No statistically significant differences for alcohol consumption and smoking were observed between the groups. Comorbidities, such as diabetic retinopathy, dyslipidemia, coronary artery disease, and peripheral vascular diseases, were similar in both groups. There were no differences between the counts for neutrophils, platelets, monocytes, or lymphocytes between the groups.

Differences between serum levels of PCT and IL-6 were found to be statistically significant. The median serum levels of PCT in the DFO group were 108.5 pg/mL (range, 65.0–124.0 pg/mL) and 57.0 pg/mL (range, 37.2–77.0 pg/mL) (P = .02), and IL-6 levels in DFO group were 22.0 pg/mL (range, 3.0–86.5 pg/mL) and 3.5 pg/mL (range, 1.0–9.5 pg/mL) (P = .02) (Figure).

Figure 1.

(A, B) Box plots showing diff erences in median values and (C) receiver operating characteristic curves depicting better diagnostic value for procalcitonin and IL-6. (D) Receiver operating characteristic curves for NLR, PLR, MLR, LNR, and SII.
a P<.01
IL-6: interleukin-6; NLR: neutrophil-to-lymphocyte ratio; PLR: platelet-to-lymphocyte ratio; MLR: monocyte-to-lymphocyte ratio; LNR: lymphocyte-to-neutrophil ratio; SII: systemic immune-infl ammation index

The ROC analysis showed that out of all the candidates tested, PCT had a sensitivity of 79% and specificity of 70% at a positive diagnostic test cutoff of 64.0 pg/mL (P = .02). Interleukin 6 had sensitivity of 75% and specificity of 64% at a cutoff of 4.2 pg/mL (P = .02). The clinical utility index of both was found to be fair. Analysis reference intervals on ratios of NLR, PLR, MLR, LNR, and SII revealed a fair test candidate for MLR with a sensitivity of 74% and specificity of 67% at a positive diagnostic test cut-off of 0.3 (P = .02) (Table 2).

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