Usefulness of Procalcitonin in Diagnosing Diabetic Foot Osteomyelitis: A Pilot Study

Introduction. Infected diabetic foot is the leading cause of hospital admissions for people with diabetes mellitus. Diabetic foot osteomyelitis (DFO) causes high morbidity and significant mortality. Current diagnostic tests for DFO are either expensive, invasive, or of low diagnostic yield. Objective. The objective of the study was to determine whether serum levels of procalcitonin (PCT), an inflammatory marker, differ between DFO and diabetic foot ulcers without osteomyelitis (ie, cellulitis) as controls. The authors also aimed to assess the usefulness of PCT in diagnosing DFO. Methods. A case-control study was designed comparing DFO with diabetic foot cellulitis as the control. Patients were classified as having osteomyelitis and cellulitis based on the International Working Group on the Diabetic Foot diagnostic criteria. Serum inflammatory markers PCT, adiponectin, C-reactive protein-1, osteoprotegerin (OPG), osteopontin (OPN), and interleukin 6 (IL-6) were analyzed in patients with DFO and controls. Results. The median serum procalcitonin was significantly higher in the DFO group 108.5 pg/mL (range, 65.0–124.0 pg/mL) compared with 57.0 pg/mL (range, 37.2–77.0 pg/mL) controls (P = .02). Procalcitonin had a sensitivity of 79% compared with 50%, 63%, 66%, and 75% for adiponectin, OPG, OPN, and IL-6, respectively. Procalcitonin had a specificity of 70% compared with 50%, 71%, 70%, and 64%. Receiver operator characteristic curves showed a value of area under the curve of 0.73 and 0.77 for PCT and IL-6 compared with 0.4, 0.6, and 0.6 for adiponectin, OPG, and OPN, respectively. Conclusions. In this study, procalcitonin was a useful diagnostic test for DFOs and provided distinct diagnostic discrimination between DFO from cellulitis. It may serve as a useful marker for diagnosing DFO. Further studies in a larger population are needed to verify the findings.