Diagnostic performance of serum bone turnover marker lysylpyridinoline in diabetic foot osteomyelitis: a preliminary study

Objectives: The aim of the study was to determine whether serum levels of lysylpyridinoline (LP) differ between diabetic foot osteomyelitis (DFO) and diabetic foot ulcers without osteomyelitis (cellulitis). Methods: A case controlled study was designed comparing the aforementioned groups. Subjects were classified as osteomyelitis and controls based on the International Working Group diagnostic criteria. Serum LP samples were analysed using enzyme linked immunosorbent assay. Results: The serum LP levels were significantly higher in the DFO group (n: 16) than the control group (n: 11): LP median ± SD of 9.3 ± 3.5 nmol/l, interquartile range (IQR) 6.8-11.2 in DFO compared to 2.1 nmol/l 3.5, IQR 0.7-4.2 in the controls, p=0.001. The receiver operator characteristic curve in the DFO was 0.9. The diagnostic sensitivity, specificity, positive and negative predictive values were 100%, 77.8%, 89.0% and 100% respectively. Conclusions: This appears to be the first evidence of serum LP elevation in diabetic foot osteomyelitis with potential diagnostic value in clinical setting.