Interleukin Concentrations in Bone Marrow Fluid and MRI Prognostic Findings in Osteoporotic Vertebral Fractures

Objective We investigated the association between interleukin-6 (IL-6) and interleukin-8 (IL-8) concentrations in bone marrow fluid and osteoporotic vertebral fracture (OVF) prognosis to obtain insights that could improve the prediction of poor prognosis. Methods Patients with OVFs admitted consecutively to a single facility and who underwent balloon kyphoplasty were prospectively enrolled. Bone marrow fluid was collected during surgery, and IL-6 and IL-8 concentrations were measured. Independent experts blinded to patient details examined the preoperative magnetic resonance imaging (MRI) radiographs to identify poor prognostic findings. IL-6 and IL-8 levels in the groups with and without poor prognostic findings were compared using the Wilcoxon rank-sum test. Associations between log-transformed IL-6 and IL-8 levels and poor prognosis were evaluated using logistic regression with adjustments for confounding factors. Results Among the 95 enrolled patients, 49 were excluded, and 46 were included in the analysis. In the poor prognosis group, both IL-6 and IL-8 levels were higher than those in the non-poor prognosis group (median IL-6: 491 vs. 72 pg/mL, p=0.014; median IL-8: 1574 vs. 84 pg/mL, p=0.003). Associations between log-transformed IL-6 and IL-8 concentrations and poor prognosis were observed, with crude and adjusted odds ratios for IL-6 at 1.75 (95% confidence interval (CI) 1.10-2.81) and 1.95 (95% CI 1.05-3.63), respectively, and for IL-8 at 1.81 (95% CI 1.23-2.65) and 2.10 (95% CI 1.21-3.64), respectively. Conclusion IL-6 and IL-8 concentrations in the bone marrow fluid may be associated with poor OVF prognosis. Their causal roles and potential as serum prognostic markers require further investigation.