Lipid metabolism markers in relation to Brucella spondylitis: a multicenter cross-sectional study

During brucellosis, Brucella evades host immune responses to survive and multiply within macrophages, eventually triggering a systemic inflammatory response. Spondylitis is among the most common complications of brucellosis. While inflammation and dyslipidemia are closely intertwined, the association between lipid metabolism markers and Brucella spondylitis (BS) remains unclear. To investigate the potential relationship between various lipid metabolism markers and BS. A multicenter cross-sectional study was performed on 702 brucellosis patients admitted to two infectious disease hospitals in Hohhot and Xing’an League between May 2022 and March 2024. Multivariable logistic regression models and restricted cubic spline (RCS) analysis were employed to examine the independent association and dose-response relationship between lipid markers and BS. Subgroup analyses were performed based on age, sex, disease stage, and comorbidities, complemented by interaction testing. The discriminatory performance and clinical net benefit were evaluated using calibration curves and decision curve analysis. Of the 702 patients, 296 (42.2%) were diagnosed with BS. Multivariable logistic regression and RCS analysis revealed a linear positive association of HDL-C with BS (OR = 1.992; 95% CI, 1.229–3.228) and linear negative associations of MHR (OR = 0.298; 95% CI, 0.148–0.599), AIP (OR = 0.446; 95% CI, 0.256–0.776), and AI (OR = 0.819; 95% CI, 0.728–0.922) with BS ( P ≤ 0.005). No statistically significant interactions were observed across predefined subgroups. Sensitivity analysis via multiple imputation confirmed the robustness of these associations, with consistent directions across all observed relationships. HDL-C was positively associated with BS, while MHR, AIP, and AI were negatively associated with BS. This distinct lipid dysregulation pattern indicated a close association between lipid metabolic disturbance and BS. These lipid‑derived indices may facilitate stratified clinical management of brucellosis, and further prospective studies are needed to validate the current findings.