Unusual lipid pattern emerges in patients with Brucella spondylitis

People with brucellosis who develop spondylitis, one of the most common complications of the infection, show a distinctive pattern of lipid metabolism markers, according to a multicenter cross-sectional study published in BMC Infectious Diseases. Among 702 brucellosis patients treated at two infectious disease hospitals in Hohhot and Xing’an League between May 2022 and March 2024, 296 patients, or 42.2 percent, were diagnosed with Brucella spondylitis. Higher levels of high-density lipoprotein cholesterol, commonly known as HDL-C, were positively associated with the condition, while three composite lipid and inflammatory indices showed negative associations.

Brucella is an intracellular bacterium that survives and multiplies within macrophages, evading host immune defenses and eventually triggering a systemic inflammatory response. Because inflammation and dyslipidemia are closely intertwined, the research team set out to examine whether routine lipid metabolism markers could distinguish patients whose infection had spread to the spine. The study enrolled consecutive brucellosis patients and compared lipid measurements between those with and without spondylitis, adjusting for potential confounding factors in multivariable logistic regression models.

The statistical analysis revealed a linear positive association between HDL-C and Brucella spondylitis, with an odds ratio of 1.992 and a 95 percent confidence interval of 1.229 to 3.228. In contrast, three derived indices were negatively associated with the condition: the monocyte-to-HDL cholesterol ratio, or MHR, with an odds ratio of 0.298; the atherogenic index of plasma, or AIP, with an odds ratio of 0.446; and the atherogenic index, or AI, with an odds ratio of 0.819. All associations reached statistical significance at a threshold of 0.005 or lower. Restricted cubic spline analysis confirmed that these relationships were linear rather than following a more complex dose-response curve.

To test whether the associations held across different patient groups, the researchers performed subgroup analyses based on age, sex, disease stage, and comorbidities, complemented by interaction testing. No statistically significant interactions were observed across the predefined subgroups, suggesting that the lipid pattern was consistent throughout the study population. A sensitivity analysis using multiple imputation to handle missing data confirmed the robustness of the findings, with all observed relationships retaining their original directions.

The authors evaluated the discriminatory performance and clinical net benefit of the lipid-derived indices using calibration curves and decision curve analysis, tools that assess how well a model’s predicted probabilities match observed outcomes and whether the model would improve decision-making in practice. According to the study, these lipid-derived indices may facilitate stratified clinical management of brucellosis, potentially helping clinicians identify patients at risk of spinal involvement.

The researchers caution that the study design was cross-sectional, meaning that lipid markers and spondylitis were measured at the same time point. Such a design can identify associations but cannot establish whether lipid disturbances contribute to the development of spondylitis, whether the infection alters lipid metabolism, or whether both are shaped by an underlying process. The authors state that further prospective studies are needed to validate the current findings before any conclusions about causality or clinical application can be drawn.

Brucella spondylitis is among the most common complications of brucellosis, a zoonotic infection prevalent in regions where people come into contact with infected animals or consume unpasteurized dairy products. The condition can cause chronic spinal pain and structural damage, and distinguishing it from uncomplicated brucellosis often requires imaging studies. If lipid markers were confirmed in future research as reliable indicators of spinal involvement, they could offer a simple and widely available addition to the diagnostic toolkit, since lipid panels are routinely measured in hospital laboratories.

The distinct dysregulation pattern observed in this study, with HDL-C elevated while composite atherogenic and inflammatory indices were reduced among spondylitis patients, indicates a close association between lipid metabolic disturbance and Brucella spondylitis. The authors emphasize that the findings represent measured observations from a defined patient population in Inner Mongolia and that their generalizability to other regions and populations remains to be established through further research.

Subject of Research: Lipid metabolism markers and Brucella spondylitis

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

Article References: Liu, Y., Zheng, H., Zhu, P., Jin, X., Wang, C., Wang, T., Wang, X., & Wang, Y. (2026). Lipid metabolism markers in relation to Brucella spondylitis: a multicenter cross-sectional study. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14693-6

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14693-6

Keywords: brucellosis, Brucella spondylitis, lipid metabolism, HDL cholesterol, cross-sectional study, infectious diseases, inflammation, logistic regression, atherogenic index, BMC Infectious Diseases, Lipid, metabolism