Predictive role of CRP, MPV and NLR for osteoarticular involvement in brucellosis: a two-center retrospective study

Brucellosis is a systemic infectious disease frequently associated with various localized complications. This study evaluated the predictive value of baseline C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), mean platelet volume (MPV) standardized markers for predicting osteoarticular involvement in brucellosis patients. This retrospective, two-center study evaluated 230 patients diagnosed with brucellosis between January 2022 and May 2024. Patients were stratified according to the presence of osteoarticular involvement, and baseline clinical and laboratory parameters were compared between the cohorts. Of 230 patients with brucellosis, 195 were included in the comparative analysis (91 with osteoarticular involvement and 104 without focal involvement). Patients with osteoarticular involvement had significantly higher CRP ( p < 0.001) and NLR ( p = 0.016). In multivariable logistic regression with bootstrap validation, CRP was the only independent indicator of osteoarticular involvement (OR 1.024, 95% CI 1.001–1.065; bootstrap p = 0.047). ROC analysis showed moderate diagnostic performance for CRP (AUC 0.673) and limited performance for NLR (AUC 0.600). Patients with spondylodiscitis had significantly higher neutrophil counts and NLR than the other osteoarticular subgroups. Our findings suggest that CRP may be a useful adjunctive biomarker for identifying patients at increased risk of osteoarticular involvement in brucellosis. Although NLR was elevated in patients with osteoarticular disease, its independent predictive value appeared limited after multivariable adjustment. Further prospective multicenter studies are needed to validate these findings.