Associations of neutrophil-based inflammatory markers with all-cause and cardiovascular mortality in individuals with osteoarthritis.

Background: Osteoarthritis is increasingly understood as a heterogeneous disease, with certain phenotypes involving low-grade inflammation. Novel neutrophil-based inflammatory markers, including the neutrophil-to-lymphocyte ratio (NLR) and neutrophil-to-platelet ratio (NPR), have shown prognostic value in many disorders, but evidence for their relevance in osteoarthritis is limited. This study examined the associations between the NLR and NPR and all-cause and cardiovascular mortality in this population.

Methods: Utilizing data from the National Health and Nutrition Examination Survey (1999-2020), we used logistic regression and multivariate Cox proportional hazards models and Fine-Gray models to assess the relationships of the NLR and NPR with the prevalence of self-reported osteoarthritis and all-cause and cardiovascular mortality. We further used restricted cubic spline (RCS) and performed a time-dependent receiver operating characteristic (ROC) curve analysis to assess the prognostic significance of these markers for all-cause and cardiovascular mortality.

Results: A total of 3545 osteoarthritis patients were included in the analysis. After adjusting for potential confounders, a high NLR and a high NPR were significantly associated with increased risks of all-cause mortality (NLR: hazard ratio [HR] = 2.42, 95 % CI 1.84-3.18; NPR: HR = 1.57, 95 % CI 1.31-1.90) and cardiovascular mortality (NLR: HR = 1.92, 95 % CI 1.22-3.03; NPR: HR = 2.07, 95 % CI 1.42-3.01). The RCS revealed a nonlinear (J-shaped) relationship between the NLR and mortality. The ROC curve analysis indicated that the NLR and NPR had modest predictive accuracy for mortality outcomes, with area under the curve values ranging from 0.616 to 0.690 across different time points.

Conclusions: An elevated NLR or NPR is associated with increased all-cause and cardiovascular mortality in osteoarthritis patients. These results suggest that the NLR and NPR should be considered for risk stratification and personalized management strategies.