Bibliometrics, through the adoption of mathematical and statistical techniques, aims to explore the distribution pattern, quantitative relationship and changing law of literature information, which can guide not only research design but also clinical practice 27. We included a total of 1,368 articles of closely related literature in the field of OA -coagulation index. The number of publications has been on an upward trend in the last decade or so. These results suggest that there is a growing interest among researchers in the field of OA-coagulation metrics. Highly cited literature has focused on studies of inflammation, platelet derivatives, and patient-reported OA. With the development of regenerative medicine, platelet derivatives, such as platelet-rich plasma, have gained increasing attention for use in osteoarthritis 28. Several prospective cohort studies have demonstrated that intra-articular administration of PRP will alleviate pain and enhance joint function in patients with OA 29–30. In addition to facilitating coagulation, platelets constitute a rich source of cytokines and growth factors that are necessary for bone mineralization and soft tissue repair 31. The keywords associated with the OA -coagulation index were pain, risk factors, clinical trials, growth factors, and platelet-rich plasma. Cluster analysis of the keywords also focused on inflammation and coagulation. Consequently, it is reasonable to investigate the significance of markers associated with clotting in OA.
The hypercoagulable state involves immune system activation 8. The inflammatory response and alterations in the coagulation system correlate with the severity of osteoarthritis 32. Relevant mediators of the inflammatory process and inflammatory regulation include thrombin, fibrinogen, coagulation factor XIII, and factors of the fibrinolytic system, among many other hemostatic system components. During inflammation, cytokines may facilitate thrombosis by regulating the coagulation and fibrinolytic systems 7. The following cytokines are involved in the coagulation process: TNF-α (which increases platelet activation and aggregation), IL-8 (which activates neutrophils and releases coagulation-promoting factors), IL-6 (which produces fibrinogen to promote coagulation), and IL-1 (which upregulates the expression of endothelial cells and monocytes, leading to an increased procoagulant state) 32–34. The immune cells' (such as neutrophils and macrophages) activation of platelets and coagulation factors is another essential component of immune cell-mediated coagulation. These immune cells secrete chemicals that promote inflammation, such as tissue factors, chemokines, and cytokines, which can start the coagulation cascade 35–36. An increased platelet count is also a major cause of hypercoagulable states 37. D-dimer is the product of fibrinolytic enzyme-mediated degradation of cross-linked fibrin clots 38–39 and has been proven to be a sensitive marker for assessing disseminated intravascular coagulation (DIC). In conclusion, the interaction between coagulation and the immune system is of great importance for clinical practice and research 8. Coagulation factors have the power to stimulate immune cells and increase cytokine production, which promotes inflammation. At the site of damage, fibronectin serves as a scaffold for immune cells, facilitating their recruitment and activation.
Additionally, compared to healthy volunteers, OA patients had higher levels of coagulation (PLT, TT, FIB, and D-dimer) as well as immunoinflammatory indexes (ESR, CRP, IGA, IGG, and ferritin), indicating that both hypercoagulation and inflammation are involved in disease onset and progression. In addition, PLT, TT, FIB, and D-dimer have excellent discriminative capabilities and diagnostic value in OA. The PLT, PT, APTT, TT, FIB, and D-dimer correlated with several immuno-inflammatory indexes (CRP, ESR, C3, C4, IGG, IGA, IGM, and ferritin), indicating that coagulation indices correlated with immuno-inflammatory indexes. In addition to this, the coagulation index correlated with PROs (VAS score and SF-36 subscales), contributing to the differentiation of OA disease activity. The VAS and SF-36 have been proven to be valuable in measuring overall health status, disease activity, and self-perceived disease severity in patients with OA 40. Association rules are designed to uncover interesting and frequently occurring patterns and associations between item sets of data. Similarly, association rule results again support the high correlation between coagulation index, CRP, and ESR. C-reactive protein levels rise dramatically during inflammatory processes in vivo 41. Separation of the red blood cells from the plasma is measured by the erythrocyte sedimentation rate. Red blood cells stick to each other during inflammation because the blood contains high levels of fibrinogen. "Rouleaux" are stacks of erythrocytes that settle more quickly 42. These results indicate that coagulation-related indices in OA are involved in the inflammatory response.
Following that, we identified additional parameters linked with VAS disease activity, which we analyzed by univariate regression analyses of PLT (OR = 1.275, p < 0.001), FIB (OR = 1.667, p = 0.024), D-dimer (OR = 2.346, p < 0.001), ESR (OR = 2.326, p < 0.001) and CRP (OR = 2.312, p < 0.001) were identified as independent risk factors for OA disease activity. In multivariate logistic regression, only PLT (OR = 1.874, p = 0.015), D-dimer (OR = 1.534, p = 0.003) and CRP (OR = 1.456, p = 0.021) remained independent predictors of OA disease activity. Based on the results of the AIC and BIC evaluations, we observed that the addition of PLT and D-dimer to the model controlling CRP increased the OR while decreasing the AIC and BIC, implying that the model is more accurate in identifying disease activity. Interestingly, our results imply that PLT and D-dimer may improve, rather than replicate, existing models for evaluating disease activity. The results further confirm the strong clinical utility and high benefits of the model by introducing nomogram plots, clinical decision curves, and correction curves.