Comparative Analysis of Coagulation Activation in Rheumatoid Arthritis Patients Treated With TNF Inhibitors Versus JAK Inhibitors: A Prospective Study.

Objectives: This study aims to investigate the activation of the coagulation system of RA patients and assess changes during anti-inflammatory treatment with tumor necrosis factor blockers (anti-TNF) and Janus kinase inhibitors (JAKi).

Methods: Biomarkers for the coagulation system, including D-dimer, fibrinogen, prothrombin time, activated partial thrombin time, prothrombin fragment 1 + 2, thrombin-antithrombin complex (TAT), activated factor IX, antithrombin complex, and von Willebrand factor (vWF), were longitudinally measured in 83 RA patients treated with anti-TNF and 38 RA patients with JAKi. Data were collected at baseline, after 1, 3, and 6 months.

Results: The mean age was 57 (±14) years; 76% was female. The mean DAS28-CRP was 3.6 (±1.3) for anti-TNF users and 4.1 (±1.4) for JAKi users at baseline and declined in both groups. Baseline coagulation markers levels were comparable between groups. In anti-TNF users, D-dimer and fibrinogen levels significantly declined (-0.31 mg/L, p = 0.01 and -0.71 g/L, p < 0.001, respectively), whereas TAT significantly increased after 6 months follow-up (1.46 μg/L, p = 0.03) and no effect on vWF (p = 0.98). In JAKi users, vWF declined significantly during the 6 months follow-up (-37.41%, p < 0.001); additionally, there were reductions of D-dimer, fibrinogen, and TAT that did not reach significance (-0.17 mg/L, p = 0.59; -0.49 g/L, p = 0.12; and 0.68 μg/L, p = 0.27, respectively).

Conclusions: The prothrombotic tendency in active RA declined during effective treatment with both anti-TNF and JAKi. Altogether, the biomarkers used in this study suggest that an increased VTE risk in the first 6 months due to either treatment with anti-TNF or JAKi is unlikely.