Venous Thromboembolism Risk Following Total Joint Arthroplasty in Rheumatoid Arthritis Patients Treated with Janus Kinase Inhibitors Versus Tumor Necrosis Factor Inhibitors: A Propensity Score-Matched Cohort Study.

Background: Janus kinase (JAK) inhibitors have been linked to higher venous thromboembolism (VTE) rates than tumor necrosis factor (TNF) inhibitors in rheumatoid arthritis (RA) populations, yet it is uncertain whether this risk extends postoperatively after total joint arthroplasty (TJA). Methods: A retrospective propensity score-matched cohort study was performed using a large federated network of de-identified electronic health records. Adults with RA undergoing primary total knee or hip arthroplasty were identified, and patients were categorized based on the use of a JAK inhibitor or a TNF inhibitor within 3 months of surgery. Propensity score matching was conducted in a 1:1 ratio based on demographics, comorbidities, and medications. The primary outcome was VTE, defined as deep vein thrombosis or pulmonary embolism occurring from postoperative day 1 through 365 days; patients with VTE prior to this window were excluded. Results: Before matching, 305 JAK inhibitor users and 1299 TNF inhibitor users met inclusion criteria; after propensity score matching, 304 patients remained in each cohort, and exclusion of patients with prior VTE yielded 284 JAK inhibitor users and 288 TNF inhibitor users for analysis. VTE occurred in 17 JAK inhibitor users (6.0%) and 11 TNF inhibitor users (3.8%), corresponding to a risk ratio of 1.57 (95% confidence interval [CI], 0.75-3.29; p = 0.230). Kaplan-Meier analysis demonstrated a hazard ratio of 1.56 (95% CI, 0.73-3.33), with no statistically significant difference between groups (log-rank p = 0.248). Conclusions: Among RA patients undergoing primary TJA, JAK inhibitor use was not associated with a statistically significant increase in postoperative VTE compared with TNF inhibitor use, although VTE events occurred numerically more often in the JAK inhibitor cohort. These findings do not exclude a clinically relevant increase in postoperative thrombotic risk with JAK inhibitors, and larger studies are required to clarify the magnitude of risk and to inform thromboprophylaxis strategies.