Risk of Venous Thromboembolism in Rheumatoid Arthritis Save

Know-it-now

• RA confers a 50–100% excess risk of venous thromboembolism (VTE) that remains even when remission is achieved. Disease control reduces but does not eliminate thrombotic risk.
• Disease activity is the strongest RA-specific modifiable risk factor; tight inflammatory control is anti-thrombogenic.
• JAK inhibitor use may be associated with VTE risk, but the association is inconsistent - ORAL Surveillance and Swedish registry data suggest a signal (particularly for tofacitinib and baricitinib), while most other observational cohorts do not
  • individualized risk-benefit assessment is warranted, especially in patients ≥65 years or with prior VTE/CVD.
• No validated RA-specific VTE risk stratification tools or biomarkers exist.

RA confers a 50–100% excess risk of venous thromboembolism (VTE) compared with the general population, with adjusted hazard/odds ratios ranging from 1.3–2.2 across large cohort studies (Vojinovic, Askling, Antovic; Rheumatology, 2026). Absolute incidence is 3–6 events per 1000 person-years, peaking in the first year post-diagnosis before gradually declining but remaining chronically elevated. VTE risk in RA exceeds that in psoriatic arthritis but is lower than in SLE or systemic sclerosis, positioning systemic inflammation as a shared but variably weighted risk factor across autoimmune disease. Traditional risk factors (age, obesity, smoking, immobilization, diabetes) remain relevant, and prior VTE remains the strongest predictor of recurrence. Pregnancy-related VTE risk appears elevated in RA, though less well-characterized than in SLE or antiphospholipid syndrome.

Risk Modification. Disease activity is a dominant driver: DAS28-ESR elevation confers approximately 2-fold increased VTE risk versus remission, with persistent elevation compounding risk over time. Notably, even DAS28-defined remission carries ~35% excess risk versus the general population, suggesting residual risk from cumulative disease burden or comorbid factors. Seropositivity (anti-CCP2, IgM RF) independently associates with modestly increased VTE risk (HR 1.33–1.38), though this likely reflects a broader higher-inflammatory-burden phenotype rather than a distinct thrombotic mechanism. Antiphospholipid antibody prevalence in RA is highly variable (5–75%) with no consistent association to thrombotic events demonstrated to date; application of the 2023 ACR/EULAR APS classification criteria may help refine this association in future studies.

Mechanisms. VTE risk arises through immunothrombosis: inflammatory cytokines (IL-1β, TNF-α, IL-6) drive endothelial activation and tissue factor expression, upregulate procoagulant markers (vWF, factor VIII, fibrinogen, prothrombin fragments F1+2), and suppress endogenous anticoagulants (antithrombin, TFPI, protein C). Platelet-derived extracellular vesicles (PEVs), elevated in proportion to disease activity, amplify both synovial inflammation and systemic procoagulant activity, and can disseminate via lymphatics beyond the joint. Increased blood viscosity from acute-phase reactants (fibrinogen, RF-associated immunoglobulins) and disease-related immobility further contribute via the venous stasis component of Virchow's triad.

Treatment Effects. 

• Glucocorticoids independently increase VTE risk, particularly at higher doses and during current/recent use, beyond confounding by disease activity — supporting minimization of dose/duration.  

• VTE risk has not been linked to csDMARDs (including MTX and leflunomide), TNF inhibitors, rituximab, abatacept, or tocilizumab. 

• JAK inhibitors: VTE risk with baricitinib and tofacitinib was established before the ORAL Surveillance study (dose-dependent VTE increase with tofacitinib versus TNFi). The latter well-designed, prospective and appropriately powered study resulted in regulatory restrictions in patients ≥65 years or with prior VTE/CVD/malignancy risk factors. These results have been questioned by lesser power, retrospective or emulated observational studies (US claims data, French and Korean nationwide cohorts, 5-year US registry data) have largely not replicated this signal. A notable exception is Swedish registry data (Molander et al.) showing 50–100% higher VTE risk with baricitinib and tofacitinib versus TNFi — roughly double the overall RA population risk and triple that of the general population — with a similar signal for baricitinib reported by Salinas et al. The authors emphasize that observed inconsistency likely reflects residual confounding, low event rates, and methodological heterogeneity rather than resolving the underlying question of class effect versus drug-specific selectivity.

Prevent VTE. No RA-specific thromboprophylaxis guidelines exist; current practice extrapolates from general population protocols (LMWH/DOACs for major surgery or hospitalization-associated immobilization). Extended anticoagulation may be reasonable in patients with ongoing high disease activity, prior VTE, aPL positivity, or continued glucocorticoid/JAKi exposure. Effective disease control  and careful patient selection function as VTE prevention.