Disease activity as a risk factor for venous thromboembolism in rheumatoid arthritis analysed using time-averaged DAS28CRP: a nested case–control study

The objective of this study is to clarify the clinical features and risk factors of venous thromboembolism (VTE) in patients with rheumatoid arthritis (RA). We retrospectively reviewed the prevalence of VTE in RA patients who visited Hokkaido University Hospital from 2010 to 2019 and had more than 2 years of follow-up. To explore the risk to develop VTE, we selected 260 RA patients without VTE (non-VTE) via density sampling and identified the risk factors for VTE by multivariate logistic regression analysis. Univariate conditional logistic regression analysis showed older age (p < 0.0001, Odds Ratio [OR] 1.08, 95% Confidence Interval [CI] 1.04–1.14), increase of the body mass index (BMI) (p = 0.001, OR 1.17, 95% CI 1.06–1.31), higher prevalence of RA-associated lung disease (p = 0.002, OR 2.10, 95% CI 1.33–3.30) and more frequent glucocorticoid usage (p = 0.001, OR 2.09, 95% CI 1.34–3.51) in RA patients was associated with the development of VTE significantly. Furthermore, patients with higher time-averaged disease activity score 28 (DAS28) CRP were at elevated risk (p < 0.0001, OR 3.25, 95% CI 1.94–6.12). In conditional multivariate logistic regression analysis, time averaged DAS28CRP was significantly associated with the development of VTE (p = 0.0001, adjusted OR 3.40, 95% CI 1.77–7.85). Disease activity was identified as a major risk factor of VTE in patients with RA, suggesting that sustained clinical remission could be beneficial for decrease the risk of VTE.