Practical Utility of D-dimer Test for Venous Thromboembolism in Systemic Lupus Erythematosus Depends on Disease Activity: a Retrospective Cohort Study

Background: The D-dimer test is a screening tool for venous thromboembolism (VTE); however, its utility for patients with systemic lupus erythematosus (SLE) remains unclear. Here, we examined the utility of the D-dimer test as a screening tool for VTE in SLE patients. Methods: SLE patients (n = 276) and ageand sex-matched patients with non-rheumatic disease (n = 1,104), all of whom underwent D-dimer testing to screen for VTE, were enrolled. The sensitivity and specificity and receiver operating characteristics curve of the D-dimer test were compared in both groups. Then, subgroup of SLE patients in whom the D-dimer test can be useful was sought. Results: The incidence of VTE was more common in SLE patients than controls (10.9% vs. 4.0%). Although the sensitivity of the D-dimer test was comparable between SLE patients and controls (93.3% vs. 90.9%), the specificity of the test was profoundly lower in SLE patients compared to controls (28.4% vs. 84.4%). The area under the curve (AUC) of the D-dimer for VTE was 0.669 in SLE patients and 0.90 in control group. Multiple linear regression analysis demonstrated that SLE disease activity index-2000 (SLEDAI-2K) was significantly associated with D-dimer levels in SLE patients (beta = 0.155; P = 0.022). Subgroup analysis showed that the AUC is moderate (0.768) with low disease activity, while it is low (0.518) with high SLEDAI-2K. Conclusion: The D-dimer test may not be a useful screening tool for VTE in patients with active SLE. D-dimer test for predicting VTE in SLE patients should be differentially applied according to disease activity of SLE.